History of production technology
In the history of the production technology there have been numerous inventions that within the production technology introduced more efficient methods of production or processing of certain materials allowed only. The production technology consists of the three main areas
- the manufacturing technology , the workpieces gives a certain form,
- the energy technology which is concerned with the provision of mechanical, thermal or electrical energy, and
- the process engineering that takes care of the transformation of materials. The conversion of ores into metals is dealt with here in particular; for chemical raw materials, see technical chemistry .
Production technology already reached a high level in pre-industrial times. Metals could be melted from ores in racing furnaces and later in blast furnaces , alloyed and processed into workpieces by casting or forging . The heat required for this could be generated by burning wood and charcoal , mechanical energy was provided by wind and water mills and used to operate bellows or hammer mills. Wood was worked by sawing , drilling or turning .
From the first industrial revolution , the production technology began to develop faster: For refining of pig iron is used the puddle that on coal based that even with the new steam engine was used. It was used to drive new machine tools that were used to manufacture textile, steam and machine tools. The factory was created as a new place of production .
In the course of high industrialization , new processes emerged with which steel could be manufactured as a cheap mass product ( Bessemer , Thomas and Siemens-Martin processes ). The rationalization movement also established large-scale production in mechanical engineering, which is based on typification, standardization , standardization and interchangeability .
Around 1900 could be in the second industrial revolution by means of turbines in power plants produce electric energy for driving one of the electric motors could be used. With electrolysis , new materials like aluminum could be obtained and steel could be produced with electric furnaces . The machine tools received an individual electric drive and were significantly more powerful thanks to new cutting materials such as high-speed steel . In addition, it was now possible to machine fits . The scientific management of Frederick Winslow Taylor and the mass production on the assembly line by Henry Ford made sewing machines , bicycles and automobiles mass products and consumer goods .
The third industrial revolution is finally characterized by flexible automation on microelectronic base (computers, robots, CNC machines), new energy sources such as oil or nuclear energy , as well as the Toyota Production System . With the LD process , a process for steel production was created that surpasses all previous processes in terms of quality and performance.
Stone age
The use of simple tools such as sticks or stones has already been proven in monkeys. The planned production of tools, on the other hand, has only been known since the development of prehistoric systems of work and action by humans and is also used in anthropology to distinguish early (ape) humans from animals. In this context, we are also talking about Homo Faber - the man who produces. The tools were mostly made of stone , which is why this period is known as the Stone Age ; also were next to used wood , bone and antlers . The oldest tools that are still preserved were simple rubble tools , which, however, already have special chipping edges and have been dated to around 2 million years ago. For this they were hit against a larger rock (so-called anvil technique) and were suitable for cutting, stabbing, scraping , scratching and hitting. Later they started hitting stones and wooden sticks against the stone to be worked. With this hammer stone technique more precise results could be achieved. A million years ago they could be used to make hand axes, which were an early universal tool. In the Neolithic there were special tools for sawing , cutting and scraping. There were also needles, harpoons, sickles, spear and arrowheads and axes. Around 40,000 years ago, stones could be drilled using fiddle bits and whorls . The techniques are technically related to fire drilling, an early technique used to create fire (fire was the first non-muscular energy source used by humans) and has been known for about 400,000 years. A bow string was wrapped around a stick, set in rotation by the back and forth movement of the bow and at the same time pressed axially against another piece of wood. The resulting frictional heat was used to make a fire and the rotational energy was used to drill. With the against 6000 BC A kiln created in the 4th century BC , clay could be burned into ceramics and thus for the first time a material could be produced artificially and not only taken from nature. The painted pottery production also became one of the first specialized professions: Outside the settlements were the pottery workshops with the kilns.
Towards the end of the Stone Age, people began to settle down, which was also associated with a transition from hunting and gathering to agriculture and livestock. This transition is known as the Neolithic Revolution and is only equivalent in significance to the Industrial Revolution in the 18th century.
Coarse teeing devices, approx. 1.7 million years.
Hand ax, a million years old.
Flint dagger with a fine blade, 2900 BC Chr.
Bronze Age: Early advanced civilizations in Mesopotamia
With the discovery of copper , gold and silver , corresponding manufacturing processes were also developed: forging and casting . The alloying of tin to copper produced bronze , which heralded the Bronze Age , in which the first advanced civilizations also emerged.
Materials: copper and bronze
Copper is one along with gold and silver of the few metals that in nature dignified , so in metallic form, occur. Early copper finds date from the sixth millennium BC. At first it was processed into jewelry and cult objects only by hammering, since the melting temperature (1083 ° C) was not yet reached in the furnaces. However, it was possible to roast copper ores in order to subsequently melt metallic copper out of them in charcoal . The melting temperature was also reached through the use of anthracite coal and bellows . When it was discovered that different metals can be alloyed (mixed), this was used specifically to influence hardness and strength . Initially arsenic was used , but soon tin was used to make bronze. Shares between 5% and 10% tin prevailed because bronze has a lower melting point (around 900 ° C) than copper, is harder and stronger, but can still be processed. Weapons, armor, tools such as axes, chisels or hammers were then made of bronze; In agriculture, however, bronze was hardly used. Gold and silver were also mined and processed into representative objects, foils and gold leaf .
Manufacturing technology: casting and forging
For a long time, the processing of copper caused difficulties. When hammering, forging and driving it becomes stronger in the cold state, but also harder and more brittle and thus more brittle ( strain hardening ). At first, it was not possible to pour it, but later, when the necessary temperatures were reached, it was difficult because it tended to form bubbles. Bronze, on the other hand, has very good castability , so that bronze casting has become the preferred manufacturing process. The casting of gold and silver was also known. It was not until the late Bronze Age that bronze forging began to gain acceptance, as it is stronger and harder than copper. All the basic forging processes were known: stretching , upsetting , driving, stamping and fire welding . Until the 20th century, fire welding was the only welding technology . From the blacksmith's tools, various hammers were known for rough and fine machining, as well as anvils , files and, relatively late, pliers . In the past, clamps and long bronze tweezers were used to handle hot workpieces. No holes in metal are known. Machining processes were mainly used for woodworking . This includes rasping , drilling with the drill bit , grinding and turning . Corresponding simple machines are also used for drilling, grinding and turning.
Iron Age: Greco-Roman Antiquity
Around 1500 BC Iron was discovered by the Hittites . In contrast to the previously known metals , it does not occur in its pure form, but has to be melted from ores . It gradually supplanted bronze, which is why the new era is also known as the Iron Age . In ancient Greece, however, bronze was still used for weapons, armor and tools for a long time. Iron was also the first metal that could only be worked on when hot.
Materials: iron
Unlike copper, iron ores are found throughout the Mediterranean. The ore was first placed in furnaces that reached between 1200 ° C and 1300 ° C. In this temperature range, the ore transforms into solid metallic iron and liquid slag . The melting temperature of iron (1538 ° C) could not yet be reached, so that the materials cast iron and steel as well as the process of iron casting were not yet available. The slag ran out of the furnace, which is why it was also called the racing furnace . What remained was a sponge iron, the rag , which still contained some cinder residue. They were removed by hammering and the pellet was compacted in the process. The result was wrought iron , a malleable iron material that contained almost no carbon and comes very close to today's steel, but was obtained in a different way and was therefore more contaminated with accompanying elements. Aristotle differed in any case already in the Meteorologica the pig iron from wrought iron, which contains no more slag residues. Since the low-carbon iron is too soft for tools and weapons, it was annealed on charcoal, which consists largely of carbon, so that it absorbed the element mainly in the outer layers. Also, the hardening by quenching in water or oil were known and also correctly Plutarch (45-125 n. Chr.) Is explained by the rapid cooling. Before that, Pliny the Elder (24–79 AD) was of the opinion that the water quality had the decisive influence.
The use of brass , an alloy of copper and zinc, is also documented from Roman times .
Manufacturing technology: New casting processes and tools
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Casting was apparently still unknown in early Greek times: in the works of Homer from the 7th or 8th century BC. Chr. We only talk about forging, but never about casting. From 700 BC It is documented. Initially, solid casting was used , in which the workpiece is made entirely of metal. The lost wax process was used for small bronze statuettes : First a model was made from wax and then covered with clay and placed in an oven. This fired the clay and melted the wax out. Then bronze could be poured into the mold and, after solidification, the clay mold could be smashed. For larger workpieces from about half a meter in height, however, a lot of material was used, so that larger still images were made as hollow castings . Here, the rough shape of the later model was first carved out of clay, then surrounded with a layer of wax, the thickness of which corresponded to that of the later bronze layer. The final shape was worked into the wax layer, which in turn was surrounded with several layers of clay. The wax was then melted out by the liquid bronze. From the fifth century BC onwards there was a change to so-called indirect casting, in which the individual parts of the workpiece were first cast (e.g. body, arms, legs and head in still images) and then they were soldered together . Both hard and soft soldering are mentioned in Pliny .
The Greek and Roman blacksmiths had advanced skills in forging. This process was used to produce bronze helmets and breastplates, as well as bowls, sieves, tubes or sheets. They were able to use the strain hardening that occurred in a targeted manner to forge thin, but still hard and strong armor. Smaller jewelry and coins could be punched and minted. The joining techniques used were fire welding , soldering and riveting . Files and whetstones made of pumice stone or emery were used for finishing . Chasing and planing is also documented . For drilling, the auger bit was initially used , which consisted of a twisted square rod and only supplied sawdust, but no chips. It was replaced by the spoon drill , which was in use until the 19th century. For the processing of glass and precious stones, drills were also used, the tips of which were set with diamond fragments.
The first approaches to machine work were turning, drilling and grinding. These machines were driven by means of a fiddle bow (mainly a drill) or with a cord that was moved back and forth by a second worker, as was customary with the cord pull lathe, which is used for processing wood, horn, ivory, alabaster and bronze has been.
Energy technology: Göpel, Tretrad and watermills
There were three different ways of generating mechanical energy, all of which produced a continuous rotating movement: the Göpel , the treadmill and the water mills . Göpels were widespread machines in which horses or donkeys ran in circles while people worked on pedal bikes. Watermills originated in Roman times and were described by Vitruvius in the first century AD. They emerged from the bucket wheels known from Egypt , but were not used to any significant extent until late antiquity. They only spread in the Middle Ages.
Division of labor: specialized craft businesses and professions
As early as Hesiod (8th century BC) the blacksmith was explicitly mentioned as a specialized craftsman. Other craftsmen who worked in their own factories, the ergasteries , are from 500 BC. Occupied. Xenophon reports 300 BC From the mass production of shoes based on the division of labor: there were craftsmen who were exclusively occupied with patching, cutting or assembling leather. A manual series production has been handed down for the manufacture of weapons and armaments. In Roman times, large companies with up to 100 people were already set up to produce items for daily use or military equipment. In addition, there were numerous specialized and therefore highly qualified blacksmiths in the Roman Empire. A distinction was made according to the processed material in gold , silver , copper , coarse and fine forge , the latter two using iron. Other blacksmiths specialized in certain products or product groups. These include the tool , knife , sickle, nail, sword , helmet, lance or arrow smith. Other professions were locksmiths, foundries , candelabra and lantern makers, ring makers and lead workers.
middle Ages
In the Middle Ages , technology generally developed faster again. Many technical innovations improved labor productivity, which was also due to the abolition of slavery at the end of ancient times. The collar increased the usable pulling power of horses, thereby reducing transport costs. This encouraged the emergence of central companies that supplied goods to a larger area. It was now worthwhile for these companies to build watermills. In the early Middle Ages, village handicrafts produced scythes , sickles and plows for agriculture . Together with the collar and the three-field economy , this increased food production, which led to strong population growth. The result were numerous cities in the 12th and 13th centuries . The associated urban culture with its independent, flourishing handicrafts was the determining economic and technical force for the rest of the Middle Ages, whereas before it was mainly the monasteries . The bottleneck in production was human and animal productivity, which could hardly be increased. The only way to increase production was therefore to use technology such as was described in great detail by the monk Theophilus Presbyter in the 11th century.
Energy technology: wind and water mills
The introduction of windmills and water mills was an important step from artisanal to industrial production. From the eighth to the tenth century, water power spread north of the Alps in general. There were around 5000 mills in England around 1100. At first they were mainly used to grind grain, from 970 onwards they are used to drive hammer mills . They were also used in sawmills and milling devices or to drive bellows in iron works . The disadvantage was that one was bound to the availability of natural resources. Watermills were therefore mostly built outside the cities in the surrounding area and financed by the nobility. Farmers and craftsmen were allowed to use them for a fee. Often other businesses settled near the mills, which means that production was concentrated outside the cities, but this also led to new cities being built in the vicinity of the mills. The watermill was supplemented by the windmill from the 11th century, especially in the north-western coastal regions of Europe.
Materials: damask and cast iron
In the early Middle Ages, the technique of damascene emerged , in which several alternating layers of hardenable, high-carbon wrought iron and tough, low-carbon wrought iron were joined by fire welding. In the late Middle Ages, bellows powered by hydropower and the new blast furnaces instead of the racing furnaces led to higher temperatures, which ultimately made it possible to cast iron and thus also to produce the material cast iron . In order to obtain forgeable iron, the pig iron from the blast furnace was melted again in a fresh fire . The properties of iron could be specifically influenced by tempering , carburizing , quenching and annealing . The Benedictine monk Theophilus Presbyter described the hardening of files in the 11th century: First ox horn was burned and mixed with salt and sprinkled over the files, which were then annealed in the oven. They were then quenched in water and tempered in the oven.
Manufacturing technology: wire drawing and new lathes
A process that was widespread in fine forging was the press plate technique , in which a metal sheet was placed on a die and then knocked out. For example, it was possible to manufacture cover sheets for disc brooches in a manual series production, since the die was hardly worn. The Tauschieren or plating was applied to ornaments in belt accessories or baldric incorporate. To do this, the pattern was first engraved with a graver and then knocked out with silver or brass wire. The surface was then smoothed with a whetstone until the iron and inlay were flat. Instead, with the Niello technique, powdered metal was melted into the engraving. Wire was originally twisted and forged as in ancient times. In the Middle Ages, wire drawing with a drawing iron was used in order to produce the large amounts of wire that were mainly needed for ring armor ("chain mail").
The antique cord pull lathe was further developed in two different ways: The rocker lathe , which was used in particular in woodworking, could be operated by only one person, as one end of the cord was attached to a rocker that was operated with the foot and that other end above the lathe on a swinging bar that worked as a spring. The English name for the lathe "lathe" comes from this lath. Now the worker had both hands free to control the tool. For metalworking, lathes were used that were equipped with wheel or crank drives and therefore enabled continuous rotary motion and higher forces and cutting speeds. The disadvantage was that an assistant was needed for the operation. Vices have been used in the locksmith's shop since 1528 , which enabled more precise work, as both hands were free to guide the tool. Drill bits with racing spindles or drills were used for drilling .
Crank drive of a lathe. From the stand book of Jost Amman (1568)
Thimble with racing spindle
Wood turner with rocker lathe
Division of labor: guilds
At the beginning of the Middle Ages, there was little division of labor . Blacksmiths and fine blacksmiths often worked in the same forge. Later it was as high as in antiquity, new blacksmiths, pan, plow and pincer smiths as well as file cutters . In addition to the professional division of labor, there were also regional differences. In the area around Solingen there were numerous hammer mills on tributaries of the Wupper , which were driven by water mills to forge blades. The grinding mills for finishing were located directly on the Wupper, as they required more energy that was not available on the secondary runs. Therefore, the forged blades were transported there for up to an hour. In the cities of the High Middle Ages, new organizations that dealt with specific crafts were established: the guilds . In them the knowledge about the production of a certain trade was institutionalized and passed on for the first time. Linked to this was the manual production method, in which the company was run by a master and journeymen and apprentices helped with the work. The type of journeyman examination and the number of masters in a city were determined by the guilds.
Harness polisher with grinder in the background
Mail shirt maker
Knives
Farrier
File cutter
Armorer
Pan smith
Renaissance (1500 to 1700)
During the Renaissance, a continuous transition from manual to industrial production methods can be observed. In England, people gradually began to use hard coal for domestic consumption instead of the previously customary but increasingly expensive charcoal, which could not yet be replaced in industry, especially in iron production and processing. The metallurgy became more efficient through improvements in details such as box blowers. The new rolling and boring mills form the transition to industrial machine tools and the new factories later developed into factories.
Energy technology: hard coal
All previous machines were used side by side as energy machines: the treadmill, the Göpel, water and windmills as well as the wheel drive with crank and flywheel.
In England in particular, wood and charcoal became scarcer and therefore more expensive. In contrast, hard coal was available in many regions and also cheaper, which was also due to the fact that the energy density was twice as high as that of charcoal. A car or ship load could carry twice the amount of energy, which had a favorable effect on transport costs. In addition, the high energy density made higher temperatures possible, which was particularly desirable in metallurgy and foundries. However, hard coal was heavily contaminated with undesirable substances such as sulfur. The use of hard coal posed no particular challenges for household consumption, but the air pollution caused by hard coal also led to its ban at times. Hard coal could not yet be used in metalworking because the liquid metal absorbed the impurities and thus became unusable.
Materials: box blower and cementing
The blast furnaces got bigger and bigger and, thanks to their larger capacity, now achieved daily outputs of between 2000 kg and 2500 kg of pig iron. However, this required a larger air supply than was possible with the previous bellows, so that these were replaced by box blowers, which were also more robust. There were two different possibilities for further processing into forgeable and usable iron with carbon contents between 0.1% and 1.5%, both of which were described by Georgius Agricola and Vannoccio Biringuccio in the middle of the 16th century. The pig iron could be melted again together with slag in the fresh stove. The pig iron (4–5% carbon) was then turned into a viscous lump, which was removed with tongs. The reverse route was known as cementing . Here they started with iron, which contained almost no carbon and glowed for a few days together with charcoal in the furnace .
Production technology: rolling and boring mills, artificial turning
In the 16th century, people slowly started rolling metals . For iron, however, stable roll stands, hard roll surfaces and a lot of force are required, which is why for a long time only non-ferrous metals were processed by rolling. There is even evidence of an early form of flow production for the rolling of lead plates , although this was only possible because the recrystallization temperature of lead is 3 ° C below room temperature and therefore no work hardening occurs. Other metals had to be annealed again and again in order to be able to process them further. The preferred connecting elements were rivets for non-detachable connections and wedges for detachable connections. Screw connections were known in principle. However, the threads had to be filed by hand, which was generally considered too time-consuming. Cannons were first cast from bronze over a core and then drilled out . For this purpose, vertical or horizontal boring mills were developed. Later it was also possible to drill iron cannon barrels from solid pieces.
The turning of wood was further developed in the arts and crafts. Oval workpieces ( oval turning ) or guilloches , complex patterns as decoration, for which fancy lathes were used, but which were not used outside of the arts and crafts, were now also possible . Charles Plumier wrote the book L'art de tourner (The Art of Turning) about turning.
Division of labor: manufactories
Which is established as a new place of production factory , which is characterized by wage labor , a high degree of division of labor was characterized by manual labor - in contrast to the factory - centralization of production and. The previous master craftsmen mostly procured raw materials on their own account, only very valuable materials such as precious metals and gemstones were provided by clients. In the factory, on the other hand, the materials were owned by a publisher and the workers were only paid according to piece wages. Compared to the handicraft, in which a master made a complete product with journeymen from raw materials, in the factory there were usually only a few steps per employee, which led to a high degree of specialization and thus productivity. This high degree of division of labor was first described by Adam Smith in 1776 in his much-cited example of pin production: One worker was exclusively occupied with pulling the wire, while another was responsible for stretching, cutting, sharpening, grinding and assembling the head .
The first industrial revolution (1700 to 1860)
The industrial revolution that started in England in the 18th and 19th centuries was the first of three waves of industrialization. In production engineering , it was shaped by the use of hard coal, steam engines , machine tools , new, more efficient methods and resources for steel production such as puddling and the coke oven, and the factory as a new form of organization.
Energy technology: steam engines
The most famous machine of the Industrial Revolution, which also became its symbol, is the steam engine, which existed in two variants: the atmospheric steam engine by Thomas Newcomen and the double-acting steam engine by James Watt. Since with them one was no longer bound to the availability of natural energy sources as with the wind and water mills, the new machines favored the development of factories in the cities.
The first working steam engine from 1712 came from the English blacksmith Thomas Newcomen . He let water vapor flow in under the piston in the cylinder, which condensed to water on the inner walls of the cylinder and thus created a negative pressure compared to the ambient air pressure. Normal atmospheric pressure then did work by pushing the piston down, which is why this version of Newcomen is also known as the atmospheric (piston) steam engine. However, it had poor efficiency because the condensed water cooled the cylinder, which was reheated by the steam. It was therefore only used in areas where no other means were available; mainly in the field of mine drainage. Contemporaries particularly criticized the efficiency: You need an ore mine to build the machine and a coal mine to operate it.
In the second half of the century, James Watt constructed an improved version in which the water vapor no longer condensed in the cylinder, but in a separate container, the condenser, which was connected to the cylinder by a pipe. In addition, Watt surrounded the cylinder with another larger cylinder, in which the pressure of the steam boiler acted, which now did the work instead of the ambient pressure. The Watt version is therefore also known as a double-acting steam engine. These changes increased the efficiency of the machine considerably, so that it could now be used economically in many areas, including in the textile industry and in mechanical engineering for driving machine tools.
Both Newcomen and Watt had problems building the cast iron cylinders. They were much larger than previously common workpieces and were difficult to produce with the required accuracy. It even took Watt several years after filing the patent application until he finally found a manufacturer in John Wilkinson who was able to drill out the cylinders. He used boring mills that were originally intended for drilling cannons. Wilkinson himself then used the first steam engine to drill additional cylinders in his company. From this it becomes clear that the different areas of production technology must progress equally and mutually benefit.
Materials: coke oven and puddle iron
The production of usable iron from ores still took place in several steps:
- the melting of the ores in the blast furnace into pig iron,
- refining the pig iron to reduce the carbon content, and then
- forging and rolling into bars, rails or sheets.
What was new was the technical implementation of these processes, which was now based primarily on hard coal and therefore made ferrous materials cheaper and also made it possible to expand production volumes. In production engineering, iron or steel could now be used as a construction material for machine tools, making them more precise and efficient. Most of the iron, however, was used for steam locomotives and rails, as well as bridges.
For the ore to be smelted in the blast furnace, it was necessary for the ore to come into contact with coal, as the carbon was required for chemical reactions. This was not a problem with charcoal, which consists almost entirely of carbon, but the cheaper bituminous coal was heavily contaminated with sulfur and other elements that made the product bad. Abraham Darby came up with the idea of coking hard coal. The main product was coke , which could be used to melt the ores, and tar as a by-product . As the tar pits near the ironworks continued to fill up, chemists became aware of this and found methods of making tar paints and medicines from them. A significantly lower coal / coke consumption was possible with the hot air blowing from James Beaumont Neilson . The air supplied to the furnace was heated, which resulted in higher temperatures and better steel.
There were two different methods of freshening with coal to shield the iron from the sulfur in the coal. From 1740 developed Benjamin Huntsman the crucible steel in the steel in crucibles given several days and was heated in a coal fire long. The result was a homogeneous steel of excellent quality. Because of its relatively high hardness, it was preferred for cutting tools and scissors. However, it was very expensive and could only be produced in small quantities.
The more important method was puddling , which was invented by Henry Cort in 1784 . When puddling, the pig iron was placed on a stove under which coal was burned. The liquid pig iron came into contact with the oxygen in the air and burned the carbon contained in the iron. Since the low-carbon iron has a higher melting point, lumps formed which eventually grew into rags and were removed from the stove. In order to ensure that all parts of the melt came into uniform contact with oxygen, a worker had to constantly stir the melt vigorously, which required a lot of experience. The quality of the steel produced thus crucially depended on the puddlers. Although puddling enabled larger production volumes than before, it was a manual process that could not be mechanized and was the bottleneck in the entire process chain from ore to finished product.
The iron, which was refined by puddling, was then worked under a forge hammer to drive out the last remains of slag and to make the material more homogeneous. This forging process also had a major impact on the quality of the steel. Only then was it rolled into sheets or rails.
Manufacturing technology: machine tools
From around 1800, the pre-industrial lathes and boring mills became real machine tools with a tool that was guided by the machine and no longer by humans, as well as with drives that were based on steam power and no longer on muscle power or wind and water mills. The lathes for the production of cylindrical objects such as axes , shafts , bolts , spindles or screws were of particular importance for industrialization . The tool holder was an essential component : the worker only had to move the tool using cranks, which was significantly less strenuous, enabled much more precise workpieces and also required less experience. The last point in particular was decisive, because good skilled workers were so rare in England that emigration was banned. The export of machine tools was also prohibited, but both the machines and the skilled workers found their way to the continent and thus helped to spread the new technology. Corresponding machines have been developed for most of the known machining processes. In addition to lathes, the most important were drilling machines , planing machines for the production of flat surfaces, guides for machines and profiles, and forging hammers that were driven by steam power and were mainly used in heavy industry. The milling machine , on the other hand, enabled a completely new process with milling that was suitable for tasks similar to planing.
Henry Maudslay , an English engineer and manufacturer, is of particular importance to machine tools . His influence on machine tools corresponds roughly to that of Watt on steam engines. Nothing on his machines was new; the individual design details such as the machine drive, tool holder or the lead screw were known from other areas. His achievement is based on the fact that he combined the individual details from precision mechanics, the woodworking industry and others in one machine. In addition, almost all of the next generation of engineers in this field had completed an apprenticeship at Maudslay, so that he is also considered the founding father of the machine tool industry. His first machine was a special lathe for the production of screws, which could now be made so evenly that they could be interchanged with one another.
The decisive impetus for the construction of machine tools came from the textile industry. Here the spinners couldn't keep up with the processing of the wool, so mechanical spinning machines were built. The weaving mill was a new bottleneck, so that mechanical looms were also built. Both were initially made of wood and were mostly powered by water power. The individual parts were manufactured in the vicinity of the textile factories: wooden parts by carpenters, metal parts in the foundry, precision mechanics and blacksmiths. The spindles in particular were required in very large numbers (between 1790 and 1810 there were 2.3 million spindles). Therefore, in mechanical engineering, people began to increasingly use machines themselves to produce machines. As the textile machines had more and more spindles (the first only four per machine, later over 100), there was a move towards building frames, spindles and transmissions from metal in order to minimize friction losses. In addition, the water wheels were replaced by steam engines. However, the machine tools with their wooden frames were not designed for the production of the metal parts, as significantly higher machining forces occurred here. That is why they began to manufacture the machine tools themselves from steel or cast iron.
Division of labor: factories
From around 1770 onwards, factories emerged from the factories in which power machines such as the steam engine and working machines were used, including textile and machine tools. The first factories came into being in the textile industry, later machine factories were added, which typically produced steam and machine tools as well as textile machines. The factories had a great influence on the skills required by the workers. They used to use the tools themselves, which required some experience. Now the machine took over this task itself, the workers only had to monitor it, supply it with raw materials and intervene in the event of malfunctions. This change has often been described both contemporary and in more recent research as a dequalification process. Another difference to the manufactory is that the work cycle was now set by the machine itself and no longer by humans. In mechanical engineering, the mechanical energy was usually transmitted from central steam boilers via transmissions to the factory halls, which was then transmitted to the individual machines by belts. Since the transmissions became more and more inefficient with greater distance from the steam engine and their practical range was limited to a few hundred meters, this promoted the development of central factories in the vicinity of the steam engines.
High industrialization (1860 to 1900)
High industrialization is part of the first wave of industrialization in which the leading states finally changed from an agricultural to an industrial state. There are various definitions and delimitations of what exactly is meant by high industrialization : in part, it means high industrialization in Germany between 1870 and 1914, and in part it also means the second industrial revolution . This section mainly describes the development of production technology in Germany and the USA - the two leading industrial nations - when the second industrial revolution began between around 1860 and 1900. The most important innovations concern the development of processes for the mass production of inexpensive and at the same time high-quality steel and the rationalization movement that went hand in hand with economical large-scale production. The machine tools were partially automated and the steam engines achieved significantly higher speeds and outputs.
Materials: mass steel process
The bottleneck in steel production was still freshening in the puddle furnace. Pig iron could be melted in good quality and in sufficient quantities in the steadily growing blast furnaces. The further processing of the puddle iron in mechanized rolling mills also happened quickly. In order to meet the great demand from the railway industry, some attempts were made to mechanize puddling as well, but this was unsuccessful. The experience of the puddlers could not simply be translated into machines. This was remedied by three competing processes: the two bottom blowing or wind-freshening processes by Bessemer and Thomas and stove freshening by Siemens and Martin.
Bessemer method
In the 1850s, Henry Bessemer came up with the idea of putting the liquid pig iron into a converter and blowing air through nozzles in the ground. The oxygen contained in the air burned the carbon and other undesirable accompanying elements in just 20 minutes and at the same time heated the pig iron, so that the refurbished steel was now liquid and could be cast for the first time. The process of blowing air through pig iron is also known as wind freshening. With the Bessemer process , it was only possible to generate and maintain the highest temperatures in the metallurgy system up to that point with air, and in doing so did not consume fuel as in the past, but also generated heat. The process was therefore significantly cheaper. In addition, the Bessemer steel was of very good quality: It was very pure and homogeneous and, thanks to its great hardness, withstood the loads to which it was exposed as a rail material. Puddle iron rails, on the other hand, usually had to be replaced after 10 years. In the USA in particular, numerous Bessemer systems were built in the late 1860s and early 1870s. However, the process had two disadvantages. It was only suitable for ores that were low in phosphorus , which were rare in Germany in particular, and the chemically neutral nitrogen in the air dissolved in the structure of the steel and made it hard but also brittle. In addition, almost all of the carbon was burned during the refining process, so Bessemer steel was not particularly strong.
Thomas method
The Thomas process by Sidney Thomas and Percy Gilchrist has been a variant of the Bessemer process since 1878, which was suitable for ores rich in phosphorus and was therefore used primarily in regions on the Rhine and Ruhr , in Belgium , Luxembourg and Lorraine . However, it also required a certain minimum content of phosphorus, so that there was little interest in it in England and America, as corresponding ores were not found here. Thomas steel was even harder and more brittle than Bessemer steel and was more suitable for less stressed cases such as wire or pipes and less for bridge or ship building.
Siemens-Martin process
An alternative to the two bottom-blowing or wind-freshening processes was the Siemens-Martin process , which is counted as stove freshening and is named after the three brothers of the famous Werner von Siemens , Friedrich , Otto and Wilhelm, and the French ironworker Pierre Martin . The process was based on a special oven in which the air supplied was heated strongly before it was ignited. Instead of heating the stove with this hot air, one heated another stream of air, which was now even hotter than the first. In this way, temperatures could now be permanently maintained that were above the melting temperature of steel. After several hours the steel was freed from the accompanying elements. Due to the slower process, the desired carbon content could be set very precisely. In addition, no nitrogen dissolved in the steel, so that the Siemens-Martin process resulted in a higher quality steel, which, however, was somewhat more expensive due to the more complex process. Most of the steel, however, was produced using this process until 1960, as it was also excellent for recycling scrap.
Elimination of forging
The forging of the steel, which is common with puddling in order to homogenize the material, could be omitted with the three new processes, since they all produced liquid steel which was already much more homogeneous than puddle iron could ever be. However, steelmakers were reluctant to give up forging, as a thorough forging process was the hallmark of good steel. For a long time, customers in particular could not believe that a better product was possible with less effort. Krupp was the last industrialist in Germany to give up forging, but forbade his representatives to reveal that Krupp steel, which was known for its high quality, was only rolled.
Energy technology: high-speed steam engines
The steam engines were further improved by numerous technical details and had better efficiency and higher performance. With the boilers, higher and higher temperatures and pressures were reached, which made more strokes per minute possible. These have much higher manufacturing requirements, so that they could only now be manufactured. However, the limits of what was technically feasible were reached: Since the pistons had to be accelerated and braked continuously as they moved up and down, the number of strokes was limited. For even higher performance, a completely different technology was required, which was available with the steam turbines in the second industrial revolution.
The dynamo-electric principle by Werner von Siemens made it possible from the 1860s to build generators that generate electrical energy from mechanical energy. By reversing the principle, electric motors were obtained that were used to drive trams. Using electricity, energy could now be transmitted over many kilometers with practically no delay. This would not have been feasible with the previous transmissions in the factory halls. In industry, however, electric motors have not yet caught on because they were still quite prone to failure.
Manufacturing technology: automatic machines and special machines
The first attempts to automate machine tools were made in the USA. Initially, there were hand-operated turret lathes for small parts such as screws that could independently move the tools and change the tools that were clamped in a turret. This eliminated the time-consuming manual reclamping of the various tools. Although the machine had to be set up by a specialist, it could be operated by a semi-skilled worker. Later there were revolver automatic lathes that had a mechanical drive. The worker only took on changing the workpieces. In the USA, preference was given to using special machines instead of the universal machines customary in Europe . They were only suitable for a narrowly limited range of workpieces such as flanges , screws or gears, but were very productive.
Both the automats and the special machines benefited from the particular economic circumstances in America. There was a great shortage of skilled workers who also demanded high wages, which is why they were tempted to automate as much work as possible and transfer machines. In Europe, Americans were said to be addicted to using machines. The other factor was the large US domestic market, which allowed larger production volumes, so that the use of special machines was worthwhile. In Europe, most of the companies only served the smaller national markets, so they preferred to stick to the less productive universal machines, which were much more flexible and enabled a broader production program.
Organization: rationalization, fast operation and American production system
A rationalization movement gradually established itself in America , which culminated in the early 20th century. At that time, rationalization was primarily understood to mean increasing the economic efficiency of production. The aim was to produce as much as possible with the existing workers and equipment, or a certain amount of production at the lowest possible cost. It was only with the resulting organizational principles that the real potential of the new technologies was fully exploited.
Fast operation
Although the steel in a converter in the Bessemer works was refined after only 20 minutes, only five to six batches could be produced per day. The converter was idle for the rest of the time. This was mainly due to the high need for repairs to the converter floors, which were worn out after six batches at the latest and had to be repaired for around 10 hours. In Europe people tried to use new materials that are more heat resistant. In America, where there was a very great need for steel, they didn't dwell on it for long. You simply changed the entire floor in a few minutes and then continued production. As a result, the output per converter rose to 48 batches per day within a few years and even to 72 later on peak days. In contrast, the costs of the floors did not play a major role. American steelworks now produced around the clock and thus for the first time both fast and well, which particularly impressed observers from Europe. Because up to now, producing well meant producing slowly and thoroughly. This production method in the steel industry was called hard driving in America and fast operation in Germany .
American production system
In mechanical engineering, too, attempts were made to find various ways of rationalization. Up to now, machines that corresponded to customer requirements were mainly produced to order, each of which was only manufactured in small numbers. Now attempts were made to achieve high quantities, which were associated with lower unit costs. Great progress was made in the field of standardization and typing, which made the transition to large- scale production possible. Associated with this was the transition to interchangeability , in which the individual parts of the same machines can be interchanged and which is only possible with very precise production. However, fits still had to be made by hand because machines were not yet accurate enough. The system of standardization, typing, interchangeability, precision manufacturing and mass production became known in Europe as the “American production system” and was imitated here by individual companies. The company Ludwig Loewe was a pioneer in Germany and showed its factory to anyone interested. With the new system it was now possible to manufacture numerous machines and machine parts in large numbers at low cost. The most important are screws, nuts, weapons, sewing machines, and bicycles .
Samuel Colt, the inventor and producer of the revolver named after him, was convinced that there was nothing that could not be produced by machines and thus initiated an early debate about what machines can and cannot do.
Second industrial revolution (1900 to 1950)
At the center of the Second Industrial Revolution from 1900 to the middle of the century was electricity. Now you could build steam turbines that are much more efficient than piston steam engines. Together with the new generators , it was possible to generate electrical energy in power plants and make it available over long distances with almost no loss or delay. The new form of energy was initially used for lighting, but soon afterwards also for driving trams and machines using electric motors . Electricity also led to the new field of electrochemistry . With it one could manufacture aluminum on an industrial scale and use it as a new material. In addition, electricity was used as an information carrier to control and regulate machines, for various new welding processes and in electric furnaces in the steel industry. The rationalization movement reached its climax with Taylorism , Fordism and the mass production associated with them . The assembly of cars on the assembly line at Ford is particularly well known .
Energy technology: steam turbines, power plants, electric motors, control and regulation
An important innovation for generating mechanical energy were the steam turbines , which provided significantly higher outputs of around 10,000 HP (7.5 MW) and were more efficient because they generate a continuous rotational movement instead of the constant up and down movement of the piston steam engine. Newcomen and Watt also originally wanted to build turbines, but failed because of the higher technical requirements that the production technology at the time could not yet meet. In order to reduce the very high speeds of up to 18,000 revolutions per minute, the company soon switched to using several expansion stages and impellers. The turbines spread very quickly, especially in power plants, as there was a high energy requirement and the piston steam engine had reached its technical performance limit.
Power plants
The steam turbines were mainly used to generate electrical energy. Around 1880 it was smaller local power generators that soon grew larger and larger and supplied entire regions. Since 1920 at the latest, there have been national supply networks into which the energy was fed by the power plants . In America, Thomas Alva Edison assumed that electricity was only needed for lighting and therefore built numerous smaller systems that he could switch on and off as required, so that the individual systems always ran at full load, which is efficient. In Germany, on the other hand, the pioneer Emil Rathenau and his Allgemeine Elektrizitäts Gesellschaft ( AEG ) tried to build as few large systems as possible that were more efficient overall; provided that he found customers who also wanted to use electrical energy during the day when hardly any energy is required for lighting. Rathenau identified potential buyers in electrochemistry, where electricity was needed to extract aluminum, in trade, where electric motors could be used to drive machines, and in public transport for trams. He actively helped with the transition to the use of electrical energy: He granted very low tariffs during the day, accepted old steam engines as part of the purchase of electric motors and offered numerous detailed technical solutions to make the motors more flexible or robust.
Electric motors
The main problem with the early DC motors offered by the electrical industry was their high susceptibility to overload. The most important argument for buying electric motors has always been that you only need to drive individual machines with them when they are really needed and could save that much energy. With the previous steam engines, all transmissions always had to be driven, regardless of whether all or only one machine was required. If they were switched on suddenly under full load, only the leather belts of the drives slipped through when overloaded. The electric motors, on the other hand, did not give any externally perceptible signs of overload and simply burned out. This could be prevented by starting up slowly, but this required a certain amount of patience, which was driven out of the factory workers in the young, productivity and fast-working industry, among other things through performance-oriented piecework wages. Therefore, the more robust three-phase motor was initially used , the speed of which depends on the frequency of the alternating current required. In practical terms, this meant that it could only run at a constant speed. To switch it on and off, all you had to do was press a button and if it was overloaded it would stop instead of burning out.
Control systems
The current monitor contactor control contributed to the implementation of the DC motor . This is an electrical control that ensures that the speed increases to the extent that is maximum permissible. This did not mean that the motor itself had become more robust, but it was reliably protected against overload. The new technology was initially used in trams , where the train driver could immediately set the controller to maximum speed from a standstill without the engine burning out. It soon established itself in industry, especially for driving cranes , conveyor belts and machine tools. In the first two, the dual character of electricity as a carrier of energy and information was used and the operating devices were not installed near the machines, but in positions that offered a good overview. All you had to do was lay cables. This would not have been so easy with mechanical controls.
In addition, electricity was used to automate machines , for example in rolling mills in the steel industry or for sawmills . These consisted of a drive for the saw and a servomotor that pushed the tree trunks into the saw. Both motors were connected to each other so that they could regulate themselves. If the saw frame ran easily and drew little power, the speed of the adjusting motor was increased so that it pushed the logs faster. When the motor of the saw then drew more current, the servo motor was braked so that it was always working with maximum power. If the saw got stuck, a short-term tolerable peak current was generated, which ensured that the servomotor ran backwards and enabled the saw again. In other areas, mechanical buttons are used, for example in copy milling or in trades where a tear-sensitive product had to be wound up, such as in the paper industry or spinning mill. Here the bobbins for winding the yarn originally ran at a constant speed. As the circumference continued to increase during winding, the thread speed also increased and with it the tensile force in the thread. Since the maximum force occurred at the end of the process, most of the time the machine had to run at a speed that was lower than what was actually permitted. Now, however, a button could measure the circumference of the bobbin and set the speed of the motor accordingly, which made it possible to increase productivity by around 20%. The decisive factor in the introduction of the electric motors was not the energy savings, as was originally assumed, but that the already existing potential of machines could be used much better. The electric motor originally had no particular advantages over steam or combustion engines; He received this only through a clever regulation and control.
Manufacturing technology: welding, high speed steel and fits
The forging and stamping were new manufacturing processes, could replace manual work. Both were used particularly in the automotive industry for the production of connecting rods, crankshafts and body parts. In assembly, riveting was replaced by various welding processes from around 1900 : With manual arc welding , the energy required for melting is provided via an electric arc, with resistance welding, on the other hand, through the development of heat in an electrical resistor. In the 30s and 40s, gas shielded welding and submerged arc welding were added. In particular, welding made it possible to manufacture very large objects such as bridges, ships or locomotives more economically. In shipbuilding there was a transition to sectional construction , in which the segments of the hull consist of several identical modules that are prefabricated separately and transported to the shipyard, where they are welded together. When assembling the locomotives, the rivets were replaced by the welders, which hardly promised any advantages, but changes in the construction made it possible to save effort in the upstream stages of the foundry and forging.
Machine tools
For machine tools, the productive special and single-purpose machines were initially increasingly used, since in the vehicle industry and in general mechanical engineering many products could be produced in sufficiently high quantities. The First World War intensified this tendency, since the uniform military standards now took the place of the house norms of the various companies. After the war and increasingly after the global economic crisis , however, the disadvantages of the special machines became more apparent: they were not very flexible. For this reason, there was an increasing trend towards using universal machines that could be used for a short time like special machines due to additional devices. The fundamental conflict between cost-effective mass or large-scale production with special machines on the one hand and the flexibility required by the market on the other, however, persisted throughout the 20th century.
The machine tools themselves have been improved by two technical innovations, the electric motor and the electric controls. The latter made it easier to operate, as numerous functions could be automated. They also made copy milling possible, with which workpieces with complex shapes could also be manufactured economically in medium quantities. However, the prerequisite was the use of electric motors as a drive. Initially, large individual machines were electrified, as they caused a jolt in the entire hall when switched on and off. In the second step, the central steam engines were replaced by central electric motors. It was only in the third phase that a move was made to equipping each individual machine with a single drive. The machines could now be positioned relatively freely and according to the flow of material, since only cables had to be laid through the halls and the transmissions were superfluous.
Cutting materials
Around 1900, normal tool steel was still used as a cutting material , with which machining rates of only about 5 kg per hour were possible. An important innovation was the high-speed steel from the smelter Maunsel White and Frederick Winslow Taylor , on which Taylorism goes back, and contains about 8% tungsten and 3% chromium. This enabled cutting speeds to be around three times higher than before. However, the machines required a correspondingly higher performance and more stable frames. Only machine tools equipped with an individual electric drive were able to fully exploit the potential of high-speed steel. The new cutting material thus promoted the electrification of machine tools. Their output increased from 3–5 HP around 1900 to 90 HP around 1910. Another cutting material from 1907 is stellite , an alloy of chrome, cobalt and tungsten that was even more powerful. This could cut off up to 250 kg per hour. Before 1900, attempts were made to manufacture castings or forgings that were as precise as possible, which required little post-processing, as the machining was slow. With the new, high-performance cutting materials, it was now worthwhile to produce coarse raw material, which saved a lot of effort in model and mold making. It was now customary to remove up to 60% of the raw material; In contrast, the increased material costs only played a subordinate role. When the prices of raw materials rose after the First World War, however, there was an increasing trend towards staggered production with casting, forging and finishing by machining. From 1927 the first hard metals were available, which allow a cutting speed three times higher than the high-speed steel. The most important and oldest include hard metals based on tungsten carbide , such as WIDIA ([hard] Wie Dia mant).
Fits
Around 1900 the achievable accuracy of grinding machines was for the first time better than that of skilled work by hand with files and scrapers. Also fits could now be made by machines. On the one hand, this was due to the better machine accuracy, but more important were the more precise measuring equipment such as screw micrometers , which were also integrated into the machines, and test equipment such as limit gauges , which made it possible to easily check the finished workpieces. In the 19th century, the designers still verbally specified fits. For example, a press fit that can be joined by hand, wooden hammer or metal hammer. From 1900 onwards, a change was made to specifying the dimensions of the two workpieces involved in a fit to within a few hundredths of a millimeter. This made it possible for the first time to manufacture both parts in separate plants. The great importance of the new fit system can be seen from the fact that the dissertation The fits in mechanical engineering by Georg Schlesinger , who made a decisive contribution to the elaboration, was translated into numerous languages.
Materials: composite economy, chrome-nickel steel and aluminum
With the new electric ovens, electricity made it possible to produce so-called electric steel . These steel mills were excellent scrap recyclers, but played only a subordinate role in the overall market. As before, three different processes were in competition here: the Bessemer and Thomas processes with the somewhat cheaper steel and the Siemens-Martin process with the better quality steel. In the Bessemer and Thomashütten they tried to improve the quality and thus to achieve the longed for "Siemens-Martin equality", but this did not succeed. However, all processes were extremely productive, so that there was overcapacity for the first time. So far, attempts have been made to optimize the costs of individual systems; the production volume was a resultant quantity. Now, like the market price, it was determined by cartelization , group formation , protective tariffs and other economic influences. In the vertically integrated steel groups, with their ore mines, blast furnaces, Bessemer or Siemens-Martin smelters and the rolling mills, it was now a matter of minimizing costs for the entire company.
Verbundwirtschaft
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These savings were achieved primarily through the so-called Verbundwirtschaft , which wants to recycle all by-products and also focuses on energy savings. In the blast furnace, for example, what is known as blast furnace gas is produced , which has long been used to heat the incoming air in the boiler. However, only about 20% of the gas was used. Now attempts were made to use it further: First, it was burned in the steam boilers of the rolling mills. This created a rigid technical link between the number of blast furnaces and the number of rolling mills. When the company switched to electric drives, it was used to drive generators instead: the gas was "converted into electricity". In addition, the liquid pig iron from the blast furnace began to be fed directly into the converters (Bessemer and Thomas processes) or Siemens-Martin furnaces without remelting it, which is more energy-efficient. The refined iron was allowed to cool just enough to set and then rolled. In the ideal case, the heat generated in the blast furnace was sufficient for the entire process, which was known as “ rolling in one heat ”. The slag, which had always been falling off, was now processed into sand, stone and cement. The slag from Thomas-Werke was particularly popular because it contains a high proportion of phosphoric acid and can therefore be processed into fertilizer . The Thomas works were even among the largest fertilizer manufacturers. This Thomas credit contributed significantly to the cost advantages of the procedure, since the Thomasstahl was cheaper by this credit.
Chrome-nickel steel
In the chemical industry, some processes, such as the Haber-Bosch process for the production of ammonia, which was new at the time, required very high pressures and temperatures of up to 330 bar and 550 ° C. The hydrogen involved in the process diffused into the steel of the reactor walls, dissolved the carbon it contained and thereby reduced the strength of the steel, which led to reactor explosions. As a result, high-alloy steels were found that did not get their strength from carbon but from other metals as alloying elements and are therefore chemically resistant. The most important representative is the austenitic , rustproof chrome-nickel steel . The new steels and chemical processes thus helped each other to achieve an industrial breakthrough.
Aluminum and other non-ferrous metals
The extraction of most non-ferrous metals ( non-ferrous metals ) was similar to steel production. The main ones include lead , copper , tin and zinc , all of which have been known since ancient times. The ores were melted in the blast furnace and then freed from undesirable accompanying elements. In the case of steel this is referred to as refining, in the case of non-ferrous metals as refining . However, they usually have much lower requirements than ferrous materials. During industrialization, their production rose in percentage terms faster than that of iron, but at a much lower level. However, aluminum made significantly higher demands . It was already known in the 19th century, but still very expensive: At the court of the French Emperor Napoleon III. Selected guests received aluminum cutlery, while the rest of the court had to be content with gold and silver cutlery. Aluminum was actually abundant, for example in bauxite , the most important ore. However, it has a high chemical affinity for other elements, which is why aluminum cannot be extracted in blast furnaces. On an industrial scale it could only be gained through the new electrochemistry . Very high currents of around 4000 amperes against 1900 or 40,000 amperes towards the end of the 1930s flow during production. In 1990 over 300,000 amps were common. Aluminum was mainly used in aircraft construction because it is light and corrosion-resistant, but also for electrical cables. The pure metal is still far too soft for that. Alfred Wilm discovered an alloy with magnesium , silicon and copper, known as duralumin, which is stronger than steel in relation to its mass.
The filaments of incandescent lamps are now made of osmium or tungsten instead of the previously usual carbon filaments , as they have a higher melting point and therefore enable more efficient lamps. The name of Osram derived from these metals ago. Because of their high melting point, they could only be obtained through electrochemistry. In addition to incandescent filaments, tungsten has been used in numerous new cutting materials , e. B. in high-speed steel or in hard metals with tungsten carbide. Magnesium was also obtained electrolytically for a long time. Shortly before the Second World War, they started using coal to reduce magnesium oxide , which made large-scale industrial production possible. The by-product was napalm , an oil- magnesium vapor that was originally condensed to recover the metal. It was soon discovered that it could be used as an incendiary device for military purposes.
Organization: Scientific management and mass production
At the beginning of the 20th century there were two important innovations in the area of the organization of production: Taylor's " Scientific Management ", later known as Taylorism , and the mass production of cars by Henry Ford, also known as Fordism . The relationship between Taylor and Ford has been widely discussed in the scientific literature. Overall, it can be said that Taylor was more concerned with work organization and workers than with technology, while at Ford it is the other way around.
Taylorism
Frederick Winslow Taylor is considered to be the most important representative of the rationalization movement that originated in the last decades of the 19th century and reached its peak at the beginning of the 20th century. His methods, which he calls “scientific management”, consist of several important parts. On the one hand, the way of working was no longer left to the individual worker, but was dictated by engineers. This is often referred to as “separating hand from head work”. For this purpose, so-called company offices were founded - forerunners of today's work preparation - in which engineers determined the optimal working method. For this purpose, the work processes were broken down into individual work steps and measured with a stopwatch. Gantt, for example, used so-called time and movement studies to determine the time it takes a bricklayer to grip a brick and the time it takes to lay the mortar, place the brick, etc. The implementation of Taylor's “Scientific Management” was handled differently in different companies and countries and is referred to as Taylorism to distinguish the original idea .
Fordism
Around 1900, cars were still handcrafted, similar to carriages before, and were correspondingly expensive. Henry Ford suggested that there would be great demand for cars if only they were cheaper. Therefore, he began to manufacture cars as a mass product and was not only able to reduce the price by half, but also double the wages of the employees. From the 1920s onwards, assembly on the assembly line was a special feature of Ford's production, but this was more the result of mass production, replacement construction, rationalization and the use of highly productive special machines. Also important was the standardization, which was particularly pronounced at Ford and even went so far with its famous Model T that only black was offered as a color. He turned the car from an expensive luxury item into a consumer good and his factory into a real “place of pilgrimage” for European engineers.
The assembly line was regarded as the epitome of modern production, but only a small part of those employed in industry worked here. With a few exceptions, such as the production of light bulbs and switches in the electrical industry, less pronounced forms of flow production were widespread, such as variants in which the workplaces were arranged in the order in which the raw parts passed through, but with intermediate storage every station.
Third industrial revolution (1950 to 1990)
Throughout the 20th century, cutting materials such as high-speed steel , carbide or diamond were continuously improved. They made it possible to machine increasingly hard materials. From around 1980 on it was also possible to machine hardened steel. From the middle of the century, turning, milling, drilling and grinding machines became more and more automated and flexible thanks to the CNC control . They were supplemented by industrial robots , especially in assembly . The laser developed in the 1960s was used for precision measuring equipment and for completely new processes such as laser cutting and welding .
In the steel industry, the new, highly productive LD process emerged which replaced all older processes with the exception of the electrical process. Electrical energy was generated in nuclear power plants, while crude oil replaced coal as the most important energy source. The most important new form of organization was the Toyota Production System .
Manufacturing technology: automation and flexibility
In 1949, John T. Parsons came up with the idea of representing the geometry data of workpieces by means of numbers and processing them by computers in order to control the machine tools. With financial support from the US Air Force , which had given Parsons the contract to build rotor blades, and with advice from MIT , Parsons was able to realize his idea. This created the first numerically controlled machine ( NC machine , from English numerical control) that could automatically manufacture more complex workpieces. Since the hardware of the machines controlled by punch cards and electron tubes was very expensive and the programming was complex and also expensive, they did not catch on. This changed with the introduction of the microprocessor in the 1970s: Now the computers were much more powerful, more robust and also more flexible. Instead of exchanging a whole set of punch cards, all that was left to do was load a new program. Therefore, the new machines, which were called CNC machines ( computerized numerical control ) to distinguish them from the older generation , also offered economic advantages, so that they spread quickly.
From around 1950 computer-aided design options were also developed, known as CAD ( computer-aided design ). For a long time, however, there was no connection between design and production. But this also changed with the microprocessors . Now the CAD data could be passed on to the CNC programs, which calculated the required control data from them. The connection between construction and production and other areas such as quality assurance or production planning and control is known as CIM ( computer-integrated manufacturing ).
While drive concepts were still decentralized in the second industrial revolution (from central steam engines to individual electric drives), there were now two further decentralizations in information technology: The programming, which had long been carried out by engineers in the work preparation , gradually shifted to the skilled workers ( workshop-oriented programming , WOP). On the other hand, central computers were initially used, which passed the CNC programs on to several machines (DNC, distributed numerical control ) in order to divide the initially high acquisition costs for the computers over several machines. Later it was decided to equip all machines with their own microprocessor.
From the 1970s onwards, the first flexible manufacturing systems (FMS) were created, which consist of several CNC machines, workpiece and tool stores as well as supplementary equipment such as measuring or washing machines, all of which are connected by a transport system. In contrast to the older flow production with production lines , in which the sequence in which the workpieces run through the machines is fixed, the individual workpieces can take different routes with an FMS. With them, medium-sized series in a fully automatic production were now possible. While an FMS is a technical option for increasing flexibility, island production is based on the fact that several machines and employees are organizationally combined and commissioned with the independent production of a limited range of workpieces. Accordingly, the performance evaluation of the individual employees was also abandoned and the evaluation of the entire group was switched on ( group work ).
In the particularly innovative automotive industry, industrial robots were used more and more frequently . In addition to the actual assembly of the individual parts, they were also used for spot welding , painting and as a transport system in flexible manufacturing systems. Their great advantage is that they can be programmed flexibly, similar to CNC machines.
As early as 1946, John Brown and Eric Leaver published their highly acclaimed article Machines without Men in Fortune magazine , in which they described a factory in which machines manufacture inexpensive products fully automatically. This vision of the deserted factory seemed to come ever closer with the various PC-based technologies. However, it was difficult to automate tasks such as programming, maintenance, servicing and intervening in the event of malfunctions.
The laser developed in the 1960s was used for precision measuring equipment and enabled completely new processes such as laser cutting and welding .
Materials: LD process
Since the invention of the Bessemer and Thomas processes, the owners of the respective plants have tried to match the quality of their steel to that of Siemens-Martin steel without losing their cost advantages. Bessemer himself already knew how this “Siemens-Martin equality” would be possible: Instead of the nitrogen-containing air, you only had to blow pure oxygen into the converter. However, this was very expensive for a long time. After industrial refrigeration had made great advances in the late 1940s, liquid oxygen could now be extracted from air. The steelworks initially only enriched the air used with oxygen, which already led to noticeable increases in quality. In 1952, two test systems were built in Linz and Donawitz that blew pure oxygen from above onto the liquid crude steel. After the two places the new process became known as the LD process . With it, significantly higher temperatures could be reached again, which makes it ideal for recycling scrap, which was previously mainly reserved for the Siemens-Martin works. Today (2016) it is by far the most economical and powerful process and has quickly established itself in the industry over almost all other processes, so that it was standardized for the first time in around 100 years. Only the electric steel process still has a significant share.
The capacity of the converters increased from around 30–50 t (1950) to 100–200 t (1960) and finally over 400 t (1980). The annual capacity of such a converter around 1980 was around 3 million tons, with two to four converters in one plant for economic reasons. The economically sensible minimum capacity of an integrated steelworks consisting of blast furnace, converter and rolling mill increased from two million tons in the 1950s to around eight million tons ten years later. In the 1980s it was twice as much. The daily output of blast furnaces doubled from 5000 t to 10,000 t. In addition, steel production was further developed in the direction of continuous flow production. Instead of pouring the liquid steel into permanent molds and allowing it to solidify before rolling , continuous casting was used , in which a continuous strand was produced that could be cut into pieces of any size. The last step on the way to continuous production was thin strip casting , in which the steel is poured onto a thin strip, solidified and can be rolled immediately.
Steel was increasingly being replaced by light metals (especially aluminum) and plastics, primarily for reasons of weight. However, in 1990 steel was still the most important material with a worldwide production volume of 200 billion US dollars. For plastics it was 100 billion, for all other metals together 50 billion.
Energy technology: petroleum and nuclear energy
In the second half of the 20th century, electrical energy was still generated in power plants, transferred to industry via lines and converted into mechanical energy there by means of electric motors or used for electrolysis and in electric ovens. However, some primary energy sources such as crude oil , natural gas and uranium for nuclear energy were new . Mainly driven by cheap crude oil, there was strong growth in energy consumption between 1950 and 1973, which in Western Europe rose by 4.5% per year. The consumption of crude oil grew by a factor of 15 within 25 years and replaced coal as the most important energy source; society developed into a consumer society . With the oil and environmental crisis in the 1970s, there was a return to regenerative energy sources, which experienced a renaissance, not least because of the efforts to protect the climate that became important from the 1990s onwards .
Petroleum and gas
Petroleum has been known since ancient times, but was hardly used. At the end of the 19th century, primarily in the USA, the first oil fields were developed to produce petroleum that was used in lamps. It was initially transported in barrels on wagons. In the early 20th century, mass production of automobiles increased the demand for gasoline, diesel, and other fuels that can be made from petroleum. Therefore, lines were built that reduced transport costs to about a tenth. From around 1950, oil replaced coal as the most important raw material. This change was not limited to production in the energy sector: in heavy industry it was used for the process heat required in blast furnaces and in the chemical industry, petroleum-based petrochemistry replaced coal-based chemistry . The advantages of crude oil lay in the higher energy density, which on the one hand enabled higher combustion temperatures and on the other hand had a favorable effect on transport costs.
Natural gas was also increasingly used in power plants. However, since the industrialized countries were dependent on oil imports, the oil price had an ever greater influence on economic development. This became particularly clear during the 1973 oil crisis. As a result, efforts were made to find alternative energy sources. In heavy industry they just went back to using coal; however, the general economic downturn and the lack of demand for steel from other sectors hit them particularly hard and led to a steel crisis . Further points of criticism were the high environmental pollution in the form of emissions of pollutants such as soot and nitrogen oxides ; later also from carbon dioxide , which is one of the most important greenhouse gases and is one of the main causes of current global warming .
Nuclear energy
As an alternative to coal and oil, nuclear energy was promoted in energy production. In contrast to the combustion of oil or coal, which are chemically based on reactions in the atomic shell, it is based on processes in the atomic nucleus. In nuclear fission, the fission products have a lower mass than the starting materials, which is referred to as a mass defect . The missing mass is converted into energy. In the 1950s and 1960s there was intensive research into nuclear energy in many industrialized countries. Initially it was shaped by debates about the merits of different reactor concepts. These include the heavy water reactor and the light water reactor that prevailed, as well as the pressure and boiling water reactor . The first power plant went online in 1954 and after a start-up phase in the 1960s, the installed capacity increased sharply in the 1970s and 1980s and then largely stagnated at a very low growth trend from the late 1980s. Initially, power plants with an installed capacity of around 100 megawatts were planned, but the minimum economic size soon increased significantly and unit sizes were well above one GW. Initially greeted with euphoria, nuclear energy came under fire. a. because of their military origins, the possibility of building nuclear weapons, and security considerations, they have come under increasing criticism. At the latest since the Chernobyl accident in 1986, which led to an uncontrolled meltdown , nuclear energy has only been expanded to a small extent.
Organization: Toyota Production System
In the 1970s, European and American companies faced increasing competition from Japan, especially in automobile production. The Japanese factories were significantly more productive than western ones, not because of other technologies, but because of better organization. The organization introduced by Taiichi Ohno at Toyota , which has since been known as the Toyota Production System and is often referred to as Lean Production , became particularly well known . In social science studies it is sometimes referred to as Toyotism, based on Taylorism and Fordism, or also as Post-Fordism. In the famous 1990 study The Machine that Changed the World by James P. Womack , Daniel Roos, and Daniel Jones , it was thoroughly analyzed and popularized. The title of the German translation, The Second Revolution in the Auto Industry, alludes to the introduction of mass production by Ford. Some elements go back to western inventions. Toyoda Eiji , for example, visited Ford's factories herself in the 1950s; later, Toyota's factories were visited by numerous western engineers to learn from the Japanese. The elements of the Toyota production system include the elimination of any waste (called muda in Japanese ), group work , a production that largely does not need stocks (for which the just-in-time concept and Kanban are used), a special one Quality management , continuous improvement processes ( called kaizen ) and autonomation . “Just in time” means that parts should be delivered exactly when they are needed in assembly, which means that storage is largely unnecessary. The Kanban system triggers the production of parts when intermediate storage falls below a certain target value instead of leaving the initiation of the order to the management. One of the most important quality management methods is the zero-defect principle , which originated in Japan. Other important methods that come from the West are Six Sigma and Total Quality Management .
Production technology at the turn of the 21st century (1991 to 2010)
The history of production technology and industrial production in the last few decades has largely not yet been examined by the history of technology. This section shows developments that have been dealt with in engineering, economics or social science works in recent years.
manufacturing engineering
The most well-known innovations in manufacturing technology include generative manufacturing processes , which are often referred to in the media as 3D printing , but this is only one of several specific processes. Sometimes there is even talk of a new industrial revolution: it is known as the digital revolution . However, such a revolution is denied by some scientists. What all processes have in common is that they can use electronic 3D data (mostly CAD data) to not only process a workpiece as with the CNC control, but also to build it up in layers. Since the shape of the workpiece no longer has to be stored in the tool (as with casting molds or punching tools), very flexible production is possible, which is particularly suitable for small series or individual production. The finite element method is used in simulation, research and work preparation. This makes it possible, for example, to simulate the forces that occur during machining or the deformations during forging or flows when pouring the melt into the mold, in order to optimize the molds based on this.
Numerous internet-based technologies or new simulation technologies are also being discussed and, to a large extent, are already in use. This includes Industry 4.0 , which alludes by name to the previous three industrial revolutions, and also the digital factory , the Internet of Things or Smart Factory . But the machining processes, the principles of which have remained unchanged since their invention, made even more progress: Thanks to new cutting materials, it was possible for the first time to drill, mill or turn hardened steel in the 80s. A few years earlier this had been considered impossible in principle. This so-called hard machining or hard cutting is used to enable multi-sided machining in just one clamping.
While in the second half of the 20th century Germany and Japan had the largest shares in the world market for machine tools, at the beginning of the 21st century China became the most important manufacturing nation with a share of 21% (as of 2009). However, China is still dependent on imports: As a consumer of machine tools, it ranks first with a world share of 33%.
Materials
Economic growth in China also led to changes in heavy industry. In the 1970s to 1990s, global crude steel production was still around 700 million tons per year, it rose to over 1500 million tons in 2012. The rise of the Chinese steel industry, which is almost exclusively responsible for the expansion of production, goes alongside economic and organizational ones Reasons also go back to the introduction of modern technology. These include continuous casting, blowing pulverized coal into the blast furnace, various technologies that extend the service life of the blast furnaces , continuous rolling processes, energy savings resulting from skillful process management and " slag splashing ". As the importance of recycling increased and the electric arc process is particularly suitable for this, its share increased to over 30% and partly replaced the LD process. Steel has been replaced by lighter materials in numerous areas of application. Often through aluminum and titanium, but also through the new composite materials, in particular through carbon fiber reinforced plastics (CFRP). Nevertheless, steel will remain the most important material. The ferritic TRIP steels produced since the 1990s, for example, excrete a phase when deformed, which further increases deformability and strength. The Thixoforging and -watering are new methods based on the thixotropic based, a state in which a material after pretreatment at a stage is between solid and liquid and can therefore be particularly easy to edit. Superconductors are materials that no longer have any electrical resistance below the so-called transition temperature. From 1986 onwards, ceramic high-temperature superconductors were discovered with a transition temperature high enough to be cooled by cheap liquid nitrogen instead of liquid helium.
Energy Technology
While the stocks of oil, coal and uranium are basically finite, renewable energies such as solar energy , wind and water energy are practically unlimited. In the first phase of the Industrial Revolution, hydropower was the most important source of energy in the production of goods and always played an important role in regions with a lot of water and great differences in altitude. In Sweden and Austria, for example, it has always been more important than fossil fuels. In the 20th century, however, it was no longer based so heavily on water mills, but on modern hydropower plants with water turbines .
Windmills, which supplied mechanical energy and of which around 30,000 with a total output of several 100 MW were still in operation in the North Sea bordering countries around 1900 , were initially largely replaced by electricity in the second third of the 20th century, starting in the 1970s used again in the form of electricity-generating wind turbines . In 1979, various Danish companies began to manufacture wind turbines in series; in the 1990s this development accelerated significantly, so that the wind industry has been one of the fastest growing industrial sectors in the world since then. Solar energy was also used for heating purposes before industrialization. The PV was used in the 1950s in satellite technology and more explored in the 1980s as well as other renewable forms of energy. It was used on a somewhat larger scale for the first time in the 1990s, when the 1000 roofs program was adopted, and finally from 2000 with the 100,000 roofs program and EEG as well as similar funding measures in other countries.
A disadvantage of some renewable energies such as wind and solar energy is their fluctuating generation curves, which require the balancing of generation and demand with the help of conventional power plants or, in the case of largely or completely regenerative energy systems, balancing with networks and energy storage systems.
organization
After the collapse of the Eastern Bloc , a new wave of globalization set in, which also had an impact on the organization of production. Often parts of companies were outsourced to Eastern Europe or the People's Republic of China , as wage costs were lower there. Associated with this, the importance of inter-company logistics also increased , since intermediate products were often manufactured in low-wage countries, while production steps that required complex technology remained in highly industrialized, high-wage countries . The supply chain management deals with such supply chains of several companies. Globalization also led to increasing competitive pressure and ever shorter innovation and product life cycles . In 1990, for example, a car model was manufactured for eight years, but in 2014 it was only two years. Since the service life of the machines used for production is significantly longer, they have to meet higher flexibility requirements in order to be able to produce future models. In addition, the number of variants has increased in many product areas, which is also associated with higher flexibility requirements. In order to achieve the cost advantages of mass production even with a large number of variants, many companies have developed concepts known as mass customization . Each product is individually designed according to customer requirements (customization), but manufactured by means of mass production.
Because of the high level of automation, the organization in production became increasingly complex . Since machines cannot handle unforeseen situations, the increasing degree of automation often led to malfunctions. Since the 1990s, people have often returned to their strengths over machines: They can react flexibly to unforeseen situations. Another reason for the great complexity was the high number of variants for mass customization.
Another trend is the shortening of process chains . Instead of further processing a product over many stages in different companies, one tried to get to the finished product in just a few steps. This happened, for example, with the so-called complete machining , in which a single machine masters several manufacturing processes. With a machining center, there is no need to transport between machines that only master a single process.
literature
- Günter Spur : Production technology in transition. Carl Hanser Verlag, Munich, Vienna, 1979, ISBN 3-446-12757-7 .
- Martina Heßler: The cultural history of technology. Campus Verlag, Frankfurt, New York, 2012, ISBN 978-3-593-39740-5 , especially chapter 3. History of industrial production: Rationalization and its limits.
- Christian Kleinschmidt: Technology and Economy in the 19th and 20th Century. Oldenbourg, Munich, 2007, ISBN 978-3-486-58030-3 .
- Ulrich Wengenroth (Hrsg.): Technology and economy. Volume 8 by Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture , Düsseldorf, VDI-Verlag 1993, ISBN 3-18-400868-1 .
Individual evidence
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna, 1991, pp. 25-40.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna, 1991, pp. 38-48.
- ↑ Wolfgang König (ed.): Propylaea History of Technology - Volume 1. Propylaea, Berlin, 1997, p. 38.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna, 1991, pp. 38, 42, 44.
- ↑ Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 101.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 38, 42, 44 f.
- ↑ Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 97.
- ↑ Helmuth Schneider: The Gifts of Prometheus - Technology in the Ancient Mediterranean between 750 BC. And 500 AD P. 97–110 in: Dieter Hägermann, Helmuth Schneider: Propylaea History of Technology Volume 1 - Agriculture and Crafts - 750 BC Until 1000 AD Propylaea, Berlin 1997.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 48–65.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 49.
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↑ * Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 98 f.
- Günter Spur: About the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 49–51.
- ↑ Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 99 f.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 49, 51.
-
^ A b * Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 51.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 104 f.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 56.
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↑ * Driving, drilling, connecting: Günter Spur: About the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 54–56.
- Drifting: Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 101 f.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 54.
-
↑ * Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 62, 64, 67.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 1. Propylaea, Berlin 1997, pp. 307 f., 311 f.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 51.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 57 f.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 67, 70 f., 77.
-
↑ Wolfgang König (ed.): Propylaea history of technology. Propylaea, Berlin 1997:
- Volume 1: pp. 346-408, 419-435
- Volume 2: pp. 76-107.
-
↑ * Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 67, 72-74.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 2. Propylaea, Berlin 1997, pp. 77, 98 f.
-
↑ * Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 68, 79-81.
- Wolfgang König (Hrsg.): Propylaea history of technology. Propylaea, Berlin 1997, Volume I, pp. 423-425 (Damast), Volume II 390 (cast iron).
-
↑ * Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 69 f., 79-81.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 2. Propylaea, Berlin 1997, pp. 377, 391.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 89, 91 f.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 69, 85-88.
-
↑ * Example Solingen: Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 76.
- Regional distribution in general: Wolfgang König (Hrsg.): Propylaen Technikgeschichte - Volume 1. Propylaen, Berlin 1997, p. 426.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 74 f.
- ↑ Wolfgang König (Ed.): Propylaen history of technology - Volume 3. Propylaen, Berlin 1997, pp. 29–33.
- ↑ Wolfgang König (ed.): Propylaea history of technology. Propylaeen, Berlin 1997, Volume 2: p. 357, Volume 3: pp. 85-93.
- ↑ Wolfgang König (Hrsg.): Propylaen technology history - Volume 3. Propylaen, Berlin 1997, pp. 188-190, 194, 196 f.
- ↑ Martina Heßler: Cultural history of technology. Campus Verlag, Frankfurt / New York, p. 41 f.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 137.
- ↑ Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 322.
- ↑ Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology. S. 205–208 in: Ulrich Wengenroth (Ed.): Technology and Economy , Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture. Düsseldorf, VDI publishing house.
-
↑ * Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, pp. 58–60, 358–368.
- Günter Spur: About the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 141 f.
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 3. Propylaen, Berlin 1997, p. 383.
- ↑ a b Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 330.
- ↑ Ulrich Wengenroth: Iron, steel and non-ferrous metals. In: Ulrich Wengenroth (ed.): Technology and economy. 1993, p. 103 (Volume 8 by Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture. Düsseldorf, VDI-Verlag).
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 3. Propyläen, Berlin 1997, pp. 383 f., 397.
- ↑ Gottfried Pump: Chemical Industry. In: Ulrich Wengenroth (ed.): Technology and economy. 1993, pp. 161-163 (Volume 8 by Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture. , Düsseldorf, VDI-Verlag).
-
↑ * Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, pp. 127–129.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, pp. 390–393, 395.
-
↑ * Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 129.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 397.
-
↑ * Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich, Vienna 1991, p. 130.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 399 f., 406 f.
- Ulrich Wengenroth: Iron, steel and non-ferrous metals. In: Ulrich Wengenroth (ed.): Technology and economy. 1993, pp. 101-103 (Volume 8 by Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture. Düsseldorf, VDI-Verlag)
-
↑ * Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 402 f.
- Ulrich Wengenroth: Iron, steel and non-ferrous metals. In: Ulrich Wengenroth (ed.): Technology and economy. 1993, pp. 100-103 (Volume 8 by Armin Hermann, Wilhelm Dettmering (ed.): Technology and Culture. Düsseldorf, VDI-Verlag).
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich / Vienna, 1991, p. 147.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich / Vienna 1991, pp. 146, 151 f, 155.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich / Vienna 1991, p. 146.
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 3. Propylaen, Berlin 1997, p. 319.
- ↑ Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology. Pp. 215–217, 219. Ulrich Wengenroth (Ed.): Technology and Economy. Volume 8 by: Armin Hermann, Wilhelm Dettmering (ed.): Technology and culture. VDI publishing house, Düsseldorf
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich / Vienna 1991, p. 156, 170.
- ↑ Wolfgang König (Ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, pp. 321, 334, 336 f.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich / Vienna 1991, p. 160.
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 3. Propylaen, Berlin 1997, p. 333.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich / Vienna 1991, pp. 147, 159.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich / Vienna 1991, pp. 148, 156.
- ↑ Wolfgang König (ed.): Propylaea History of Technology - Volume 3. Propylaea, Berlin 1997, p. 321.
- ↑ Günter Spur: On the change in the industrial world through machine tools. Carl Hanser Verlag, Munich / Vienna 1991, pp. 145 f.
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 3. Propylaen, Berlin 1997, pp. 324–326, 330.
- ↑ Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology. Pp. 189 f., 195-201. Ulrich Wengenroth (Hrsg.): Technology and economy. Volume 8 by: Armin Hermann, Wilhelm Dettmering (ed.): Technology and culture. VDI publishing house, Düsseldorf
- ^ Lothar Gall (Ed.): Encyclopedia of German History - Volume 79. Christian Kleinschmidt: Technology and economy in the 19th and 20th centuries. Oldenbourg, 2007, p. 8 f.
- ↑ Martina Heßler: Cultural history of technology. Campus Verlag, Frankfurt / New York, pp. 43–47.
- ↑ Ulrich Wengenroth: Eisen, Stahl und Buntmetalle in Ulrich Wengenroth (ed.): Technik und Wirtschaft , 1993, pp. 103-109 (Volume 8 by Armin Hermann, Wilhelm Dettmering (ed.): Technik und Kultur , Düsseldorf, VDI- Publishing company.)
- ^ Lothar Gall (Ed.): Encyclopedia of German History - Volume 79 Christian Kleinschmidt: Technology and Economy in the 19th and 20th Centuries, pp. 17f.
- ↑ Wolfgang König (Ed.): Propylaen Technikgeschichte , Propyläen, Berlin, 1997, Volume IV: pp. 71-78, 286f.
- ^ Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, p. 161.
-
↑ Articles in: Ulrich Wengenroth (Ed.): Technology and Economy , Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture , Düsseldorf, VDI-Verlag:
- Michael Mende: From wood to coal - process heat and steam power , pp. 318–321.
- Ulrich Wengenroth: Elektroenergie , pp. 325–334.
- ^ Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, pp. 291–295.
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 4 , Propylaen, Berlin, 1997, pp. 86-93.
- ↑ Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology p. 218 f. in: Ulrich Wengenroth (Hrsg.): Technology and Economy , Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technology and Culture , Düsseldorf, VDI-Verlag.
- ↑ Martina Heßler: Cultural history of technology. Campus Verlag, Frankfurt / New York, p. 47 f.
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 4. Propylaen, Berlin 1997, pp. 288 f., 427-431.
- ↑ Ulrich Wengenroth: Iron, steel and non-ferrous metals, p. 111 f. in: Ulrich Wengenroth (Hrsg.): Technology and economy. Volume 8 by: Armin Hermann, Wilhelm Dettmering (ed.): Technology and culture. VDI publishing house, Düsseldorf.
- ^ Lothar Gall (Ed.): Encyclopedia of German History - Volume 79. Christian Kleinschmidt: Technology and economy in the 19th and 20th centuries. Oldenbourg, 2007, pp. 18, 23.
-
↑ Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
- Michael Mende: From wood to coal - process heat and steam power p. 321f.
- Ulrich Wengenroth: Elektroenergie , pp. 325–345.
- Thomas Herzig: From the workshop center to the network economy , pp. 483–500.
- ↑ Michael Mende: From wood to coal - process heat and steam power p. 321f. in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
- ↑ Ulrich Wengenroth: Elektroenergie , S. 328–331 in: Ulrich Wengenroth (Ed.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture , Düsseldorf, VDI-Verlag )
- ↑ Ulrich Wengenroth: Elektroenergie , p. 333f. in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
- ↑ Ulrich Wengenroth: Elektroenergie , S. 335f in: Ulrich Wengenroth (Ed.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture , Düsseldorf, VDI-Verlag)
- ↑ Ulrich Wengenroth: Elektroenergie , p. 337 in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
- ↑ Ulrich Wengenroth: Elektroenergie , p. 340 in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
-
↑ * Fritz, Schulze (ed.): Manufacturing technology , 10th edition, Springer, 2012, 117.
- Michael Mende: Montage - Bottleneck in the automation of production systems , p. 272, 278–280 Ulrich Wengenroth (Ed.): Technology and Economy , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and culture , Düsseldorf, VDI-Verlag)
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↑ Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
- Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology , pp. 220–234.
- Volker Benad-Wagenhoff: Manufacturing organization in mechanical engineering , pp. 250–252.
- Michael Mende: Assembly - bottleneck in the automation of production systems , pp. 257–286.
- ^ Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, p. 344.
- ^ Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, p. 344f.
- ↑ Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology , p. 228-230 in: Ulrich Wengenroth (ed.): Technology and Economy , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (ed. ): Technology and Culture , Düsseldorf, VDI-Verlag)
- ↑ Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology , p. 223f. in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
- ^ Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, p. 345f.
- ↑ Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology , p. 225f. in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
- ^ Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, p. 385.
- ↑ Volker Benad-Wagenhoff, Akos Paulinyi, Jürgen Ruby: The development of manufacturing technology , p. 221 in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technology and Culture , Düsseldorf, VDI-Verlag)
- ↑ Ulrich Wengenroth: Eisen, Stahl und Buntmetalle , pp. 115–119 in: Ulrich Wengenroth (Ed.): Technology and Economy , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture , Düsseldorf , VDI-Verlag).
- ↑ Ulrich Wengenroth: Elektroenergie , p. 342 in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
- ↑ Ulrich Wengenroth: Eisen, Stahl und Buntmetalle , p. 118 in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI -Publishing company).
- ↑ a b Wolfgang König (Ed.): Propylaea History of Technology - Volume 5 , Propylaea, Berlin, 1997, p. 46.
- ↑ Ulrich Wengenroth: Eisen, Stahl und Buntmetalle , p. 133 in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI -Publishing company).
- ↑ Ulrich Wengenroth: Eisen, Stahl und Buntmetalle , pp. 130, 132-135. in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag).
-
↑ * Martina Heßler: Kulturgeschichte der Technik, Campus Verlag, Frankfurt, New York, pp. 47–54.
- Michael Mende: Assembly - Bottleneck in the automation of production systems , pp. 257–286 in: Ulrich Wengenroth (Ed.): Technology and Economy , (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture , Düsseldorf , VDI-Verlag, 1993.)
- ↑ Michael Mende: Montage - Bottleneck in the automation of production systems , p. 271 in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag)
-
^ * Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, pp. 511, 514.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 5 , Propylaea, Berlin, 1997, p. 412f.
- ^ Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, pp. 516f., 519.
-
^ * Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, p. 552.
- Wolfgang König (Ed.): Propylaea History of Technology - Volume 5 , Propylaea, Berlin, 1997, p. 419.
- ↑ Wolfgang König (ed.): Propylaea History of Technology - Volume 5 , Propylaea, Berlin, 1997, p. 410.
-
↑ * Wolfgang König (Ed.): Propylaea History of Technology - Volume 5 , Propylaen, Berlin, 1997, p. 419.
- Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, p. 550.
-
↑ * Wolfgang König (Ed.): Propylaen history of technology - Volume 5 , Propylaen, Berlin, 1997, pp. 419-421.
- Günter Spur: On the change in the industrial world through machine tools , Carl Hanser Verlag, Munich, Vienna, 1991, pp. 567f, 573.
- ↑ Martina Heßler: Kulturgeschichte der Technik, Campus Verlag, Frankfurt, New York, p. 60.
- ↑ Ulrich Wengenroth: Eisen, Stahl und Buntmetalle , pp. 124–127, 130 in: Ulrich Wengenroth (Ed.): Technology and Economy , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture , Düsseldorf, VDI-Verlag).
- ↑ Wolfgang König (Ed.): Propylaea History of Technology - Volume 5 , Propylaea, Berlin, 1997, pp. 285–337.
- ^ Karl H. Metz: origins of technology Schöningh, Paderborn, 2006, pp. 454–467, 501–517.
- ^ Frank Uekötter , Environmental History in the 19th and 20th Centuries , Munich 2007, pp. 28f.
- ^ Karl H. Metz: Origins of Technology , Schöningh, 2006, pp. 457f., 460.
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 5 , Propylaen, Berlin, 1997, p. 326.
- ↑ Joachim Radkau: Nuclear Energy - Large-Scale Technology Between State, Economy and Public , p. 346 in: Ulrich Wengenroth (Ed.): Technology and Economy , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology and Culture , Düsseldorf, VDI-Verlag).
- ↑ Joachim Radkau : Nuclear energy - large-scale technology between the state, business and the public , p. 347f. in: Ulrich Wengenroth (Hrsg.): Technik und Wirtschaft , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Hrsg.): Technik und Kultur , Düsseldorf, VDI-Verlag); Wolfgang König (Ed.): Propylaea History of Technology - Volume 5 , Propylaea, Berlin, 1997, pp. 292, 296f.
- ↑ Nicola Armaroli , Vincenzo Balzani , Energy for a sustainable world. From the Oil Age to a Sun-Powered Future , Weinheim 2011, pp. 130f.
- ↑ Joachim Radkau: Nuclear Energy - Large-Scale Technology Between State, Economy and the Public , pp. 352, 361 in: Ulrich Wengenroth (Ed.): Technology and Economy , 1993: (Volume 8 by: Armin Hermann, Wilhelm Dettmering (Ed.): Technology und Kultur , Düsseldorf, VDI-Verlag).
- ^ Karl H. Metz: Origins of Technology , Schöningh, 2006, pp. 431f., 465f.
- ↑ Wolfgang König (Ed.): Propylaen History of Technology - Volume 5 , Propylaen, Berlin, 1997, p. 423f.
- ↑ Martina Heßler: Kulturgeschichte der Technik, Campus Verlag, Frankfurt, New York, pp. 67–69.
- ↑ Andreas Gebhardt : Generative Manufacturing Processes , Hanser, 2013, 4th edition, p. 3
- ↑ Petra Fastermann: 3D printing - How generative manufacturing technology works , Springer, 2014, p. 1 ISBN 978-3-642-40963-9 .
-
↑ König, Klocke: Manufacturing Process , Springer:
- Volume 1 - Turning, Milling, Drilling , 8th Edition, pp. 215, 226.
- Volume 4 - Forming , 5th edition, pp. 48, 58.
- Volume 5 - Urformen , 4th edition, p. 6.
-
↑ * Werker Skolaut (Ed.): Maschinenbau , Springer, 2014, pp. 1133f., 1136f.
- Christian Brecher (Ed.): Integrative Production Technology for High-Wage Countries , Springer, 2008, pp. 6–8
- ↑ König, Klocke: Production Process Volume 1 - Turning, Milling, Drilling , Springer, 8th Edition, p. 297.
- ^ Hirsch: Machine tools , 2nd edition, 2011, Springer, p. 7
- ↑ * Stahlinstitut VDEh (ed.): Stahlfibel , 2007, p. 2
-
↑ Ruiyu Yin: Metallurgical Process Engineering , Springer, 2011, pp. 12, 15-20.
- Archive link ( Memento of the original from January 22, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved January 22, 2016.
- ↑ Julia Carolin Imlau: Relationship between microstructure, damage process and mechanical properties in TRIP steels p. 1f. 2008, in Bleck, Dahl, Gammal, Gudenau, Senk (eds.): Reports from the Institute for Metallurgy ISBN 978-3-8322-7952-3
- ↑ Doehge Behrns, manual forming , Springer, 2nd edition, 2010, p 7, the 686th
- ↑ Ilscher, Singer: Material Science and Manufacturing Technology , Springer, 5th Edition, 2010, p. 278
-
↑ * König, Klocke: Manufacturing process 4 - forming , Springer, 5th edition, 2006, p. 285f.
- Skolau (Ed.): Maschinenbau , Springer, 2014, pp. 995f., 1120.
- Ruge, Wohlfahrt: Technologie der Werkstoffe - Production, Processing, Use , 9th Edition, 2013, pp. 299f.
- ↑ Walter Minchinton, The energy base of the British industrial revolution , in: Günter Bayerl (ed.): Wind and water power. The use of renewable energy sources in history , Düsseldorf 1989, 342–362, p. 348.
- ^ Karl H. Metz: Origins of Technology , Schöningh, 2006, p. 503
- ↑ Vaclav Smil , Energy in World History, Westview Press 1994, p. 112.
- ↑ Nicola Armaroli , Vincenzo Balzani , Energy for a sustainable world , Weinheim 2011, p. 235.
- ↑ See Konrad Mertens, Photovoltaik. Textbook on basics, technology and practice , Munich 2015, p. 38f.
- ↑ Volker Quaschning , Regenerative Energy Systems. Technology - calculation - simulation . 8th updated edition. Munich 2013, pp. 50–52.
- ↑ Dieter Specht (Ed.): Further development of production , Gabler, 2009, p. 1.
- ↑ Peter Nyhuis (Ed.): Theory of Logistics , Springer, 2008, p. 2.
- ^ Daniel Bieber: Technology development and industrial work , Campus Verlag, 1997, pp. 113, 120, 122, 124.
- ↑ Skolau (Ed.): Maschinenbau , Springer, 2014, pp. 1120, 1136.
