A conventional or rigid transfer line is a production system made up of several machines in which the workpieces run through the machines in a predefined order and is used to process a single product type or a very narrow range of products. It is basically used for fully automatic large series or mass production. On the other hand, one speaks of a flexible transfer line if the transfer line can be converted to a different product type in a reasonable time. Both variants of the transfer line are linear - with a flexible production system , on the other hand, the structure and the workpiece flow are arbitrary. The individual machines consist of machine tools such as milling , turning and drilling machines for the actual processing as well as measuring and testing machines and washing machines. They are linked by transport and handling devices. These include, for example, industrial robots or conveyor belts . The individual machines and conveyor systems are coordinated via a central master computer . Transfer lines therefore have a very high productivity and a very low flexibility . The machines perform various machining operations at the same time. After each cycle, the workpiece is passed on to the next work station so that all the necessary work steps are carried out one after the other on each machine . If the transfer line consists of presses , one also speaks of a transfer press or a transfer press . The number of processing stages then corresponds to the number of tools. They are used, for example, in the automotive industry to manufacture body parts from sheet metal by means of stamping and deep drawing or solid parts such as crankshafts by drop forging .
The cycle is the time span in which the workpiece is machined; it is based on the longest machining time. Therefore one tries to keep the processing times the same. Uneven processing times would mean that one or more machines would come to a standstill, which would be inefficient. The assembly line balancing as a branch of production management deals with issues of the belt efficiency, the allocation of individual operations to the machines, and other issues affecting the efficiency of transfer lines and other types of flow production.
In most cases, a tool change system is only designed in such a way that a sister tool can be exchanged, as each processing step is carried out by a machine specially designed for this purpose. Such transfer lines are mainly used in large-scale production, for example in the automotive industry.
Transfer lines are a special technical implementation of flow production . Other types of continuous or serial production manage without machines and consist of manual workstations, which are, however, arranged in the order of the work steps to be performed. In addition, in a transfer line all workpieces are moved on at the same time, which is why bearings between the individual processing stations are superfluous.
- Neugebauer: Werkzeugmaschinen , Springer, 2012, p. 17f.
- Bozina Perovic : Spanende Werkzeugmaschinen , Springer, 2009, p. 298.
- Weck: Machine tools 1 - types of machines and areas of application , Springer, 5th edition, 1998, pp. 82–84.
- Hans-Otto Günther , Horst Tempelmeier : Production and Logistics , Springer, 2003, p. 16.