16 types of loss according to JIPM
The 16 types of losses according to JIPM (Japan Institute of Plant Maintenance) is a scheme developed over the last 30 years that makes it possible to categorize the states of machines. The aim is to directly name downtimes, malfunctions, decreasing production speeds, missing resources in order to initiate corrective measures for these incidents and thus to increase the system effectiveness and service life. This is used in the context of the TPM system .
application
These 16 types of loss are mainly used in industry. Faults and downtimes in machines and processes can thus be made transparent. This creates the opportunity to specifically target grievances and malfunctions and to identify and remedy the causes.
The recording of the incidents is also the basis for process improvement strategies such as Six Sigma , Kaizen or CIP .
Three categories
The 16 types of loss are divided into three categories:
- Machinery and equipment
- Employee
- resources
In the case of “machines and systems” or “main losses”, all incidents that can be traced back to the production system are noted. In the category “Employees” or “Loss of human work”, incidents are included that have arisen due to human neglect. In the category "Resource" or "Loss of production", incidents should be noted that were caused by auxiliary equipment or production media (e.g. compressed air, electricity ...).
Category machines and systems
The first eight losses, called the eight major losses, affect the efficiency of the production facilities:
- System failures
- Conversion and adjustment
- Tool change
- Start-up losses
- Short downtimes / idling
- Speed losses
- Scrap / rework
- planned downtime / shutdown
The losses due to "system failures" arise from sporadic or chronic errors in the production facilities and go hand in hand with a reduction in the output quantity (machine stops and cannot produce) and / or with an increase in quality problems. The goal must be to achieve zero system failures.
Even during the loss of “retooling and setting” , i.e. the conversion from one product to the next, the machine stands still and cannot produce. Many companies have already held set-up time reduction workshops to achieve set-up times in the single-digit minute range ('Single Minute Exchange of Dies - SMED', developed by Shigeo Shingo in Japan). This is done by separating internal and external activities. So far, the setting times have been neglected. The aim must be for the first part to leave the machine in good condition (first-time-right).
With the type of loss "tool change" , losses arise through the exchange of tools, such as B. turning tool. The cause could be normal wear and tear or tool breakage.
Start-up losses occur in the period from machine start-up after repairs, the start of a shift or other downtimes until the machine reliably produces perfect quality. In addition to the loss of productive time, there are often losses in the number of pieces due to scrap.
Short- term malfunctions of up to 10 minutes are the cause of the type of loss “standstill and idling” . They are easy to fix, for example by removing a jammed workpiece, cleaning a sensor or clearing a jam in the material feeder. Although at first glance these problems are negligible, some of them have a significant impact on productivity. To eliminate them, it is important to get to the bottom of the causes of the phenomenon that occurs.
The type of loss "speed loss " occurs when machines or systems run too slowly. Either the speed envisaged in the construction is not achieved or the selected speed does not correspond to what is currently technically feasible. In the event of quality problems, the running speed of a machine is often reduced without getting to the bottom of the root cause. In addition, the optimal speeds are often not always known to the employees.
In "scrap and rework" a reduction in production volume by defective products or products that have to be improved is produced. The rework often occupies the machine or process again and it cannot be produced regularly
The eighth type of loss “planned downtime” reduces the available production time: (Shutdown): They arise, for example, through preventive maintenance measures or the preventive replacement of wear parts. This reduces the available runtime. While the measures are essential, even in this case it is possible to take action to reduce the amount of time required. Examples include the standardization of activities and the use of set-up time optimization methods (e.g. SMED ).
Category Employees
The five types of losses in the “Employee” category affect the efficiency of human work. They have a direct impact on the productive working hours of employees:
- Management losses
- Move
- Line organization
- logistics
- Measure / adjust
“Management losses” arise from neglect of management, e.g. B. Waiting times due to missing material or missing instructions for employees. The management losses also include overproduction and excessively high inventories, which result from a lack of planning processes.
"Movements" are caused by poor arrangement in the workplace, poorly trained employees in optimal work processes and poor factory layout.
Incorrect "line organization" results from waiting times due to poorly coordinated production lines or poorly planned multiple machine operation.
Inadequate “logistics” becomes visible when production is suspended due to logistical activities such as loading and unloading. Losses in this area also arise from unnecessary transport processes.
"Measure and Adjust" are related to the implementation of quality control processes such as B. surface inspection or the like.
Resources category
The last three types of loss prevent the efficient use of production resources:
- Energy losses
- Volume losses
- Molds, devices, tools
"Energy losses" arise from the careless use of electricity, compressed air, steam, air, water, etc. Conveyor belts often run unnecessarily, the pressure in the compressed air lines is too high or the compressed air connections are leaking.
"Volume losses" or "yield losses" refer to the materials used in production. The losses arise, for example, from over-dimensioned wall thicknesses or insufficiently utilized raw materials in the production process.
In the case of “molds, devices and tools” , losses arise, for example, from product changes that require new tools or from tool breakage.
implementation
The above losses can be recorded with good process data management systems. However, many machines or processes are not yet prepared or designed for automatic recording. In the context of Industry 4.0 , however, it will be possible for machines or processes to be equipped with sensors that can record the corresponding parameters. However, as long as this is not yet possible, the recording is carried out manually by the employee on site, close to the process. Aids here are a prepared entry sheet or an Excel list.