One of the most popular methods for the improvement of production processes is the statistical process control. However the expression statistical process control is actually not a correct description. The term statistical process regulation would be more applicable to the task situation. SPC helps recognize and evaluate the dispersion of processes significantly contributing to reducing rejects, rework and defective products.
Using statistical methods (in this case in particular sampling technique and normal distribution) product parameters that are relevant for the quality are evaluated and analysed (as a result of the production process steps, e.g. surface hardness).
By comparing these analysis results, it is possible to evaluate if a treatment process' parameters need to be adjusted and to which extend. This form of data evaluation, control and subsequent improvement of the process is colloquially called SPC (statistical process control; while "control" can be understood as "directing" or "regulating").
The statistical process control aims at tracking the essential test criteria following a process. This way deviations can be recognized at an early state and appropriate correction measures can be made or the client is consulted before faulty products occur. Another declared aim is to check if the plants are suitable for complying with the required tolerances before their commissioning.
The only practical way to perform a control chart analysis in AMS is to use „comparable" positions and processes.
Via suitable search criteria - inspired by those of the detailed order search - a selection of comparable and evaluable positions is enabled.
These criteria are:
Positions and individual tests of positions can be selected and deselected by the user individually. Numerous test characteristics are provided and can be analysed.
The following rules of conduct / parameters can be set for the control chart:
The control chart is inspired by recognized and approved layouts. However individual customer requests can be implemented.
The control chart gives information on:
Cp | Cpk |
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