The global crisis has reduced significantly the demand for products and many factories are running at short production levels. Can your supply-chain still guarantee good --non defective-- products at low production levels?
The verification of process capability to meet customer requirements typically takes place over a long period of time. Random samples at regular intervals are taken while the process runs at functional equilibrium, in a steady state, and under statistical control. These required conditions are essential for true long-term capability determination. Statistical control being a major assumption, is validated through a statistical control chart, while normality is verified through a goodness of fit test. Meeting these major assumptions guarantees valid predictability of defective rates.
In contrast to process capability, the validation of the machine capability to meet process requirements, takes place over a much shorter period of time. Smaller samples may have to be collected continuously over a short time frame, which may require some compensation over long term capability studies. Although the underlying assumptions may still require verification, the methods and formulas may differ.
To eliminate out-of-specification problems, both machine capability as well a process capability have to be analyze, and short term versus long term performance capability must be taken into consideration.
After 20 years in the field of conducting machine and process characterization studies, we have developed three highly effective tools to assist you eliminate out-of-specification defects.
