QS-9000 4.9g Process Capability



Process capability

QS9000 4.9g states "suitable maintenance of equipment to ensure continuing process capability".
There are no. of factors like man, measurement system used,method of manufacture etc that play a role in maintaining process capability. Hence how can maintenance of equipment by itself ensure proces capability.Does anyone have a different stand on this matter?

M Greenaway


Like you say maintenance alone does not ensure process capability, it is just one factor - I dont think QS9000 tries to say that it is the only factor, just an important one that must be addressed.


Quite Involved in Discussions
I read an article about 4 years ago that said when the majority of companies purchase new machineery that in about a years time that they are running at less than 70 % of their capability. All due to a lack of PM.


Maintenance and capability

I read this a little differently. I don't see it as preventive maintenance is the only method. I see it more like you cannot allow lack of maintenance to affect your process capability. As you pointed out, there are many factors. The location of this requirement tends to support my interpretation.


I agree with Dave,

I think what the standard is trying to accomplish through the requirement is - reduce the role of Special causes so as to improve process capability. Nevertheless, other factors such as Operators, Measurement system, etc, which are common causes that lead to variation/non-conformity should be addressed.
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