In the production of a precision mechanical component, a critical dimension is measured every hour, and at that time we take a sample of n=5 units. From 30 initial samples we find that x-bar = 200 and S-bar = 0.5,
What are the centerline and UCL, LCL for the x-bar and S charts?
Observing the charts we conclude that the process is in a state of statistical control. If the part specifications are 199 Â± 2, what are:
Two remedies to the low Cpk have been suggested:
– Center the process at the target – i.e. X-bar-bar = 199
– Reduce the standard deviation to half of its original value through better tooling maintenance.
Which will achieve a higher Cpk?
they will both achieve the same Cpk, or
Neither change will improve Cpk