Tell me about SPC if know the cp and cpk value with formula.

Question

Accepted Answer

SPC stands for Statistical Process Control. Cp and Cpk are indices used to measure process capability.

SPC is a method of quality control which uses statistical tools to monitor and control a process.
Cp is a measure of process capability that compares the spread of the process to the tolerance range. Cp = (USL - LSL) / (6 * standard deviation)
Cpk is a measure of process capability that accounts for process centering. Cpk = min((USL - mean) / (3 * standard deviation), (mean - LSL) / (3 * standard deviation))
A Cp value greater than 1 indicates that the process is capable of meeting specifications, while a Cpk value greater than 1 indicates that the process is centered within the specification limits.
For example, if the upper specification limit (USL) is 10, the lower specification limit (LSL) is 5, the mean is 7, and the standard deviation is 1, Cp = (10 - 5) / (6 * 1) = 0.83 and Cpk = min((10 - 7) / (3 * 1), (7 - 5) / (3 * 1)) = 0.67

Top JVR Forgings Incoming Quality Incharge interview questions & answers