C_p (C_pk)

Process capability

Treatment

C_p ≥ 1.67

Excessive

Process capability is far too good. The specifications could be reduced as appropriate, or consider simplifying quality inspection to simplify management and reduce costs.

1.67 > C_p ≥ 1.33

Ideal

An ideal state. The process should be standardized, monitored by control charts or other means.

1.33 > C_p ≥ 1.00

Warning

Keep the process in a controlled state, otherwise there is a risk of non-conformity in the product, which requires attention.

1.00 > C_p ≥ 0.67

Poor

Existence of non-conformity products, requiring full speed inspection or tightened inspection, and the need for proper management and improvement of the process.

0.67 > C_p

Very poor

Urgent measures should be taken to improve the quality and investigate the causes.