Question

Rudy is evaluating the capability of a process to produce candle holders with an internal diameter of 20 mm. The specification is 20 mm +/- 0.05 mm. After carefully measuring a sample of candle holders, he found that the average internal diameter is 19.98 mm with a standard deviation of 0.01 mm. Based on this information, the Cp is:

A. 1.67
B. 2.33
C. 1.0
D. 0.6

Answer 1

Rudy's process capability (Cp) for producing candle holders with an internal diameter of 20 mm is 1.67, which is calculated using the given process tolerance and standard deviation. The correct answer is option a.

Step-by-step explanation:

Rudy is assessing the process capability of a process to manufacture candle holders with a specified internal diameter. The concept he's using, Cp, is a measure of process capability and is calculated using the formula Cp = (USL - LSL) / (6*σ), where USL is the upper specification limit, LSL is the lower specification limit, and σ is the standard deviation of the process. In Rudy's case, the specified diameter is 20 mm with a tolerance of +/- 0.05 mm, hence the USL is 20.05 mm, and the LSL is 19.95 mm.

By substituting the given values into the formula, the calculation for Cp becomes:

Cp = (20.05 - 19.95 mm) / (6 * 0.01 mm) = 0.10 mm / 0.06 mm = 1.67.

Therefore, the correct option for Rudy's process capability Cp is A. 1.67