Before a process can be improved, it must first be measured. This is accomplished by identifying process input and output variables and documenting their relationships. This phase will consider

1. Process analysis and documentation
2. Probability and Statistics
3. Collecting data and summarizing data
4. Probability Distributions
5. Measurement System Analysis

Process Capability Analysis

Reading

1. Chapter 11 (pp254-274 and pp282-283)
2. Chapter 12 Measurement System Analysis pp302-322)
3. Review Notes related to chapters 6, 11 and 12

Assignement

1. What conditions must existprior to calculating the processcapability ?

2. Distinguishbetween gage repeatability and gage reproducibility ?

3. Light bulbs are tested for luminance. Random samples of 5 are chosen.

The summary information below is for 30 Samples.

The specification limits are 90 lumes

a. Estimate the process standard deviation

b. Assume that all points on both charts plot within the control limits. What are the natural tolerance limits of the process?

c. What are your conclusion regarding the ability of the process to produce items conforming to specifications? Find Cp and Cpk.

d. Assuming that if an item exceeds the upper specification limit it can be reworked and if it is below the lower limit it must be scrapped, what percent scrap and rework is the process now producing?

e. It the process were centered on at u = 90, what would be the effect on the percent scrap or rework?

4. Is it possible for a process to be in control and still produce nonconforming output? What are some corrective measures under this circumstances?

5. A customer has recently tightened the specification for a part your company supplies. The specification are now tighter the machine being used for the job is capable of. Identify the alternatives to solve this problem.