PROD 315 Summary Assignment 2 Statistical Process Control

This assignments objective is to summarize the steps, understanding of kinds of variation, conclusions, and errors in conclusions in using statistical process control to check process control.

ABC Corporation is monitoring the output of metal parts produced in its new planing machine. Measures of the lengths of twenty samples of 5 each resulted i an overall mean of a 200" and a mean range of 20".

Step 1: Estimating the distribution

1. What is being measured to monitor the process? Is it an attribute measure? Or variable measure?

2. What is the historical distribution of the process output? (That is, what are the distribution values?)

3. What control chart(s) that should be used for these measures?

Step 2: Designing the control charts

4. For each of the charts you identified in #3 above, what are the values of the centerline, UCL and LCL?

Step 3: Monitoring the process

5. The following two samples were collected this morning. The parts were measured and the following results were obtained. Use these data to check for process control. (For monitoring, calculate the sample stats and compare to the design limits from question 4.) Is the process in control? Why?

	Units					Sample stats		Hypothesis conclusions
Sample	1	2	3	4	5	X-bar	R	Decision about X-bar chart (in control or out of control)	Decision about R chart (in control or out of control)	Decision about the process (in control or out of control)
1	190	202	205	185	210
2	220	212	227	196	235

Concepts:

6. What is the possible error committed in conclusions drawn above for each of the 2 samples?

Sample 1:

Sample 2:

7. What causes of variation (common or assignable) are present in the process now, after sample 2? (Based on your answer to #5 above.)

8. What should the managers next step(s) be?