The operator of several CNC machines in a contract manufacturing firm has recently been trained to implement
Question:
The operator of several CNC machines in a contract manufacturing firm has recently been trained to implement statistical quality control for her workstation. One of her first tasks is to perform capability analysis for a part that is a critical component for one of the main products manufactured in the facility (required as part of the company's ISO 9000 certification). The metal part includes a hole that must be precisely located and sized; with design specifications of 15.00 mm diameter with a tolerance of +/- 0.30 mm as the lower and upper limits. Over the past few weeks the operator has collected the following data for the operation; 20 samples of five parts (n = 5) with measures of the sample mean for the diameter and range in the measure within the samples provided.
Sample | Sample | Sample |
Number | Mean (mm) | Range (mm) |
1 | 15.60 | 0.40 |
2 | 15.80 | 0.40 |
3 | 14.80 | 0.30 |
4 | 14.90 | 0.30 |
5 | 16.40 | 0.25 |
6 | 14.40 | 0.20 |
7 | 14.80 | 0.40 |
8 | 14.90 | 0.15 |
9 | 14.90 | 0.30 |
10 | 15.00 | 0.40 |
11 | 14.90 | 0.10 |
12 | 13.60 | 0.10 |
13 | 14.90 | 0.20 |
14 | 15.10 | 0.20 |
15 | 14.20 | 0.25 |
16 | 14.10 | 0.20 |
17 | 15.70 | 0.25 |
18 | 15.30 | 0.40 |
19 | 15.10 | 0.30 |
20 | 15.40 | 0.50 |
Average; | 14.99 | 0.280 |
- What type of statistical quality control chart should be used for this situation? Explain your choice.
- Comprise the necessary calculations and construct control charts for the quality measure for the part using three sigma (3 ) limits?
- Is the process in control? Explain why or why not? Provide the necessary calculations and/or sketches to support your explanation.
Auditing and Assurance services an integrated approach
ISBN: 978-0133125689
15th edition
Authors: Alvin a. arens, Randal j. elder, Mark s. Beasley