Total Quality Management
Procedure
There is no page limit to the answer to Section A.
Section B must be word-processed and should be approximately 6 sides of A4, font size 11 (approximately 3000 word limit). Diagram can be part of the Appendix and do not count in page/word restriction).
Assignment Brief.
Section A: SPC theory
1. Sigma is a measure of variation. With the aid of diagrams and using the normal distribution curve, explain this concept.
2. What is "Goalpost Mentality"? Why does it give producers false hope that they are satisfying their customers? What is a better way of looking at your performance capability?
3. The following results were obtained by taking samples of five (5) items at regular intervals.
|
Sample Number
|
Sample Mean ( )
|
Sample Range (R)
|
|
1
|
280.6
|
5.5
|
|
2
|
280.3
|
4.5
|
|
3
|
278.6
|
4.0
|
|
4
|
281.0
|
6.5
|
|
5
|
278.8
|
6.0
|
|
6
|
280.7
|
6.5
|
|
7
|
281.0
|
5.0
|
|
8
|
279.6
|
4.0
|
|
9
|
279.8
|
3.0
|
|
10
|
280.7
|
4.5
|
|
11
|
279.6
|
5.5
|
|
12
|
281.7
|
4.5
|
|
13
|
280.8
|
4.0
|
|
14
|
281.4
|
6.5
|
|
15
|
282.0
|
6.0
|
|
16
|
281.7
|
6.5
|
|
17
|
280.5
|
5.0
|
|
18
|
279.8
|
4.0
|
|
19
|
281.4
|
3.0
|
|
20
|
279.6
|
4.5
|
a) Construct manually drawn Xbar and R charts for the above data. Please clearly label the charts with the relevant data. Comment on the results and the state of the process.
UCL X‾ = X‾ + A2R‾ UCL R = D4R‾
LCL X‾ = X‾- A2R‾ LCL R = D3R‾
|
When sample size (n)
|
2
|
3
|
4
|
5
|
|
A2
|
1.880
|
1.023
|
0.729
|
0.577
|
|
D2
|
1.128
|
1.693
|
2.059
|
2.326
|
|
D3
|
0
|
0
|
0
|
0
|
|
D4
|
3.268
|
2.574
|
2.282
|
2.114
|
b) The specification asks for a tolerance of 280mm +/- 5mm. Calculate the process capability indices Cp and Cpk and comment on these. What level of process capability should you strive to achieve for Cp and Cpk? Do different industries have different expectation?
Section B: SPC Implementation
4. As initial guidance read the texts listed (below) on SPC implementation anduse othermore current literature.
- Antony, J., Balbontin, A. and Taner, T. (2000), "Key ingredients for the effective implementation of statistical process control", Work Study, 49 (6), 242-247.
- Does, R.J., Schippers, W.A.J. and Trip, A. (1997), "A framework for implementation of statistical process control", International Journal of Quality Science, 2(3), 181-198.
You are the Quality Manager in a manufacturing company and feel it is time to implement SPC. Describe your recommendations in a report to the Directors, which must include:
a) A method for implementing SPC across the shop floor, including pre-requisites for implementation, the implementation process and procedures to follow to ensure that the benefits of SPC can be achieved. This must be in the form of a flow chart which must be in the same format as the flowchart example below.
b) Evaluate one process improvement tool or technique which could be used to support the implementation process. Please include a diagram and a description of the tool and discuss how this tool could benefit the implementation process.
c) Suggest a quality costing method which could be used to analyse the benefits of the implementation process. Please include a diagram and a description of the tool and discuss advantages and disadvantages associated with this method.