Designing a Quality Improvement Program and Applying Statistical Process Control

Section A: Statistical Process Control (SPC) Theory

Design a quality improvement program, select and identify suitable tools and techniques. Discuss the importance of performance measurement and explain how performance measurement system, benchmarking, and other techniques can help a company achieve continuous improvement.

Compare the different approaches to quality costing and evaluate the effectiveness of these methods.

1. Your process has a normal histogram with mean located at 10 mm, 1s points at 9.9 and 10.1 mm, 2s points at 9.8 and 10.2 mm, and 3s points at 9.7 and 10.3 mm.

a. Construct a histogram and discuss the importance of sigma as a measure of variation. (8 marks)

b. If your customer will accept parts measuring between 9.7 and 10.3 mm, how many parts of every 1,000 produced would you expect to scrap? What would have to be done to bring the scrap rate down to what it had been at the former customer specification? (7 marks)

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? (10 marks)

3. In developing a control chart, the analyst recognizes that there are two types of variation in a system. Specify the types of variation. Explain the difference and what should be done to eliminate these variations (5 marks)

4. The following results were obtained by taking samples of five (5) items at regular intervals.

a) Construct control charts for the sample means and ranges showing the control limits and comment on the results.

b) The specification asks for a tolerance of 74inch +/- .04inch.  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. (10 marks)

Explain variation, apply SPC to a simple example and calculate process capability. Plan the implementation of SPC in a manufacturing organization.

You are the Quality Manager in an electric car manufacturing company and feel it is time to implement some form of improvement programme. Describe your recommendations in a report to the Directors, which must include:

1. A method for implementing SPC across the company, including pre-requisites for implementation, the implementation process and procedures to follow to ensure that the benefits of SPC can be achieved. This should be in the form of a flow chart with an additional 1 page justification. (20 marks)

2. A summary of one relevant tool/technique which could be applied alongside statistical process control and its benefits. (10 marks)

3. Select a quality costing method and analyse the benefits this technique could bring to the company and also evaluate any issues with the quality costing method. (10 marks)

4. Overall structure and clarity of the report (10 marks)