ENGR 630: Quality and Reliability Management

1. You are required to read lecture notes of Six Sigma. You are encouraged to read any Six Sigma reference books and materials to help you understand its principles and applications.

2. The philosophy of Six Sigma is Continuous Improvement (CI) toward 6s-goal. As a 6s-project leader, you are required to guide your team members to use correct quality assurance techniques to find the root-causes and remove them. Please write a guideline of quality assurance technique selection for your team members. This guideline should include all quality assurance techniques, which you have learned in this course so far. For each technique, please write brief guideline statements to help your team members selecting correct techniques. Please feel free to group and sort the techniques based on problem types, project stages, techniques types, whichever you feel is most user- friendly. (Note: This summary may help you lead real 6s-projects in the future, and help your coming final examine).

3. One continuous improvement case study is given below. Please use your guideline of quality assurance technique selection to select correct quality assurance technique(s). When you make a selection, please site your guideline statements with bold font. While you are using your guidelines, you may find missing information. Then you should revise your guidelines accordingly.

4. After you complete this case study, examine your guidelines and identify any unused techniques. You are required to explain why these techniques are not used. If you think some of those techniques can be used for further analysis of the continuous improvements, please explain why and how.

5. Continuous improvement case study 1:

The Quality Ice Cream Company has following quality issues. You are required to utilize all the information and data in this case study to make decisions and recommendations for quality improvements.

The Quality Ice Cream Company has recently introduced a new flavor, sour grape. The company has not been able to meet demand for this new product due to quality problems. Many batches have been discarded. The company has collected a large amount of data but is at a loss about how to use the data. Quality Ice Cream is overwhelmed with numbers. The company has asked you to lead a 6s project team to address the problems. Your team members have collected following information about the processes.

Process Description:

1. Pull ingredients from warehouse.

2. Blend ingredients in mixer.

3. Pump mixture to freeze machine.

4. Run freeze machine until consistency is correct.

5. Extrude ice cream into package.

6. Inspect and test ice cream.

7. Transfer packages to finished good storage.

Reject Log:

Number of Rejects by Cause

Date Ice Crystals Soupy Too Stiff Tastes Bad Off Color

2/1 1 7 0 0 1 2/2 0 2 0 0 0 2/3 2 4 0 1 0 2/4 1 6 1 0 0 2/5 0 5 0 1 1 2/6 1 4 0 1 0 2/7 0 3 0 1 0 2/8 0 5 0 0 0 2/9 1 2 0 1 0 2/10 2 4 0 1 0

Ice crystals seem to be related to the mixing process. Soupy and too stiff refer to consistency. Soupy is viscosity below 5,000 cps (centipoises); too stuff is viscosity above 6,000 cps. Tastes bad and off color seem to be related to raw materials.

One of the production operators believes that the consistency of the ice cream (measured by the ice creams viscosity) is related to the length of time in the freeze machine. She had collected some data but didnt know what to do with them.

Run Time Viscosity

(min) (cps)

93 5,500 90 5,100 89 4,950 94 5,375 93 5,400

97 5,750 77 3,000 83 4,200 95 5,600

81 4,300

Based on the given information, select correct quality assurance tools to analyze the quality problem. Explain your reasons of selecting these assurance tools. Demonstrate how to use selected tools.

Based on your analysis results, interpret these results. What do you recommend for quality improvements and further investigations?