Tiger Tools, a division of Drillmore Industries, was about to launch a new produ

Question

Tiger Tools, a division of Drillmore Industries, was about to launch a new product. Production Manager Michelle York asked her assistant, Jim Peterson, to check the capability of the oven used in the process. Jim obtained 18 random samples of 20 pieces each. After he analyzed the data, he concluded that the process was not capable based on a specification width of 1.44 cm. Michelle was quite disappointed when she heard this. She had hoped that with the introduction of the new product, her operation could run close to full capacity and regain some of its lost luster. The company had a freeze on capital expenditures of more than $10,000, and a replacement oven would cost many times that amount. Jim Peterson worked with the oven crew to see if perhaps different settings could produce the desired results, but they were unable to achieve any meaningful improvements. Still not ready to concede, Michelle contacted one of her former professors and explained the problem. The professor suggested obtaining another set of samples, this time using a smaller sample size and taking more samples. Michelle then conferred with Jim and they agreed that he would take 27 samples of five observations each. If this new product is a low volume item with a large cost of passing along defective products, what inspection plan would you recommend? Why should Jim Peterson collect the mean and range data for each sample rather than just the mean measurements? What might a higher frequency of sampling detect that a lower frequency of sampling might miss? For example, what might sampling every 30 minutes detect that might be missed if samples are taken every 4 hours? The oven process is charted, no points fall outside the control limits, and run tests do not indicate anything special, so Michelle would also like to monitor the percentage of items coming out of the oven that display unacceptable surface cracking. Which chart should she use? The oven is a costly, irreversible process. In which place would you recommend inspection be done? Michelle would like to improve the oven process; which do you recommend?

Explanation / Answer

Since the product is low volume with high cost of passing along the defects the inspection plan has to be very tight and thorough. Because slight defects could result into very high costs. Therefore, intensive inspection plan is used.

Jim should collect mean and ranges data rather than just mean data because, while the mean measurement only shows the central tendency of process, the range data will show the variability changes in the process that is the changes in process dispersion.

If lower frequency of sampling is taken that is samples are taken at longer intervals then according to central limit theorem, the average measurement might not be true within the change in samples. Therefore, higher frequency or samples are taken at shorter intervals to reach true average measurement.

When the number of defects per unit of measurement can be counted such as cracks, tears etc. then c-chart should be used. The surface crack is a defect which can be counted using centimeters as a unit of measurement. Therefore, she should use c-chart.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.