playing the role of a quality manager for a new manufacturing plant – Gainsborough Manufacturing Company. As part of your job, you will use the Quality Analytics simulation to simulate the process stability and capability of the plant before handing it over to operations. The CEO also wants to know the lowest possible total cost of quality.
Connection to the course learning outcomes
Calculate the control limits and the capability indexes of a process
Use control limits in real time to maintain control of a process
Analyze control charts post hoc to determine whether a process is capable
Examine quality control investment decisions to minimize total cost of quality
Use data analytics to examine a process capability and examine various costs of quality
Examine the relationship between internal failure costs, external failure costs, appraisal costs and prevention costs and how they contribute to the total cost of quality
Differentiate between a process that is statistical control and a process that is capable
Instructions
Your task in this assignment is to ensure that the manufacturing process at Gainsborough Brewery is both stable and capable and that the total cost of quality is as low as possible. To achieve this, you will face the following challenges:
Challenge 1 (20%): You will calculate control limits for X-bar and R charts. Simulate daily production, one batch at a time, by clicking “Run Next Batch” repeatedly. With each click, the simulation will generate the next batch processed, draw a random sample from the batch, and calculate the mean and range of the sample. Run your cursor over the points on the X-bar and R charts to see the explicit values. Be sure to copy the sample means and ranges to Minitab in order to calculate the control limits for this process. Remember to save your file. You’ll need to use these control limits in Challenge #2. Note that a production shift – an entire day of production -- starts at 7:00 a.m. and ends at 10:00 p.m.
You can manually calculate control limits for the means and the ranges using the formulas from the attached terminology primer sheet, or you can calculate them with Minitab. The results will be approximately the same. You will need to use the data from the 6th production shift (the data you will copy and paste into Minitab to calculate the control limits).
Use the ranges to calculate the control limits of the range chart
Stat>Control Charts>Variable Charts for Subgroups>R
Use the means to calculate the control limits of the mean chart
Stat>Control Charts>Variable Charts for Subgroups>Xba