Individual Assignment 2: Instructions
In this individual assignment, you will be 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).
Note:
The subgroup size is 5.
Challenge 2 (20%)
: In this challenge, you will use the control limits that you calculated in Challenge #1. Enter their values in the boxes at the upper right of the X-bar and R charts. As the sample means and ranges are plotted, you will use the control charts to determine whether or not the process is in control. If you find that the process is out of control, you can re-calibrate the equipment or make a labor substitution in order to bring the process back into control.
Your goal is to minimize the number and cost of internal and external defects by keeping the process in control
. Adjusting a process is costly, but will improve the quality of the process through changing the underlying process mean or standard deviation. Experiment with Challenge #2 as many times as you would like.
Challenge 3 (20%)
: In Challenge #3, you will receive data that describes the frequency of defects for four different processes. Use this information to calculate the process capability index for each process and interpret it. Your goal in this challenge is to determine whether or not each process is capable of producing to specifications.
Challenge # 3 is independent of Challenges 1 and 2
.
Challenge 4 (40%)
: In Challenge #4, you can experiment with investments in prevention and appraisal. Investments in prevention include labor training, new equipment, and switching suppliers. Each of these investments is expensive but will improve the quality of the process by changing the underlying process mean or variance. Investments in appraisal include larger SPC sample sizes and increased frequency with which samples are taken and inspected. Larger and more frequent inspections will increase appraisal costs, while providing more opportunities to detect defects internally. Each time you make an investment in prevention and/or appraisal, press “Run to End” to view the effect of this investment in the long term. You may run this challenge as many times as you’d like as you try to minimize the total cost of quality.
Performance measurement: How your performance will be measured?
Your performance will be measured as follows:
Challenge 1
: Your ability to accurately calculate the control limits of control charts.
Challenge 2
: Your ability to control and minimize the total cost (TC) of quality of a process.
Challenge 3
: Your ability to examine the capability of a process and calculate the capability index of a process.
Challenge 4
: Your ability to make the appropriate investment decisions related to quality assurance and quality control, to minimize the total cost (TC) of quality of a process.
How to get the most out of this assignment?
To access the simulation, you must purchase it using the link provided below. This is a unique link generated for this section of the class. Make sure you are enrolled in your section of PJM6135 simulation. Here is the correct link:
https://hbsp.harvard.edu/import/994551
Links to an external site.
Once you have access to the simulation, the first thing to do is to review the preparatory materials, which include:
To achieve the highest score; that is, to be the best quality manager you can be, you need to follow a structured approach. The first step is Preparation – Click on the Prepare tab on the simulation to read about your task. This is an important step to understand the quality challenges that you have to face. See the “How to Play” PDF file in attachment.
Grading Scheme
Your grade will be based on the following benchmarks
Challenge 1
: The upper and lower control limits for the R-chart and X-bar chart are accurate (100%). A ± 5% deviation from the true values will be acceptable.
Challenge 2
: Your total cost of quality is less than or equal to $4,000 (TC <= $4,000).="" this="" is="" a="" benchmark.="" students="" have="" achieved="" lower="" total="" cost="" of="" quality.="" if="" you="" achieve="" a="" total="" cost="" of="" quality="" of="" $4,000="" or="" less,="" you="" will="" earn="" 100%="" of="" the="" grade.="" if="" you="" achieve="" a="" tc="" higher="" than="" $4,000,="" for="" example,="" a="" tc="" of="" $4,500,="" your="" grade="" will="" be="" calculated="" as="">
[100% - ($4,500 - $4,000)/4,000] = 88% of the grade.
Challenge 3
: Your capability indexes should be accurate. If your capability indexes are accurate you will earn 100% of the grade. This is a fail or pass challenge.
Challenge 4
: Your total cost of quality should be less than or equal to $8,000 (TC <= $8,000).="" this="" is="" a="" benchmark.="" students="" have="" achieved="" lower="" total="" cost="" of="" quality.="" if="" you="" achieve="" a="" total="" cost="" of="" quality="" of="" $8,000="" or="" less,="" you="" will="" earn="" 100%="" of="" the="" grade.="" if="" you="" achieve="" a="" tc="" higher="" than="" $8,000,="" for="" example,="" a="" tc="" of="" $8,500,="" your="" grade="" will="" be="" calculated="" as="" follows:="" [100%="" -="" ($8,500="" -="" $8,000)/8,000]="94%" of="" the="">