Case Study Topic: Chapter 6S Statistical Process Control • Read the case description below, watch the 2 videos above that accompany the case (links to these are posted in Module 5). • Then, answer the questions listed at the end of the case. Case Description Frito-Lay, the multi-billion-dollar snack food giant, produces billions of pounds of product every year at its dozens of U.S. and Canadian plants. From the farming of potatoes-in Florida, North Carolina, and Michigan-to factory and to retail stores, the ingredients and final product of Lay’s chips, for example, are inspected at least 11 times: in the field, before unloading at the plant, after washing and peeling, at the sizing station, at the fryer, after seasoning when bagged (for weight), at carton filling, in the warehouse, and as they are placed on the store shelf by Frito-Lay personnel. Similar inspections take place for its other famous products, including Cheetos, Fritos, Ruffles, and Tostitos. In addition to these employee inspections, the firm uses proprietary vision systems to look for defective potato chips. Chips are pulled off the high-speed line and checked twice if the vision system senses them to be too brown. The company follows the very strict standards of the American Institute of Baking (AIB), standards that are much tougher than those of the U.S Food and Drug Administration. Two unannounced AIB site visits per year keep Frito-Lay’s plant on their toes. Scores, consistently in the “excellent” range, are posted, and every employee knows exactly how the plant is doing. There are two key metrics in Frito-Lay’s continuous improvement quality program: (1) total customer complaints (measured on a complaints per million bag basis and (2) hourly or daily statistical process control scores (for oil, moisture, seasoning, and salt content, for chip thickness, for fryer temperature, and for weight). In the Florida plant, Angela McCormack, who holds engineering and MBA degrees, oversees a 15-member quality assurance staff. They watch all aspects of quality, including training employees on the factory floor, monitoring automated processing equipment, and developing and updating statistical process control (SPC) charts. The upper and lower control limits for one check point, salt content in Lay’s chip, are 2.22% and 1.98%, respectively. To see exactly how the limits are created using SPC, watch the Frito Lay Control Charts video above that accompanies this case. To learn how to create a basic control chart in Excel, watch the “Create a Basic Control Chart video that is posted in Module 5. Obtain the Excel spreadsheet posted in Module 5 for this assignment. You will use this file to answer the discussion questions below and to create your control chart. Save your completed file, adding your full name where indicated so that each uploaded file has a unique filename. Angela is now going to evaluate a new salt process delivery system and wants to know if the upper and lower control limits at 3 standard deviations for the new system will meet the upper and lower controls specifications for the existing system. The process standard deviation is assumed to be the same as the existing process. The data (in percent) from the initial trial samples are:
Discussion Questions to Answer 1. Angela has asked you to evaluate the sample data and provide your findings to her. Do not simply give final answers! You must show how you derived your answers and explain what the results mean. Does the new salt delivery system process meet specifications? Why or why not? 2. Create control charts in Excel from this data using the techniques shown in the “Create a basic control chart” video. Put your control charts in the worksheet provided. Hint: The Excel video only shows an x-bar chart. Is this the only type you should do? 3. What are the advantages and disadvantages of Frito-Lay drivers stocking their customers’ shelves? 4. Why is quality a critical function at Frito-Lay?