Situation A particular manufacturing process goes as follows: resin pellets are fed to an extruder and the continuous extruded material is formed into the final shape by passing through a die. The finished product is rolled in a coil for storage and subsequently shipped to a customer. Coils may vary in length depending upon the customer’s needs. In one product line, the die used to create the final shape has two cavities, creating a double product. Each half of the double product is a complete finished product itself, so the double product is split down the middle. Two continuous rolls are formed. Available data There are specifications for the width of the strip of finished product. Therefore, data are collected regularly from each roll of the finished product to assure that the product meets specifications. Because customers purchase the product in rolls, measurements are made at the end of the roll of product. Data on product width in inches for one double product line are summarized in the table. Specifications for width for this product are .95 ± .03 inches. All of the product was produced on May 8. Questions 1. The manufacturer wants to know if all of the product can be expected to meet the specifications. What is the best way to analyze the given data in order to determine if all of the product from this particular production line meets specifications? Hint: In your analysis, use a process behavior chart (Individuals and Moving Range or Average and Range) along with a capability analysis to answer the question. 2. What additional data would you recommend that this company collect if they want to understand and improve their process? Hint: Think of process improvement as running “On Target with Minimum Variation.” What data would be needed and how should it be analyzed to tell them that this is being accomplished? 3. What other questions should the manufacturer ask about this situation? What questions would be more useful for the customer to ask about the finished product?
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