Optional Process & Quality Homework
Autor: Ведран Продановић • June 3, 2015 • Study Guide • 1,066 Words (5 Pages) • 1,297 Views
Optional Process & Quality Homework
Problem 1
A manufacturing plant has 100 orders arrive each day. All orders go through the order processing area, where, on average, there are 25 orders in the system. Of the incoming orders, 70% are “A” orders, which are routed through workcenter A, where the average inventory of orders is 14. The remaining 30% are “B” orders, which are routed through workcenter B, where the average inventory of orders is 1.5. The system is assumed to be in steady-state where incoming orders equal the outgoing orders.
The plant manager wants to know, on average:
- How long does an order (A or B) stay in the order processing area?
- How long does it take an A order to work its way through the plant?
- How long does it take a B order to work its way through the plant?
- How long does it take the average order (A or B) to work its way through the plant?
Problem 2
The Lenovo Refurbishing Company repairs used laptops that are returned under warranty. The center receives and processes on average 200 laptops per day. All laptops are tested upon receipt: 30% are immediately rejected, and the remaining 70% are sent to the refurbishment area. On average there are 21 laptops in the testing area waiting or being worked on. In the refurbishment area, there are 16 laptops waiting or being worked on.
- What is the average throughput time for all laptops entering the system?
- What is the average throughput time for a laptop that goes through both testing and refurbishing?
Problem 3
A quality team at Milburn Textiles has been charged with setting up control charts to monitor the dyeing process. The ideal temperature for the drying process is 140 degrees. If the temperature is too hot, the fabric will be too dark; if the temperature is too low, streaks can develop. Either condition can ruin large rolls of expensive fabric. The team has gathered the following temperature data:
Observation | |||||
Day | 1 | 2 | 3 | 4 | 5 |
1 | 136 | 137 | 144 | 141 | 138 |
2 | 143 | 138 | 140 | 140 | 139 |
3 | 140 | 141 | 144 | 137 | 135 |
4 | 139 | 140 | 141 | 139 | 141 |
5 | 137 | 138 | 143 | 140 | 138 |
6 | 142 | 141 | 140 | 139 | 138 |
7 | 143 | 141 | 143 | 140 | 140 |
8 | 139 | 139 | 141 | 140 | 136 |
9 | 140 | 138 | 143 | 141 | 139 |
10 | 139 | 141 | 142 | 140 | 136 |
Construct a X-bar and R chart.
Problem 4
Since on-time delivery is a key order winner in the pizza business, the manager of Gonzo’s Pizza has decided to set up control charts to track the proportion of deliveries that take longer than 30 minutes. The manager’s first step is to take samples of deliveries when things are working normally. The manager takes samples of 50 deliveries over the next 15 days. The sample results are as follows:
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