Chapter 11
Planning Production Activity
DISCUSSION QUESTIONS
11-1. Q: Why is a vigorous production capability so important to the United States in the “post-
industrial society”?
11-2. Q: What are some of the positions that engineers fill in a large manufacturing plant?
A: Fig. 11-1 and the text description of it provide a starting point for an answer.
11-3. Q: What subjects will be important in the education of the manufacturing engineer for the twenty-
first century?
A: According to the SME report on The Manufacturing Engineer in the 21st Century,
11-4. Q: Discuss some of the factors that would be most important in selecting a site for (a) a Portland
cement plant, (b) a research “think tank,” and (c) a shoe factory.
A: The text identifies some of the factors generally important in locating a plant. (a) Portland
11-5. Q: Distinguish between (a) product layout, (b) process layout, and (c) group technology.
11-6. Q: List some of the characteristics that make the Dunn and Savastano Orthodontics business
compete with other practices.
11-7. Q: Distinguish between MRP and MRP II.
11-8. Q: Describe how the kanban is used in the just-in-time production system.
A: Kanban refers to the cards (Figure 11-9) used for production ordering and inventory
11-9. Q: What are some of the reasons for using a flexible manufacturing system?
11-10. Q: What is the relationship between flexible manufacturing systems and the group technology
concept introduced earlier in the chapter?
A: Group technology is the process of dividing products into groups that require similar
11-11. Q: Discuss how the management functions of planning, organizing, leading, and controlling relate
to the production planning process.
PROBLEMS
11-1. Q: (a) If it costs $2 per unit to store an item for one year, $40 setup cost every time you produce
a lot, and you use 1000 units per year, how many lots of what size should be manufactured each
year? (b) How would your answer change if the setup cost becomes $10?
A:
11-2. Q: Setup for a stamping operation required a time-consuming fixture installation and testing that
took four hours each time a different part was to be produced; typically twelve hours production
was made for inventory of a given stamping before the machine was stopped to permit setup for
a new part. After careful process analysis, fixtures and transfer methods were revised to permit
setup in fifteen minutes. Discuss the implications for this change on (a) optimum batch size, (b)
order frequency, and (c) machine and labor productivity.
A: Decrease of setup time S from 4 hours to 1/4 hour is a factor of 16; by the square root rule this
11-3. Q: A production plant with fixed costs of $300,000 produces a product with variable costs of $40
per unit and sells them at $100 each. What is the break-even cost? Illustrate with a break-even
chart.
A: Each unit sold provides a contribution C1 = (S–V1) = ($100 – 40) = $60 towards covering fixed
11-4. Q: A machine tool salesperson offers the plant of question 11-8 equipment that would increase
their fixed cost by $180,000 but reduce their variable cost from $40 to $25. Should the plant
accept this suggestion if they can sell their entire plant capacity of 10,000 units per year at $100
each? Illustrate by modifying the break-even chart of question
A: Each unit sold provides a contribution C2 = (S–V2) = ($100 – 25) = $75 towards covering fixed
11-5. Q: A plant is beginning production of a light-alloy product and finds that it takes 400 hours to
produce the first item. How many hours should it take to produce each of the following: (a) the
second item; (b) the eighth item; (c) the thirty-seventh item? (Hint: Refer to Table 11-1)
A: (a,b) According to that table, the learning rate for a light alloy product can be taken as 80%. If
11-6. Q: The first two units of a product cost a total of $9,000 to produce. If you believe an 80%
learning curve applies, how much would you expect the fourth unit to cost?