Question & Answer

Define process capability.

How is a process operating in statistical control distinguished from one that is not?

What are the two principal aspects of product quality?

Five jobs are waiting to be scheduled on a machine. For order A, the remaining process time = 5

days, and the due date is day 8. For order B, the remaining process time = 7 days, and the due

date is day 16. For order C, the remaining process time = 11 days, and the due date is day 22. For

order D, the remaining process time = 9 days, and the due date is day 31. For order E, the

remaining process time = 10 days, and the due date is day 26. Determine a production schedulebased on (a) shortest processing time, (b) earliest due date, (c) critical ratio, and (d) least slack time.

All times are listed in days.

The current date in the production calendar is day 14. There are three orders (A, B, and C) to be

processed at a particular work center. The orders arrived in the sequence A-B-C at the work

center. For order A, the remaining process time = 8 days, and the due date is day 24. For order B,

the remaining process time = 14 days, and the due date is day 33. For order C, the remaining

process time = 6 days, and the due date is day 26. Determine the sequence of the orders that

would be scheduled using (a) first-come-first-serve, (b) earliest due date, (c) shortest processing

time, (d) least slack time, and (e) critical ratio.

In the previous problem, propose a way of scheduling to meet the weekly demand if there were four

machines instead of three.

Four products are to be manufactured in Department A, and it is desired to determine how to

allocate resources in that department to meet the required demand for these products for a certain

week. For product 1, demand = 750/wk, setup time = 6 hr, and operation time = 4.0 min. For

product 2, demand = 900/wk, setup time = 5 hr, and operation time = 3.0 min. For product 3,

demand = 400/wk, setup time = 7 hr, and operation time = 2.0 min. For product 4, demand =

400/wk, setup time = 6 hr, and operation time = 3.0 min. The plant normally operates one shift

(7.0 hours per shift), five days per week and there are currently 3 work centers in the department.

Propose a way of scheduling the machines to meet the weekly demand.

Solve Problem 41.9 except that the following is known in addition to the information given:

scheduled receipts of M5 are 250 units in period (week) 3 and 50 units in period (week) 4.

Requirements are to be planned for component C5 in product P1. Required deliveries for P1 are

given in Table 41.1. Ordering, manufacturing, and assembly lead times are as follows: for P1 and

S2, the lead time is one week; for C5, the lead time is three weeks; and for M5, the lead time is 2

weeks. Given the product structure in Figure 41.4, determine the time-phased requirements for M5,

C5, and S2 to meet the master schedule for P1. Assume no common use items. On-hand inventories

are 200 units for M5 and 100 units for C5, zero for S2. Use a format similar to Table 41.2 and

develop a spreadsheet calculator to solve. Ignore demand for P1 beyond period 10.

Quantity requirements are to be planned for component C2 in product P1. Required deliveries for

P1 are given in Table 41.1. Ordering, manufacturing, and assembly lead times are as follows: for

P1 and C2, the lead time is one week; and for S1 and M2, the lead time is two weeks. Given the

product structure in Figure 41.4, determine the time-phased requirements for M2, C2, and S1 to

meet the master schedule for P1. Assume no common use items and all on-hand inventories and

scheduled receipts are zero. Use a format similar to Table 41.2 and develop a spreadsheet

calculator to solve. Ignore demand for P1 beyond period 10.

The two-bin approach is used to control inventory for a particular low-cost component. Each bin

holds 1200 units. The annual usage of the component is 45,000 units. Cost to order the component

is around $70. (a) What is the imputed holding cost per unit for this data? (b) If the actual annual

holding cost per unit is only 7 cents, what lot size should be ordered? (c) How much more is the

current two-bin approach costing the company annually, compared to the economic order quantity?

Current setup time on a certain machine is 3.0 hr. Cost of downtime on this machine is estimated at

$200/hr. Annual holding cost per part made on the equipment, Ch = $1.00. Annual demand for the

part is 15,000 units. Determine (a) EOQ and (b) total inventory costs for this data. Also, determine

(c) EOQ and (d) total inventory costs, if the changeover time could be reduced to six minutes.

A certain piece of production equipment is used to produce various components for an assembled

product. To keep in-process inventories low, it is desired to produce the components in batch sizes

of 150 units. Demand for each product is 2500 units per year. Production downtime costs an

estimated $200/hr. All of the components made on the equipment are of approximately equal unit

cost, which is $9.00. Holding cost rate = 30%/yr. In how many minutes must the changeover

between batches be completed in order for 150 units to be the economic order quantity?

Assembly of a product requires that a component part be ordered and stocked. Demand for the

product is constant throughout the year at 7800 units annually. The cost to place an order is $95.

The cost of the part is $56 and the holding cost rate is 22%. When units are ordered, they take two

weeks to arrive. Determine (a) the economic order quantity and (b) the reorder point. (c) The parts

are prepackaged in multiples of 100. It saves the supplier unpacking and repackaging time if they

can ship in multiples of 100. The supplier has offered to reduce the price by $1 per unit if even

multiples of 100 are purchased. How much would be saved (if anything) by taking this offer?

A product is produced in batches. Batch size = 2000 units. Annual demand = 50,000 units, and unit

cost of the product = $4.00. Setup time to run a batch = 2.5 hr, cost of downtime on the affected

equipment is figured at $250/hr, and annual holding cost rate = 30%. What would the annual

savings be if the product were produced in the economic order quantity?

Given that annual demand for a product is 20,000 units, cost per unit = $6.00, holding cost rate =

2.5%/month, changeover (setup) time between products averages 2.0 hr, and downtime cost during

changeover = $200/hr, determine (a) economic order quantity and (b) total inventory costs for this

situation.

A product is made to stock. Annual demand is 86,000 units. Each unit costs $9.50 and the annual

holding cost rate is 22%. Setup cost to produce this product is $800. Determine (a) economic order

quantity and (b) total inventory costs for this situation.

There are 15 correct answers in the following multiple choice questions (some questions have multiple

answers that are correct). To attain a perfect score on the quiz, all correct answers must be given. Each

correct answer is worth 1 point. Each omitted answer or wrong answer reduces the score by 1 point, and

each additional answer beyond the correct number of answers reduces the score by 1 point. Percentage

on the quiz is based on the total number of correct answers.

41.1 Which one of the following terms best describes the overall function of production planning and

control: (a) inventory control, (b) manufacturing logistics, (c) manufacturing engineering, (d) mass

production, or (e) product design?

41.2 Which of the following are the three categories of items usually listed in the master production

schedule: (a) components used to build the final products, (b) firm customer orders, (c) general

product lines, (d) orders for maintenance and spare parts, (e) sales forecasts, and (f) spare tires?

41.3 Inventory carrying costs include which of the following (two best answers): (a) equipment

downtime, (b) interest, (c) production, (d) setup, (e) spoilage, (f) stock-out, and (g) storage?

41.4 Which of the following are the three terms in the economic order quantity formula: (a) annual

demand rate, (b) batch size, (c) cost per piece, (d) holding cost, (e) interest rate, and (f) setup cost?

41.5 Order point inventory systems are intended for which of the following (two best answers): (a)

dependent demand items, (b) independent demand items, (c) low production quantities, (d) mass

production quantities, and (e) mid-range production quantities?

41.6 With which of the following manufacturing resources is capacity requirements planning primarily

concerned (two best answers): (a) component parts, (b) direct labor, (c) inventory storage space, (d)

production equipment, and (e) raw materials?

41.7 The word kanban is most closely associated with which one of the following: (a) capacity planning,

(b) economic order quantity, (c) just-in-time production, (d) master production schedule, or (e)

material requirements planning?

41.8 Machine loading refers most closely to which one of the following: (a) assigning jobs to a work

center, (b) floor foundation in the factory, (c) managing work-in-process in the factory, (d) releasing

orders to the shop, or (e) sequencing jobs through a machine?

What are the three phases in shop floor control?

How is a pull system distinguished from a push system in production and inventory control?

Identify the principal objective in just-in-time production.

What are some of the resource changes that can be made to increase plant capacity in the short run?

Identify the inputs to the MRP processor in material requirements planning.

In MRP, what are common use items?

Define reorder point inventory system.