Reference no: EM131105025
Problem 5-8
A manager is trying to decide whether to purchase a certain part or to have it produced internally. Internal production could use either of two processes. One would entail a variable cost of $17 per unit and an annual fixed cost of $200,000; the other would entail a variable cost of $14 per unit and an annual fixed cost of $240,000. Three vendors are willing to provide the part. Vendor A has a price of $20 per unit for any volume up to its maximum capacity of 30,000 units. Vendor B has a price of $22 per unit for demand less than 1,000 units, and $18 per unit for larger quantities. Vendor C offers a price of $21 per unit for the first 1,000 units, and $19 per unit for additional units.
a. If the manager anticipates an annual volume of 10,000 units, which alternative would be best from a cost standpoint? For 20,000 units, which alternative would be best? (Omit the "tiny_mce_markerquot; sign in your response.)
b. Determine the range for which each alternative is best.
Problem 5-9
A company manufactures a product using machine cells. Each cell has a design capacity of 250 units per day and an effective capacity of 230 units per day. At present, actual output averages 200 units per cell, but the manager estimates that productivity improvements soon will increase output to 222 units per day. Annual demand is currently 60,000 units. It is forecasted that within two years, annual demand will triple. How many cells should the company plan to acquire to satisfy predicted demand under these conditions? Assume that no cells currently exist. Assume 245 workdays per year. (Round up your answer to the next whole number.)
Problem 5-11
A manager must decide which type of machine to buy, A, B, or C. Machine costs (per individual machine) are as follows:
Product forecasts and processing times on the machines are as follows:
a. Assume that only purchasing costs are being considered. Compute the total processing time required for each machine type to meet demand, how many of each machine type would be needed, and the resulting total purchasing cost for each machine type. The machines will operate 10 hours a day, 230 days a year.
Consider this additional information: The machines differ in terms of hourly operating costs: The A machines have an hourly operating cost of $13 each, B machines have an hourly operating cost of $15 each, and C machines have an hourly operating cost of $15 each. What would be the total cost associated with each machine option, including both the initial purchasing cost and the annual operating cost incurred to satisfy demand?
Problem 5-13
The manager of a car wash must decide whether to have one or two wash lines. One line will mean a fixed cost of $5,700 a month, and two lines will mean a fixed cost of $9,690 a month. Each line would be able to process 15 cars an hour. Variable costs will be $3 per car, and revenue will be $5.95 per car. The manager projects an average demand of between 14 and 18 cars an hour. Would you recommend one or two lines? The car wash is open 260 hours a month.
Problem 5-14
The following diagram shows a 4-step process that begins with Operation 1 and ends with Operation 4. The rates shown in each box represent the effective capacity of that operation.
Determine the capacity of this process.
Problem 5-15
The following diagram describes a process that consists of eight separate operations, with sequential relationships and capacities (units per hour) as shown.
a. What is the current capacity of the entire process?
b-1. If you could increase the capacity of only two operations through process improvement efforts, which two operations would you select, how much additional capacity would you strive for in each of those operations?
Problem 6-2
A manager wants to assign tasks to workstations as efficiently as possible, and achieve an hourly output of 331/3 units. Assume the shop works a 60-minute hour. Assign the tasks shown in the accompanying precedence diagram (times are in minutes) to workstations using the following rules:
a. In order of most following tasks. Tiebreaker: greatest positional weight.
b. In order of greatest positional weight.
c. What is the efficiency?
Problem 6-3
A manager wants to assign tasks to workstations as efficiently as possible, and achieve an hourly output of 4 units. The department uses a working time of 56 minutes per hour. Assign the tasks shown in the accompanying precedence diagram (times are in minutes) to workstations using the following rules:
a. In order of most following tasks. Tiebreaker: greatest positional weight.
b. In order of greatest positional weight.
c. What is the efficiency?
Problem 6-8
A shop works a 400-minute day. The manager of the shop wants an output of 200 units per day for the assembly line that has the elemental tasks shown in the table. Do the following:
b. Assign tasks according to the most following tasks rule.
c. Assign tasks according to the greatest positional weight rule.
d. Compute the balance delay for each rule. Which one yields the better set of assignments in this instance?
Problem 6-18
For the set of tasks given below, do the following:
|
Task
|
Task Time
(seconds)
|
Immediate
Predecessor
|
|
A
|
45
|
-
|
|
B
|
11
|
A
|
|
C
|
9
|
B
|
|
D
|
50
|
-
|
|
E
|
26
|
D
|
|
F
|
11
|
E
|
|
G
|
12
|
C
|
|
H
|
10
|
C
|
|
I
|
9
|
F, G, H
|
|
J
|
10
|
I
|
|
|
193
|
|
Assign tasks to stations for a desired output of 500 units in a 7-hour day to balance the line using the longest operation time heuristic. Break ties with the most following tasks heuristic. Calculate the percentage idle time for the line. Use the actual bottleneck cycle time in your calculation.
Problem 7-1
An analyst has timed a metal-cutting operation for 50 cycles. The average time per cycle was 10.9 minutes, and the standard deviation was 1.20 minutes for a worker with a performance rating of 139 percent. Assume an allowance of 16 percent of job time. Find the standard time for this operation.
Problem 7-4
Given these observed times (in minutes) for four elements of a job, determine the observed time (OT) for each element. Note: The second element only occurs every other cycle.
Problem 7-5
Given these observed times (in minutes) for five elements of a job, determine the observed time (OT) for each element. Note: Some of the elements occur only periodically.
Problem 7-6
Using the following data, develop an allowance percentage for a job element that requires the worker to lift a weight of 30 pounds while (1) standing in a slightly awkward position, (2) in light that is very inadequate standards, and (3) with intermittent very loud noises occurring. The monotony for this element is low. Include a personal allowance of 5 percent and a basic fatigue allowance of 4 percent of job time.
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