Problem 1: Consider the construction of a simple 8" X 10" wood picture frame. The picture frame consists of four wood pieces that are cut from the wood molding, four staples to hold the frame together, a piece of glass, a backing board made of cardboard, six points to hold the glass and backing board to the frame, and a clip for hanging the picture frame to the wall.
a. Construct an assembly chart for the picture frame.
b. Construct a flowchart for the entire process from receiving material to final inspection.
Problem 2: A book publisher has fixed costs of $300,000 and variable costs per book of $8.00. The book sells for $23.00 per copy.
a. How many books must be sold to break even?
b. If the fixed cost increased, would the new break even point be higher or lower?
c. If the variable cost per unit decreased, would the new break-even point be higher or lower?
Problem 3. An assembly line is to operate eight hours per day with a desired output of 240 units per day. The following table contains information on the product's task times, and precedence relationships:
Task Task Time (Seconds) Immediate Predecessors
A 60 seconds No predecessors
B 80 seconds A
C 20 seconds A
D 50 seconds A
E 90 seconds B, C
F 30 seconds C, D
G 30 seconds E, F
H 60 seconds G
a. Draw or explain the precedence diagram.
b. What is the workstation cycle time?
c. Balance this line using the longest task time.
d. What is the efficiency of your line balance?
Problem 5: SYSTEM DESCRIPTION EXERCISE
The beginning step in studying a productive system is to develop a description of the system. Once the system is described, we can better determine why the system works well or poorly and recommend production-related improvements. Since we are all familiar with fast-food restaurants, try your hand at describing the production system employed at, say, a McDonald's. In doing so, answer the following questions:
a. What are the important aspects of the service package?
b. Which skills and attitudes are needed by the service personnel?
c. How can customer demand be altered?
d. Describe the process flow of the production/delivery system.
e. Can the customer/provider interface be changed to include more technology? More self-serve?
f. Which measures are being used to evaluate and measure the service? Which could be used?
g. How does it measure up on the seven characteristics of a well-designed service?
Problem 6. Burrito King ( a new fast food franchise opening up nationwide) has successfully automated burrito production for its drive-up fast food establishments. The Burro-Master 9000 requires a constant 45 seconds to produce a batch of burritos. It has been estimated that customers will arrive at the drive-up window according to a Poisson distribution at an average of one every 50 seconds. To help determine the amount of space needed for the line at the drive-up window, Burrito King would like to know the expected average time in the system, the average line length (in cars), and the average number of cars in the system (both in line and at the window)
Problem 7. To support National Heart Week, the Heart Association plans to install a free blood pressure testing booth in El Con Mall for the week. Previous experience indicates that, on the average, 10 persons per hour request a test. Assume arrivals are Poisson from an infinite population. Blood pressure measurements can be made at a constant time of 5 minutes each. Assume the queue length can be infinite with FCFS discipline.
a. What average number in line be expected?
b. What average number of persons can be expected in the system?
c. What is the average amount of time that a person can expect to spend in line?
d. On the average, how much time will it take to measure a person's blood pressure, including waiting time?
e. On weekends, the arrival rate can be expected to increase to nearly 12 per hour. What effect will this have on the number in the waiting line?
Problem 8. An engineering firm retains a technical specialist to assist four design engineers working on a project. The help that the specialist gives engineers ranges widely in time consumption. The specialist has some answers available in memory, others require computation, and still others require significant search time. On the average, each request for assistance takes the specialist one hour.
The engineers require help from the specialist on the average of once each day. Since each assistance takes about one hour, each engineer can work for seven hour, on the average, without assistance. One further point: Engineers needing help do not interrupt if the specialist is already involved with another problem. Treat this as a finite queuing problem and answer the following questions:
a. How many engineers, on the average, are waiting for the technical specialist to help?
b. What is the average time that an engineer has to wait for the specialist?
c. What is the probability that an engineer will have to wait in line for the specialist?