AIMS 3770 – Dr. Leon
Problem Set 8: Bottleneck Analysis
1. Consider the three-station work cell at Case Manufacturing where the product only
needs to go through one of the two parallel machines at station 1 before proceeding to
station 2:
Station 1: Cutting
20 min/unit
Station 1: Cutting
Station 2: Framing
Station 3: Assembly
12 min/unit
8 min/unit
20 min/unit
a. What is the throughput time of this work cell? 20+12+8=40 min
b. What is the bottleneck station? Station 2
c. What is the bottleneck time of this work cell? 12 min/unit
d. If the company operates 8 hours per day, 6 days per week, what is the weekly
capacity of this work cell? 48 hours * 60 min/hr / 12 min/unit = 240 units
2. The manager at Case Manufacturing has asked you to evaluate the three-station work
cell in problem 1 if he adds a parallel machine at station 2.
a. What is the throughput time of this modified work cell? 20+12+8 = 40 min
b. What is the bottleneck station? Station 1
c. What is the bottleneck time of this modified work cell? 20 min/2 = 10
min/unit
d. If the company operates 8 hours per day, 6 days per week, what is the weekly
capacity of this work cell? 48 hours * 60 min/hr / 10 min/unit = 288 units
e. How did the addition of the second machine at workstation 2 affect the
performance of the work cell in problem 1? The second machine at Station 2
moved the bottleneck to Station 1, with a bottleneck time of 10 minutes,
which increased capacity from 240 to 288, or 48 units /wk. Parallel stations
have no impact on throughput time.
f. If the manager were to add another parallel machine to the modified work cell,
which station would you recommend he add the next machine to? Station 1.
There would be three parallel machines at station 1 along with two parallel
machines at station 2. The new bottleneck would become station 3 then.
3. Pullman Luggage Company, Inc. assembles two wheel carrier parts for its luggage
pieces, parts 1 and 2. Part 1 is first processed at workstation A for 15 minutes per
unit and then processed at workstation B for 10 minutes per unit. Part 2 is
simultaneously processed at workstation C for 20 minutes per unit. Workstations B
and C feed the parts to an assembler at workstation D, where the two parts are
assembled. The assembly time at workstation D is 15 minutes.
a. Draw a flowchart to represent this four-station work cell.
Station A
15 min/unit
Station B
Station D: Assembly
10 min/unit
15 min/unit
Station C
20 min/unit
b. What is the throughput time of this work cell? 15+10+15 = 40 min
c. What is the bottleneck station? Station C
d. What is the bottleneck time of this work cell? 20 min/unit
e. What is the hourly capacity of the process? 60 min/20 min/unit = 3 units/hour
f. What suggestion would you make to improve the performance of this work
cell? Describe how the work cell performance will be affected with your
suggestion. Need to identify a way to release the jobs through the process
associated with Station C faster: possibilities include changing product design
for part 2 or investing in faster equipment so that the process time at station C
is decreased. Could also consider setting up a second parallel line for station
C so that a part 2 is released every 10 minutes to station D. All of these
changes would increase the capacity of the workcell. The throughput time
would remain 40 mins.