Throughout Problems
5.4. The Process Flowchart from Problem 4.4
2 min
molding
1 min
welding
aut. molding machine
3 min
eng. ass.
1 engine assembler
1 molding operator
1 min
3 min
stamping
welding
start
30 min
continuous welding machine
FA
1 welder
end
2 min
stamping
10,000lbs press
10 final assemblers
1 press operator
7 min
seat ass.
2 seat assemblers
Throughput Problems – Set2
Ardavan Asef-Vaziri
Nov-2011
2
5.4. The Process Flowchart from Problem 4.4
Resource Pool
Molding machine
Molding operator
10,000lbs press
Press operator
Welding machine
Welder
Engine assembler
Seat assembler
Final assembler
Throughput Problems – Set2
Theoretical
capacity of a Number of
Unit Load resource unit resources
[min/job] [jobs/hr]
in pool
2
30
1
2
30
1
3
20
1
3
20
1
4
15
1
4
15
1
3
20
1
7
8.57
2
30
2
10
Ardavan Asef-Vaziri
Nov-2011
Theoretical
Capacity of
Resource
pool/hr
30
30
20
20
15
15
20
17.14
20
3
5.4. The Process Flowchart from Problem 4.4
Unable to meet demand for this bike, Honda wants to increase
throughput. A team member suggests cross-training the engine
and seat assemblers.
This suggestion should not be implemented because these
resources are non-bottlenecks and therefore do not impact
system throughput.
We suggest increasing bottleneck capacity by decreasing
welding times by design or process improvements.
Other options are buying another welding machine and adding
another welder, outsourcing some welding.
Throughput Problems – Set2
Ardavan Asef-Vaziri
Nov-2011
4
Problem 5.5
5.5 – NewLife Finance handles two types of claims: hospital and
physician. NewLife charges the HMOs $10 per hospital claim
(HC) and $9 per physician claim (PC). The variable costs per
claim are negligible. The theoretical capacity of the process is
375 claims per day in the case of HC and 545 claims per day for
PC.
a. What of the two types of claims is more profitable for
NewLife?
b. Assume that the maximum number of PCs available for
processing per day is 400. What is the best product mix for
NewLife?
Throughput Problems – Set2
Ardavan Asef-Vaziri
Nov-2011
5
Problem 5.5
(a) PC:is the more profitable product:
The profit from HC is 10×375 = $3750 per day.
The profit from PC is 9 × 545 = $ 4905 per day
(b) Assume 480 minutes per day.
The unit load for HC is 480/375 = 1.28 minutes per claim.
The unit load for PC 480/545 = 0.88 minutes per claim.
The time to make 400 PC claims is then 0.88 × 400 = 353 minutes
per day.
This leaves 480-353 = 127 minutes for HC.
At 1.28 minutes per unit, this allows for 127/1.28 = 99.8 (roughly
100) units.
The best mix is 400 PC and 100 units of HC per day. (80% and
20%)
Throughput Problems – Set2
Ardavan Asef-Vaziri
Nov-2011
6
Total Unit Load for Product mix
Compute the unit load and the total unit load for each Load batch
of Regular tile, Jumbo tile and a product mix of 75% Regular and
25% Jumbo . Load Batches are 4 and 9 for regular and jumbo,
respectively. Set-up Batches are 300 and 100 for regular and
jumbo, respectively.
Product L -Batch S-Batch
Cutting time
Setup time
Regular 4 units 300 L-batch 2 min/L-batch 30 min/S-Batch
Jumbo 9 units 100 L-batch 1 min/L-batch 30 min/S-Batch
Unit Load (Tp )
Sp/Qp
Total unit load
Throughput Problems – Set2
Regular
2
30/300=0.1
2+0.1=2.1
Jumbo
1
Mix
(2×0.75)+(1×0.25)=1.75
30/100=0.3 (0.1×0.75)+(0.3×0.25)=0.15
1+0.3=1.3
(2.1×.75)+(1.33×.25)= 1.9
Ardavan Asef-Vaziri
Nov-2011
7
Effective Capacity of a Resource Unit
Theoretical Capacity of a resource unit =
(1/Unit Load) × Load Batch × Scheduled Availability
Scheduled Availability – the scheduled time period during
which a resource unit is available for processing flow units.
Availability factor = Net Availability/Scheduled Availability
Effective Capacity of a resource unit =
(1/Total Unit Load) × Load Batch × Scheduled Availability
Effective Capacity of a pool =
(c/Tp) × Load Batch ×Scheduled Availability
Throughput Problems – Set2
Ardavan Asef-Vaziri
Nov-2011
8
Problem 5.6
5.6 – Recall from this chapter that the Tile&Style Company
produces kitchen and bathroom tiles in two sizes: jumbo and
regular. A bundle of tiles contains 4 jumbo tiles or 9 regular tiles
and is cut out of single, larger plate. The cutting time per bundle
is 1 minute for jumbo and 2 minutes for regular. Currently, 75%
of the bundles are regular, and 25% are jumbo. Typically,
Tile&Style produces 300 bundles of regular tiles before it
switches over and produce 100 bundles of jumbo. The switching
time from one size to the other is 30 minutes in both directions.
Plates are cut into tiles by a cutting machine that is available 8
hours per day. The availability loss factor is 20%.
a. Compute the theoretical capacity of the process (bundles per
hour)
b. Compute the effective capacity of the process (bundles per
hour)
Throughput Problems – Set2
Ardavan Asef-Vaziri
Nov-2011
9
Problem 5.6.
Th Unit load
S/Q
Unit load
Regular
2
0.1
2.1
Jumbo
1
0.3
1.3
Mix
2×0.75+1×0.25
0.1×0.75+0.3×0.25
2.1×0.75+1.3×0.25
Mix
1.75
0.15
1.9
Theoretical Capacity = 480/1.75 = 274.3 Aggregate Product
Effective Capacity = .8(480)/ 1.9 = 202.1 Aggregate Product
What is an aggregate product?
It is 0.75 Regular and 0.25 Jumbo
Therefore; 202.1 aggregate is 151.57 regular bundle and 50.52
Jumbo bundle: 9(151.57) , 9(50.52).
Throughput Problems – Set2
Ardavan Asef-Vaziri
Nov-2011
10