Cell Layout and Performance
Term Project
Modeling Analysis of Manufacturing Systems
Bryan Baker
April 12, 2001
1 Description
The term project report that I am proposing is to analyze the performance of a manufacturing cell
in the Pratt & Whitney Turbine Module Center. Since the cell is moving to East Hartford, the
opportunity is available to change the layout in order to maximize performance. Its previous
layout was more geared toward cellular manufacturing, however some performance was lacking
due to some dated equipment. The analysis will include verification of layout type best suited for
the desired throughput of product in order to meet customer demand. Some of the different types
of layouts that can be focused on include Product Layout, Process Layout, and cellular layout, or
Group Technology.
Characteristic
Product
Process
Group
Throughput time
Low
High
Low
WIP
Low
High
Low
Skill Level
Choice
High
Med-High
Product Flexibility
Low
High
Med-High
Machine Utilization
High
Med-Low
Med-High
Worker Utilization
High
High
High
Unit Production Cost
Low
High
Low


To simplify the problem and the model significantly, only three of the higher volume parts
that are manufactured by the cell will be looked at to determine optimal layout and cell
efficiency.
Buffer location
Major issues in design of cells comes about is the allocation of function and products to cells, this
in turn actually determines the overall structure of the cell. Which determines which cells will be
connected by flows of parts and products.
3 Theoretical Modeling
Cell Unit A - Grinding
Dept
Operation (min)
Blade1
(52L472)
Blade2
(53L822)
Blade3
(54L422)
Wt.
Average
15.000
2.000
3.000
15.000
2.000
3.000
15.000
2.000
3.000
3.800
3.890
3.890
3.890
3.800
3.890
3.890
3.800
3.810
3.890
3.890
3.830
3.500
3.500
3.500
3.500
3.500
3.467
1.380
1.380
1.380
1.600
1.800
1.733
2.000
1.380
1.200
1.350
2.000
1.380
1.200
1.400
Cycle time
2.000
1.380
1.200
1.417
51.497
3.000
3.000
3.000
3.000
7.651
7.320
0.000
9.437
2.000
2.000
2.000
2.000
0.780
0.780
0.000
0.520
0.870
0.000
0.000
0.290
Cycle time
15.247
2754-A WIRE EDM"V" NOTCHES
15.000
2754-A CMM INSPECT EDM NOTCHES
2.000
2754-A FILL TURBINE BLADE WITH
3.000
POLYETHYLE
2754-A GRIND ROOT FACES
3.830
2754-A GRIND MATE FACES
3.890
2754-A GRIND CC & CV ROOT SERRATION
3.890
2754-A GRIND BOTTOM OF ROOT AND
3.800
AIRFOIL T
2754-A GRIND SEALS
3.500
2754-A Forced air to remove excess coolant
3.400
(DRY)
2754-A BUFF EDGES OF ROOT SERRATIONS 1.380
AND
2754-A IN-LINE INSPECTION OF MACHINED
1.800
FEA
2754-A BAKE TO REMOVE POLY FILL
2.000
2754-A BREAK EDGES, ROOT BOTTOM
1.380
2754-A INSPECT & MARK ,
1.200
2754-A INSPECTION CODE 5
1.500
Cell Unit C – Hole Drilling
2754-C FILL TURBINE BLADE WITH
POLYETHYLE
2754-C LASER DRILL (63) AIRFOIL HOLES
PER
2754-C BAKE TO REMOVE BACKING
MATERIAL F
2754-C AIRFLOW LASER DRILLED HOLES
PER PO
2754-C REMOVE RAISED EDGES FROM
LASER DRI
Cell Unit D - Finishing
2754-D PRECIPITATION HEAT TREAT PER
PWA 1
2754-D REMOVE OXIDE ON END OF ROOT
2754-D SHOT PEEN BLADE ROOT PER
NMOP-0016
2754-D X-RAY BLADE
2754-D WELD COVER TO BLADE PER SPEC.
PWA
2754-D WATERFLOW BLADE FOR
OBSTRUCTIONS
2754-D AIRFLOW ALL AIRFOIL HOLES
2754-D FINAL INSPECTION
9.910
9.910
9.910
9.910
0.410
0.684
0.410
0.684
0.410
0.684
0.410
0.684
0.880
1.300
0.880
1.300
0.880
1.300
0.880
1.300
0.590
0.590
0.590
0.590
0.780
0.800
0.780
0.700
0.780
0.800
Cycle time
0.780
0.767
15.321

To understand how to start assigning machines and product in order to produce an estimate
for layout, demand of the product must be known. From this, cycle time, and machine
requirements can then be determined. Demands for the particular three blades in review are
as follows:
Part
Blade 1
Blade 2
Blade 3

Avg. Weekly demand
320
230
290
Working time will be estimated at 8 hours per shift,2 shifts per day, 5 days per week, with
only 2 fifteen-minute breaks per shift. This gives total available minutes per week of
approximately 4500. Calculating cycle time based on the demand yields:
c

Deviation +/- (10%)
32
23
29
4500
 5.011 min
898
Using the average processing time as seen in the first table, the lower bound on number of
workstations needed to perform each operation in order to meet the demand can be
calculated. The lower bound provided that all the operations could be done on the same
machines would simply be calculated as processing time divided by cycle time shown in the
table below.
Cell Unit
A- Grinding
C – Hole Drilling
D - Finishing
Processing time
(min)
51.497
15.247
15.3211
Cycle time
Lower Bound
15.41
15.41
15.41
10.276
3.0427
3.057
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28

WIRE EDM"V" NOTCHES
CMM INSPECT EDM NOTCHES
FILL TURBINE BLADE WITH
POLYETHYLE
GRIND ROOT FACES
GRIND MATE FACES
GRIND CC & CV ROOT SERRATION
GRIND BOTTOM OF ROOT AND
AIRFOIL T
GRIND SEALS
Forced air to remove excess coolant
(DRY)
BUFF EDGES OF ROOT
SERRATIONS AND
IN-LINE INSPECTION OF
MACHINED FEA
BAKE TO REMOVE POLY FILL
BREAK EDGES, ROOT BOTTOM
INSPECT & MARK ,
INSPECTION CODE 5
FILL TURBINE BLADE WITH
POLYETHYLE
LASER DRILL (63) AIRFOIL HOLES
PER
BAKE TO REMOVE BACKING
MATERIAL F
AIRFLOW LASER DRILLED HOLES
PER PO
REMOVE RAISED EDGES FROM
LASER DRI
PRECIPITATION HEAT TREAT PER
PWA 1
REMOVE OXIDE ON END OF ROOT
SHOT PEEN BLADE ROOT PER
NMOP-0016
X-RAY BLADE
WELD COVER TO BLADE PER
SPEC. PWA
WATERFLOW BLADE FOR
OBSTRUCTIONS
AIRFLOW ALL AIRFOIL HOLES
FINAL INSPECTION
Machine lower bound
Average processing 3 Shifts 2 shifts 1 shift
time
15.00
2
3
6
2.00
1
1
1
3.00
1
1
2
3.81
3.89
3.89
3.83
1
1
1
1
1
1
1
1
2
2
2
2
3.50
3.47
1
1
1
1
2
2
1.38
1
1
1
1.73
1
1
1
2.00
1.38
1.20
1.42
48.15
3.00
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
9.44
2
2
4
2.00
1
1
1
0.52
1
1
1
0.29
1
1
1
15.25
9.91
2
2
4
0.41
0.68
1
1
1
1
1
1
0.88
1.30
1
1
1
1
1
1
0.59
1
1
1
0.78
0.77
1
1
1
1
1
1
Assigning operations to workstations then becomes a simple task, since most of the
operations can only be run on one piece of equipment. The only operations where multiple
machines are needed are operation 1, operation 17, and operation 21. The assignment of
parts to these machines becomes pretty simple also, since there are only three parts to go
through operation 1, 2 parts to go through operation 17, and all three parts to go through
operation 21.

The assignment will be as follows:
Operation 1
Operation 17
Operation 21
Part 1
EDM 1
Laser 1
PHT 1
Part2
EDM 2
Laser 2
PHT2
Part3
EDM 3
PHT3
4 Simulation Modeling

Unit A
Unit C
Unit D
Throughput and machine usage improvements due to buffer locations and cell layout
improvement.
Throughput –
No buffer
(part 1,2,3)
248,177,117
132,113
265,196,184
Throughput –
With buffers
(part 1,2,3)
220,222,220
448,446
445,447,444
Buffer
Locations
Demand
EDM, Polyfill
Laser, Polyfill
PHT, Polyfill
320,230,290
320,230,290
320,230,290
Machine
usage before
50%
23%
65%
Machine
usage - after
75%
97%
98%
5 Discussion
The production cell to produce the demanded quantity of product is still best configured in a
cellular type layout. It actually ends up to be more of a combination between Product Layout
and Process Layout. The layout may also change a bit if other parts were looked at.
The best configuration for the Grinding Unit, however, is the only part of the cell that was still
struggling to meet demand. Since the demand was actually targeted lower than the maximum,
then it may be possible to use over time to take care of some of these issues. Possibly since there
were some issues with blockage of PolyFill, the parts could be done on the machine in the Hole
Drilling unit. The travel distance would go up but since travel time was modeled to be relatively
high, this may not matter.
The Hole Drilling Unit and the Finishing Unit succeeded immensely in improving efficiency
simply by strategically adding large buffers to the higher processing time or bottleneck
operations. With production levels capable of much more than the demand, it may be wise to
scale back in order to more effectively use the equipment. Unfortunately there were many
operations which could not be performed on other equipment.