1

Rod Support Systems Cost Comparison

Ref. Time Estimation Booklet

2.810 Nov 2, 2016, T. Gutowski

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Example Problem

Job Shop to large scale production

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Picking Manufacturing Systems

•  Job Shops – very flexible, low volumes, high variety

•  Flow shops – arrange dedicated equipment in order of operations, balance flow, deskill jobs

•  Transfer Lines – automated transfer, hardwired flow shop •  Flexible Mfg. Systems (FMS) – automate transfer between

machines, allow skipping and double back

•  Toyota cell – special arrangement of flow shop with many machines per operator

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Job shops - flexible

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Flow Shop - dedicated

L

M

D G L M

A A

L M G G

L D

Receiving

Shipping

6

VM

Toyota Mfg Cell

S

L

L

HM

VM

G

Final inspection

Finished part cart

Raw material cart

Worker position

Worker path

Part movement

Decoupler (Kanban square)

OUT

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Machining Systems Classification

Ref J T. Black

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Designing a cell for the “Rod Support” Goal one part every 2.5 minutes

•  Material; Aluminum extrusion •  Tolerance + 0.005”, except for the two 0.50” radius corners

which have + 1/64”

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Process planning How would you machine this part?

Assumption: 1.  We begin with a stock size of 2.5” X 2.25” X 12” 2.  This will be manufactured in a job shop for very low quantity

We will use: -  A bandsaw to roughly cut the stock to size -  A manual vertical mill to create the planar features and the holes -  A belt sander to sand the radii ( assuming the tolerance is not

very high)

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Process plan Machine Operation

Horizontal band saw Saw stock to ~4.125”

Manual vertical mill

Mill two ends to length 4”

Mill width to 2”

Mill out 2”X1.5”X4”

Drill hole 1” diameter

Bore 1” radius

Belt sender Sand 0.5 radii

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Time estimation (minutes) Machine Operation (V = Volume, A =

Area, P = Perimeter) Fixture Tool

Change Run (R=Rough, F=Finish)

Deburr/Inspect/ Measure

Horizontal band saw

Saw stock to ~4.125” A = 5.6525 in2, P = 9 in 0.23 - 2.02 0.30D, 0.05I

Manual vertical mill

Mill two ends to length 4” V = 0.703 in3 A = 11.25 in2, P = 19in

0.20 0.20 2

0.13R 0.75F

0.63D, 0.05I, 0.13M

Mill width to 2” V = 2.5 in3 A = 10 in2, P = 13in

0.20 - 0.46R 0.67F

0.43D, 0.05I, 0.13M

Mill out 2”X1.5”X4” V = 12 in3 A = 14 in2, P = 15in

- - 2.19R 0.93F

0.50D, 0.05I 0.13M, 0.13M

Drill hole 1” diameter - Center drill - Pilot drill ½” - Pilot drill 63/64” - Ream

0.20

2 2 2 2

0.03 0.05 0.04 0.01

0.21D, 0.05I 0.17M

Bore 1” radius V = 0.79 in3 A = 1.57 in2, P = 7.28in

0.20 2 0.96R 0.01F

0.24D, 0.05I 0.06M

Belt sender Sand 0.5 radii V = 0.05 in3 A = 0.79 in2, P = 3.14in

0.08 - 0.20R 0.21F

0.10D, 0.05I 0.06M, 0.06M

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Summary Times (minutes) fixture tool change cutting inspect

Saw 0.23 2.02 .35

Mill -ends 0.4 2.0 0.88 .81 -width 0.2 1.13 .61 -hog out 3.12 .81 -hole 0.2 8.0 0.13 .43 -bore 0.2 2.0 0.97 .35

Sand 0.8 0.41 .27

TOTAL 1.31 12.0 8.66 3.63 Total = 25.6 minutes

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Summary Times (minutes) fixture tool change cutting inspect

Saw 0.23 2.02 .35

Mill -ends 0.4 2.0 0.88 .81 -width 0.2 1.13 .61 -hog out 3.12 .81 -hole 0.2 8.0 0.13 .43 -bore 0.2 2.0 0.97 .35

Sand 0.8 0.41 .27

TOTAL 1.31 12.0 8.66 3.63 Total = 25.6 minutes

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Cell Features

1.  Start with extrusion (eliminate milling) 2.  Use form drill 3.  Use hole cutter for 1” dia

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Cellular Layout (One operator)

Cold Saw

Radial Arm Drill Press

w/ hole saw

Drill Press w/ form drill

Belt Sander

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Cellular Layout (One operator)

# Machine

Ope ration (V = volume , A=Are a, P = pe rime te r)

FixtureTool

Change

Run (R= rough, F = finish)

De burr, Inspe ct,

Me asure (Time )

Manual Time

Machine Time

20Radial Arm Drill Press

1" Rad half hole use hole cutter

0.12 0 0.24 0.35 0.47 0.24

30 Drill Press 1" dia from drill 0.12 0 0.04 0.43 0.55 0.040.2 0 0.1 0.270.2 0 0.1

0.1

0.72

0.4Sand 2*0.5" radBelt Sander40 0.8

0.32 0 0.72 010 Cold SawSaw extrusion to 4", A=2, P=9 without

D+I+M

0.32

Note; Times in minutes

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Cellular Layout (One operator) RA Drill Press .47+.05/.24

Walking Time 0.2Total Manual Time 2.34Max. Machine Time 0.72

Cycle Time 2.34

Cold Saw .32+.05/.72

Drill Press .55+.05/.04

Belt Sander .8+.05/.4

Walking time

manual

Note: times in minutes

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Standard Work for Rod Support Cell

PART: Rod Support Operators:PROCESS# OPERATION Man Walk Auto

1 Extrusion 32 Cold Saw 19 3 433 Rad Arm Drill Press 28 3 144 Drill Press 33 3 25 Belt Sander 48 3 0

16060 80 100 120TIME {secs}

20 40 140

Note; Times in Seconds

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Cost Estimate

•  Variable Costs – labor and materials

•  Fixed Costs – equipment C/N

N

C = F + V N

N*

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Job shop (Small quantities, Aluminum block)

# Machine

Operation (V = volume, A=Area, P = perimeter)

Fixture Tool Change

Run (R= rough, F =

finish)

Deburr, Inspect, Measure

(Time)

Deburr, Inspect, Measure

0 0.3 Deburr0.05 Inspect

0.20 2 0.13 0.63 Deburr0.20 0.75 0.05 Inspect

0.13 Measure0.46 0.43 Deburr0.67 0.05 Inspect

0.13 Measure2.19 0.5 Deburr0.93 0.05 Inspect

0.13 Measure0.13 Measure

Drill hole 1" diameter

* Center drill*Pilot drill 1/2" 2 0.05 0.05 Inspect

*Pilot drill 63/64" 2 0.04 0.17 MeasureReam 2 0.01

2 0.96 0.24 Deburr0.1 0.05 Inspect

0.06 Measure0.2 0.1 Deburr

0.05 Inspect0.06 Measure0.06 Measure

Totals 1.31 12 8.75 3.63 25.69

3700.21

00.08Sand 0.5" radii,

V=0.05, A=0.79, P=3.14

250

60 2

0.03 0.21 Deburr

Bore 1" radius, V=0.79, A=1.57,

P=7.280.2

0

0

0.2

2

Mill out 2"*1.5"*4", V=12, A=14, P=15

240 0.00

30 2Mill width to 2",

V=2.5 A=10 P=130.20

20 2Mill two ends to

length 4'', V=0.703, A=11.25, P=19

Saw stock to ~4.125", A=5.625,

2.020.23 110

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Job shop (Large quantities, Aluminum extrusion)

# MachineOperation (V = volume, A=Area,

P = perimeter)Fixture Tool

Change

Run (R= rough, F =

finish)

Deburr, Inspect, Measure

(Time)

Deburr, Inspect, Measure

0.3 Deburr

0.05 Inspect

0.13 MeasureDrill hole 1" diameter

* Center drill*Pilot drill 1/2" 2 0.05 0.05 Inspect

*Pilot drill 63/64" 2 0.04 0.17 MeasureReam 2 0.01

2 0.96 0.24 Deburr0.1 0.05 Inspect

0.06 Measure0.2 0.1 Deburr

0.05 Inspect0.06 Measure0.06 Measure

Totals 0.71 10 2.32 1.53 14.56

Saw extrusion to 4", A=2, P=9

0.23

Sand 0.5" radii, V=0.05, A=0.79,

P=3.140.0840 3

10 1

0.21

00.21

0 0.72

Deburr

30 2Bore 1" radius, V=0.79,

A=1.57, P=7.280.2

20 2 0.2

2 0.03

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CNC production, aluminum block

# Machine

Operation (V = volume, A=Area, P = perimeter)

Fixture Tool Change

Run (R= rough, F =

finish)

Deburr, Inspect, Measure

(Time)

Deburr, Inspect, Measure

0.3 Deburr0.05 Inspect0.13 Measure

2.19 0.5 Deburr0.93 0.05 Inspect

0.13 Measure0.13 Measure

0.01 0.1 Deburr0.05 0.05 Inspect

0.06 Measure0.06 Measure

Drill hole 1" diameter

* Center drill*Pilot drill 1/2" 0.5 0.05 0.05 Inspect

*Pilot drill 63/64" 0.5 0.04 0.17 MeasureReam 0.5 0.01

0.96 0.24 Deburr0.1 0.05 Inspect

0.06 MeasureTotals 0.58 3 6.39 2.34 12.31

0

Deburr

50 2Bore 1" radius,

V=0.79, A=1.57, P=7.28

0.13 0.5

0.03

Contour mill 0.5" radii, V=0.05,

A=0.79, P=3.14230

0.21

00

40 2 0

0.5

2.02

20 2Mill out

2"*1.5"*4", V=12, A=14, P=15

0.13

10 1Saw stock to 4", A=5.625, P=9

0.32

0.5

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Flow shop (Unbalanced work load)

# Machine

Ope ration (V = volume , A=Are a, P = pe rime te r)

FixtureTool

Change

Run (R= rough, F =

finish)

De burr, Inspe ct,

Me asure (Time )

Deburr, Inspect, Measure

Operation Time

0.3 Deburr0.05 Inspect0.13 Measure

0.05 Inspect0.17 Measure

0.2 0.2 0.1 Deburr0.2 0.21 0.05 Inspect

0.06 Measure0.06 Measure0.24 Deburr0.05 Inspect0.06 Measure

Totals 0.96 0 1.41 1.53 3.90

0 0.72

20 2A 0.12

10 1Saw extrusion to 4",

A=2, P=9 0.32

0.21 Deburr

30 3Sand 0.5" radii,

V=0.05, A=0.79, P=3.14

40 2B

Drill with hole cutter 1" radius (use 0.82

in̂ 3/min) V=0.196, P=7.28

0.12 0

Drill hole 1" diameter (R=6.28)

0 0.04

0

0.24

1.52

0.59

1.08

0.71

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Flow shop (Improved work load) # Machine

Ope ration (V = volume , A=Are a, P = pe rime te r)

FixtureTool

Change

Run (R= rough, F =

finish)

De burr, Inspe ct, Me asure

(Time )

Deburr, Inspect, Measure

Operation Time

0.3 Deburr0.05 Inspect0.13 Measure

0.05 Inspect0.17 Measure

0.2 0.2 0.1 Deburr0.2 0.21 0.05 Inspect

0.06 Measure0.06 Measure0.24 Deburr0.05 Inspect0.06 Measure

Totals 0.96 0 1.41 1.53 3.90

0.71

20

1.04

0.21

10 1Saw extrusion to

4", A=2, P=9 without D+I+M

0.32

2A

Deburring+ Inspect+Measure of sawing +Drill hole 1" diameter

(R=6.28)1.07

30 3Sand 0.5" radii,

V=0.05, A=0.79, P=3.14

0 1.08

0.12 0

40 2B

Drill with hole cutter 1" radius (use

0.82 in̂ 3/min) V=0.196, P=7.28

0.12

0 N/A

0 0.24

0 0.72

0.04 Deburr

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Comparison

Time (Min./ part)

LaborLabor cost

($/hr)Equipme nt

Equipme nt cost ($)

Mate rial Cost ($/part)

Horizontal Bandsaw

1,700

Vetical Mill (Manual)

15,000

Belt Sander 1,600Cold Saw 15,000

Vetical Mill (Manual)

15,000

Belt Sander 1,600Cold Saw 15,000

CNC Vertical Mill w/ Tool

Changer125,000

Auto Indexer 2,000Cold Saw 15,000Drill Press 10,000

Radial Arm Drill Press

17,000

Sander 2,500Cold Saw 15,000Drill Press 10,000

Radial Arm Drill Press

17,000

Sander 2,500Cold Saw w/

feed20,000

Drill Press w/ feed

7,500

Radial Arm Drill Press w/

feed22,000

Sander 1,500

1.92

1.08Flow Shop 2

37.131 Multi-

functional worker

2.34Cellular 1

1.92

120 1.924 Medium

skilled workers

CNC Production

1204 Medium

skilled workers

1.52Flow Shop 1

2.88

1 Experienced

CNC Machinist

37.139.31

14.56Job Shop 2

2.88

1.9230.381

Experienced Machinist

Job Shop 1 25.691

Experienced Machinist

30.38

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Comparison of Various System

Time (Min./ part)

LaborLabor cost

($/hr)Equipme nt

Equipme nt cost ($)

Mate rial Cost ($/part)

Horizontal Bandsaw

1,700

Vetical Mill (Manual)

15,000

Belt Sander 1,600Cold Saw 15,000

Vetical Mill (Manual)

15,000

Belt Sander 1,600Cold Saw 15,000

CNC Vertical Mill w/ Tool

Changer125,000

Auto Indexer 2,000Cold Saw 15,000Drill Press 10,000

Radial Arm Drill Press

17,000

Sander 2,500Cold Saw 15,000Drill Press 10,000

Radial Arm Drill Press

17,000

Sander 2,500Cold Saw w/

feed20,000

Drill Press w/ feed

7,500

Radial Arm Drill Press w/

feed22,000

14.56Job Shop 2

2.88

1.9230.381

Experienced Machinist

Job Shop 1 25.691

Experienced Machinist

30.38

2.88

1 Experienced

CNC Machinist

37.139.31CNC

Production

1004 Medium

skilled workers

1.52Flow Shop 1 1.92

100 1.924 Medium

skilled workers

1.92

1.08Flow Shop 2

37.131 Multi-

functional worker

2.34Cellular 1

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Cost Calculation without considering Inventory holding cost

Cycle Time (min)

Material ($/lb)

Labor ($/hr)Fixed Cost

($)Variable Cost

($)Job Shop 1 25.69 2.88 30.38 18,300 15.89Job Shop 2 14.56 1.92 30.38 31,600 9.29

CNC 9.31 2.88 37.13 142,000 8.64Flow Shop 1 1.52 1.92 100 44,500 4.45Flow Shop 2 1.08 1.92 100 44,500 3.72

Cellular 2.34 1.92 37.13 51,000 3.37

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Cost for increasing production volume

Unit cost vs. Number of Units

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

0 10000 20000 30000 40000 50000 60000

Production number

Uni

t co

st

Job Shop1

Job Shop2

CNC production

Flow Shop1

Flow Shop 2

Cellular Mfg.

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Close-Up

Flow Shop Cell

Job Shop

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Cost for increasing production volume

Production Number

Job Shop1 Job Shop2 CNC production

Flow Shop1 Flow Shop 2 Cellular Mfg.

500 52.5 72.5 292.6 94.0 93.1 105.4700 42.0 54.4 211.5 68.5 67.7 76.21,000 34.2 40.9 150.6 49.5 48.6 54.43,000 22.0 19.8 56.0 19.8 18.9 20.45,000 19.5 15.6 37.0 13.9 13.0 13.67,000 18.5 13.8 28.9 11.3 10.4 10.710,000 17.7 12.5 22.8 9.4 8.5 8.530,000 16.5 10.3 13.4 6.4 5.6 5.150,000 16.3 9.9 11.5 5.9 5.0 4.4

Lowest variable cost

Note: annual capacity for cell is >150,000 parts

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COMMENTS (parts/shift)

•  Job Shop (33) & CNC (52): flexible, skilled labor

•  Flow Line (444): high output, 4 workers •  Cell (205): lowest variable cost, but

demanding work