operations & manufacturing strategies

OMS 605 1

Pro-Coat at HAL,Inc.

A Case Study Write-up for the OMS 605 W-12 Term University of Michigan- Ross School of Business

Aniruddha Srinath Rehan Syed Sam Beck Yue Ma

OMS 605 2

Critical Process is Expose:-Critical Bottleneck = 2879/day

W0= 1353

Note:-

-Consider Clean1, Coat1 & Coat2 together as part of a single equipment .

For the equipment, consider the data of the conveyor

- The exposing is done in batches (jobs, as per the problem) and the time

Raw Process time= T0= 546 min= 546/(60*24)= 0.47 day

Critical WIP= Critical bottleneck x Raw process time

2879 x 0.47=

Critical WIP=W= 1500 (as stated in the class slide)

is for the batch size.

- The same analogy holds for touch up also.

TH= w(w+W0-1)*rb= 1500/(1500+1343-1)*2879= 1520

However, Ken is only getting an average of around 1200 per day.

The layout

Machine

Name

Process

or Load

Time

(min)

Std Dev

Process

Time

(min)

Conveyor

Trip Time

(min)

Number

of

Machines MTTF MTTR Avail

Setup

Time

Clean1 0.33 0 15 1 80 4 0.95 0

Coat1 0.33 0 15 1 80 4 0.95 0

Coat2 0.33 0 15 1 80 4 0.95 0

Expose 103 10 - 5 300 4 0.99 10

Develop 0.33 0 2.67 1 300 3 0.99 0

Inspect 0.5 0.5 - 2 - - 1.00 0

Bake 0.33 0 100 1 300 3 0.99 0

MI 161 64 - 8 - - 1.00 0

Touchup 9 0 - 1 - - 1.00 0

The Numbers- At a glance

Calculate for Practical Worst Case (PWC)

Batch Size 60

Hours/Day 19.5

Machine

Name

Process

or Load

Time

(min)

Std Dev

Process

Time

(min)

Conveyor

Trip Time

(min)

Number

of

Machines MTTF MTTR Avail

Setup

Time

Rate

(p/day)

Time

(min)

Clean1 0.33 0 15 1 80 4 0.95 0 3377 36.5

Coat1 0.33 0 15 1 80 4 0.95 0 3377 36.5

Coat2 0.33 0 15 1 80 4 0.95 0 3377 36.5

Expose 103 10 - 5 300 4 0.99 10 3065 114.5

Develop 0.33 0 2.67 1 300 3 0.99 0 3510 22.7

Inspect 0.5 0.5 - 2 - - 1.00 0 4680 0.5

Bake 0.33 0 100 1 300 3 0.99 0 3510 121.0

MI 161 64 - 8 - - 1.00 0 3488 161.0

Touchup 9 0 - 1 - - 1.00 0 7800 9.0

538

Present- TH= 304, WIP=1353


OMS 605 3

ASSUMPTIONS

1. Current arrival rate is 154 as that is the rate required to produce 3000 with no yield loss.

2. Accordingly, our initial yield rate is 92% to get us closer to the daily throughput of 1200

3. The starving and blocking at the expose bottleneck brings down the 1304 projected throughput to the 1200 throughput given in the case.

4. Cleaning, Coat 1, and Coat 2 are cominable into one conveyer

5. Conveyers can be models as the loader and belt

6. The parallel servers in the belt is equal to the capacity of the loader, which is 180 in this case.

Analysis of the 1200 Throughput situation

VUT Calculator Wallace J. Hopp and Mark L. Spearman, 2000 Load CCC Expose Load Develop Inspect Load Bake MI Touchup

MEASURE: STATION: 1 2 3 4 5 6 7 8 9 10

Arrival Rate (parts/hr) ra 154.000 141.680 130.346 119.918 110.325 101.499 93.379 85.90837659 79.03570646 72.71284995

Arrival CV ca2

0.000 0.000 0.468 0.632 0.357 0.358 0.473 0.460693456 0.7623802 0.739929982

Natural Process Time (hr) t0 0.006 0.750 0.029 0.006 0.045 0.008 0.006 1.667 0.045 0.003

Natural Process SCV c02

0.000 0.000 0.423 0.000 0.423 1.000 0.000 0.000 0.158 0.000

Number of Machines m 1 180 5 1 180.000 2 2 180.000 8 1

MTTF (hr) mf 80 26.66 300 300 300 200 200 300 200 200

MTTR (hr) mr 0 4 10 0 3 0 0 3 0 0

Availability A 1.000 0.870 0.968 1.000 0.990 1.000 1.000 0.99009901 1 1

Effective Process Time (failures only) te' 0.006 0.863 0.030 0.006 0.045 0.008 0.006 1.683333333 0.044722222 0.0025

Eff Process SCV (failures only) ce2' 0.000 1.210 22.245 0.000 1.745 1.000 0.000 0.035290658 0.158018595 0

Batch Size k 1 1 60 1 1 1 1 1 60 60

Setup Time (hr) ts 0.000 0.000 0.250 0.000 0.000 0.000 0.000 0 0 0

Setup Time SCV cs2

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0

Arrival Rate of Batches ra/k 154.000 141.680 2.172 119.918 110.325 101.499 93.379 85.90837659 1.317261774 1.211880832

Eff Batch Process Time (failures+setups) te = kt0/A+ts 0.006 0.863 2.024 0.006 0.045 0.008 0.006 1.683333333 2.683333333 0.15

Eff Batch Process Time Var (failures+setups) k*s02/A

2+ 2mr(1-A)kt0/A+ss

20.000 0.900 1.167 0.000 0.004 0.000 0.000 0.1 0.018962963 0

Eff Process SCV (failures+setups) ce2

0.000 1.210 0.285 0.000 1.745 1.000 0.000 0.035290658 0.002633643 0

Utilization u 0.924 0.679 0.879 0.660 0.028 0.423 0.257 0.803402411 0.441831553 0.181782125

Departure SCV cd2

0.000 0.468 0.632 0.357 0.358 0.473 0.461 0.7623802 0.739929982 0.715479187

Yield y 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920

Final Departure Rate ra*y 141.680 130.346 119.918 110.325 101.499 93.379 85.908 79.03570646 72.71284995 66.89582195

Final Departure SCV ycd2+(1-y) 0.080 0.511 0.662 0.409 0.409 0.515 0.504 0.781389784 0.760735583 0.738240852

Utilization u 0.924 0.679 0.879 0.660 0.028 0.423 0.257 0.803402411 0.441831553 0.181782125

Throughput TH 141.680 130.346 119.918 110.325 101.499 93.379 85.908 79.03570646 72.71284995 66.89582195

Queue Time (hr) CTq 0.000 0.000 0.920 0.003 0.000 0.001 0.000 0.000228062 0.016261241 0.012329177

Cycle Time (hr) CTq+te 0.006 0.863 2.944 0.009 0.045 0.010 0.006 1.683561396 2.699594574 0.162329177

Cumulative Cycle Time (hr) S i(CTq(i)+te(i)) 0.006 0.869 3.813 3.821 3.866 3.876 3.882 5.565253056 8.26484763 8.427176808

WIP in Queue (jobs) raCTq 0.000 0.001 119.930 0.404 0.000 0.143 0.011 0.019592463 1.285218674 0.896489625

WIP (jobs) raCT 0.924 122.204 383.735 1.063 4.959 0.989 0.525 144.6320264 213.3643644 11.80341712

Cumulative WIP (jobs) S i(ra(i)CT(i)) 0.924 123.128 506.863 507.926 512.885 513.874 514.399 769.876 1010.453 1210.68

Throughput per day 2762.760 2541.739 2338.400 2151.328 1979.222 1820.884 1675.213 1541.196 1417.901 1304.469


OMS 605 4

-Reducing variability decreases utilization.

-However, that alone does not increase throughput.

-We need lesser WIP in order to achieve greater throughput at the

-However, we also need to expand capacity significantly (like adding another

expose machine) in order to really reach 3000 units. `

-This will require a huge cost investment as well as a large expansion in the

building.

-We want to try the other options mentioned above.

same utilization level.

T

TH=1304, CT=8.42 hrs, WIP=1211

TH=1353, CT=9.1 hrs, WIP=1500

2. Cut MTTR of BN by half 3. Cut set-up time of BN 4. Maximise use of BN process 5. Decrease Std variation of process time

1. Increase working hours 6. Add operator to BN 7. Have someone working BN processes during breaks & shift changes

Options to work out


OMS 605 5

1. Increase Working Hours to 21 hours- Get .5 hours by making members in each shift work 10 minutes overtime (during shift change)

We can have workers from less utilized areas take a break when the line is running and ask them to work on the bottlenecks during breaks

Cumulative ChangeWIP 1211 0% Change

TH 1404 8% Increase

Increase the cycle time


MEASURE: STATION: 1 2 3 4 5 6 7 8 9 10


Arrival CV ca2

0.000 0.000 0.543 0.666 0.330 0.331 0.469 0.455976946 0.809392828 0.772712072



0.000 0.000 0.423 0.000 0.423 1.000 0.000 0.000 0.158 0.000


MTTF (hr) mf 80 26.66 300 300 300 200 200 300 200 200

MTTR (hr) mr 0 4 10 0 3 0 0 3 0 0

Availability A 1.000 0.870 0.968 1.000 0.990 1.000 1.000 0.99009901 1 1



Batch Size k 1 1 60 1 1 1 1 1 60 60

Setup Time (hr) ts 0.000 0.000 0.250 0.000 0.000 0.000 0.000 0 0 0

Setup Time SCV cs2

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0




2+ 2mr(1-A)kt0/A+ss

20.000 0.900 1.167 0.000 0.004 0.000 0.000 0.1 0.018962963 0


0.000 1.210 0.285 0.000 1.745 1.000 0.000 0.035290658 0.002633643 0

Utilization u 0.995 0.731 0.947 0.710 0.030 0.455 0.277 0.865202596 0.475818596 0.195765365

Departure SCV cd2

0.000 0.543 0.666 0.330 0.331 0.469 0.456 0.809392828 0.772712072 0.743098594

Yield y 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920



Utilization u 0.995 0.731 0.947 0.710 0.030 0.455 0.277 0.865202596 0.475818596 0.195765365

Throughput TH 152.578 140.372 129.142 118.811 109.306 100.562 92.517 85.11537619 78.3061461 72.04165441

Queue Time (hr) CTq 0.000 0.000 2.763 0.004 0.000 0.002 0.000 0.001253058 0.023372309 0.014106915




WIP (jobs) raCT 0.995 131.609 672.011 1.290 5.340 1.089 0.567 155.8523961 230.382269 12.85058006




OMS 605 6

2. Add workers to the expose process. In the previous step, we had shown the number of machines in expose as 5 as we were having people from other processes pitch to complete the expose process. Increasing manpower here would create a more robust process.


TH 1404 8% Increase

Add operators for expose- it is not increasing throughput but is improving my process


MEASURE: STATION: 1 2 3 4 5 6 7 8 9 10


Arrival CV ca2

0.000 0.000 0.543 0.666 0.330 0.331 0.469 0.455976946 0.809392828 0.772712072



0.000 0.000 0.423 0.000 0.423 1.000 0.000 0.000 0.158 0.000


MTTF (hr) mf 80 26.66 300 300 300 200 200 300 200 200

MTTR (hr) mr 0 4 10 0 3 0 0 3 0 0

Availability A 1.000 0.870 0.968 1.000 0.990 1.000 1.000 0.99009901 1 1



Batch Size k 1 1 60 1 1 1 1 1 60 60

Setup Time (hr) ts 0.000 0.000 0.250 0.000 0.000 0.000 0.000 0 0 0

Setup Time SCV cs2

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0




2+ 2mr(1-A)kt0/A+ss

20.000 0.900 1.167 0.000 0.004 0.000 0.000 0.1 0.018962963 0


0.000 1.210 0.285 0.000 1.745 1.000 0.000 0.035290658 0.002633643 0

Utilization u 0.995 0.731 0.947 0.710 0.030 0.455 0.277 0.865202596 0.475818596 0.195765365

Departure SCV cd2

0.000 0.543 0.666 0.330 0.331 0.469 0.456 0.809392828 0.772712072 0.743098594

Yield y 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920



Utilization u 0.995 0.731 0.947 0.710 0.030 0.455 0.277 0.865202596 0.475818596 0.195765365

Throughput TH 152.578 140.372 129.142 118.811 109.306 100.562 92.517 85.11537619 78.3061461 72.04165441

Queue Time (hr) CTq 0.000 0.000 2.763 0.004 0.000 0.002 0.000 0.001253058 0.023372309 0.014106915




WIP (jobs) raCT 0.995 131.609 672.011 1.290 5.340 1.089 0.567 155.8523961 230.382269 12.85058006




OMS 605 7

3. Reduce set-up & repair time through out the line- This is decreasing my WIP

Cumulative Change

WIP 874 28% Change

TH 1404 8% Increase

Reduce set up time & repair time


MEASURE: STATION: 1 2 3 4 5 6 7 8 9 10


Arrival CV ca2

0.000 0.000 0.444 0.558 0.276 0.277 0.427 0.416611768 0.794256567 0.761002711



0.000 0.000 0.423 0.000 0.423 1.000 0.000 0.000 0.158 0.000


MTTF (hr) mf 80 26.66 300 300 300 200 200 300 200 200

MTTR (hr) mr 0 2 5 0 1.5 0 0 1.5 0 0

Availability A 1.000 0.930 0.984 1.000 0.995 1.000 1.000 0.995024876 1 1



Batch Size k 1 1 60 1 1 1 1 1 60 60

Setup Time (hr) ts 0.000 0.000 0.125 0.000 0.000 0.000 0.000 0 0 0

Setup Time SCV cs2

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0




2+ 2mr(1-A)kt0/A+ss

20.000 0.225 0.308 0.000 0.002 0.000 0.000 0.025 0.018962963 0


0.000 0.346 0.088 0.000 0.757 1.000 0.000 0.008910671 0.002633643 0

Utilization u 0.995 0.683 0.875 0.710 0.030 0.455 0.277 0.860919415 0.475818596 0.195765365

Departure SCV cd2

0.000 0.444 0.558 0.276 0.277 0.427 0.417 0.794256567 0.761002711 0.731837984

Yield y 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920 0.920



Utilization u 0.995 0.683 0.875 0.710 0.030 0.455 0.277 0.860919415 0.475818596 0.195765365

Throughput TH 152.578 140.372 129.142 118.811 109.306 100.562 92.517 85.11537619 78.3061461 72.04165441

Queue Time (hr) CTq 0.000 0.000 0.574 0.004 0.000 0.002 0.000 0.000957157 0.022936646 0.013893145




WIP (jobs) raCT 0.995 123.019 343.082 1.196 5.314 1.082 0.566 155.0540477 230.3451874 12.83384052




OMS 605 8

4. Increase the yield to 94%. This increases my throughput but also requires me to further reduce my BN set-up time


TH 1741 34% Increase

Increase yield & also reduce expose set up time


MEASURE: STATION: 1 2 3 4 5 6 7 8 9 10


Arrival CV ca2

0.000 0.000 0.464 0.547 0.233 0.234 0.431 0.417161598 0.916188957 0.732581723



0.000 0.000 0.423 0.000 0.423 1.000 0.000 0.000 0.158 0.000


MTTF (hr) mf 80 26.66 300 300 300 200 200 300 200 200

MTTR (hr) mr 0 2 2.5 0 1.5 0 0 1.5 0 0

Availability A 1.000 0.930 0.992 1.000 0.995 1.000 1.000 0.995024876 1 1



Batch Size k 1 1 60 1 1 1 1 1 60 60

Setup Time (hr) ts 0.000 0.000 0.125 0.000 0.000 0.000 0.000 0 0 0

Setup Time SCV cs2

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0 0 0




2+ 2mr(1-A)kt0/A+ss

20.000 0.225 0.093 0.000 0.002 0.000 0.000 0.025 0.018962963 0


0.000 0.346 0.027 0.000 0.757 1.000 0.000 0.008910671 0.002633643 0

Utilization u 0.995 0.698 0.907 0.758 0.032 0.507 0.315 0.989791689 0.753529671 0.23757246

Departure SCV cd2

0.000 0.464 0.547 0.233 0.234 0.431 0.417 0.916188957 0.732581723 0.691234317

Yield y 0.940 0.940 0.940 0.940 0.940 0.940 0.940 0.940 0.940 0.940



Utilization u 0.995 0.698 0.907 0.758 0.032 0.507 0.315 0.989791689 0.753529671 0.23757246

Throughput TH 155.895 146.542 137.749 129.484 121.715 114.412 107.548 101.094664 95.02898412 89.32724508

Queue Time (hr) CTq 0.000 0.000 0.766 0.005 0.000 0.002 0.000 0.159458224 0.383717576 0.017120438




WIP (jobs) raCT 0.995 125.693 384.195 1.405 5.791 1.252 0.648 197.2914231 310.062481 15.88128542




OMS 605 9

- After carrying out 4 changes in the HAL procoat line, we have been able to take our TH, WIP situation closer to the Best Case Line

- However, we have concluded that we are still not able to meet Ken's requirement of 3000 boards a day.

- We have worked on the WIP front, reducing the WIP to the best extent possible.

- If Ken and Mr Petitto still insist on the 3000 figure, they need to make significant investments in equipment (like the Expose equipment)

and building, as well as increasing manpower, which is a business stand-off.

Initial TH & WIP condition

TH & WIP condition after implementation of proposals 1~4

In Conclusion, but in need of further action


OMS 605 10

THANK YOU FOR THE INITIATION INTO THE FACTORY PHYSICS CULT !
