Elimination of wastage is one of the main criteria for “All inclusive growth”. Among the seven kinds of waste in Lean Toyota Production System – wastage on rework and scrap is a vital one. To minimise this waste the root cause of the chronic issues are to be identified and the manufacturing process is to be made robust. When solving chronic issues, on many occasions, the solution is found to be modifying current product / process specifications. This is because the traditional practice of accepting conformance to specification as gateway to quality – has camouflaged the root cause. Hence use of Scientific tool like Shainin Techniques which is impervious to specification will enhance the finding of root cause – in long standing chronic issues. Shainin Technique is a problem solving tool which is used to solve the chronic problems in simple manner. Dorian Shainin , an American famous statistician has developed these techniques based upon more than 50 years of his experience. There is a famous saying at Motorala, wherein these techniques are used to attain “six sigma” Shainin Philosophy is that “Do not let the engineers do the Guessing,Let the parts do the Talking”.

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Shainin technique - Overview
Dorian Shainin , an American famous statistician has developed these
techniques based upon more than 50 years of his experience. There is a
famous saying at Motorala, wherein these techniques are used to attain “six
sigma”
Shainin Philosophy is that
“Do not let the engineers do the Guessing,
Let the parts do the Talking”.
Without Deming, the US, would not have had a quality philosophy;
Without Juran, it would not have had a quality direction;
Without Shainin, it would not have solved quality problems;

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Definition of Problem
Starter takes high current during load test(Run torque)in Starter
performance test stage in manufacturing assembly line.
Result in Assembly Line rejection.
Increase in Internal failure cost
What is the problem ?
What is the Effect of the problem?

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Shainin Problem solving
Speed, Efficiency and flexibility
Analysis
Shainin Tools : 1.Shainin Iso plot 2. Component Search
3. Paired Comparison 4. Shainin Full factorial 5. Scatter plot
GREEN Y – Current drawn more than specification in the Starter
Shainin Philosophy is that “Do not let the engineers do the
Guessing, Let the parts do the Talking

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To ensure the capability of the
measurement equipment-
Performance test rig shainin
isoplot plotted.
30 Samples Performance
current values during load test
measured on two separate
occasions and plotted as shown
in fig.
The result confirmed that the
discrimination ratio is greater
than 5 hence the accuracy of
the measurement system is
good.
Shainin’s Isoplot Method
316
318
320
322
324
326
328
330
332
334
336
338
340
342
344
346
348
350
316
318
320
322
324
326
328
330
332
334
336
338
340
342
344
346
348
350
Measurement 1 (Amps)
Measurement2(Amps)
M
Discrimination Ratio
D = Range / M
D = 31.7 / 4.87 = 6.50
M

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1st 2nd 3rd 4 th 5th
CHECK CHECK CHECK CHECK CHECK
1 331.9 332.0 332.2 332.6 333.2
2 332.5 334.2 334.6 333.5 332.0
3 335.2 332.4 335.5 334.5 336.2
4 333.6 334.5 335.2 334.2 334.2
5 333.5 332.6 330.3 333.6 332.5
6 332.4 333.2 332.5 334.5 335.1
7 358.2 358.6 359.4 360.2 360.5
8 362.3 360.2 356.6 358.2 356.2
9 359.6 357.5 359.2 358.2 358.2
10 360.2 362.5 359.6 358.2 359.2
11 359.2 358.2 357.2 356.8 358.6
12 357.4 357.2 358.2 356.5 356.5
SL.NO
Ball Park stage : 6 Good and 6 Bad Starters were taken for selecting Best of Best
(BOB) and Worst of Worst (WOW) samples for study .
SAMPLE
INITIAL
READING
FIRST
READING
SECOND
READING
BOB 330.3 332.6 334.2
WOW 362.5 360.4 359.4
CONFIRMS
NOT ASSY
VARIATION
Component Search method
D = (Median WOW – Median BOB) = (359.4-332.6)
d = (Range of WOW + Range of BOB)/2=(3.1+3.9)/2
D/d = 26.8/3.50= 7.65
D/d ratio > 1.25,
Red X is not due to
Assembly variation
D/d Ratio:
Good remains Good
& bad remains bad
after reassembly
D/d ratio used to check whether the group of best and bad unit
selected for experimentation really contains the Red X or Pink X.
Stage:1 Disassembly & Reassembly:
Stage:2 Test of significance:

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Sl No SWAPPING ON PRIORITY IN BOB IN WOW
1 INITIAL RUN 334.2 359.4
2 Fixing Bracket assembly 334.6 358.4
3 Reassemble and Rechecking 333.4 357.2
4 CE Bracket assembly 335.2 359.4
5 Reassemble and Rechecking 335.9 361.1
6 Armature assembly 337.6 360.5
7 Reassemble and Rechecking 335.6 359.4
8 Yoke assembly 358.9 332.4
9 Reassemble and Rechecking 336.2 359.2
10 Switch assembly 335.8 357.4
11 Reassemble and Rechecking 335.2 357.9
Component Search method
Elimination Stage :
Fixing bracket
assembly
Yoke
assembly
CE bracket
assembly
Armature
assembly
The following sub assemblies selected for swapping based on the
experience & knowledge and swapped in the assembly sequence.
Switch
assembly
Reversal

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Component Search method
320
325
330
335
340
345
350
355
360
365
370
375
380
INITIALRUN
FixingBracket
assembly
Reassemble
and
Rechecking
CEBracket
assembly
Reassemble
and
Rechecking
Armature
assembly
Reassemble
and
Rechecking
Yokeassembly
Reassemble
and
Rechecking
Switch
assembly
Reassemble
and
Rechecking
Yokeassembly
Reassemble
and
Rechecking
AMPS
Control Decision Limits : Mean (Bad)±2.776 d
UCLWOW
LCLWOW
UCLB OB
LCLB OB
Control Decision Limits : Mean (Good)±(2.776 d
bar/1.81)
d bar = BOB range + WOW range / 2
Capping
Run
Capping Run
Capping
run test
conducted
to
reconfirm
the
Swapping
results are
repeated
Swapping result - Graph
The decision limit for Swapping and product specification for Good & Bad are not same.
This decision limit is decided based on the variation during disassembly and reassembly
of the chosen pair of Good and bad.
It decides whether their response are interchanged during swapping.
The decision limit will be different for different pairs of good & bad Whereas product specification
will remains same for all units.

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Paired comparison method
.
All the Parameters in
yoke assembly are
verified and results
are written in
ascending order and
the end count
counted to know the
significance impact of
the parameter
measured. From
Tukey test the
magnetic flux in yoke
assembly is the root
cause with
confidence level of
99.7%
This is comparing
both specified and
unspecified
features of good &
bad to find
presence of
significanct
difference if any.

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B (Better) VS C (Current) TEST
Flux
kM
Current
Amps
168.6 334.2
170.2 332.6
169.6 333.2
167.6 335.6
168.0 334.9
166.7 336.6
164.6 338.2
167.6 335.6
Suspected Good Flux
Flux
kM
Current
Amps
153.1 359.4
153.8 358.9
154.6 357.9
151.2 361.2
152.6 359.9
153.2 359.3
155.2 356.4
153.5 359.2
Suspected Bad Flux
Magnetic flux (Kilomaxwells) indirectly
proportional to the current when torque remains
constant
Lower the magnetic flux higher the current drawn
for the same torque
Inference:
B vs C test is done to verify and confirm the findings. 8 Pairs of starters having flux of suspected
better and current values are assembled and Tukey test applied on the response-current drawn
Flux Current
170.2 332.6
169.6 333.2
168.6 334.2
168.0 334.9
167.6 335.6
167.6 335.6
166.7 336.6
164.6 338.2
155.2 356.4
154.6 357.9
153.8 358.9
153.5 359.2
153.2 359.3
153.1 359.4
152.6 359.9
151.2 361.2
16Endcount
With the
confidenc
e level of
99.98%

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Shainin - Full Factorial
Shainin “Full factorial” can tell the direction in which the significant factor has to be modified
to get the best output when the factor is less than or equal to four.
The Selection of Factor Levels - Adequacy of levels confirmed - through D/d Test Before
experiment
Confirmation of Significance – through B vs C Test
The details of the experiment results are shown in the Table
Factors Possible range
Voltage 800 – 900 V
D/d test used
To select levels of factor
To check whether the group of best
and bad unit selected for
experimentation really contains the
Red X or Pink X.
Low
level
High
level
Low
level
High
level
Low
level
High
level
Low
level
High
level
800V 825V 800V 850V 800V 875V 800V 900V
156 160 152 163 153 164 152 172
152 153 156 156 158 160 156 168
148 158 148 160 150 167 148 165
Experiment-1 Experiment-2 Experiment-3 Experiment-4

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Test for Significance - D/d Test
Levels Experiment -1 Experiment -2 Experiment -3 Experiment -4
800 - 825 V 800 - 850 V 800 - 875 V 800 - 900 V
Low 156 152 153 152
Low 152 156 158 156
Low 148 148 150 148
High 160 163 164 172
High 153 156 160 168
High 158 160 167 165
D 6 8 11 16
d 7.5 7.5 7.5 7.5
D/d ratio 0.80 1.07 1.47 2.13
Advantage
Voltage level of 825 – 850 as high level Not adequate for experiment- In case
experiment has been conducted with this level – we will find insignificance at the
end of experiment only – D/d ratio helps in avoiding that.
High level
between
875 to 900
to be chosen

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Voltage level from 875V to 900V gives best results with the
confidence level of 99%
Voltage Flux
875 164.6
880 166.7
885 168.5
890 168.9
895 170.2
900 171.6
Expected Good Voltage
Voltage Flux
800 152.1
805 153.1
810 154.2
815 155.4
820 156.6
825 158.1
Expected Bad Voltage
B (Better) VS C (Current) TEST
Tukey Test - End count calculation Voltage Flux
800 152.1
805 153.1
810 154.2
815 155.4
820 156.6
825 158.1
875 164.6
880 166.7
885 168.5
890 168.9
895 170.2
900 171.6
Endcount 12
Inference:
With the
confidenc
e level of
99.7%

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334.48
339.5
349.2
355.4
359.4
152.2
160.4
168.4
164.2
158.0
145
147
149
151
153
155
157
159
161
163
165
167
169
800 825 850 875 900
Voltage
MagneticFlux1
330
335
340
345
350
355
360
365
370
Current
Realistic Mfg.
Tolerance
TargetValue
Min
Max
The purpose of scatter plot is to fine tune optimized parameter & determine the
design center and also the realistic tolerances of process parameter.
Scatter plot drawn with voltage, magnetic flux and current value
The result clearly indicates that the voltage value nominal 880V and maximum
voltage 898V gives better results
Shainin – Scatter Plot

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Implementation of Corrective Action
Voltage specification fine tuned from 800V / 900V to
880V / 898V in the magnetizing process of yoke assembly.
Poka Yoke introduced to prevent the process start when the
voltage is less than 880V. (Process starts only when the voltage
reaches 880V)

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Summary
PROBLEM
First the adequacy of the measurement system confirmed through Isoplot
To identify what is wrong in the Red X - Paired comparison between good and
bad units is done. It revealed the deficiency in the specification of Magnetic flux.
Automobile Gear reduction Starter takes high current during load test in performance stage
Analysis summary
Then to narrow down quickly on the part contributing to the defect - Component
search is done. Yoke assembly is found as a Red-X
The finding is confirmed through B Vs C test

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Summary
ACTION TAKEN
RESULT
Lower magnetic flux in Yoke assembly resulting high current in Gear reduction starter
Magnetizing process specification optimized
High current during load test problem eliminated.
ROOT CAUSE
The tolerance for the Significant process parameter is set using Scatter plot
The process parameter contributing to the Flux level of the product is ascertained
through Factorial experiment

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This paper explained the use of Shainin Technique to solve chronic issue
by modifying the process specification
This case study emphasis's the Shainin principle of
“conformance to specification does not guarantee good quality” and
“Never hesitate to question the specification in case of problem
In manufacturing industries, to eliminate the vital waste, the chronic
issues are to be eliminated by making the process more robust.
Elimination of wastage is must for “All inclusive growth”.
Conclusion

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