Due to manufacture defects of key ways in gear and hollow shaft during milling process by Key seating and Fro-mag machine, it is being rejected by costumer, and here is a little analysis on it.

1. Rejection of Hollow shaft and Gear
due to internal keyway’s defects in
“Milling Process”
MACHINE:
 Key Seating Machine
 Fromag Machine
N T E R N S H I PI P R O J E C T
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2. N T E R N S H I PI P R O J E C T
 Rejection Rate for Key way Process _ Data range From January-2013 to March-2014
Month No. of Rejection % Rejection by Month
Jan-13 1 3.03030303
Feb-13 2 6.060606061
Mar-13 3 9.090909091
Apr-13 4 12.12121212
May-13 2 6.060606061
Jun-13 1 3.03030303
Jul-13 2 6.060606061
Aug-13 5 15.15151515
Sep-13 0 0
Oct-13 0 0
Nov-13 2 6.060606061
Dec-13 1 3.03030303
Jan-14 1 3.03030303
Feb-14 6 18.18181818
Mar-14 3 9.090909091
33
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3. N T E R N S H I PI P R O J E C T
Average Rejection Per Month
2.20
Current Performances
Target Rejection/Month
2.00
By March 2015
1
2
3
4
2
1
2
5
0 0
2
1 1
6
3
0
1
2
3
4
5
6
7
Rejection
Month
Month wise Rejection Data
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4. N T E R N S H I PI P R O J E C T
Machine wise key way Rejection
Machine Number of Rejection
Cumulative %
Rejection
Key Seating 32 96.96969697
Broaching KS 100 1 100
32
1
0
5
10
15
20
25
30
35
Key Seating Broaching KS 100
Machine wise key way Rejection
Neglect the Broaching KS
100 for analysis , Since it
has only one case of
Rejection
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5. N T E R N S H I PI P R O J E C T
Reason for Rejection Frequency % of Rejection
Wrong Dimension 22 68.75
Damage 5 15.625
Surface Roughness 3 9.375
Wrong Milling slot 1 3.125
Heat Treatment 1 3.125
Rejection Data Table for Key Seating
22
5 3 1 1
68.75 %
15.625 %
9.375 %
3.125% 3.125 %
0
10
20
30
40
50
60
70
80
Wrong Dimension Damage Surface Roughness Wrong Milling slot Heat Treatment
RejectionFrequency/%
Rejection Type
Rejection Chart
Frequency % of Rejection
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6. N T E R N S H I PI P R O J E C T
Rejection Type- Cause Frequency % Rejection
Wrong Dimension 22 68.75
Width + 15 46.875
Depth + 5 15.625
Taper Depth 1 3.125
Wrong axis inclination 1 3.125
Damage 5 15.625
Internal Key way wall Damage 5 15.625
Surface Roughness 3 9.375
Ra > 3.2 ,Not OK 2 6.25
Key-way width measured : 0.20/0.24mm from
USL, Demand: 32 JS9(±0.031) 1 3.125
Wrong milling slot 1 3.125
Heat Treatment 1 3.125
Pivot Analysis
84.375%
Neglect These
for Analysis
Purpose
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7. N T E R N S H I PI P R O J E C T
S.No. Rejection Comment/s Reason
1
Key way width plus
Dimension
Parallel key will be fitted on shaft and will create internal
backlash. Theoretically, it should not have any effect after that.
As bore dimension is with in designed tolerance data, this
deviation will not effect any functional activities.
2
Key-way width
Dimension
Reason for Non-Conformity
Keyway width found plus by 0.05mm from upper limit.(36JS9)
Recommended action
Already the necessary action(CAPA) has been taken by the
shift officer and operator.
Cutter with adjusted by tool room as per requirement.
3 Key-way width
Dimension
The deviation was generated due to machine vibration. The
same was already rectified with the help of maintenance.
4 Key way width
Dimension
To be used in GB KZA 225.
5 Key way width found
plus by 7mm,Key way
width required 18 JS9
,Measured 25 JS9
Job-card & drawing was not supplied/available to machine/operator
along with the job during operation.
8D
MD SL-KGP_8d 2014-04-03
6
Key way width plus.
Used by increasing the matting pinion key-way width & key width.
Re-GEN done as GR No. 5010521003 dt 20.08.13
Rejection Memo cancelled
Refer mail dated 21.08.13 by Mr. N. Dalal & Re mail dated 23.08.13
Width + (15)
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8. N T E R N S H I PI P R O J E C T
Width +(15)
S.No. Rejection Comment/s Reason
7 Key-way width plus by 10mm.,Specification:
22 JS9,Measured: 32 JS9
[Normal key-way made as per DIN 6885-1,
JS9]
Job-card & drawing was not supplied/available to
machine/operator along with the job during
operation.8D,MD SL-KGP_8d 2014-04-03
8 Key-way width plus by 10mm.Specification:
22 JS9,Measured: 32 JS9
[Normal key-way made as per DIN 6885-1,
JS9]
Job-card & drawing was not supplied/available to
machine/operator along with the job during
operation.8D,MD SL-KGP_8d 2014-04-03
9 Key way width plus by 0.2mm
Operator mistake
8D
IFAWS-13-07-003
10 REJECTED DUE TO KEYWAY WIDTH(+)
BY 0.08MM DURING KEYWAY ENDING
11 REJECTED DUE TO KEY WAY WIDTH (+)
BY 0.04 mm
12 Rejected due to Key Way width (+) by
0.03mm.
13 Rejected due to Key Way width (+) by
0.03mm.
14 Rejected due to internal keyway width (+) by
0.05mm.
15
WRONG KEYWAY WIDTH DONE DURING
INTERNAL KEYWAY OPERATION; OBSERVED -
28, REQUIRED - 25
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9. N T E R N S H I PI P R O J E C T
Depth + ( 05 )
S.No Rejection Reason Comments
Reason
1
Key-way depth
Dimension
Operator (Mr. Amal Koley was being informed
to be very much cautious while doing the
keyway operation specially for big gears.
Though the limit failed after two jobs.
2
Key-way depth
Dimension
Due to mal-functioning of limit switch key-way
depth got increased.
Limit switch has been repaired and
successive jobs are accepted without any
deviation.
3
1Pc Rejection due to keyway
depth (+) by 3.5mm.
Required : 311.9+0.3
Observed: 317.70.
8D
IFAWS-13-08-001
4
KEY WAY DEPTH + BY 1.3MM
FROM USL. SPECIFICATION
FOR KEY WAY DEPTH IS -
3.8+0.2mm, MEASURED VALUE
5.3mm
5
Dimension
Reason for Non-Conformity:
In key way milling m/c there is no scope for
adjusting the proper depth. Depth is being
purely set by the operators on the basis of
experience. - By Parts Mfg.
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10. N T E R N S H I PI P R O J E C T
Wrong Axis’s Inclination ( 01 )
S.No Rejection Reason Comments Reason
1
Key-way depth taper
Dimension
Comments by Parts Mfg.
Being the old machine (Key-way setting m/c) there is
always some taper but being the higher length this taper
is more.
The machine will be replaced within 2 months.
Taper Depth ( 01 )
S.No Rejection Reason Comments Reason
1
Dimension
Recommended action by Parts Mfg.:
During setting os this type so big gears at key-way seating machine
operators must be very much cautious, so that probability so axis out
does not occur.
Clamping wasn’t done
properly.
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11. N T E R N S H I PI P R O J E C T
H
Damage ( 05 )
S.No Rejection Comments Reason
1
Key way damaged during key-
way cutting.
Chilled material, some machinability related issue as
reported by Parts Mfg.
Hardness verified and found within the acceptable limit.
Hardness verified on Other parts (finished parts)
manufactured with same bar/heat batch, hardness
results found almost same (acceptable). There is no issue
of machinability of those parts.
2 Keyway wall damage during
keyway cutting.
3 Internal Keyway Damaged
during keyway cutting operation
4
Internal Key way wall damaged.
Surface very rough & uneven,
step present on key-way wall.
5 Both side key-way wall damaged
during key-way cutting.
Key-way wall surface roughness
not acceptable.
(TR 14-01-114-3)
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12. N T E R N S H I PI P R O J E C T
Surface Roughness ( 03 )
S.No Rejection Comments Reason
1 Deviation 1:
Key-way surface roughness / surface quality
non-conforming.
Deviation 2:
Key-way width measured over size by
0.20/0.24mm from USL.
Demand: 32 JS9 (±0.031)
Measured value: 32.23/32.27mm
Note: The same was offered at 18.02.14
finished part. Defect detected at finish part
inspection, rectification done but not
satisfactory.
Hence rejected (withdrawn the QM lot & re
GRN done at location 16, scrap yard) ->
Rejected
2 Key way surface roughness NOT OK.
Very rough.
Ra > 3.2 NOT OK
3 Key way surface roughness NOT OK.
Very rough.
Ra > 3.2 NOT OK
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13. N T E R N S H I PI P R O J E C T
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