Lever 3000 Load

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Lever 3000 (Load class 2000 Nm)
Missing Teeth Segment
20 March 2019
Adient Proprietary and Confidential
Improving the experience of a world in motion
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Lever 3000
Recliner – Process Flow & Controls – Lever II
Assembly Steps
Area of interest
Place Driver assembly
into Guide
Place Teeth Segment - A
into Guide
Place Teeth Segments
– B into Guide
Teeth segment
adjustment
Presence check
Greasing of
Teeth Segments
Process flow & Controls
Potential for fall-off
2
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Camera check
Greasing
Feed and load
Control Disc
Presence check
- Control Disc
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Lever 3000
Recliner – Why made?
Why? Missing front Toothed Segment B
> Why? Toothed Segment B fell out of guide before
assembly of control disc due to collision between
Work piece carriers
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PCA
•
Optimization of grippers for pick and place of toothed segments B to reduce chance of
misplacement. implemented on 8 Feb 2019
Previous system
> Why? Toothed Segment B was not properly placed
into guide slot during assembly process (Placed in
tilted condition)
> Why? Gripper of pick and place Toothed Segments B
not properly adjusted
Locator to Guide on Base Plate
Fixed unit without any adjustments to
compensate variation
Additional Units in updated system for
accurate positioning with additional DoF
1) AFAG Module
Additional rotary freedom for proper lead in
1
2) Positioning Plate
Additional vertical flexibilty for Locator to
touch Guide before Gripper
3) Push-out Fixture
To slide Teeth Segments directly into the
slot and push down by compressing Grease
3
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3
Updated system
2
Lever 3000
Recliner – Why shipped?
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PCA
Why? Missing front Toothed Segment B
> Why? 100% online detection of front Toothed Segment
B failed
• Optimization of sensing device for detection of presence
and position of toothed segments B
a) Diameter of pins enlarged
b) Position of pins optimized to be at the middle
• implemented on 21 Jan 2019
> Why? Sensor for detection of presence of front Toothed
Segment B not adjusted to detect sloped Toothed
Segment B (sloped Toothed Segments B can fall out of
sub-assembly before next process step / assembly of
control disc)
> Why? Failure of sloped Toothed Segments B not
considered in PFMEA
Segment A Sensor Placement – Difference in height
is significant to be detected
Segment B Sensor Placement– Difference in height is
insignificant to be detected in case of tilted teeth
segment
4
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Lever 3000
Recliner – Detection method ∆W2
Adient Proprietary and Confidential
Principle : Use increase in W2 angle to rest of the population to identify Outliers as Suspect
Upper Limit Standard (31 deg) (Control limit is set at 30.5deg)
All NOK Parts
identified
Limit line
Safety margin
Algorithm:
If W2 > Moving Median of 100 data + 2,43°
“Moving Median”
of 100 parts
Lower Limit Standard (23 deg) (Control limit is set at 23.5 deg)
2,43°
=> Suspect
(Based on
statistical analysis)
=> Otherwise, OK
1. All parts identified for NOK W2 angle increase were opened and found to have missing segment.
Adient -vs 4 segments. W2 is 100% monitored and recorded
2.5 Mean shift in W2 angle was able to identify recliners with 3 segments
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Lever 3000
Recliner – Detection method ∆W2
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Detection method – Explanation
Principle : Use increase in W2 angle to rest of the population to identify Outliers as Suspect
W2 - 4 Teeth Segments – OK Recliner
4,855° (Mean shift
based on Layout)
Mean Shift
Limit Curve defining
boundary between OK
and suspect parts
“Moving Median”
of 100 parts
NOK variation
W2 - 3 Teeth Segments
NOK Recliner
= =
+3S (3*0,5405°) = 1,621°
-3S (3*0,5405°) = 1,621°
(Max sigma of 10 Campaigns 1,6123° (Max sigma of 10 Lots)
2,43° Used as limit curve to
determine suspect parts
6
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Sorting Procedure:
For each lot,
•
Sigma = 0,5405°
•
Calculate „Moving Median“ for each data point based on
next 100 data
•
Median is chosen over Average to improve stability
against Outliers
•
Moving Median curve is the Base line
•
Offset by 2,43° to define the Limit curve (Offset Factor =
4,5 * Sigma)
•
Any data point lying above the limit curve is declared as
Suspect
Explanation – Mean Vs Median
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Lever 3000
Recliner – Detection method ∆W2
Derivation of Mean Shift in W2
Upper and Lower Toothed Segment
Functional principle
(shown = Upper; Lower is 180° rotated)
4x Contacts between
Excenter to Teeth segment
Excenter is allowed to float to
support all 4 Teeth segments at
the same time
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With missing Teeth segment - B,
Excenter looses support at one of four
contact points and has to turn more to
find the next possible support
Contact points
Gap
W2 angle depends on,
• Variation in functional
geometry of all components
in recliner
• Variations are relatively
constant for particular batch
of production; but, changes
over time with mixup of
batches
Left and Right Toothed Segment
(shown = Left; Right is 180° rotated)
Gap
When all other conditions remain the same,
Increase ΔW2:
+4.855° (Based on CAD study on Nominal geometry)
7
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Lever 3000
Recliner – Detection method ∆W2
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Derivation of standard deviation in W2
CONTROL BUILD for verification
W2 – Recliner with 4 Segments - OK
Process Capability Report for OK
LSL
USL
Process Data
LSL
23
Target
*
USL
31
Sample Mean 24,7078
Sample N
225
StDev(Overall) 0,404899
StDev(Within) 0,386348
Overall
Within
Overall Capability
Pp
3,29
PPL
1,41
PPU 5,18
Ppk
1,41
Cpm
*
Potential (Within) Capability
Cp
3,45
CPL
1,47
CPU 5,43
Cpk 1,47
23,1
Max 0,54045
PPM < LSL
PPM > USL
PPM Total
Observed
0,00
0,00
0,00
24,2
Performance
Expected Overall
12,33
0,00
12,33
25,3
26,4
27,5
28,6
29,7
Mean
Sigma
N
: 24,71°
: 0,405°
: 225
30,8
Expected Within
4,93
0,00
4,93
W2 – Recliner with 3 Segments - NOK
Process Capability Report for NOK
LSL
USL
Process Data
LSL
23
Target
*
USL
31
Sample Mean 29,4421
Sample N
225
StDev(Overall) 0,424322
StDev(Within) 0,427133
Max Standard deviation 0,5405° is chosen to set the sorting criteria
24,0
PPM < LSL
PPM > USL
PPM Total
8
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Overall
Within
Overall Capability
Pp
3,14
PPL 5,06
PPU 1,22
Ppk
1,22
Cpm
*
Potential (Within) Capability
Cp
3,12
CPL 5,03
CPU 1,22
Cpk 1,22
Observed
0,00
0,00
0,00
25,2
Performance
Expected Overall
0,00
120,60
120,60
26,4
27,6
Expected Within
0,00
132,52
132,52
28,8
30,0
Mean
Sigma
N
: 29,442°
: 0,427°
: 225