LED Radial Insertion machine : Chain Clip Wear Test Report

Chain Clip Wear Test Report

Introduction

The purpose of this experiment was to determine the wear on three critical to function chain clip dimensions due to three springs of equal free length and different spring constants, and also to analyze the wear effects on functionality. Both dual span and small triple span configurations were included in the test. Thirty dispense heads on the Radial 6380A sustaining machine were modified and used for the test. Each clip was run for 50,000 cycles. Due to the variation in clamping force of the five different configurations tested, some test heads had components replaced more frequently than others, resulting in some test clips seeing more new components than others. The ANOVA analysis (Appendix 2, page 7) shows however that the number of new components presented to the test clips was not statistically significant and therefore not a significant contributor to wear.

Below is an outline of the five configurations tested:

Carrier Clip

 

Two chain clip issues drove this experiment: components migrating up and/or down in the clip and concern that heavier springs will accelerate wear.

Upon completion of the test, force and distance measurements were taken using a test fixture and a 2.5mm setup tool.

Setup and Data Collection 

Wear Data: See Appendix 1

Dimensions A,B and C were identified as critical to function (see Appendix 3 for detail).  2.5mm, steel, .021 in. square, .030 diagonal leaded LED’s were used for the test. These LED’s have an average distance between leads of .0743 in. (See illustration on page 2)

Dual Span Clips:

The clip housing “tooth”, dimension C, is .074 +/-.002 in. Therefore, wear was not observed on the sides of the tooth, but was observed on the corner radii.  On the dual clip, a 2.5mm component is engaged by two clamps: the left lead by the full clamp on the left and the right lead by the half clamp on the right.

Triple Span Clips:

Due to the dimensioning scheme of the triple span clip, dimension C is not tooth width, but distance to the side of the tooth as shown, .038 +/-. 003 in. As in the case of the dual span clip, wear was observed on the corner radii.  This is a reasonable result since the tooth width is .062 +. 000/-. 005 in. and the average distance between component leads was .0743 in. On the triple clip, a 2.5mm component is engaged only by the left clamp: the left lead by the full clamp and the right lead by the half clamp.

Force and Distance Measurements: See Appendix 2

Appendix 2 shows comparison graphs of unused (unworn) clips versus tested (worn) clips and the effect of wear on performance. The clip measurements were taken using a 2.5mm setup tool since 2.5mm components were used for the wear test.

Summary

Assumption:  2.5mm component used for test is a suitable representative to determine chain clip wear.

Dual Span Clips:

Dimension A: spring force is not a significant source of wear.

Dim B and C: spring force is a significant source of wear.

(See Appendix 1 for supporting ANOVA analysis)

Backward ‘force to release’ performance degrades significantly for the dual span test clips with the 10249111 springs. The 10249241 spring performs more consistently between the unworn and worn chain clips.

Distance to release was the same for unworn and test (worn) clips.

Radial 6380A dual span chain clips use the 10249225 spring.

Radial 6380B “XT”  dual span chain clips use the 10249241 spring.

 

Carrier Clip 01

Triple Span Clips:

Dimension A and C: spring force is not a significant source of wear.

Dimension B: spring force is a significant source of wear.

(See Appendix 1 for supporting ANOVA analysis)

Forward ‘force to release’ and forward’.050” lean force’ performance is poor for both worn and unworn clips, although the clips with the 10249111 spring performe slightly better in these two categories than the 10249241 spring.

The heavier 10249111 spring performs better overall than the current production 10249241 spring.

Distance to release was the same for unworn and test (worn) clips.

Radial 6380A triple span chain clips use the 10249241 spring.

Radial 6380B “XT”  triple span chain clips use the 10249111 spring.

 

Carrier Clip 09

 

The illustration below shows the setup for a .050” forward lean. The backward .050” lean measurements were set up with the same gap between the test fixture attachment, mounted behind the tool, and the 2.5mm setup tool. The force measurement was taken at the point where the 2.5mm tool touched the test fixture attachment, which was approximately the same height as the tool in the clip.

 

 

 

 

 

Carrier Clip 03

050 in. forward lean

The ‘force to release’ force measurements were taken at the point where the 2.5mm setup tool disengaged from the chain clip clamps with at least one lead.

Conclusion

The data presented here leads to the following conclusions:

  1. Overall, a higher spring constant results in improved holding ability in both the worn and unworn clips.  However, it is nit clear whether wear at 50,000 cycles significantly decreases clip performance. Further testing would be required to determine at what point performance begins to decline.
  1. The performance of the triple span clip improves with the heavier 10249111 spring, although it is not as dramatic an improvement as the dual span clip with the heavier spring.

Appendix 1

Minitab Analysis of  worn clip Data

Descriptive Statistics: DIM A, DIM B, DIM C

Variable             N       Mean     Median     TrMean      StDev    SE Mean

DIM A               30      2.323      1.900      2.200      1.600      0.292

DIM B               30      2.413      2.300      2.335      1.456      0.266

DIM C               30      0.583      0.200      0.504      1.431      0.261

Variable       Minimum    Maximum         Q1         Q3

DIM A            0.000      7.000      1.375      3.300

DIM B            0.000      6.100      1.400      3.250

DIM C           -1.700      4.400     -0.425      1.325

 

The means above reflect 1000 times the change in dimension value.

 

Carrier Clip 04

*Note: Dimension C should increase with wear, not decrease (see clip housing prints at end of report). Data may be suspect due to the measurement equipment and/or the operator of the equipment.

One-way ANOVA: DIM A versus NUM COMPONENTS

Analysis of Variance for DIM A

Source     DF        SS        MS        F        P

NUM COMP    2      2.73      1.36     0.52    0.603

Error      27     71.47      2.65

Total      29     74.19

Individual 95% CIs For Mean

Based on Pooled StDev

Level       N      Mean     StDev  ——-+———+———+———

5         20     2.420     1.876             (—–*—–)

10          4     2.700     1.140        (————-*————)

15          6     1.750     0.373  (———–*———-)

——-+———+———+———

Pooled StDev =    1.627                 1.2       2.4       3.6

>> P-value greater than .05: Number of new components presented to clip is not significant

One-way ANOVA: DIM B versus NUM COMPONENTS

Analysis of Variance for DIM B

Source     DF        SS        MS        F        P

NUM COMP    2      7.95      3.97     2.00    0.155

Error      27     53.57      1.98

Total      29     61.51

Individual 95% CIs For Mean

Based on Pooled StDev

Level       N      Mean     StDev  ——-+———+———+———

5         20     2.220     1.539            (—–*—-)

10          4     1.875     0.826   (———–*———–)

15          6     3.417     1.141                  (——–*———)

——-+———+———+———

Pooled StDev =    1.409                 1.2       2.4       3.6

>> P-value greater than .05: Number of new components presented to clip is not significant

One-way ANOVA: DIM C versus NUM COMPONENTS

Analysis of Variance for DIM C

Source     DF        SS        MS        F        P

NUM COMP    2      0.56      0.28     0.13    0.880

Error      27     58.86      2.18

Total      29     59.42

Individual 95% CIs For Mean

Based on Pooled StDev

Level       N      Mean     StDev  ———-+———+———+——

5         20     0.635     1.592            (—–*——)

10          4     0.725     1.825    (————–*————–)

15          6     0.317     0.382   (———–*————)

———-+———+———+——

Pooled StDev =    1.476                    0.0       1.0       2.0

>> P-value greater than .05: Number of new components presented to clip is not significant

Descriptive Statistics: COMP SPAN

Variable             N       Mean     Median     TrMean      StDev    SE Mean

COMP SPA            21     74.290     74.400     74.237      1.025      0.224

Variable       Minimum    Maximum         Q1         Q3

COMP SPA        72.300     77.300     73.750     74.700

One-way ANOVA: DIM A: Dual Span Clip vs. Spring

Analysis of Variance for DIM A_1

Source     DF        SS        MS        F        P

SPRING_1    2      0.01      0.00     0.00    0.997

Error      15     18.40      1.23

Total      17     18.41

Individual 95% CIs For Mean

Based on Pooled StDev

Level       N      Mean     StDev  ——–+———+———+——–

1           6     1.717     1.025   (—————*—————)

2           6     1.700     1.579  (—————*—————)

3           6     1.750     0.373   (—————*—————)

——–+———+———+——–

Pooled StDev =    1.108                  1.20      1.80      2.40

>> P-value greater than .05: Spring type is not significant to change in Dim A

One-way ANOVA: DIM B: Dual Span Clip vs. Spring

Analysis of Variance for DIM B_1

Source     DF        SS        MS        F        P

SPRING_1    2     12.91      6.45     4.98    0.022

Error      15     19.42      1.29

Total      17     32.33

Individual 95% CIs For Mean

Based on Pooled StDev

Level       N      Mean     StDev  ——+———+———+———+

1           6     1.550     1.111   (——-*——-)

2           6     1.700     1.161    (——-*——-)

3           6     3.417     1.141                  (——-*——–)

——+———+———+———+

Pooled StDev =    1.138                1.2       2.4       3.6       4.8

>> P-value less than .05: Spring type is significant to change in Dim B

One-way ANOVA: DIM C: Dual Span Clip vs. Spring

Analysis of Variance for DIM C_1

Source     DF        SS        MS        F        P

SPRING_1    2     3.274     1.637     4.57    0.028

Error      15     5.368     0.358

Total      17     8.643

Individual 95% CIs For Mean

Based on Pooled StDev

Level       N      Mean     StDev  -+———+———+———+—–

1           6   -0.7000    0.5329   (——-*——–)

2           6   -0.4000    0.8025        (——-*——–)

3           6    0.3167    0.3817                    (——-*——–)

-+———+———+———+—–

Pooled StDev =   0.5982          -1.20     -0.60      0.00      0.60

>> P-value less than .05: Spring type is significant to change in Dim C

One-way ANOVA: DIM A: Triple Span Clip vs. Spring

Analysis of Variance for DIM A_2

Source     DF        SS        MS        F        P

SPRING_2    1      6.90      6.90     2.12    0.176

Error      10     32.62      3.26

Total      11     39.52

Individual 95% CIs For Mean

Based on Pooled StDev

Level       N      Mean     StDev  —–+———+———+———+-

2.5-2       6     2.467     1.338  (———-*———-)

2.5-3       6     3.983     2.176             (———-*———-)

—–+———+———+———+-

Pooled StDev =    1.806               1.5       3.0       4.5       6.0

>> P-value greater than .05: Spring type is not significant to change in Dim A

One-way ANOVA: DIM B: Triple Span vs. Spring

Analysis of Variance for DIM B_2

Source     DF        SS        MS        F        P

SPRING_2    1     10.08     10.08     5.78    0.037

Error      10     17.46      1.75

Total      11     27.54

Individual 95% CIs For Mean

Based on Pooled StDev

Level       N      Mean     StDev  ——+———+———+———+

2.5-2       6     3.617     1.680                  (———*———)

2.5-3       6     1.783     0.818   (———*———)

——+———+———+———+

Pooled StDev =    1.321                1.2       2.4       3.6       4.8

>> P-value less than .05: Spring type is significant to change in Dim B

One-way ANOVA: DIM C:Triple Span vs. Spring

Analysis of Variance for DIM C_2

Source     DF        SS        MS        F        P

SPRING_2    1      0.85      0.85     0.48    0.505

Error      10     17.84      1.78

Total      11     18.69

Individual 95% Cis For Mean

Based on Pooled StDev

Level       N      Mean     StDev  ——-+———+———+———

2.5-2       6     1.583     1.150   (———–*———–)

2.5-3       6     2.117     1.499        (———–*———–)

——-+———+———+———

Pooled StDev =    1.336                 1.0       2.0       3.0

>> P-value greater than .05: Spring type is not significant to change in Dim C

 

Appendix 2

 

 

 

 

Appendix

Carrier Clip 05

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dual Span Chain Clip Housing: P/N 42717602 of Assembly 42804703

 

 

 

Carrier Clip 07

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Triple Span Clip Housing: P/N 90055417 of Assembly 90055421

 

 

 

Carrier Clip 08

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