Quote:
Originally Posted by NotEric6
Alright so after Sunday's test, we found out that the adjuster fails prematurely when cyclically loaded. We believe we actually instigated the failure slightly by heating up the unit by loading it at 10 Hz (friction/movement builds heat). Regardless, we don't believe it would have reached our goal of 50,000 cycles. It did last fairly long though and in most cases, the unit wouldn't have failed in our opinion. It would have still lasted multiple seasons but not long enough for us to take it to production.
We have already machined up replacement adjusters and ordered high strength alloy rod ends. This will add about 0.2 lbs per LCA, however, we have effectively increased the strength of these two pieces by 75%. Realistically, we don't need to re-test, but we want to.
On top of that, we are going to test the OEM unit and see how it fairs in the same tests we are testing our LCA in. The person who is testing said he can probably get it on the bench next weekend.
Thanks for your patience,
Eric
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FMEA squad up!
Even when threads are "helped" with a glass bead blast, hardening, or heat treatment... there's always stress concentration due to shape. Many times, you've got residual stresses too.
Fatigue testing will find the weak point and initiate a crack. At this point, the crack is its own stress concentration. The material's toughness dictates how much concentration... and it's just a matter of cycles before the part is #rekt.
Thanks for posting the news publicly.
There is no failure in R&D... we follow the cycle:
test --> anomaly --> problem definition --> root cause --> corrective action --> re-test
It's only a failure once you've put it in the field, and it seems like you guys are going the extra mile to ensure customer satisfaction.
