Trackwise #(b)(4).The investigation has been started since the complaint was received, and the following contents has been conducted: 1.Analysis of production: the dhr of the reported lot 3000295949 has been reviewed.No non-conformity is observed indicated the reported failure.All the products had been performed 100% mechanical function test during production.They all passed the function test, which demonstrate the knob can be tightened and link arm can be tightened.2.Trend analysis: 20 may 2022 to 20 may 2023, the occurrence rate is approx.(b)(4)% which is under anticipated occurrence rate.3.Device was not received for evaluation; the specific root cause for this failure could not be confirmed.4.Review complaint historical data, the failure knob difficult/ unable to tighten-arm does not lock happened before and has been investigated.The most probable root cause for the knob tighten abnormal could be acme nut lead in thread broken for the reason that rotating to lose the knob anti-clockwise rapidly for several circles and then rotating to tighten the knob clockwise rapidly, or rotating the knob leaner or too much strength used, which caused acme screw misaligned with the acme nut lead in thread, acme nut lead in thread broken, then the knob could not be tighten, and link arm could not be tightened.
|