The required notch thickness in the sampling area is 0.0120".The notch thickness in this area on the failed device is.0098" or 0.0022" u/min.This reduction in material thickness in the notched area will increase the probability of breakage, however, the increase in probability would have to be quantified via experimentation.The notch thickness on the second, undamaged, device returned measured 0.0120" which equals the target dimension for this feature.The returned, defective sample has a sharp curvature at the distal end where the stylet tip broke off.The break appears to have occurred at the radius formed between the tip and the notched area.It is possible rapid wrist flipping of the device in an attempt to free the stylet tip emulated cyclic loading and lead to fracture.A definitive root cause was not identified during investigation and a corrective action was not possible to be implemented without a root cause.This event will be re investigated if new information becomes available in the future.
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