Additional information/ correction: d4 - lot added.D9 - date returned to the manufacturer.H3 - device evaluation.H4 - production date added.H6 - codes updated.Investigation results: visual investigation: the tap arrived with broken off tip, the broken off pieces were enclosed.During a visual inspection we found the treaded end of the tap bent.In the next step we made a microscopical inspection of the fracture surface.Here we found the typical signs of a multi axial stress condition of bending and torsion.Batch history review: the device quality and manufacturing history records have been checked for the available lot number and were found to be according to our specifications valid at the time of production.Review of the complaint history revealed that no similar complaints have been filed against products from this batch number.There are no similar complaints against the same lot number with this error pattern.The review of risk assessment revealed that the overall risk level (severity 3(5) x 1(5) probability of occurrence) according to din en iso 14971 is still acceptable.Explanation and rationale: the root cause for the breakage of the tap was a overload situation, caused by levering in conjunction with mechanical overload.Conclusion and measures / preventive measures: based upon the investigation results the root cause is most probably user related.There is no indication for a material-, manufacturing- or design-related failure.Based upon the investigations results a capa is not necessary.
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