Botle Manufacturing Defect

Glass failure analysis expert performs a root cause failure analysis on a bottle failure. In this case a manufacturing defect was causing numerous failures on a manufacturing line. The tops of these small bottles were coming off. The upper left photomicrograph is with the two halves of the bottle re-assembled. The upper right photomicrograph is of one of the glass fracture surfaces. The failures were occuring just below the transfer ring at a glass molding defect. The molding defect is a fold in the glass that acts as a stress concentrator. The lower left photograph is of an unused bottle with the defect. This is an unacceptable manufacturing defect and the parts werre returned as non-conforming.

Plastic Failure Analysis

Plastics failure expert performs a root cause failure analysis on a plastic automobile door handle. The handle is from a van's sliding side door. The product failure occured when the user was trying to close the van's sliding door. This is a products liability issue because the handle failed in a brittle manner and a personal injury occured. The lower photograph is of the handle assembly after it was removed from the vehicle. The two arrows point to the two fracture surfaces on the broken handle. The upper photograph is of the fracture surface on the handle piece that came free. The failure started as a fatigue crack (see arrow). It initiated at a molding defect similar to the one indicated by the second arrow on the left of the photograph. Molding defects are manufacturing defects caused by improper molding conditions. The molding defect created a stress riser allowing crack initiation. The crack progressed due to fatigue. The final failure mode was overload, and it was mostly a brittle failure.