Microscopy

Optical Birefringence

• Part design
• Failure Analysis
• Functional testing
• Assessment of residual stress in a material
• Assessment of molded in stress
• Evaluate stress points in a material due to an external force
• Evaluate areas of high or uniform stress
• Monitor annealing process

Above:
A. Fringe patterns revealing a stress gradient.
B. A cross-polarized view of a failed port housing.

Work We've Done

Failure Analysis of Broken Plastic Part

Responding to a customer complaint our client submitted parts that had broken during use to determine the cause of the failure. The item was a translucent injection molded plastic hose fitting that had produced a brittle failure and cracked and broken at the hose insertion point.

Optical birefringence showed that the specific area on parts molded in the same lot showed high stress in the area where the failed part had broken. Other parts did not show this same level of stress. These results indicated the root cause of the failure was likely in the molding/manufacturing process rather than contamination or raw material issue.

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