2021-01: Specifications for Threaded Rods and Bolts
Customer: US Bolt Supplier
Primary Issue: The customer needed proper specifications for the raw material and the finished product to reduce complaint from their customers and give a benchmark to their overseas raw material suppliers
2021-02: Development of Syringe
Customer: US Medical Device Manufacturer
Primary Issue: Proprietary
2021-03: Failure of Aluminum After Market Suspension Brackets
Customer: US After Market Supplier
Primary Issue: Suspension brackets failed short time after installation. An examination of failed parts revealed that our customer's overseas suppliers was supplying cast, instead of required forged parts. The castings were of poor quality with a significant amount of dross incorporated in the parts, rendering them unsuitable for fatigue sensitive applications.
2021-04: Failure of Plastic Latch on Heat Furnace Cover
Customer: US Consumer
Primary Issue: The customer noted that the furnace was making excessive noise when burners came on. The noise was attributed to vibration of the cover. The cover was held in place by two plastic latches. One of these latches had failed causing the cover to vibrate and generate noise. It was noted that the cover was improperly installed, resulting in tensile stresses in the tabs holding two halves of the latch together.
The tabs failed due to environmental stress cracking (ESC), wherein certain polymeric materials failed under low but sustained tensile stress.
Root Cause: Improper installation of the cover.
2021-05: Failure of Wine Bottle Stopper From Environmental Stress Cracking (ESC)
Customer: US consumer
Primary Issue: Wine bottle stoppers began to fail when bottles with stoppers were stored for extended period, destroying wine. The stoppers were designed as swell latches with expandable rubber bushings.
The plastic shaft that compresses bushings is pulled upwards using a metal handle, to which it is attached. The pin from the metal handle puts sustained stress on the connecting holes on the shaft. Over time, the connecting holes failed via ESC, as the grade of plastic used was not resistant to ESC.