Customer Problem

A transmission gear supplier was shipping gears that were too soft, resulting in luxury automobile transmission failures. The gear supplier was forced to pay the automobile manufacturer for the entire cost of the failed transmission. The supplier decided to inspect 100% of their gears for proper heat treat.

The Solution

The gear supplier installed an InSite HT eddy current test instrument and encircling coil downstream from their induction hardening system. The InSite HT simultaneously tests components at eight unique frequencies, helping it to capture multiple failure modes including:

  • Misplaced case
  • Shallow case
  • Excessive case
  • Air cool
  • Short quench
  • Delayed quench

The InSite HT is very easy to set up. Known good components are used to develop the heat treat testing standards. The data captured from the good components automatically creates acceptance thresholds for all eight frequencies. The components under test are compared to these acceptance thresholds. Testing times of less than 1 second per part are achievable, making it easy to install in a production line.

The InSite HT has full industrial I/O capabilities, enabling it to interface with material handling systems. The system can be set up to send alarms on consecutive rejects, indicating that there is a process issue on the production line. These could include power failures or bent/damaged induction heating coils. Plugged cooling nozzles can also cause an improper quench which, depending on the severity of the reduced flow, could result in improperly heat treated parts.

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