Challenge:
JML Optical was contracted to make in high volumes a customer-designed, precision optical assembly for an FDA-regulated medical device. The assembly met all specifications and passed all in-process quality tests, but JML’s customer was experiencing a high rate of failure during system quality testing. Troubleshooting showed that the system failure was due to optical assembly performance.
Solution:
How the optical assembly caused system test failure was not obvious. JML’s engineering team researched possible reasons including testing methods, material supply chain, fabrication, and assembly processes. A thorough tolerance analysis at the component level showed a clear statistical correlation between the amount of spherical aberration produced by a certain optical surface and the system-level test results.
JML proposed several changes that would address the performance issue. They included:
- Implement a new component level testing process, focusing on spherical aberration
- Design a new testing fixture for the assembly and calibrate it to the client’s testing equipment
Results
After implementation of the first two changes above, the passing rate of system-level quality tests increased from 50% to 99%. The customer was able to decrease the acceptance testing rate for JML’s product from 100% to 8%.