We Screwed Up: CNC Fixture Movement

January 11, 2022

What Happened?

We received material that was towards the small end of the raw material tolerance. Our CNC clamping fixture was not able to properly clamp this smaller material and allowed the parts to shift during machining causing a misalignment between drilled holes and milled slots. Our typical inspection has us doing 100% on the first and last parts ran on a shift with critical dimensions being checked per machine load. The nature of this non-conformity was not caught using this method until hundreds of parts were already run.

How did we respond?
First we quarantined all of the suspected non-conforming parts and worked with the customer to determine a fit, form, function test to sort the parts. After sorting, the non-conforming parts were tagged to be reworked.

How did we correct the problem?
We re-sequenced the machining operations to reduce the opportunity for undersized material to move in the fixture. We also added the fit, form, function spot check to our in-process inspection to verify alignment.

What were the results?
With these changes, we were able to eliminate the issue of movement and misalignment. Our original inspection process caught this issue before any non-conforming parts were shipped to the customer. Our additional inspection process will help prevent this issue from happening again in the future.

Mistakes can happen but the response is what matters. When we make mistakes we do our best to learn from them and make it right for our customers. We welcome challenges! Contact Us today to see if we can develop a better process for making your part.