Thickness Testing Equipment

Question:

We currently use an anodized aluminum 1.3-inch diameter T-Nut on one of our products. This T-Nut is molded in place using a polyurethane material. The T-Nut has a threaded central hub (#10 metric thread) with a flange that has eight holes drilled and chamfered in it.

To try and simplify production of these parts, I have tried to eliminate the eight holes that are drilled and chamfered in the flange. However, without the eight holes, the polyurethane cannot mechanically hold the part in place. So I had T-Nuts removed from production before they had the eight holes drilled in the flange. I had them anodized and used a primer on the T-Nut to make the polyurethane bond to the anodized surface. These parts perform as well or better on a pull-out test as the parts with the eight holes in the flange. These T-Nuts are a critical interface on a medical product. If they were to pull out of the product, the user could be injured.

So my question is: Is there any way to check every T-nut automatically using thickness testing equipment to be sure that each T-Nut has the appropriate amount of primer on its surface? We cannot simply pull a few samples out of a batch and test them. I think we need to be able to check every one. If we cannot do it using an automated process, then the cost to have an employee inspect every one will offset the cost savings of eliminating the eight drilled holes. C.K.

Answer:

Certainly, in this age of robotics, there is a way to check every T-nut automatically. Thickness testing equipment is available for testing practically everything over anything today. Suppliers of thickness testers are listed under Testing Equipment, thickness of coating, on pages 526-530 of the 2002 Products Finishing Directory And Technology Guide.