Contamination Control Techniques
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-14
In manufacturing equipment in a clean room environment, screw threaded holes in assemblies have been highlighted as contamination sources. Tapped through holes are easy to clean, but allow contamination to drop out during screw insertion. Tapped blind holes are extremely difficult to clean, but trap insertion debris. This article proposes techniques to suppress the release of contaminants using implants or adhesive films. Implants can be forced midway into closed holes after screw tapping but prior to entry into the clean room. The implant is positioned 3 or 4 clear threads from the top of the hole to allow screw 'lead in'. The material of the implant can be chosen to fully compress, to cater for compression between the screw and the hole bottom.