MrClean
Mechanical
- Feb 15, 2006
- 6
I’m working on designing a seal to keep contamination away from a potentiometer in a greasy environment. The 1st pass was bare aluminum lightly spring loaded against Delrin 500. The surface roughness on the aluminum was about 63 micro-inches. Contact pressure about 7 psi. Action is reciprocating at 2 fpm. There is no pressure differential across the seal. At 30,000 cycles, the Delrin was badly shredded, though not badly enough to disable the pot. The aluminum showed little wear. The seal needs to last at least 10 times as long without serious damage.
I am considering changing the plastic to Nylatron GS, oil filled UHMW, oil filled nylon 6, or Delrin AF, specifying a smoother finish on the aluminum, as well as circumferential surface grain direction, and possibly anodizing or hard anodizing the aluminum.
Lightly lubricating the seal at assembly is possible, though subsequent lubrication is not.
Due to space limitations, purchasing an off-the-shelf sealed potentiometer is not an option.
Does anyone have any experience with these plastics or others in a similar application?
Any other thoughts?
I am considering changing the plastic to Nylatron GS, oil filled UHMW, oil filled nylon 6, or Delrin AF, specifying a smoother finish on the aluminum, as well as circumferential surface grain direction, and possibly anodizing or hard anodizing the aluminum.
Lightly lubricating the seal at assembly is possible, though subsequent lubrication is not.
Due to space limitations, purchasing an off-the-shelf sealed potentiometer is not an option.
Does anyone have any experience with these plastics or others in a similar application?
Any other thoughts?