Pin in Cam Profile
Pin in Cam Profile
(OP)
I am currently running a metal dowel pin in a milled out cam profile shaped similar a tear/water drop. The material that the profile is milled into is a sort of hard plastic but I am seeing extreme wear (abrasive) at the top of the profile where the pin has to switch direction. Does anyone have a suggestion for a lightweight material that would wear less than the plastic when coupled with a metal dowel pin?





RE: Pin in Cam Profile
If I were to venture a guess of what is causing your problem based simply on the limited information provided in the OP, I'd say your cam profile and pin diameter are creating a very high pressure angle at this particular point. And the high pressure angle is producing excessive contact stress on the plastic cam surface.
RE: Pin in Cam Profile
RE: Pin in Cam Profile
Here is a picture of the cam profile. On the left side channel you can see the wear. The pin is a standard 0.5 inch metal dowel pin.
RE: Pin in Cam Profile
Can you provide a sketch of the mechanism's geometry? Is the follower mounted on a rocker arm or does it just translate? How is the follower positioned and how is it constrained relative to the radial cam surfaces? Is there any form of compliance or elasticity in the mechanism, such as a preload or return spring?