Uneven Wear
Uneven Wear
(OP)
I have two plastic round plates (disks)in contact. One is rotating against the other one. (A type of brake application). The wear of the thickness of the plates is uneven. A cross section would show a wavy pattern from the inside radius to the outside radius. Any idea what could cause this? thanks.






RE: Uneven Wear
Another possibility is variations in crystalinity due to differential cooling in the mould 9or elsewhere for that matter.
Another possibility is variations in orientation due to turbulence in the flow during moulding.
It's very hard to say without more details of the test and the method of manufacture of the plates and the make up of the plastic.
Regards
pat
RE: Uneven Wear
RE: Uneven Wear
1) Increase crystalinity (as you have indicated), but by useing neucleating agents. Titanium Dioxide generally works well, so long as a white colour is OK, and Molybdenum DiSulphide works great in nylons, so long as black is OK
2) Fillers such as carbon fibre or Aramid fibre pulp also work well, but are costly
Fibres may reduce overall wear, but exagerate the uneven of it if the cause of it is variations in flow direction dureing fill. Look at progressive short shots to see how it fills
Regards
pat
RE: Uneven Wear
Try to use 2 different hardnesses of the same material (maybe add a filler to one) or evan use 2 different materials.