FKM O-Ring crack issue

[Ahmad Uzair]

We are designing an O-Ring using FKM hardness 65shA.
However we have crack issue after molded.
From theory to be known that FKM should be hard, but from our rheometer slab, the part brittle and crack after cure.
This O-Ring to be use for piston in air compressor but the test fail out due to the crack issue.
Our first FKM use was Fluoroelastomer FC 2174.
This part have too much crack issue.

Our 2nd trial was using Tecnoflon® FOR 7352.
The crack issue improve but still if the crack couldn't solve then problem may still happen for the piston.

Molding condition:
Temp M/C: 170C
Pressure: 150kgf/cm2
Bump: 5 time
Curing time: 360sec


“I have no special talents. I am only passionately curious.”-Albert Einstein

 

[sankar777]

Try 160°C
3 Bump
and 120kgf/cm2
When using 160°C Temp you can post cure in oven