State of cure - quick test
State of cure - quick test
(OP)
Is there a consistent/recognised method for quickly checking/verifying a good state of cure on EPDM or NBR extrusion?
I would like the operator to verify set-up and processing of material is OK before the lab perform the final product tests (lab testing occurs around 12-16hrs after curing and takes just over 24 hours to complete all tests).
Any ideas or suggestions welcome....
I would like the operator to verify set-up and processing of material is OK before the lab perform the final product tests (lab testing occurs around 12-16hrs after curing and takes just over 24 hours to complete all tests).
Any ideas or suggestions welcome....





RE: State of cure - quick test
RE: State of cure - quick test
The uncured rubber is tested on an MDR before release and a button is tested on a Shore A deadload.
Machine parameters are preset and the operators work within them. Parameters are established during the pre-production runs.
RE: State of cure - quick test
Regarding testing of cured product, I think BS, ISO and ASTM standards all require a minimum of 16hours conditioning before testing to ensure the rubber compound has fully matured.
RE: State of cure - quick test
My boss has asked if there is a quick test for verifying the state of cure that goes beyond a hardness check.
So I thought I would ask on here and see if anybody has any ideas.
This check wouldn't replace the test but would stop the operator running x metres of extrudate that then fails testing and subsequently needs post curing.
RE: State of cure - quick test
Or, you could do a little Taguchi type testing to find an optimal batch composition to make your end product insensitive to minor changes in controlled variables.
RE: State of cure - quick test
RE: State of cure - quick test
RE: State of cure - quick test
RE: State of cure - quick test
Don't discount poor mix from the equation if the problem comes and goes batch to batch.
The fingernail test isn't so good for non-resilient materials.
RE: State of cure - quick test
A quick test that I sometimes find useful, is to use a pair of scissors to cut a thin section of the profile in the direction of the extrusion. I then pull and hold for a little bit. If the section returns to its original length, that gives me an idea about the grade of vulcanization. I suppose it's a kind of a quick field version of the tension set.
I admit that this test falls under the same category as the fingernail but like a chef tasting his sauce; it could give you a hunch...
/Mathias