shiny parts

[degete]

Problem: - textured area of the parts(ABS)is more shiny than a few weeks ago(all 4 cav.);
- mold was checked:- cavities textured surface, air vent,etc...
I believe that is an injection process problem...injection speed,packing time? can anyone give me a hint?Thanks.

 

[Demon3]

It could be your ABS. When I worked for one of the largest ABS producers we looked a lot at ABS and gloss as problems did crop up. ABS can be very sensitive to any change in manufacture because the rubber particles afffect gloss. So, if you change the rubber particle size or cross-linking at all then the gloss can change a lot, especially the gloss measured at lower angles.

It could also be molding (I'm not expert in that so wait for answers from the likes of Pat and Pud).

Could also be changes in additives like mold release.

There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell

 

[Pud]

Sounds like underpacking to me...pressure/time.

Cheers

Harry

 

[patprimmer]

Poor venting or under packing typically results in increased gloss, but so does a change in the rubber dispersion.

Another possibility is a build up of mould deposit.

My money is with Harry that it is under packed.

Does the machine still hold a cushion.

Regards

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[degete]

the injection process seems ok...already done a variation in injection parameters on underpacking ideea...no result...
we will insist now on material properties.
thanks to all...keep you in touch

 

[patprimmer]

Does the machine hold a consistent cushion.

Regards

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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.