PA66 GF30% - our injection moulder has problems has problems with this material

[Rdpere]

The problem is that so far we have been injection moulding a part with a different material, "PS GP 154", but the product is cracking - it isnt strong enough when applying force to it, doesnt satisfy its function.

We suggested to our injection moulder to make some tests with a different material that has the same shrinkage, so we wouldnt need to modify the injection mould tool, but is 3x stronger (tensile strength): with PA66 GF30%.
Now the injection moulder is saying all kinds of things, that he really advises against testing this material because one of the reason was that you need to "dry" the product for 3 weeks after product is ejected from the mould.

I assume this is happening because he does not know how to properly prepare the material for injection molding - he doesnt dry or store the granulate as it recommended, because i was asking a little bit around and nobody is saying that this is a problem with this material.

Also here is written that you need to predry granulate or store it properly:

http://www.viewmold.com/sources/Pla...6_injection_molding_processing_condition.html

My question is: do you have any tips with how to deal with this material (PA66 GF30%) when processing it? What to be careful, processing parameters, ..?

 

[Pud]

All nylons are hygroscopic and absorb moisture from the air. At melt temperatures the water degrades the polymer. (Hydrolysis) If really excessive moisture it also gives silvery streaks on the surface.
If your moulder hasn't got a dryer I would suggest you find one that has - and fast!


Politicians like to panic, they need activity. It is their substitute for achievement.

 

[MacGyverS2000]

Drying for 3+ weeks after mold ejection?! That's a new one on me, for any material...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Pud]

Dan,
I suspect they meant conditioning. Absorbing moisture to improve impact strength. A little knowledge is a dangerous thing....

Judging by the original material grade no. I'm guessing it's a general purpose polystyrene. Virtually anything would be better.


Politicians like to panic, they need activity. It is their substitute for achievement.

 

[Rdpere]

Thank you for all the input.
He has a dryer but as you said ... its like a conditioning, not actually drying.
He is saying that he doesnt have a good machine to process PA66GF30, that the heater is not ok and that he would need a new tool to injection mould with PA66Gf30 and he can only try with normal PA6 without glass fibers. And also that hot runner would be needed (but im a little spectical about it).

I think that the material IS hard to mould (high viscosity) and he is saying that there is a lot of warpage when they already tested with that material. Like there is too thich material on some parts and this is why they cant mould with PA66gf30.
Maybe to remachine the mould a little bit, bigger gate for instance, and it should work ... or any other suggestions?