Is there any additives which improves the surface of the plastic?

[undertow17]

I am now working at the company which specialized in processing the engineering plastic that mainly uses the nylon 6, nylon 6,6. and every time I make the plastic with the extruders with a certain ratio of the ingredients, sometimes the plastic I made meets the standard of the physical or mechanical properties, but it is too hard to improve the surface of them. Whenever I do the injection molding to make the specimen to test the mechanical properties, the surface of them is really really bad relative to the other competitors. Are there any guys who can give me some advice to improve the surface?

Regardless of the additive or base resins, I hope I can get some precious advices from you guys.

Thank you in advance.

 

[undertow17]

I have been thinking about the reason why the surface of the plastic is bad. I think maybe, it is because the setting of the injection molding I use is a bit wrong. not the additives or something like that. Is there any website where I can get some information?

 

[Compositepro]

A bad surface finish is often associated with gate location and the polymer flow pattern as the mold fills. Ideally, the polymer should replicate the mold finish. If there are waves or knit lines in the melt flow front these will freeze as they touch the mold surface. There is plenty of literature out there, but I have no particular recommendations.

 

[Pud]

Tool surface temperature has a big influence on finish, as does melt temp and injection speed. PA6 = 60C to 80C and PA66 =80C to 100C tool surface temp.

If the extrusion grade is of low MFI you may have difficulty anyway.

Look up "processing conditions PA6 PA66". Google should give you plenty of hits.

H



www.tynevalleyplastics.co.uk

It's ok to soar like an eagle, but weasels don't get sucked into jet engines.

 

[D2S]

In semi-crstaline polymers like PA66 and PA6, you can improve the surface finish with higher injection speeds. Increased mold temps help more with amorphous polymers like PC, ABS, PS, etc.

You will find that PA6 has better surface finish than PA66 primary because it flows better (lower viscosity). Additives like glass fiber or minerals will reduce surface finish. Your finish will never be better than the mold surface finish.