polyamide Nylon 6 injection problem

[kanibaltaki]

hi

I own plastic injection machine and I am now making some automotive cable parts
I used POM material and everything was good now when changed the material to PA6 AND PA 66 i faced some problems
See the picture in the attached file .
the part formed containing bubbles I want a solution to this problem .

PA 6 injection profile i used

POM injection profile i used

Thank you

 

[Pud]

Dry the nylon before processing it. See what your processing guide says.

www.tynevalleyplastics.co.uk

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

 

[Demon3]

Pud is right as usual and much better at processing problems than me. You need to dry the PA 6 very well before molding it. Do not leave bags open after drying as they will instantly take up moisture from the air. Or, if POM worked well, why not switch back?

Dr. Chris DeArmitt
President

Expert plastic materials help

http://www.phantomplastics.com

 

[kanibaltaki]

thank you PUD & Demon 3 . I did dry the PA6 before processing for 4 hours 70 c° and Bubbles began to disappear i have no drying instruction in the processing guide may i ask what to do to get a pure partes with good color and finishing process
can i elevate the drying température or add more time for drying process .
thank you so much

 

[Pud]

PA6 needs drying for AT LEAST 4hrs @ 80°C. Start the time from when the bulk is actually up to temperature.
If still foaming, continue drying. I would suggest you dry for at least 8hrs until you know your dryer performance - if it's just a hot air dryer, I would strongly recommend you invest in either a dessicant or vacuum dryer. You'll soon repay your investment cost.

In a vacuum dryer, temp can be increased to 100°C - needs a vacuum to prevent surface oxidation.

NOTE: Even without showing foaming, moisture content can be too excessive causing brittle mouldings which look fine.

H



www.tynevalleyplastics.co.uk

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

 

[kanibaltaki]

thank you so much Mr.PUD
this is what i found i must be dried the PA6 8 HRS in température between 75° 80° to avoid oxidation next week i will try this method and i will return with a good results
Thank you

 

[kanibaltaki]

heeey
actually i had a good résult i dried the material for 6 hs and it works very well
thank you all