“Splay” issue on PA66 GF30% with UV stabiliser.

[Pilot]

Please check also diameter of machine nozzle and tool inlet. sometimes the splays can come from big shear, try to reduce injection speed. Please check also front of melt on short shot parts. If you will have a "bubles" on the front of melt, please check, if backpressure is working on the machine. Backpressure setting value must change plastication time. If not, please check servo valve (replace it) or control card.

[stevenchengcn]

My experience: PA+GF,the barrel and nozzle temperature from the material supplier is 280 degree.the surface is awful,while the temperature decrease t0 235-240 degree,all is ok.
also many times,my ABS injection with slays on surface,and lower temperature solve this.
So my conclution is to try the low temperature as far as possible.

[Airwinghma]

Greetings;

I was taught many years ago that there were two main causes of splay, heat and moisture. The old school way to tell is you could smell the heat splay and not moisture. Grab a part right out of the mold and smell the splay. I have found it to be true.

Most of the advice above will solve your heat source.


Scott

[rickbatey]

So your 'splay', should be the UV stabilizer being damaged or consumed in the barrel due to the high barrel temps, mold temps, and residence time. I've seen this many times when running UV or FR resins. As long as you can fill the parts, you need to start working the temperatures down until the issue goes away. Either that or run a reverse barrel heat profile. Lastly, get a press with a smaller screw diameter.
Rick