I am having issues with material feeding, what is going on?
Some items to check for:
The feeding throat is blocked by melted material. In this situation you can lower the heat that is in proximity of the feeding throat
Do barrel temperatures match with the material data sheet? An important item to check
Are you using the right screw? Some materials might require different screws
Water cooling for the feed throat? Make sure and check
Check the placement of the material hopper and ensure that is properly in place
I am having issues with shorts shots, what can I check for?
The check ring isn’t closing. Here you will need to increase decompression after plasticizing. Also make sure to check the shot size. Too small? Depends on the material
Is the injection pressure constant? Things like ambient conditions, cooling water, not fully dried material, and regrind affect the viscosity changing. This also leads to changes in injection pressure so here you should increase injection volume
Is the right check ring being used? Some materials require specialized check rings that close faster
I am experiencing variations in cycle time, what’s going on?
Important to note which movement is the one that is varying
For example, if variations are deduced to happen during plasticizing check to see if maximum torque is being reached
Also check if barrel temperatures matching what is listed on the material data sheet. If not, then increase
My parts are coming out with flash, sink marks or burn marks, what can I do?
Flash - Is the injection pressure constant? Things like ambient conditions, cooling water, not fully dried material, and regrind affect the viscosity changing. This also leads to changes in injection pressure so here you should decrease injection volume and also increase clamp force
Burn marks – Means air is not escaping the cavity fast enough. Lower clamp force to improve venting from the mold
Sink marks – Probably means your injection volume is too small so increase that along with the holding pressure and time
My material has black spots and looking like it could be degraded, what can I do?
Does the barrel/hot runner temperature match with what is listed on the material datasheet
Is the shot size too big? Depending on the material, the shot size needs to be within the correct range
Is the right barrel, screw, and check ring being used? Some materials require specialized equipment