White streaks or spots

[dinho]

Hi,
1- yes the location is the same.
2- the part is like a "cup" and the location of the gate is in the bottom "direct injection", the defect is between 30/50 mm/Sec (between 30/60 mm for injection course).
3- No, the defect appeared in all parts between 30/60 in the injection course, but sometimes it appeared at the start of the injection.
4- the defect appeared internally in the parts and externally it appeared a few times.

[Bryan E]

Based on your description listed above and the defect shown I would suggest you check your nozzle heater bands and or thermocouple. It appears your injecting a cold slug of material because of the direct gating.There is no other place for the cold slug to go except for the surfaces of the part. All too the nozzle thermocouple is placed directly under a heater band causing the heats to appear to be up to temperature but actually be much lower.

[dinho]

thank you I will check them.

[Airwinghma]

Greetings;

I would suggest looking at your dryer also. Drying temp? Drying time? Dew point? Does the part run well for a while after it has been down and then start with the streaks? Does the material pop and hiss when purging?

Just something else to look at

[dinho]

thank you for your suggestion, I will check them.