Raft extrusion problem while printing with PLA

Hi, I have some problems while extruding just the first layers of the raft using an external PLA filament. The extrtuder seems like chattering with the material that can’t flow continuously. Obviously also the quality of the raft gets worse. As extrusion temp I used 210C.
This problem is not present while printing with Z-Ultra T. To solve it I tried to calibrate the table and to increase the Z-Offset but I didn’t obtain any results. The printer is pretty new with less of 100hr of printing. What could be the cause of such a problem?
I uploaded a video in google drive: https://drive.google.com/open?id=1CwRmeQYH30xvz5UJupL8v2nuBEcQB7Xr

Thank you in advance

Did you find any solution to this? Mine 300Plus is doing the exact same thing, only chattering when printing raft.

Hi,

Are you using Z-PLA/Z-PLA Pro material, or some external one? Is Z-SUITE up-to-date?

Best regards,
Karolina

I am using external PLA. Yes, my Z-SUITE is updatet.
I have measured the filament, it is exactly 1,75mm.
I know you are not responsable for external materials, but i have read about others who have the same challenges with Zortrax PLA.

Thank you for your help!

Hi,

Yes, it is difficult to provide settings which work best with external materials, users need to tweak the settings on their own. Still, you could try increasing the extrusion temperature even more, or try Z-GLASS profile - for some users it does the trick.

As for challenges with Zortrax PLA - most often this happens on M200/M300 printers, where a separate hotend for Z-PLA Pro is required.

Best regards,
Karolina

Hi, I could almost fix the problem by increasing the extruding temperature up to the upper limit of the temperature range of the material. Moreover I introduced a positive z-offset which seems to help the raft extrusion.

Thank you for your help Karolina! Using Z-GLASS Profile did the trick. I had a little bit stringing on the part printed with Z-GLASS, so i now know i just need to find the right temprature in between the 2 profiles (Z-GLASS and Z-PLA).

Hi Baba
Thank for your reply. I’m know sure that i get what you mean by possitive z-offset. I’m printing with af platform-raft gap at 0.43mm. Is possitive Z-offset a bigger or smaler gap?

Hi @NikolajBak,

I am glad to hear that using Z-GLASS profile did the trick. I hope you will find the right temperature (210 - 240 ℃).

Best regards,
Karolina