Printing with Colorfabb XT mostly good, but fliament oozes out?


I’m trying to use ColorFabb XT on the Lulzbot Mini Printer. Mostly, it’s fabulous! It’s a lot less brittle than the HIPS material, and it doesn’t delaminate or crack anywhere near as easily. It’s allowed me to print really big prints (6.5" x 4") that when I printed in HIPS just fell apart in my hand.

To do this, I start with the Taulman n-vent profile, and then increase the printing temperature from 230 -> 255 C (ColorFabb’s recommendation), and bed temperature to 60 ->70 C.

However, I’ve noticed that the plastic continues to extrude even after it’s been switch off. If I extrude 10mm of plastic, 10mm comes out, and the extrusion stops, but more plastic continues coming out. This leads to long threads of plastic everywhere like this:

and when the printed results are seen they look like this with lots of jagged things coming out (presumably at the point when we move to a new layer?) like this:

I can see I’m close, but I’m trying to work out what I should change to fix this. Should I increase the retraction (experimenting with that)? Should I reduce the flow rate percentage?

Love to hear your thoughts. Thanks in advance!
Hobby_Knife_think.gcode (278 KB)

Have you verified the diameter of the Colorfabb filament? If you are using the standard 2.85mm filament diameter and it is actually 2.91 (the diameter of my current filament) you can have these issues.

Excessive hotend temperatures can also cause this issue. For fun and jollies, try reducing the hot end temp. Start off by reducing 5 degrees. If the oozing/stringing improves but is still there, keep backing the temps off.

You may also want to increase the amount/speed of retraction.