Optimizing Extruder(s)

Vertex 3D Printer Vertex - Your printer, creations, and ideas for im
1

Hi all,
cause i have had problems mith my both extruders, i lost steps sporadically while feeding filament with having poor look and quality with my prints often. First i tested the motor drivers as described, current was ok. I also could not find any ploblems with the filament on its way to the head.

Finaly i found the failure ! i dismonted one extruder and reasembled it with a piece of 4mm Polycarbonat plate on the workbench.
If you now test it manually with some filament you need a lot of strength and you see two errors:

a.) the distance written in the manual for the pulley to the stepper motor is wrong. I need 1.0 mm more on the left extruder and 0.9 mm on the right extruder to get the filament straight throug the extruder, looking in this direction.

b.) there is a construction fault: the pully is to close to the filament in back-front direction (if you stay in front of the printer). So the filament is bent first to the front, running in a curve arround the pulley and then bent back to the outlet.

This all takes a lot of power , is not good for the filament (cold-bend) and completely unnecessary ! Also makes loading filament difficult and annoying.

i grindet away material of the black housing with dremel tool to give the pully more cave room to go more to the back, made the holes for the screws a bit to long-slots and mounted all so that the filament now go throug the extruder straight and gently. (also i filled the gap on top of the housing with plastic-stripes i found in my den, so i can tighten the both upper screws proper)

Now it works fine, the grip and the “bites” with the filament is same as before but the motors don’t need lot of power and no steps lost.
Although i print fast, surfaces are looking good now, without disturbance.

And changing filament now is very easy.

2

From Dylan (Member: minitreintje) i got the information that there are on Thingiverse some STL’s for an upgraded extruder motor for download.

He wrote: “I installed one and now the steppermotor has more power since the filament is now straight against the pulley. I installed this one:
thingiverse.com/thing:1133248”

This also good for people who do not want to modify the original part of the extruder.

3

While i am waiting for my heatbed, not delivered till now, i experimented with ABS.

Surprising for me is: with the optimized extruders i can print ABS at low temperatures (205 bis 215 °C) without warping on the standard Buildtac !

Biggest part in ABS till now: a “doorhandle” with 120 x 40 mm, with brim and standard repetier values at 212 °C at normal speed.

4

The standard temperature for ABS was 230 °C which is too much.
215 - 220 °C would be a better starting point.
Every filament is different so it’s all about experimenting.

Dylan

5

for sure you are right.

i just want to illustrate how usefull it is to have good running extruders.

With my original ones i was not able to print PLA at 210° C in good quality (loosing steps).

Now i can print ABS at 210° C without problems. (both Velleman filament)

6

Have had the same problems and solved it the same way. Good to know, that this wasnt my fault at all :slight_smile:

7

I can follow the annoyance of Digi-Bert, I found the same problems. It makes it difficult do print other materials, especially quite hard filaments like metal-fill are mechanically degraded.

I checked the modified extruder and I can recommend it to everyone. The filament is going smooth without retarding at the extruder holes.

After replacing of the original parts the pulley position has to be reviewed an occasionally re-adjusted to allow a straight movement of the filament.