1 Topic by knightshade

  • knightshade
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Topic: Issues with Extrusion...

I've been pretty quiet on the forums here, mostly reading and learning.


Background:
Like many here, I got in on the preorder on the Solidoodle press.
When it finally arrived, life had me busy - so I didn't get a chance to play with it.
It sat for months on my desk as an over sized paperweight.


I ran into many of the common issues:
- Grinding noise when moving to the back of the machine (fixed with a rubber band for now)
- A loose grub/set screw causing knocking/thumping sound
- SoliPrint crashing when setting the Z-Offset (learned to do this manually via gcode)
- ABS adhesion issues (Hairspray seems to be working)
- Flipped the fan so that it blows air toward the extruder


With those things addressed, I've done a few printouts - with mediocre results.
Enough that I went through the first roll of filament.

With another brand of filament I started to run into new issues.
The first was A knocking/thumping sound is coming from the extruder stepper.

This video was *very* helpful - I found that my voltage for the Extruder Stepper was 0.8v (instead of the 1.5v that it should be):
https://www.youtube.com/watch?v=TJu_BaB3ey8

After tuning those - I got a wonderful print at 0.3mm layer height, and one at 0.1mm layer height.
I was finally very pleased with the print results!

When the issues started:
My extruder nozzle clogged.
Since then - things have taken a turn for the worse.
I cleaned it (soaking it in acetone, and a drill bit) and started to print again.
I've managed to get one successful print done at 0.3mm layer height....
But failure is my typical experience now.

Current Extruding Issue:
Anytime that I am trying smaller layer heights, and sometimes at 0.3mm - it stops extruding when I get to about ~20 layers.
The print head moves, but no ABS comes through the nozzle.
If I look at the filament - it is heating up and getting "soft" just below the feed gear (above the hot end.)  once that happens it stops feeding.  I can back out the filament, cut it, and get things working again...
But the issue returns as soon as I start the next print.


I've tried lowering the temperature (I was using 240C/105C) -220C/100C gave me the same issues  (should I try colder still?)
I've taken apart the hotend again, cleaned it and reassembled it.
I've run out of ideas to try....

I was hoping that someone here might have a suggestion

2 Reply by knightshade

  • knightshade
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Re: Issues with Extrusion...

I've been trying to do more reading to see if I could find any ideas.

This post had a good list of things to look at:
http://www.soliforum.com/post/99053/#p99053

trayracing wrote:

akhs001, you may have the same outcome, but there's a whole pile of scenarios for gouging, so your cause may be different. Here's some scenarios, roughly top to bottom:

  • Junky/dirty/dusty/soggy/oversized/undersized filament

  • Feed problem (kinked filament, jam at spool or feed path)

  • Dirty drive wheel

  • Misaligned drive wheel

  • Not enough idler pressure

  • Misaligned/jammed idler

  • Extruder motor too hot (softening filament at drive wheel)

  • Bottom end of extruder too hot, kinking filament

  • Top end of tube too hot (bulging filament)

  • Cooled plastic stuck in top of heat break

  • Nozzle misaligned to heat break tube

  • Nozzle tightened to heater block, not heat break tube

  • Heater set too low

  • Inaccurate temperature reading

  • Temp drops during extrude (weak wires/supply, loose heater)

  • Feed rate too high

  • Junk in nozzle body/heat break

  • Cooked filament in nozzle body/heat break

  • Junk/cooked filament stuck in orifice

  • Nozzle orifice peened too small by bed crashes/collisions.

  • Extruding first layer too close to bed (back pressure causes stripping)

I left some out, since we're talking specifically about Press with ABS. Try ruling out the easy things first so you don't make things worse rather than better. (For example, reassembling the heater block too high on the heat break pipe will overheat the bottom of the extruder and the top of the heat break tube.)

These seemed to fit the description best:

  • Bottom end of extruder too hot, kinking filament

  • Top end of tube too hot (bulging filament)

  • Nozzle tightened to heater block, not heat break tube


The last one has me wondering:
Did I not assemble the heater block correctly after clearing the clog?

3 Reply by knightshade (edited by knightshade 2016-06-07 13:18:41)

  • knightshade
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Re: Issues with Extrusion...

Had two successful prints overnight....  (about 10 hours of run time)

- Heated the print head to temp, and tightened it (at temp, had about 1/10th of a rotation to tighten)
- In Slic3r, Filiment Settings, Cooling:  Enabled "Keep Fan Always On", and bumped  the min up to 75%
- Propped the top lid open
- Left the front door open
- Went back to my original temp setting of 240C

I'm not sure which was the real issue -
But closing the door and lid, I had another failure instantly.

4 Reply by madfalcon81

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Re: Issues with Extrusion...

If the temperature of the extruder/nozzle is too high, the filament will melt before entering the nozzle so the extruder stepper cannot push it. Try lowering the temp even more (210-220C), keep the door not open/not close, somewhere in between, but keep in mind that temperature variation will make layers break apart, so try keeping a constant room temperature. Also goes for the lid. Keep fan on to 100%. What speed do you print ? ( i recommend 40-50 mm/sec maximum).

Fat kids are harder to kidnap!

5 Reply by trayracing

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Re: Issues with Extrusion...

Glad my earlier post was helpful, knightshade, and thanks for taking the time to check old posts!

A few more thoughts:
If you're only now getting softening below the drive wheel, then you're probably getting more heat to that area than before. Two likely suspects:
* The heater block touching the extruder body (or nearly so)
* Turning up the extruder reference up to 1.5v gave more power, but also more heat.

For the first, the heat break tube on the Press is quite short, so you can't put a lot of space between the heater block and extruder body without the nozzle bottoming out on the heater block. But there needs to be at least a little. (On my to-do list is to try an e3d nozzle, if they fit - those seem to have a longer threaded section)

For the second issue: for my setup, the motor feeds OK at a reference voltage of 1.3v, where the motor runs a good bit cooler. It's a matter of balancing power vs heat and YMMV. Also, my need for power went down some when I aligned the nozzle to the heat break, by stuffing an allen key down the barrel & nozzle as I tightened the nozzle. (Cheapo threads on the heater block. Sigh.)

6 Reply by knightshade

  • knightshade
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Re: Issues with Extrusion...

I had been noticing that the stepper motor for the extruder was warm to the touch, and though that it may have been related to changing the voltages.   

I had read one post where someone recommended removing the clear plastic with the solidoodle logo.
I had debated what would happen if I were to add a fan mount there to increase the air flow cooling off that area.

As you mentioned that you are working at 1.3v, and I had been extruding (with a bit of variation) at 0.85v, I have reduced it to 1.25v to see how things go for a bit.

7 Reply by trayracing

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Re: Issues with Extrusion...

I would suggest keeping the clear shield on, as it directs what meager air flow there is across the cooling fins. A blower would work better here, and designing a mount for it is on my somewhat dusty to-do list.