Extruder not working under Pronterface

I have an Orca v0.3, which I just completed building. I got a few sorta good prints out using RepSnapper, but want to use Pronterface now.

However, the GCode that pronterface produces does not output the correct 'E' values for the extruder, and so it just moves around without extruding plastic.

I've tried a lot of the suggestions in the forum here, including adding Dimension. Here is a few lines of code from pronterface using SF:

G1 E0.0
G1 F3000.0
M101
G1 X10.08 Y47.628 Z0.36 F900.0 E0.0034
G1 X11.52 Y47.628 E0.0035
G1 X11.52 Y11.412 E0.0069
G1 X12.96 Y11.412 E0.0071

Whereas RepSnapper generates similar code, but the 'E' values are in the thousands.

What am I missing?

David

What kind of motors are you using for the extruder, steppers or DC? What are the Feed Rate and Flow rate on the speed tab of SF/SFact?

You don't have your machine E_STEPS_PER_MM calibrated correctly.

See "Skeinforge 40 Changes to Dimension" in the Skeinforge topic.

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

@grog: Thanks for your response! I have stepper motors all around. I played with the Feed Rate and Flow Rate, but the best I could get out was a stringy mess. Leaving the Feed Rate at a constant 50mm/s, I get no plastic at high and low values (10 and 300) for Flow Rate. I would think that I should get too much plastic at the high mark, and no plastic at the low mark(?)

@rhmorrison: Thanks, Bob, I will look into that now and report back.

@grog
@rhmorrison

Now I wish it was a simple matter of software!

In the process of trying to measure how many E_STEPS_PER_MM ... I found that I get a VERY inconsistent amount of filament into the extruder per step.

There is not a clean path for the filament around the extruder motor cam and past the pinch roller... I have played with various alignments... each one takes a few hours to remake the setup. Anyone have some clear pictures of how the alignment should/will work best?

The default in SF is for DC motors. For stepper moters try setting the feed and flow to 25 each.

When doing test extrusions I found that the firmware settings were also too fast, so it just kept chewing up with filament rather than feeding it smoothly. I thought I needed to set the speed higher since I wasn't getting enough filament to feed through. But I actually needed to back the speed in the firmware way off. I have the Z steps set at 423 and it feeds a lot more smoothly. You might want to check to see if you have filament shreds in your extruder.

Printing a filament guide was useful, even if it came out ugly. It was still useful to get it to feed in straight - and help me print a better one.
Mine seems to like it best when it comes in pretty much vertically.

@grog

Thanks a ton for your responses. I made some progress today. I rebuild the top end of the extruder, and got the alignment fixed... it seems to be feeding a consistent amount of filament. Once it was consistent, I was able to determine my E steps per mm, which turned out to be 260. Now, at least, when I ask RepSnapper or Pronterface to extrude 10mm of filament, the extruder obeys!

So now, a STL loaded into RepSnapper outputs way too much plastic, but Pronterface is happier... but still has issues. Pronterface output is still too stringy, but much better.