Problem: Extruder to both sides

I hope someone can help.

I'm in calibration step. When I ask for print without PLA I can see that the movements of the axes are correct but the extruder is crazy. It moves to both sides. In configuration.h file I've got e_steps_per_mm=691. I've tried with other values but this seems to be the best one because with the others doesn't moves. I'm using repsnapper, so when I order "purge extruder" it moves but never at the same direction. Then I decided to try to adjust the pololu. I've spent hours doing that and doesn't works. I want to print!!! Any ideas?

Thanks a lot!

What electronics, firmware, extruder and slicer (Skeinforge, etc) and version are you using? Without these information, it's hard to be sure. But your steps per mm is probably too high. This is something that needs to be calculated and calibrated.

I'm sorry, I'm completely lost with that themes. I've got to work with reprap but, it wasn't me who had been building it until now. I know they've bought all at Maker Gear. And it is a Prusa Mendel. I'm going to try giving you some information. Arduino, ramps 1.2, A4983 stepper pololu, and I am working with repsnapper.

I think my kit is the same that the one you could see at that web.
[raisinggeeksandgearheads.blogspot.com]

Thanks a lot!

Check that your slicer and firmware are both set to either relative or absolute coordinates. If one is set different from the other it can cause the extruder to move backwards at times. And maybe try different software just in case that is the problem. Pronterface is pretty easy to work with.

Two ideas:

1) Make sure the extrusion speed is not very high. Sometimes repsnapper has values like 3000 which is too high for my hardware. Try something smaller, real low, like 25 or 50.

2) If speed is not the issue, cabling might be. Make sure this stepper is properly connected. You may exchange extruder stepper with another axis known to work (like X or Y axis) and try +1 pr +10 buttons on that axis in Repsnapper.

Good luck,

misan

Thanks, I can't try that until next week. I will answer then.

It would be best to avoid using Repsnapper to slice ST files. Use Skeinforge, SFACT or slic3r instead.

These are my conclusions after this week.

Misan,
- I've changed the extrusion speed but it was the same as before.
- Then I've connected the X axle stepper mottor, at the extruder pololu and it works great. This stepper it's different than the others. This is 1,8degrees-1A and the others 0,9degrees-2a. After doing that, I was sure that it wasn't a programming or software problem, I thought the motor was broken. I've measured the resistance of each coil of the extruder stepper and it was the same 2,8ohms (I've measured from pin one to three and from pin two to four, isn't it correct?). Now I don't know if it is the stepper. If I can, I'll change the connector but it seems ok.

Bryanandaimee, I don't know how to check your proposal!

Brnrd, why you think that my problem it is caused by Repsnapper? I've problems before printing...

Many thanks to all!

Quote

I've measured from pin one to three and from pin two to four, isn't it correct?

No the coils should be connected between 1&2 and 3&4.

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[www.hydraraptor.blogspot.com]

Mmm.. thanks, I'll check that!

Nophead, you were sure! The coils should be connected between 1&2 and 3&4... now it works! ¬¬'