1 Topic by RzTen

  • RzTen
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  • Registered: 2015-07-26
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Topic: SD2 Overextrusion / Z Axis issues?

I'm looking for some advise on printer calibration, I'm still pretty new to the whole thing...  I recently got around to printing with my Solidoodle 2 (it's been a rather hectic few years) and I've been having some issues with the calibration.  Specifically prints that are supposed to have smooth topped surfaces come out extremely wavy, as if too much plastic was being extruded.

The flow rate/wall thickness tests always come out near perfect. If I set Slic3r to a thickness of 0.42mm manually I get +/- 0.01mm on the part and if I leave it on automatic it'll try to do 0.48mm with the same margin of error.  Filament width is set at 1.74mm (the actual filament seems to vary from 1.73 to 1.75, but the bulk of it measures 1.74) with a multiplier of 0.96.  The spool is ABS plastic.

The nickel and cube tests also seem to come out well.  I've re-tightened the belts and re-greased the rails.  If I crank the infill percentages down to 80% things start looking better, but I can't find any other thread where someone has had to do that which makes me think something is still screwed up.  At 100% the extruder will start to skip while doing infill and if the print head passes back though the infill area it ends up dragging.  I have to set Z-lift over 1mm to prevent dragging and I'd rather not as it seems to make stringing a lot worse.

I don't want to lower the flow rate as it seems to be spot on and I've tired adjusting the bed height with no luck.  Is it likely the Z motor stepping is off for some reason or am I looking at the wrong thing?  It's currently set to 2268 which appears to be correct for this model.

2 Reply by Morganism

  • Morganism
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  • Registered: 2015-01-19
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Re: SD2 Overextrusion / Z Axis issues?

I would start by doing an extruder calibration. Mark your filament at 100mm and 200mm. Set it to run out 100mm and measure how much runs out. I would bet you will run over the 100mm. You can measure back from your second mark to tell how much.

Your flow rate should always be 100%, when properly calibrated.

Use this video to help:

https://www.youtube.com/watch?v=JZGdMc2ebPo

This part is very important:

Don't update the firmware to change the steps. Instead you can enter the gcode command M92 E(number of steps). Once you have the right steps/mm dialed in, you can store it in the electronics by entering M500 or in Repetier going to Config - Configure EEPROM Settings.

This is a thread discussing my problem getting this set right:

http://www.soliforum.com/topic/11212/ho … -possible/

Particularly look at the screenshot of the config for the EEPROM settings by wardjr.

Finally, look at this Instructable to measure and calculate what the EEPROM for your extruder should be.

http://www.instructables.com/id/How-to- … /?ALLSTEPS

This is the formula that is important for you:

Create a ratio from the expected extrusion length [100mm] and the actual extrusion length [105.03mm]. 

(expected length) x steps = (actual length) x new steps     

We know three of these numbers so we can easily solve for the new steps.  This will tell us the amount of steps the extruder must actually take in order to extrude 1mm.  We extrude 100mm for the test because the greater length amplifies the minute error.

A simpler form of the ratio is New steps=  (100*113.68)/105.03

New Steps=107.958

I do not know if this is exactly your problem. However, it is the next step and Solidoodles are notorious for being sent out with this set too high. I hope this helps.

Solidoodle 4-Mostly stock running off headless Raspberry Pi with Octoprint