Need major help with my extruder calibration!
I need the experts help. I calabrated my extruder in pronterface as per all the instructions on this very helpful board. The values are locked in and saved Timmy printer, but my printer does not extrude the new value amount. When I "calibrate" the extruder then hit extrude the machine extrudes more then 100mm of filimint. If I extrude a second time the machine extrudes approximately 3mm less then 100mm (97mm) of filimint. Yet the values I calabrated on pronterface remain the same. What the heck is going on here. You can see in this batman print I am underextruding, but this was after the calibration. I followed the directions exactly. What has gone wrong? Please help someone very frustrated.
Re: Need major help with my extruder calibration!
I have the same issue using pronterface. I will set the new extruder steps and the next 100mm is always way off, but if I do it a second time it is bang on. This has happened more than once, so not sure what is going on. If I recall the printer settings after using M500, the correct value is in the eeprom, but still over extrudes that first time. So maybe try it again doing more extrusions to see if same thing happens or if Timmy printer figures himself out.
Re: Need major help with my extruder calibration!
I played around with the values and still I am underestextruding. It is really frustrating. I am going to update the firmware to the newest 11 version and see if that helps reset everything. I also last night tried to tighten the belts up a bit more to see if that was a factor, but I fear it is something software wise with the board.
Re: Need major help with my extruder calibration!
There are a couple of commands you need to issue when doing this:
M83 - Use Relative Extruder
G92 E0 - Zero the extruder value.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Need major help with my extruder calibration!
Peter do I enter these codes after I calabrate the extruder or before? Is this what is needed to set the extruder back to factory preset?
Re: Need major help with my extruder calibration!
Use codes after.
When you run the codes to calibrate extruder, it knows that you move the extruder and that its been feeding. Thus, when you print, it does not usually extrude at the beginning until it catches up with how many steps the extruder used to calibrate.
Running these codes after calibration and saving will reset extruder steps to 0 so the printer doesn't thing its been used yet.
Re: Need major help with my extruder calibration!
Ah. I see. I will give it a try. I found your instructions on resetting the extruder and recalibrating. I will follow your advice.
Re: Need major help with my extruder calibration!
I just did this calibration on my newly built mk2s last weekend and was also having similar problems. I found that just changing the step count adjustment and not issuing the M500 wouldn't make a second run consistent, so had to do the M500 after every adjustment.
Didn't use the G92 E0, I expect that would help.
But one additional thing I did notice is that the factory filament holder can actually affect this test too. As the filament slack tightens up, the extruder can 'tug' on the spool, causing a small rocking motion, which in turn causes the spool to pull back on the filament until the friction between spool and holder is overcome. This will cause the filament feed to run short. Several runs of the test would result in differing amounts of filament being used (even with not changes to settings). Sometimes the difference would be a couple of cm!
Once I ensured that there was sufficient slack in the filament to run the full 100 sample, I got results that were consistent to my measuring error.
I'm in the works of replacing the factory filament holder as it clearly interferes with having quality prints.
Re: Need major help with my extruder calibration!
Well, rigged up a temporary spool holder out of some Lego (4 wheels on a plate to cradle the rim of the spool). Works better than the factory holder on top. Also used a piece of bare copper wire to make a loose loop hooked into the factory holders, which I've turned to face backwards. This gives a top guide with some mobility and reduces any friction from dragging the filament across the frame. The Lego wheels are a bit over loaded, so this isn't a great solution, but will work well enough to print anything I need to make a new holder.
Anyway, I also adjusted the extruder feed screw tension back to what is indicated in the instructions, which is spring length of ~13mm with no filament loaded. If you adjusted this to 13mm with filament loaded, then you are running with less tension than suggested, by almost a full mm.
Retested the extruder calibration and it was still pretty close, but the consistency of the measurements when I added the "G92 E0" before extruding seems to achieve more consistent results. I had started at factory setting of 161.30 and went to 165.60 previously, and now am using 167.10 and am getting repeatable results in about the 0.1mm range.
Re: Need major help with my extruder calibration!
I am still having extruding issues. I am majorly under extruding. I think my hot end may be faulty as I don't have a blockage. I was under extruding 13mm from the factory sets. I recalibrated the e-steps to 187.4 per the calculation. It seems to be working but my prints are not perfect. My z axis is set at -195 anything higher is too close. Really frustrating. My heat readings on the printer say 215c as should be, but I am not sure. Screws on the extruder are set not too tight and not too loose. I may order a new hot end, as I don't think Prusa will replace mine. I totally broke everything down and still have this issue. So, out of deductions it appears it has to be the hot end. Any one else have any ideas?