Unretraction issues
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I'm kind of having the same issues. What are some good baseline settings for accel/jerk for an extruder motor? I've never had to configure these for the extruder. Here's what I have
M201 X2500 Y2500 Z100 U100 E1000 ; Accelerations (mm/s^2)
M203 X180000 Y180000 Z1800 U1800 E3600 ; Maximum speeds (mm/min)
M566 X800 Y800 Z30 U30 E20 ; Maximum jerk speeds mm/minuteUnfortunately, I don't have any specs on my steppers. I bought them a while ago and there are no labels on them
Edit: Found them:
1.8 stepper
0.8A Current
Inductance per phase 7.5mH 20% -
Here's info on the E3D stepper. To clarify, I'm comparing 2 printers. I have one Tevo Little Monster equipped with an Amazon stepper and another with the E3D stepper. The biggest difference between the two is the steps, the E3D is double the resolution which is why I had to double the value for M92. I need to confirm this, but the behavior feels like if I have my retract set to 4mm it will retract 4mm but only unretract 2mm when resuming. Is there another config value I have to double due to the resolution? The original stepper is 1.8, the Amazon stepper is 1.8, and they work fine.
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Too much microstepping for .9 motors? If the original 1.8 motor worked that could be the case.
Maybe the feedrate for unretract is too fast?
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Are you using firmware retraction? Also, can you type M207 into gcode console and post the output?
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Here's mine:
M207
Retraction/un-retraction settings: length 2.00/2.00mm, speed 1000/1000mm/min, Z hop 0.00mmDoes that mean it is retracting 2mm instead of the 5.5mm I set in my slicer?
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Here's mine:
M207
Retraction/un-retraction settings: length 2.00/2.00mm, speed 1000/1000mm/min, Z hop 0.00mmDoes that mean it is retracting 2mm instead of the 5.5mm I set in my slicer?
It depends on the slicer and if the slicer has firmware retraction enabled. If firmware retraction is enabled in the slicer, then your retraction settings are what is output by the M207 code (assuming the slicer enables g10 / g11 commands for retraction). If slicer does not have firmware retraction enabled, it will be using the settings from the slicer. I was curious to see if firmware retraction was being used and if someone put in a bad R value in the M207 command line.
Rnnn positive or negative additional length to un-retract
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I'm using S3D, so I'll have to research what is really happening. I don't believe it is using firmware retraction because I can adjust it in S3D and impact the output. If I lower the retraction to nothing or close to nothing but it does ok. I'm almost finished putting together my 3rd Tevo LM and will start with the E3D stepper that way I will have a printer with all 3 options (Amazon, Stock & E3D) to play with.
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It's easy to check if the slicer is using firmware retraction. Just check the gcode file for G10 (with no other parameters) commands. Each one should also be followed by a G11.
Edit IIRC S3D does something differently and uses some other command instead of G10/G11. Can't remember exactly what the work around involved and later versions may not exhibit the same behaviour.
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Even easier in the process settings of s3d check the G-Code tab and see if allow M101,M102 and M103 option is ticked if so then you have firmware retraction on but AFAIk you have to set all the retraction option to as low as you can get for it to be effective.
HTH
Doug
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I do not have that checked and, you're right, it does not use G10/G11.
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Are you sure about that Dougal? I don't think M101, M102, and M103 relate to firmware retraction in S3D?
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yes they do it is the old way of doing it there is a write up about it somewhere on the Reprap forums and it does work I use it all the time. Generaly it is deprecated but DC added support into RRF to allow them to be treated correctly.
see http://reprap.org/wiki/Gcodes#M101:Turn_extruder_1_on.28Forward.29.2C_Undo_Retraction
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Whatever steps/mm setting is, retract/unretract should be in sync: length might be incorrect, but it should be the same in both directions.
Did you try at a lower speed? It may miss a few steps when doing unretract…
Could you also try to slowly increase the retract/unretract value, and see if there is a point when it suddenly start to fail?
Also, have a look at the G-Code fil to check if both values are the same! Don't you have an additional unretract negative value which may mess up things? If all seems ok, try to send both commands by hand, and measure how the filament moves after each command.
