Untouched VREF value from the extruder stepper driver

[Wolle82]

Perhaps there is someone out there who can give me the untouched VREF value for the extruder stepper driver. Further I need to know the kind of resistor on the used stepper driver (R050, R100, R200... Stepper driver: A4988), because I want to know the out of the box current rate value from the stepper motor.

Background: My extruder stepper driver was broken... Now I bought a new one and I want to set up the correct VREF. The stepper driver I bought is the (better) DRV8825 one. But I don't know the current rate value from the extruder motor. All other motors are type "42SHD0034-20B"... here we have 1A current rate (found on a datasheet). But the extruder motor is type "42SHD0227-24B". For this type I wasn't able to find the datasheet. Now I try to find out what current rate value this motor has.

Can you help me?

[Wolle82]

42SHD0034-20B (XYZ) = 1A
42SHD0227-24B (Extruder) = 0.4A (400mA)

Here is the datasheet recommended by Geeetech: http://ww1.microchip.com/downloads/en/D ... asheet.pdf

[PietriFly]

Thanks alot for sharing your results!

[killvearn]

That datasheet is wrong for our motors.
The axis motors are 42SHD0034-20B (note the two zeros) and are 34mm in lenght (not 48mm).
Other than that, with an amperage of only 0.4 per phase, the extruder motor alone, who's the biggest with 40mm of lenght would give us ridicolous vref: 0.8 x 8 x 0.05 = 0.32.

[Rogeralcon]

So what is the correct Vref? I've been having extrusion problems and I decided to change the x-axis motor to the extruder but it has less force. I have corrected the problem a bit by increasing the extruder voltage to 1.1v 24B motor but I think I should change to an stepper motor with more torque in my geeetech a10

[GxS]

On My A10M had ocassionally Y shift and toasty extruder motors. Vrefs were as follows:
X 1.1
Y 1.0
Z 1.1
E0 1.1
E1 1.1
The way I see it, if your extruder is skipping chances are you trying to shove more filament through the nozzle than it can flow, be it for temperature settings or other mechanical limitations. Especially since these are geared extruders they shouldn't lack torque as direct drive.
So following that X,Y and Z were all set to 1.1V and E0 and E1 set to 0.9V resulting in all motors being warm to the touch after 3 hour print, though Vref could be dropped tad more on extruders I think.
Other thing I noticed that Y skip was likely caused by over extrusion and setting flow to 94 to 96% helped to remedy that.