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Extrude direction reversed in repetier host

Posted by scottybfg 
Extrude direction reversed in repetier host
October 29, 2016 10:02PM
Hi All,

I'm having trouble with the extruder direction in repetier host V1.6.2.When I go to the manual control tab and extrude 10mm of filament, 10mm is fed through. But when i enter G1 E10 F400 the extruder runs in the reverse direction. I'm very confused as how this can happen.

I first noticed this when I tried to print a part and the filament was not feeding.

The printer is a maker farm i2 and has been printing on and off for the past 4 years.

Controller is a ramps v1.4 running the new marlin (updated today, still same issue), Slic3r is 1.2.9

Any help would be much appreciated, I'm usaly good at de bugging but this one has me stumped
Re: Extrude direction reversed in repetier host
October 30, 2016 04:17AM
I think you have missed a basic part of gcode

there are two modes of operation, absolute positioning and relative positioning

if your in relative mode G1 E10 F400 will move forward (extrude) 10mm, but if your in absolute mode and E is already at position 20, it will go backwards 10mm

see [reprap.org] G90: Set_to_Absolute_Positioning
and [reprap.org] G91: Set_to_Relative_Positioning

so prefix your move with a G91 command and I suspect your issue will go away

You can also use M114: Get Current Position to find out current positions of the axis and verify what is doing.

Edited 3 time(s). Last edit at 10/30/2016 04:21AM by Dust.
Re: Extrude direction reversed in repetier host
November 04, 2016 06:07AM
Thankyou

I changed the start code in slic3r to G91; Use relative coordinates

I dont know why this has become a problem now as I have always used G90 for absolute positioning
Re: Extrude direction reversed in repetier host
November 04, 2016 08:10AM
I don't think the relative positioning is an issue and changing means all co-ordinates are now changed. Though I am not familiar with marlin.
If you stay with absolute positioning then sending a G92 E0 will zero the extruder. So put that in start code or send it before any other extruder commands.
If this was a new build we would probably be saying the motor was wired the wrong way. Don't forget that in Repetier there is a setting to reverse the manual control directions - so you could be wired backwards but behave OK using the Repetier controls.
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