Start of print rams x/y carriage into frame



  • Running a CoreXY printer. I can move and home all the axis using the controls and GCode. But when I upload a print sliced in Slic3r or Cura it heats, it does the homing and then slams into the side of the printer for a minute, then starts printing in the home corner. Like it's moving the Y or X in the wrong direction. I'm just note sure why as it moves fine when I run GCode manually or use the controls from the web interface.

    For example, the line below gets me close to the center of the bed when I run it manually, but it's not working when running the gcode. That is lifted straight from the GCode file0_1567983466160_CFFFP_20mm_cube_soft_edges.gcode

    G0 F3600 X137.595 Y137.287 Z0.3



  • It sounds like you've got a motor direction reversed which is inverting your coordinate system.

    the 0,0 origin should be in the front left corner of the printer, with X+ moving the head to the right, and Y+ moving the print head towards the rear.

    It would help to see your config files and homing files.

    If you follow through this config section for CoreXY, particularly the section about testing the individual A and B motors you may be able to identify which motor needs to be reversed.

    https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCoreXYPrinter#Section_Movement_section



  • Ok, I was homing in the back right corner. I am using the Z probe as the Z endstop. When I home to the back right corner the probe is over the bed but not when I am at the front left.



  • Ideally you'd position the z probe to the center of the bed after homing X and Y before issuing G30 to home Z



  • I've got it homing ok with each individual axis but homeall is ramming the x. It's the G90 before the y movement just before G30. I'm not sure why it's causing an issue0_1567989799754_homeall.g



  • G1 Y+40 F3000 ; go to first probe point

    Try adding an X coordinate as well.



  • Changing it to G1 X+15 Y+40 F3000 does not help. Does the same thing



  • Can you post your config.g?
    Are you using sensorless homing or endstop switches?
    Did you follow the motor tests from the movement section of the corexy config that I linked to verify that the motors are turning the right direction?
    You have the origin in the front left now?
    How do you have the print bed setup in the slicer?



  • I got it working by adding a G92 X0 and a G92 Y0 after homing each axis in the homeall.g file



  • That's kind of a hacky workaround to the problem. That would indicate to me again that either a motor direction is reversed and/or the coordinate system is wrong.

    When homing to the low end the axis position is set to the axis minima as defined by M208. Which if it is 0, setting G92 X0 would be redundant.

    But without seeing the config.g I can only speculate.

    I'd also be concerned about being able to center parts on the build plate and having parts become mirrored.



  • @AgentNoise said in Start of print rams x/y carriage into frame:

    I got it working by adding a G92 X0 and a G92 Y0 after homing each axis in the homeall.g file

    Well they may be benign but they also may be masking a problem.

    You should continue to try and find the real cause.

    If you post your config.g and homing .g files we can help you.

    Frederick


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