Core XY movement issues
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@elmoret
It reproduces the error I had from the beginning. When I move X only, using G90 G1 X100, Y moves in the same direction about 3mm per 100mm movement of the X axis. It does that with the cables swapped and remapped as well. The Only time it moves correctly is when I change the steps per mm, ie M92 X320 Y 319. Then the movement in the other axis, stops.
I have already taken it apart and redone everything. I am pretty sure this is not a mechanical issue.
thanks for the reply
RJ -
@fxxtoo
What happens if you do 1/16 stepping? Just wonder if you get the same difference or another distance. Sure all the pulleys are the same? Might also be something with one motor of course. Have you tried mapping the other drivers to the xy? -
Would it be possible to try both extruder drivers on xy. Then run G1 E0100 E1-100 to see what happens then? Just thinking out loud..
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@fxxtoo said in Core XY movement issues:
It does that with the cables swapped and remapped as well.
Right - which is why I'm saying it isn't a controller issue. Behaving identically when swapping stepper motor drivers tells me it isn't the stepper drivers or the pulse trains driving the stepper motor drivers (the microcontroller).
But Tony and dc42 are more knowledgeable than I at this.
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@t3p3tony, @pro3d , @deckingman
Well I think I might have discovered the problem. I had a M350 command in my config.g file, before my M92 command. Reading some things that dc42 had said about microstepping and pr3d said about trying lower microstepping rates. So I moved the M92 X80 Y80 ahead of the M350 and started playing with that. It appears that might have caused my problems. I will play and post the results... I hope that is all it is..
rj -
PROBLEM SOLVED....
To all that have tried to help me, I want to say thank you to all of you. Turns out that I made a silly mistake in my config.g. dc42 posted , you should put the M92 command before and the firmware will take care of the M350 when it sees it based on your M92 settings. If this can help someone else from making this mistake or helps some one figure out whats wrong, then the past month of frustration will be worth it. Thanks again for the support...and the patience for a noob.I made a choice between one of two boards for my printer. I most definitely choose the right one.
thanks,
RJ -
@mrehorstdmd , @JoergS5
The spacer is milled to the thickness of what the factory specs said for the distance from the rail to the top of the bearing surface. So Its in the same plane all the way across. The piece on the outside is the Y adjuster for the home switch.
RJ -
@fxxtoo That's good news, congratulations! One advantage of all this effort is that you know your printer very well now. Now relax and enjoy printing.
The finding is valuable information and will help others in the future.
And respect, that you had the patience to fight through it!
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@fxxtoo Hm, you get M350 before M92 if you use configurator. So that is also a problem with it.
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@fxxtoo said in Core XY movement issues:
PROBLEM SOLVED....
To all that have tried to help me, I want to say thank you to all of you. Turns out that I made a silly mistake in my config.g. dc42 posted , you should put the M92 command before and the firmware will take care of the M350 when it sees it based on your M92 settings. If this can help someone else from making this mistake or helps some one figure out whats wrong, then the past month of frustration will be worth it. Thanks again for the support...and the patience for a noob.I made a choice between one of two boards for my printer. I most definitely choose the right one.
thanks,
RJErr, well I glad you've solved your problem but something is very amiss. Whether M350 comes before or after M92 should result in the same thing providing the steps per mm match the micro-stepping setting - see here https://duet3d.dozuki.com/Wiki/GCode#Section_M350_Set_microstepping_mode
Just for the hell of it, I tried both ways on my CoreXY and in both cases I get no Y movement when I ask for an X movement. I'm still on a earlier version of firmware (1.20.1 RC2) so maybe you've found a bug in later firmware???
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This post is deleted! -
@deckingman there is a comment in the cartesian type docu:
The M92 commands to set steps/mm should either come after any M350 command to set microstepping, or else the M92 parameters should be correct for the default x16 microstepping. This is because when you change microstepping, the steps/mm are automatically adjusted to take account of the change in microstepping.
https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter
Maybe the information helps. But the original config setting would be ok after this description.
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@joergs5 Yes I know that. The link you gave has the same information as the link I supplied.
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Independent of this thread, isn't it a problem if the two sides of the X axis are not connected stiff? If the tensions of the belts are not equal, there will be torsion forces in my understanding, which could lead to the 3 mm movements.
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@joergs5 Nope. The belts and motors define the motion. As long as the tensions are set to keep the X axis perpendicular to the Y axis, it will operate smoothly and will not cause any extraneous motion.
If the x axis guide rail weren't there, the motion would still work as it is supposed to.
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@mrehorstdmd Thanks a lot, this was new to me! This gives me new innovative ideas to build a new printer!
I am thinking about a Corexy with wires, so the hotend needs only the z direction fixed.
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@joergs5 As @mrehorstdmd said. If the tensions aren't equal then the axes may not be at right angles and the printed parts might no be square. But commanding 100mm of X movement should not make the Y carriage move.
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@deckingman Thanks Ian. To balance tension, I will try a seesaw, e.g. between the motors.
(after balancing I will fix it) -
@obeliks
In all honesty, I started out with the config.g file from the configurator. In the beginning I wasn't keeping notes, on changes, problems, etc. I didn't notice the issue right away. I discovered it while getting the homing worked out.
So I could have put the M350 before the M92 statement when I started playing with micro stepping. So I would have to go back and use the configurator to find out if that is true or not.
RJ -
@joergs5 Thanks! If it can help someone else to Not do what I did ans save some frustration..Perfect! rj