Flipping X or Y axis on a SCARA machine

[Carter3DP]

Hi all,
I was wondering if there was any way of flipping only one axis on a SCARA robot built with a Duet3D board?
Currently the axis are setup as the negative Y axis being forward and the positive X axis being to the right, if you were looking from the top down. I would currently like for the Y axis to be positive forward and the X axis to be in the same direction as it is.

Any help would be very appreciated,
Carter.

[dc42]

@Carter3DP by "forward" do you mean towards the front of the machine? If so and positive X is to the right, then negative Y forwards is correct. Viewed from above, positive Y should be 90deg anticlockwise from positive X. If you reverse Y then you will have a left hand coordinate system and your prints will come out mirrored.

[Carter3DP]

@dc42 By forward I do mean the front of the machine, however it is wrong as this cause any files sliced to be mirrored. If you print an R it show up flipped around. The attached image shows the issue.

[oliof]

@Carter3DP which slicer are you using? Simplify3D has a "flip Y axis" setting that sonetimes spuriously is on.

You can also temporarily try flipping your axes in RRF with M579 (i.e. M579 X-1 to flip X), but I wouldnt see that as more than a stopgap measure

[oliof]

I dimly remember from my scara times that you need to be careful defining the angular range and endstop position, I am pretty sure I got it wrong multiple times until the moves went into the direction I wanted. So a diagram of the machine with endstop positions and your config.g may also help shed light on the situation.

[dc42]

@Carter3DP if the axes on your machine are as in the second of the three diagrams in your post, then yes you need to flip an axis.

I suspect your proximal and distal motors are moving in the wrong direction. If you send G91 G1 H2 X10 or G91 G1 H2 Y10 then the corresponding arm should move anticlockwise as seen from above.

[Carter3DP]

@oliof "Carter3DP which slicer are you using?"

Simplify is one of the slicers we use, however we sell our machines, and so customers may be using different slicers (like prusa, etc.), and as such, the slicers may not have an option to flip the axis.

"You can also temporarily try flipping your axes in RRF with M579"

I haven't seen that one yet, so I will go ahead and give a try.

@dc42 "If you send G91 G1 H2 X10 or G91 G1 H2 Y10"

As you suspected, the arms moved clockwise, I will reverse polarity on the X and Y motors in config to see if there is a difference.

Thank you both for taking the time to help me!

[Carter3DP]

Flipping both motor direction polarities was the answer (at least for now, I haven't done any testing aside from jogging the machine, I am about to test that now).
Once again, thank you both for the help.

[dc42]

@Carter3DP you will need to reverse the direction of the homing moves for the proximal and distal motors, and switch the proximal and distal homing switches over from low to high end or vice versa.