Asymmetric movements

[Anonymous]

Hi,
i’ve built a Makelengelo using adafruit motor shield v2 and nema17 (200 steps) motors. I think I made the right setup but it moves more on the X than on the Y axis (with G01 X50.0 Y50.0 x moves of 7,7 cm and y of 6,5) so every image became oval
I tried both to send manual commands that through the Makelangelo software. I made a lot of attempts but I don’t know which parameter could cause this behavior. Any suggestion will be very appreciated 😀
Thank you

Massimiliano

[tjhawkey]

I have a similar problem when I test my version with the move commands (the 100 mm moves in the software). I can get the up/down movements to scale properly via adjusting the spool diameters, but the left/right movements are off (longer). Where the robot is homed affects this as well. The code expects a specific relationship between the motor axis (you enter this) and the home position (Dan defined this in the code). I think I have that correct on my machine, so I’m little confused why my left/right 100 mm moves are more like 110, while the vertical is accurate.
I can print images that look fine, but I haven’t tried printing plain squares or circles.

[Dan]

Our motors are 400 steps per turn. The number of steps per turn is hard coded into the firmware. You’ll need to change that number and upload the firmware again.

Does that help?

[Anonymous]

Hi,
Thank you for your quick reply. Unfortunately I already did that test (it’s my first time with a CNC but I have experience with Arduino programming). I also tried to change the multiplier to 8 and swap motors in the code but it always shows the same behaviour. I also thought about weight and gravity but the Y has the same movement up and down and is less than X. I tried also to draw a circle with G02 but I got an ellipse.. I’m quite lost…

[tjhawkey]

I’m properly setup for 200 steps. horizontal lines seem consistently 10% longer than vertical lines. I’ll do some more testing with different home positions and double check my machine width setting.
Home is measured from the bottom edge of the motor and not the shaft, but the machine width is shaft to shaft–right?

Thanks!

[Anonymous]

Hey guys,

i built my Makelangelo yesterday, and after calibrating it today, it came out, that I have the same issue. I’m also using Nema17 steppers and I already set the stepper_steps_per_turn variable to 200. I made a bunch of tests with different home positions and I noted that the value of the machine width does not influence the drawing at all – changing the home position does. Plot of horizontal lines are shifted to the right (from bottom of image to center) and then shifted back left again (from center to image top; so that the left end of lowermost line of the image is aligned with the left end of the uppermost line). I don’t know what to do.. I don’t think that’s the case but it seems to me as if the machine width/height inputs were just ignored , as if there was a fixed value for that.

I’m using the newest version of the firmware and the newest software (v7.7) too – apropos..can’t find the “Makelangelo.jar” in the directory of the newest software on github?

Thanks in advance and greets
mpmmxd

[Dan]

Uh…. a width change of 10mm is more than enough to see a visible difference. Perhaps I don’t understand your description. Can you post photos or video of what’s going on?

[Author]

Posts