Stepper behavior question (video)

What does this bubbleing and crancy sound mean on start and stop of steper move?
Where to look for proble?

For software i use Grbl v0.9 (seems to work the better than v0.8) in Arduino
and Universal GcodeSender 1.0.7 in PC.
motor Nema 17 model 17HS16-2004S 2A 45Ncm(64oz.in) with 1.8° step angle (200 steps/revolution).
CNC shield v3.0 on UNO
pololu DRV8825 drivers
PSU 24V 10A

Without seeing the program that is controlling the motors I can’t say.
Also, you have given us no info about the motors. Nema 17 does not tell us anything useful. See stepper motor basics

The motor on the right looked like it might be missing steps (but without the code, who can say). Missed steps could be due to trying to accelerate too quickly or an inadequate power supply.

…R

Added some more info.

Lagertha:
Added some more info.

It's better if you add data in a new Post rather than updating an older one as that makes it easier to follow the progress of the discussion.

Sorry, but GRBL is much too complex to offer any advice about it.

You need to provide a link to the datasheet for your motor. The critical piece of data is still missing - how much current does it need.

Have you the current limits on your DRV8825s set correctly?

is it an option to swap the motors to see if the problem is associated with a motor or a driver.

...R

Sounds nasty, not a normal noise, could be mis-stepping or power supply dropping out.

BTW you can't measure the temperature of a metal heatsink well with an IR thermometer,
metals are not black-body radiators.

Definitely test each motor separately with a simple GCODE G0 rapid or something,
then both together, go back and forth from a fixed location to check for mis-stepping.

You should have a cooling fan for those drivers if they are taking > 1A, they will overtemperature without it I suspect. That could be the problem.

Incidentally unloaded steppers are more likely to mis-step from resonance than
lightly loaded ones, which can be an issue.

Calibrate for max acceleration and speed and ease both settings back 20% or so.
You'll need to repeat this once the full mechanical load is there.