I square up gantry and it doesn’t stay perpendicular after one run. Why?

Lasers
1

I’ve aligned several times the gantry. I squere up the gantry – I run a job – the gantry becomes deformed from square.

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Deformation happens always in the same direction: the side opposit of stepper motor becomes further from it’s endstop.

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I’m showing it moving with my hands (running a job with stepper motor makes the same deformation).

I tried everything multiple times:

- to fasten belts before and after squaring up the gantry

- to fasten a bit into the another direction

- to loosen and fasten different screws of gantry (most times the one on the picture)

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Nothing helped. Why doesn’t it want to stay squared?

Machine is Nasum A5 Pro. The frame is squared.

(I wanted to use the machine for accurate cutting of fitting parts (like puzzle game)).

2

Looks like you’ve checked the mechanical things but have you looked to make sure they’ve installed the same size belts on each side or same size toothed gears?

There are some belts often used which are NOT GT2 compatible and are very slightly off in tooth spacing. So you could have a machine with a mismatched part(s).

3

Check the tightness of the motor couplers. They really need to be tight. Part tolerances can really vary.

4

Sorry for my late reaction, and thanks Dougl for your answer, although I didn’t get any further in this topic. I use the parts of the producer. Is there any chance that the original belts aren’t compatible with the motor? Even then they should work symmetrical, as I think.

5

Thank you, but it doesn’t seem to be a problem. The displacement of the two sides is always the same: the right side never moves back compared to the left.

6

Besides a mechanical issue, the only thing I can think of next would be to set the micro-stepping to zero, move to a position and then loosen and adjust the drive gears on the motors so that the gantry is perpendicular while making sure the motors stay powered and hold their positions.
Then switch it back to what the normal micro-stepping setting is and see if that solves your problem.

If it’s a mechanical thing then you can tell by how bad it gets without power and moved by hand.