Marling: steps for mm X different form Y

Hi,

I'am a new to reprap and I have a problem that I hope sameone can solve.

I'm using a Marling on e prusa using Megatronics Board.

I set the Steps per mm in the following way:

#define DEFAULT_AXIS_STEPS_PER_UNIT {80, 80, 200*16/1.25, 760*1.1} // default steps per unit for Prusa

When I print a square the X axis is correct but Y axis is longer by 10%.

The belt are tightened, I use the same alloy pulley, I dont use EPROM, the stepper motor work well and do not lose any steps, I tried to invert pololu X e Y with the same result...

Why this?

Very strange.

Are both belts the same type and make?

What happens if you swap the X & Y motor connections? (If you also swap the limit switches the machine will work but print mirror images). If X becomes the biggest then the problem is firmware / electronic. If it stays with Y then it is mechanical. If the pulleys have the same number of teeth then it must be different belt pitch.

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[www.hydraraptor.blogspot.com]

Hi nophead,

I swaped X & Y motor connection and the rectangle have the same shape.
So it was is a mechanical problem:

I was using T2.5 pulley on 5cm belt.

Thanks Nophead!

How many teeth in your pulley?