How to change ratio for y axis? Out by 1.5mm per 10cm

[Clare Taylor]

Hi all
I've just got another laser (have a mercury II, now have a spirit GX) My mercury is cutting a square perfectly, however my spirit GX is cutting a 20cm x 20cm square as

20cm left to right (x axis?)
20.3cm top to bottom (y axis)

What should I set my y axis ratio to to correct this? How do I calculate this

TIA Clare

[Kev Williams]

That's 1/8" off in 8", which is not even close to "good"-- is this consistent from top to bottom, and everywhere on the table?

I'd check to make sure all your set screws are tight, all motors are tightened down firm, belts aren't loose, and confirm the Y axis rails are square to the X rail.

...for starters...

[Clare Taylor]

Thanks Kev

I have adjusted the y axis ratio to -15/1000 which has fixed the cutting issue for me.
I have just had it serviced, with belts and rollers changed. I am in a remote location so unlikely to be able to get the technician back to correct any issue, and I haven't had to go over a machine before to know how to check if they are loose. I assume the belts should not be floppy and any screws should to tight?