Different size cuts

Community Laser Talk
1

Hello, I think it’s not LB problem related but maybe you could help me.

I have a big 1300 x 2500 laser; if I cut a piece on the right side and it measures 9.9 x 10 if I cut the same file on the left side of my bed it measures 10 x 10… I don’t know if it’s step calibration.

I made 120 lines with 10 mm of separation and they all measure the same, repeated same cut file and all the lines were on the same place. I did this trying to discard mother board problems. I also inverted X and y axis , but the same problem showed on X axis.

Hope you can help, thanks !!!

2

Is it not ok tu ask for something like this ok the forum . If it’s no ok sorry o will erase the topic. Just want to know, thanks !!

3

If your measurements are in mm, 0.1mm at 1300 / 2500mm is not very much. But I’m not sure I understood your question correctly.
Btw, how exactly is the height distance of your laser head to the laser bed at all four corners?

4

Hello!!! If I cut a square 30 x 30 on the right hand side of the machine bed o get 29.8 x 30… if I cut same file on the left side of my bed it measures 30 x 30

I get different size on X axis on different area of the bed.

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5

What do you measure when you rotate the same workpiece (in LightBurn) 90 degrees?

6

if you get the same error I would also guess on stepper calibration

7

When I cut a shape on left of my laser bed and then on the top right, the two pieces are of different size - on X a difference of 2 mm

Don’t rotate them

8

Are your coordinates starting from zero (datum)? Do you get the same result if you use the “start from here” method? Maybe if using absolute coordinates from zero it will be out of position when it starts and finishes. With incremental coordinates it won’t make much difference. It the machine belt driven or leadscrews?

David

9

Hello, sorry for late reply…

My machine has belts,

If we divide the machine on Y axis by half, right hand side all long the Y axis makes cuts the same, but on the left side (starting a new cut on the left, changing origin on left area) both sides have a different size on X axis, seems like on the left side of the machine it makes them longer on X axis… don’t think that absolute coordinates for example makes change since the cut is a new procedure, with new origin set. Would it ???

10

This is pretty weird behaviour I must say. If you are starting from a new origin for the different cuts then , no, it doesn’t really sound like loosing steps unless there is some mechanical stiffness in the right side that is causing it to lose steps and as you may have calibrated the axis steps on that side it would drive long on the left. It is more than likely mechanical, but have you looked the G code for both the right and left projects and compared the relative steps between two same points?

11

I don’t know how to look into the g code, my machine gas ruida controller, is it easy to look into G code??

12

Ah, I don’t think it is possible with your controller to save the sent data as a file, perhaps one of the other members will step in here?

13

I have a similar issue but with with a 400 x 600 Blue/Grey machine with Mini Grbl and would like know if you find a solution to fix this.

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14

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