What am I doing wrong - Axis Calibration?


I have used LB alongside RDworks for several years no issues.

Today I thought i would use the “machine settings>axis calibration” in LB to tighten my tolerances on cut squares. I did the cut, checked the lengths went into LB machine settings, read the controller, updated the axis figures, then wrote back to controller. All appeared good.

I then rebooted the laser and upon its initialise, instead of the head slowly homing back from bottom right (my last cut last origin) to the top left (homing position). It flew across the bed at incredible speed and hit the left gantry and stopped dead. It was that quick it startled me and made an almighty bang. The speed it moved at was really really fast.

When it hit the gantry it was well towards the front left of the laser bed, It was more of an horizontal movement across the bed instead of a diagonal movement back to its homing position and it was an accelerated speed rather than at its normal homing speed.

To rectify, I had to do a reset on the controller, re-home and then copy back my saved controller settings via RDWorks. All works fine again now sending jobs from both in LB and RDWorks.

I am now a little nervous to try axis calibration again until I find out what I did wrong?

maybe you typed in a number wrong, decimal point in the wrong place or something.

laser a square 100 x 100. then measure it accurately (pretend it was X was 97.8mm, and Y was 98.5mm)

open the axis calibration in LB

enter length it is meant to be 100mm

then enter the length is actually is (what you measured with vernier calipers ) so say this was 97.8mm

The calibration will show a figure like 0.2453645.

Just click on the write button at the bottom and it should write this straight into the machine.

do again and select Y axis in the calibration, and enter those settings.

From memory I did what what you suggested. Started with a cut size of 100mm x 100mm and actually got 100mm x 99mm.

Did the amendment, saved it back to the controller, the second cut I got 100mm x 101mm (from memory).

After the 3rd amendment I got a cut of approx 100mm x 97mm. So after this 3rd cut I thought I would re-boot the machine to see if that made a difference.

When it initialised, this is when it took off at great speed and hit the left gantry as per my first post.

What controller do you have?

Is strange because once you do the calibration the 1st time it should be spot on, assuming your measurements are correct, and there is no reason I would think they would not be.

I did mine just the other day as I installed a new controller and it was dead on 100 x 100 after doing it once.

LB did not write to my old controller correctly all the time, on my old controller I had to use RDWorks to change the settings, it cannot be compatible with all the older ones I assume. so maybe do the calibration and write the number down, do not write it to the board, but instead input that number directly into the machine panel.?


It’s a 4 year old Thunderlaser which I think uses a Ruida DSP, i took the image below whilst it was booting, this appears to show some version numbers?

I am having a very similar problem I make the adjustment and it doesn’t seem to correct properly.

try doing a default reset

then try the calibration again:

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