Intermittent problem with skipping line of engraving and cut path inconsistent

I’m having a problem at the moment that the laser sometimes skips/ moves part of the engraving to one side. It also doesn’t follow the same cut path if doing multiple cuts on the same path.
Right thats a short over view of the problem ill give you some more information on the machine. I’ve recently converted to a Ruida RDC6445s controller from a leetro mpc6535 so i could switch to using lightburn software. The machine was working perfectly fine 100% of the time on the old controller. but i cant get any consistency from the ruida one. if you do an image engraving with the same file send to the machine it will work perfectly 3 time out of 10, every time it going wrong some where different but regains it position to carry on the image. i’ll include some images at the bottom of the post to show examples of whats wrong. it also has the same issue with cutting, some times it fine other times it takes a bit of a random path then regains the orignal path.
Ive had a post running on the lightburn forum as to start with i wasn’t sure what was causing the issue. we have narrowed it down that the machine mechanically is fine, its been correctly calibrated in both x and y axis and back lash off sets done. the software seems to be fine as it will run correctly some time with the same file. Im a bit stuck, currently trying to take to a cloud ray engineer. But does anyone have any suggestions? im not sure if its the ruida controller or possibly some interference?


i have 2 videos I’ll up load showing it going wrong on the outer cut line. its suppose to do 3 over lapping cuts but it doesn’t follow the same path each time. the second video shows it deciding to skip part of the image a follow a random path changing direction in both x and y axis before then re joining the correct pattern.

video 1 you can see the laser does something strange about 1m 23s in for about 10s. video 2 i missed the first bit where its gone wrong on the image but you can see the 3 passes around the outside don’t over lap when they should have

Sorry it wouldn’t let me post it all at the same time as im a new member!

Hello sean,I’ll ask our technicians as soon as possible to see if this can be resolved.

Hello Goodman if you could please any help would be much appreciated

Check if your hardware is tight. No loose grub screws, no skipping belts, no wobbly pulleys, no play in the gantry, etc.; those will tend to shift the path in unexpected ways, particularly if some parts like pulleys are “sticky” and loosen only under specific accelerations.

This may be of help, if it turns out not to be a physical problem:

We have an RDLC320A in our machine, and there are data transmission errors over USB cable. Any important/large jobs (100kb+) get transferred via flash drive to avoid this. We get results very similar to yours when there is an error.

I’ve noticed the problem is worse with transmissions that include etching and cutting. I’ve verified the issue by downloading the transmitted file and reopening in lightburn, and you can see all sorts of strange changes appear. Are the problems consistent, i.e. if you run the same downloaded file on the laser, do you get the same results?

Hi Ive been over the mechanical side of the machine and couldn’t find any thing. i have swapped back to the leetro controller to see if that would eliminate the possibility of it being a mechanical issue. And ive had the machine running for 6 hours cutting and engraving with out any problems at all. so it seem to be related to the controller change.

Hello Austin that’s interesting i haven’t tried reloading a file that had been sent to the laser back to light burn. How are you getting access to load the file back? Can you see what’s in the machines memory through the usb cable connection?

when ive been trying the multiple repeats of the same file and getting different results. i had sent the file from light burn once but been clicking run in lightburn rather than on the machine.

managed to fix it. turned out it was the data transfer between pc and laser. i was using a usb cable to transfer files to the laser as thats what the old system had used, which was corrupting the data. switched to ethernet cable and it now works fine