Different layers appear to be misaligned or have different start points

[Woodshapes (Paul Smith)]

Hi, I’ve reposted this as I clearly chose the wrong area and didn’t get much response.

I’m desperate for a solution and I really don’t know where to start with this one. I’ve tried other sources without much success.

In layman’s terms, I’m nesting an entire sheet of different shapes for different projects.
On that sheet are two different layers, one being engrave and the other cut.
I set the sheet to engrave all items first, and then go back over and cut the shapes out.
I’ve found that the machine engraves correctly, and then when it goes back over to cut, the designs are misaligned by about 5mm.
It’s as if the machine ‘forgets’ the start point of the engrave layer relative to the cut layer, and then starts cutting in a slightly different place, thus ruining the sheets.

If I then choose to isolate an individual shape in that nested sheet and cut/engrave it independently, it works perfectly.

I can’t find any mechanical faults, I’ve considered missing steps on the motor, but it’s capable of completing the shape correctly independently.

The file is good, I’ve used it perfectly on my other machine, it runs with no errors.

I’m convinced this is a software issue, but I can’t find it, and it’s causing me chaos since it means I can only cut individual shapes on the machine and not full sheets.

It also seems like it’s isolated to X as I don’t see the fault across Y

Things I’ve done & checked…
Latest Lightburn installed
Latest windows installed
Calibrated the axis and checked steps over 200mm on both X & Y (its within 0.2mm)
Checked belt tension
Overall mechanical inspection
Swapped stepper drivers over (X&Y) with no change
Lowered the acceleration speeds in settings with no change

I’m running…
Blue & white JQ Chinese import 1300 x 900 130w
Ruida controller
Lightburn latest
Windows 10
VCarve vetric for design
3mm MDF

It’s worth noting that this is a relatively new issue, independent to one laser. I’m using the same design and file types I’ve been using for years, and they’ve historically worked fine on all three machines, and continue to be fine on 2 of them.

Some photos showing the fault on the nested sheet vs the good independent.
Excuse the focus, these were test pieces so I wasn’t worried about quality

Any help desperately appreciated thanks

[berainlb (PY)]

How are you connected to the laser from the computer? This could be a communication issue if it’s something that’s newly developed.

Do you see the misalignment in the controller display? If you run the job a second time from the controller do you get the exact same results?

As a test, try saving the RD file from LightBurn and use a flash drive to transfer to controller.

[Woodshapes (Paul Smith)]

Hi, thanks for the reply. All my machines are connected via USB from their own dedicated laptop.
Each laptop runs its own copy of lightburn, and the files are synced from our design database over Dropbox, so each laptop is picking up the exact same file type.
I’ve just also noticed that if I cut a shape with a hanging home, for example a circle, I always put the hanging hole central at the top of the shape.
This fault is occurring on those hanging holes as well, misaligning them.

So in short, it seems the inner shapes are out of sync with the outer shapes, irrelevant of the inner being cut or engrave.

It’s as if the inner has a different start coordinate.

I’ll try the test you mentioned and come back to you, thanks for the help

[berainlb (PY)]

@Woodshapes

files are synced from our design database over Dropbox

There are known issues with Dropbox and other cloud storage solutions where files can get corrupted. I’ll assume this is not the case currently if you’ve confirmed that the same file continues to work on other lasers.

@Woodshapes

So in short, it seems the inner shapes are out of sync with the outer shapes, irrelevant of the inner being cut or engrave.

Bottom line is that the root issue is going to be isolated to one of four areas:

1. from LightBurn generation - the RD file may help determine if this is the case. You can also load the RD file back into LightBurn to see if the file already looks corrupted at that point
2. in the interface from LightBurn to your controller
3. Something in the controller on your laser
4. Something in the mechanics of your laser

Just a matter of isolating each component to rule out and isolate the problem area.

[mandysue (mandy heckert)]

Have you found a resolution? I have the same issue and have no idea how to fix it. I cant continue to waste material.

[misken (Melvin)]

In my opinion, this is a mechanical issue. Especially if it is happening only on one axis. Do you have photos of the mechanics?