I’m trying to do a number of laser etches as a workflow, and even though I set the work origin to the same coordinates, the Z axis seems to drop by “a little bit” (from about 0.1mm to 0.8mm) each time I do a run. The X/Y axies also seem to move, but they seem to over around the same 0.5mm-ish area, which I can live with. The coordinates on the screen say the exact same same thing, but there is a visible drop relative to the bed and the work piece with each origin, which happens at the start of every job. This obviously causes big issues with the laser focus!
I shouldn’t have to do a refocus every time I do a new work piece (this is literally “take the old piece off, put the new one on” - the machine is not turned off. I’ve tried both rehoming and not, the same thing seems to happen). Many people have complained that the origin keeps resetting to the centre, which is also a workflow issue that needs fixing, but this is a definite issue of accuracy and repeatability. Any ideas on what could be happening appreciated.
I noticed with the current 1.14.2 firmware and the 10W laser that you only get ONE chance to home (or I’ve managed to miss it otherwise). After you home the first time on power up, load a file and do either manual or auto thickness setting, the screen that lets you pick zero doesn’t seem to allow any home again. So you can’t just ‘re-home’ between doing files unless you power cycle, right now, assuming that would take care of the Z drop you’re experiencing.
Wonder if the extra weight of the 10w is an issue…of course I’m even assuming you’re talking about the 10w in the first place!!!
You’re right to assume the 10w.
On the apps screen, tap control, then the set home button at the bottom. There’s a home button there. Luban also has a home button. You can also send G28 from any connection, like Luban or Lightburn serial to initiate a home command.
Homing doesn’t help - I mentioned that in the OP. Thanks though.
The issue is likely the changes they made when they released firmware 1.15.X. They enabled fast homing, so it slams faster into the limit switches, but ALSO reduced the pull back to 1mm. I found my origin moving all over the place and looked into it and found these changes. Basically it’s hitting the limit switch hard enough that 1mm isn’t enough pull back to let go and reclick the switch, thus it just stays there since it’s already on. So it can vary wildly.
I modified the pullback to the default 3mm, while it still does the quick home, the pull back is now enough it actually releases the limit switch and retaps it, making the origin accurate again.
Where do I find this magic setting to change the home to 3mm? It’s worth a try.
Though, in my perfectionist mind it shouldn’t be necessary - that means that during the job, it’s going out from itself (between where it thinks it is and where it actually is. If this was just a mis-measurement, then every point would be consistent to itself, but that it’s not consistent to itself really suggests a counting/measuring issue between the firmware and the steppers - which should be of great concern to everyone.
It’s part of the source code. I precompiled one with the changes for people who follow my lightburn control guide.
And the guide, which needs some updating, but still popular.
After making the changes, my origin has always been repeatable. I’ve never used the camera or user origin, from the beginning when I got the machine, I setup a fully repeatable origin so I can use absolute coordinates and never have to guess if it’ll line up or not.