Homing designation

Can anyone tell me how to get my laser to be exactly exactly on the corner of my honeycomb when I home. I did have it. But then I moved the gantry and a mess the homing up. Now, when it homes, this is the spot that it goes to instead of on the very corner?

Just so we know the rest of the story, why did you move the gantry? What problem did that solve?

The homing position is set by the two switches on the X and Y axes. When the gantry & laser head trip those switches during the controller’s startup sequence, that’s the home position.

So you can move the switches or attach shims to the contact points on the gantry / head to adjust the home position. Some machines (not mine!) have screw adjustments to fine-tune the switch trip position.

On my machine, the honeycomb is not positively located on the knife blade platform and that platform can move slightly with respect to the machine frame. If your machine is similar, the homing switches may be in the proper location, but the honeycomb or underlying platform has moved slightly with respect to the machine frame.

You may also have changed the position of the laser head on its mount, so the machine’s mechanical home position is unchanged, but the laser head is elsewhere. If you can slide the head in the X and Y directions on the mount, you may be able to reposition it with respect to the home position.

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I moved it to clean it. Lime I said, it was spot on on the corner. And after I moved the gantry touch, it homes comes there now. I just wasn’t sure I put it where it needs to be by using the move function and I pushed set origin that when at homes that’s where it would go. And then I read something about bounce back and so forth. Which I’m not too clear on.

the laser would home to its limit switches… the position should be the same each time unless the switches or adjustment screws had moved.
It could be also the gantry was knocked out of square. How about some more details on how you “moved” the gantry.

I actually did check the square on the frame and it’s good. Well, I was moving it to clean behind on the back rail and I pulled the gantry towards me. About four or 5 inches. And then when I homed, it was just bouncing in the back left-hand corner. And making all kinds of racket. Well I shut it down for a while shut down light, and when I started back up, it went back in. But, now instead of Home at Exactly on the corner of the honeycomb. It is roughly 10 mm Left and 10 mm high. Photo attached

But here’s the issue. I was having repeatability issues in the beginning. This is how I ended up here. Somehow, I messed my settings up on my control board with the firmware and so forth. So I was told to reinstall my firmware which I did. And then everything went haywire, banging, crashing booming you name it. I decided to call the company of my board. They walked me through all the settings. Everything was just working perfect. The main thing I know that they changed was while my machine is on the gantry does not move freely. The gantry now has constant tension on it. That repaired my repeatability issues. The only way I can move it is to turn the machine off and then it will freely move. Because I guess now there is current constantly going to the stepper motors. All the belt tension and everything else is correct. I went through that way before. So the company seems to think it’s something that could be corrected through Lightburn possibly. That’s why they suggested that I get on the Lightburn forum to tap the wealth of knowledge on here. Dan has not shifted. Like I said I was so happy when we first reinstalled the board it made a perfect rectangle right along the honeycomb right where it needed to be. I was like a little kid. I was so happy. Then, I had to move the gantry to clean like an idiot.
I hope I’m not leaving anything out. If I make a 300xx200 rectangle on my computer screen or should I say center of the project when I go to frame it it’s not framing in the exact spot of the honeycomb like it was before. If I draw a circle and center the project doesn’t have to be a big circle just one inch circle And I frame it will not frame exactly where it is on the computer screen like it was before. Because of said move of the Gantry position. As far as repeatability. Right now if I make that circle and frame and just keep moving the project to where the framing is on my piece of wood where I want it. It will repeat that circle better than it ever has. Fire go to finish position fire go to finish position fire go finish position and so on. Just perfect. I just need to get that. Dot to come to the corner again I think. I wasn’t sure if there was a bounce back Setting For when it hits the limiting switch. So hopefully this is enough information.

If I understand what’s going on, the machine goes through its homing sequence when you turn it on and always ends up in the same place, but that place is just slightly off the corner of the honeycomb.

Is that what happens?

If so, then select Start from: Absolute Coordinates in the LightBurn Laser window:

That will make the LightBurn workspace line up with the laser platform.

When you have done that:

  • Draw a 2 inch square in the middle of the LightBurn workspace
  • Set the layer speed to 100 mm/s and the power to 15%
  • Put cardboard on the platform
  • Start the job

The square should appear in the middle of the platform.

Is that what happens?

If so, then without moving the square or the cardboard, start the same job several times. The square should appear in the same place every time.

Is that what happens?

Maybe some better pictures of your homing switches. This shows switch is far back and your pull off would need to be about 20mm.
image

Not sure I agree. The pull off should only be enough to toggle the switch. Once the switch is found at high speed, it comes off and then creeps back on the switch to determine an accurate closure point. Then it just needs to pull off just enough to ensure the switch is open. A pull off of 3/4" would be for a switch with a really long lever.

I do see a risk of hitting the frame with the lens assembly. I would try to move that switch about 5mm or so. the loss of travel would be miniscule.

I was just referencing off the picture in order to get it on edge of honeycomb. Need better pictures to maybe see the problem. Switch doesn’t look like it can move.

I am guessing the honeycomb cannot move either. Any chance the switch actuator can be adjusted? Bottom line is SOMETHING moved.

Curious, was the banging into the frame a one time thing, or does it happen every time?

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