Proportions are off from desk top to actual cutting

I’m new to the laser world and just set up my machine. I tried to make a project from a download I bought off of Etsy. When I cut the project, it seems the Y axis is off but everything going left and right seems ok. Also my machine doesn’t frame right when I use the inch units and really only works well when I select MM. someone please help!

Let me ask a few background questions to understand the situation.

  1. Was the photo of the burned wood done in a single burn? As in the engraving and cut were all done as part of the same project and burn? Or were these done in separate runs?
  2. What coordinate system are you using in Start From in the Laser window?
  3. Can you describe your alignment procedure for how you’re positioning the work material and the start of the burn?

Can you elaborate what you mean by this? What exactly is wrong with the Y axis?

Can you explain what you are doing here? What does it mean that you are using inches or mm? What exactly happens with the framing that seems off to you?

Can you upload the .lbrn file here to review? There may be something in the design also going on.

these questions are very overwhelming lol, but please bare with me, I am new to all this.

  1. Yes everything was cut and burned in a single burn. should I do these steps separately?

  2. I have absolute coords selected in start from in the laser window

  3. I start from the homing position. I place the laser in the center of the workspace. I use a square tool to outline the amount of wood space i am using. Place the wood where I think center is, and then frame it. I use the fire button to see where the laser is framing and adjust the wood piece to that.
    I notice when I have the units set to “inches” the framing is much larger and not to scale. I did do a test cut for a 2 inch square and the measurements seem to be on point. However, when I position the laser center of the work space and frame, the area seems larger and not in the correct position. I then switch to the “MM” units and everything seems to work fine, frames correctly and goes to the correct position on the workspace.

Everything that is burned going left to right seems to be on point as far as proportion to what I am displaying on my computer. Its everything that is going up and down that seems to be off. if you notice in my picture, the small piece to the far left that has a small hole but it is off centered going up and down. it’s exactly where it needs to be distance wise from the left, just not centered going up and down. if that makes sense. Also you can see that the picture is below the center hole on the computer, but when burned, it covers the hole, as well as the wording is place on the picture. On the computer it is below the picture. I hope that answers your questions?
beer caddy imperial guard.lbrn2 (299.2 KB)

Also, the small holes are coming out distorted …not sure what thats about. i made sure the rotary was disabled

Appreciate the details. It’s hard to say with certainty but based on what you’re saying I think what’s going on is that you’re somehow losing steps along the Y-axis. I think there are a couple of possibilities or in fact they may both be contributing.
Potential mechanical issues:

  1. Check the tension of the belts along the Y-axis. Make sure there’s no visible slack on either side of the pinions that the belts are driven by. Belts should be taught but not stretching.
  2. Check that the pinions themselves are not slipping on the stepper motor shaft or the drive shaft. There are grub screws that hold the pinion in place. Double check that those are secure.

Suggest you check the X-axis while you’re at it.

Potential settings issue:

  1. The speed setting for layer 07 is unusually high at 36,000 mm/min. I suspect this is causing the stepper motor to miss steps. Once the motor has missed steps all subsequent moves will be off by the same amount.

I think in your case both of these things may be happening. The circle cut-out on the left is cut immediately after the outlines but before the engravings. This is already out of alignment which tells me it’s not only the engraving speed that caused the miss so likely something physical has caused this.

Sorry about that. There’s just a lot of nuance to this so details are important. Appreciate you answering in good detail.

No. It’s fine to do this at once. The reason I was asking was because if you had done these separately I would need to account for the possible misalignment between burns. By having these done at the same time then I know that it must be something happening within the burn.

Okay. This is probably the most straightforward until you get comfortable with the laser and LightBurn.

This whole section is throwing me off a bit. Any unit changes in LightBurn should really be purely a presentation thing. It should not affect final dimensions or behavior. In reality there’s some nuance to this. When you say you’re changing the units are you pushing the unit field in the numeric controls toolbar? Or are you doing something else?

i’m just pushing the button. I can do a video so you can see what i am saying

also this is very helpful feedback thank you for taking the time to answer. LOL, i will however, have my husband read all this so he can translate it for me hahahha

I will tighten the belts and change the speed setting for layer 7. I think the max for my machine is 10000. do you suggest a speed?

In general I find the maximum speed claims to be vastly overstated. This is something you’ll have to experiment with as you get comfortable with how your laser performs. I’d say start with something that will for sure work and then you can start dialing it up to improve times.
I think something around 1000 mm/min is a good starting point.

Philosophically you want to be going as fast as you can without compromising quality. At higher speeds, though, you’re dealing with a lot more mechanical issues like vibration and laser module momentum. It will also stress the other mechanics of the machine so you need to make sure those are in good shape. The other consideration is that wither higher speeds you’re typically having to drive the laser diode harder. There’s a tradeoff between higher power output and expected life expectancy from the laser. It’s a tradeoff you’ll need to figure out what works for you.

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i just wanted to say, you are a laser machine genius!!! i fixed the tension belts and turned that speed down. By god it worked. crazy how its all simple layer 1 issues!!! Thank you so much. everything is centered. The small holes came out perfect. I appreciate you help!

Great news. You’ll find that as you get more familiar with how settings and mechanical limitations affect your burn that you’ll start to get a feel for how things link together.

Good job on getting out good details to work from and making the proper adjustments.

Happy New Year.

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