Laser thickness changing without changing settings

Does anyone know why my laser would start out with a thinner laser engraving, and without changing any settings, end up engraving everything thicker?

I am using the same material and have used it before with no problem (acacia wood)
I have NOT changed any settings.
I have cleaned everything several times, turned everything on and off, and even recalibrated the camera.
I have ensured the laser cable is pushed in as it sometimes pulls away.

I am losing my mind a bit… I hope someone can help!



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Looks to me to be variations in the wood.

Take a close look at this picture:

You can see bands of lighter areas that follow along the individual boards, particularly noticeable in the areas circles in red. Likewise you can see much darker areas circles in blue.

image

This theory is supported by the fact that thinner areas suffer the most; thin vertical lines are especially vulnerable to this because of the physics of engraving with a laser head that scans horizontally.

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Yes, I understand what you are saying… however if you look at pic 3, 1 then 2 (because I happened to not have them in order) you can see the thickness progression, especially in the leaf detail. This has never happened in the past with any variant of wood I have used. I am not sure if I am explaining this correctly but

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This is an engrave, not a score, right?

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It appears to be a focus change to me. Are you using the set focus or inputting a material height? How are the boards elevated off the floor of the Glowforge? Were these boards done one after the other or on different days? Were they cleaned the same after engraving?

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this was my thought, too. if there’s any thickness difference in the wood, it could affect this. if what you used to prop it up to within 0.5" of the lens isn’t exactly the same, it could affect this.

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The engrave is not vary power with some gradients in the resulting texts ar those points. I even wonder about the grain of the wood affecting it a bit in combination with the lettering. Just a guess here to rule out.

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Sure the lens isn’t upside down? ‘Cup goes up’.

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all the wording is being engraved but the leaves are set to cut with the setting at 500/70. This setting has worked for a long time on this same wood.

I have tried both… however, when I use the “set focus” it is bring up an error telling me something went wrong and to refresh?

I remove the crumb tray and build up with boards I have used for this every other time. The boards are done one after another and yes everything is cleaned the same way.

Are you inputting a material height since the set focus is causing an error? Are you cleaning the optics in between boards?

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Yes & Yes

What height are you inputting?

do you think it could be the white strip that connects to the laser head?

No, I think it is a focus issue.

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I used .42

How did you arrive at that number? I believe you are forcing an out of focus situation for some of the boards. I would be interested in finding out why the set focus tool won’t work.

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my husband measured it based on what I have it sitting on and the material… he technically came up with .418 so I rounded up

me too… I have no idea

See my edit above. The set focus is much better than measuring - especially since the boards could have some variation and may not sit completely flat on the bed. The focus range of the lens is 1/2"… Your material is extremely close to the upper limit of the focus. I think you would have better luck if you didn’t raise the boards quite so high and used the set focus tool.

To test whether or not your Glowforge is working properly, I think you should print the Gift of Good Measure on proofgrade material using proofgrade settings. If the set focus works as it should, and if the print turns out as it should, your current problem is not that the machine is failing, it is the variability of the material.

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