What is the difference between focus height and thickness?

[evansd2]

Focus height means “how far above the surface of the honeycomb you want to focus the laser”.

Thickness for items on the honeycomb is generally the focus height you want, therefore, they are sort of interchangeable. There are some cases where you want to intentionally focus at a different height (called “defocusing”), like in the case of wanting a smooth engrave or perhaps a multi-pass cut on thicker materials.

Now, when you’re engraving something really thick, you have to remove the honeycomb, so now you’ve gotta do some math to get the correct focus height for your material.

Lots of info on the forums about this.

Relevant post:

Cutting Without the Crumb Tray - The NO MATH Edition

There’s a great tutorial here on cutting without the crumb tray when you want to work with thicker material. If you want to know the numbers and theory behind it, go read that first, and then come back. Thank you, @henryhbk! This method uses the digital calipers you should already have, and the not-used-often-enough ZERO button. We’re going to go through the steps from the tutorial above, but without any math or writing down numbers. The first step is to find the height of your crumb tray’s su…

Relevant search:
https://community.glowforge.com/search?q=engraving%20without%20crumb%20tray

It’s a bit of a learning curve, but spending the time to grasp all of this stuff will pay off later when you want to engrave something thick like a cutting board (or a rat skull…), etc.

Have fun. Move fast, break things, send pics

EDIT:

Since this post was written, the game has changed. Definitely look into using the set focus feature now, it can be the easiest way to get to your end goal. Lots has been written about it, just search the forum for “set focus”.