Autofocus saves the day

But I got my GlowForge on Wednesday night…

No. I wasn’t replying to your post which seemed to have something to do with the localized heat. It was a generic “don’t whine about the Proofgrade, or any other material, warping slightly” over time. It’s normal in changing environments, unless you use a press to hold the material perfectly flat until first use.


I’ve found that the PG stuff warps less than the stuff I can buy locally. But yeah, the humidity here (about 70% average) does a number on wood of any kind.

Trying to pick out a straight piece of lumber at the local hardware store involves a 20 minute search, and you have to take each piece out and look down the edge, then take the one that is the least warped.


OK, but it is surprising that in 4 days, my fresh from the factory proof grade ply are mostly warped (one was pretty flat still) given that they were stored flat since arrival in a stack on a flat granite counter. I didn’t have a heavy weight on top, but I was actually worried about slightly embossing the leather sheets. The humidity in the house has been ~40% this week.

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Not sure about the fresh from the factory as these are shipping from GFHQ directly. As for warpage.The original batch I got from them with the unit are pretty flat. The batch after that had some warpage out of the box. The batch after that all hell broke loose as in warpage, mislabeled sheets and missing pre-mask. In that batch all off the hardwoods disrobe themselves from all the masking (all from one side). The batch after that was mostly acrylic and one or two sheets of ply and hardwoods. And those are okay.

Even after you get it flat or not- storage is key. Everything I use on the big CNC I have to leave it in the garage a couple days to let it stabilize before I can use it. Or else it bends up like a taco afterwards. (not saying this is the case. Just saying overall)

With all that said, The word ‘Beta’ is on all the sheets. YMMV for now I guess.


When they announced the prerelease capabilities, it was in the long description. I think it got passed over sometimes (by me!) and/or confused with the focus issues of the lid camera on the materials for placement of design.

Multipoint autofocus is still in the hopper, as I have read it.

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I take that to mean they only do one depth measurement for focus so far. Multipoint autofocus should not be in the hopper as it is an advertised feature. @henryhbk seems to imply it is done but I suspect it is just that his pieces were still within the focus band. It isn’t a single point with a CO2 laser, more like a real hourglass, i.e. two cones joined by a small cylinder. We know it can cut 1/4" materials in one pass so it must be reasonably focused over 1/4".


Actually this reference might answer a question that has had me (and the GF team*) puzzled.

Thanks for posting that note @marmak3261 …it’s tough to remember everything you’ve read. :smiley:

*(I assume, although I was only in direct communication with Rita and Danny.)



I actually had not read your post when I typed the “don’t whine” comment. So was in no way directed at anything you have said. Posted in hopes of heading off hundreds of people that expect to lay organic material on a flat surface and for it to stay that way. Personally have never had that experience from any manufacturer, Glowforge, Inventables, and certainly not the residential lumber providers. But have never used material in an especially controlled environment.


Please do file support tickets about warped material - it’s great data for us!

Autofocus is still in its infancy - there’s a lot of future work to do. Right now it takes a single point measurement; multipoint is forthcoming.


Will multipoint run the head all over the piece first then cut, or does it scan while it’s cutting?

I’ve been cool. I’ve been calm. I’ve not tried to get too excited. But now I am so stoked to get my GF! It’s really coming together! Thanks Dan and team!


So how did this work so well?


We designed for a large margin of error. When we get multipoint autofocus, we’ll be able to run the head faster as we can reduce the MoE.

We also have a lot of secondary things that help: high quality optics reduce scatter and improve spot size, beam quality, the single-point measurement is deadly accurate (within 0.1mm), etc. Allows a few things to vary and still let you be successful.


or in other words, “magic”


That is the technical term.


Any sufficiently advanced technology is indistinguishable from witchcraft.


So, I don’t need to be entering my material thickness every time? I’m confused?

Have I missed the autofocus button somewhere?

Edit: oh shoot. Just noticed this is a rather old thread. Question still stands though lol

Material thickness does two things. Primarily, it provides the dewarp specifications for the lid image allowing more accurate placement. The second thing it does is populate the focal height field for each operation.

However. The scanning process when you hit print is measuring the material height to set autofocus. It will use the measured autofocus height unless you have changed the focal height in the job operation manually, in which it will use that value.

changed the focal height in the job operation manually

What do you mean by this, the select uncertified material dialogs or the material height settings on the graphics?

The dialog you enter in the uncertified settings is the material height. That is used to dewarp the bed image and provide a more accurate placement.

That material height setting auto-populates the focal height setting for each job operation on the left with the same value you entered into the material height box of the uncertified material box.

At this point, the possibilities fork:

A. If you leave the focal height in the job alone (unmodified), the actual laser focus will be set by the scanning/red dot measurement. So if you entered a material height of .240” but the material was actually .300”, and you left the focal height in the job operation at the auto populated value of .240”, the scanning measurement will override this and focus the laser at .300” (or the closest available figure to that value)

B: you change the value in the focal height box under the job operation in the thumbnail. The red dot measurement will be overridden by your manually entered focal height.