I wanted to engrave a plaque. The plaque was/is about 10.5x17.25 and .749 inches thick so within the glowforge’s engraving area but I’d have to use it without the honeycomb tray.
I sized the artwork in illustrator to the exact dimensions. I used the tips provided by other member’s here to get the correct focal height. I calculated this to be
1.4 -(1.000+.749)
(Thickness of the honeycomb - (thickness of my support material+thickness of the plaque).
This gives me focal length of .349inches. I put this into the settings and the glowforge zoomed appropriately.
When I imported my art, the guidelines in the artwork I placed to align the piece, lined up perfectly with the top of the piece suggesting my focal length was correct.
Yet, when I finally hit the button to burn this, the alignment was significantly off. It was 4 hour burn at 225lpi so it makes it frustrating that despite all the work before the burn, I still get imprecise results. I don’t mind it being a few millimeters off but this was significantly off the mark.
I’m including a picture that shows how far this was off in the final piece. Did I do anything wrong? Can the glowforge do precise alignment or is that just a limitation of this supposedly “pro” machine.
I think you would be much better served with the set focus tool rather than trying to calculate manually. My honeycomb tray is not 1.4". Also, have you performed the camera calibration?
Perhaps there are issue with what I do that I’ve simply avoided by luck, but when I need to get perfect alignment, this is what I do…
I place a piece of sacrificial poster-board on the tray and hold it down with magnets so it can’t move.
I then bring in my artwork and position is where I want. (When creating the artwork, I include a cut line the exact shape of the blank I will be engraving on.)
I then turn off all the engraving layers and only use the outline of the blank. This cuts an outline in the poster-board which gives me an exact template to set the blank into.
After opening the GF and placing the blank into the cutout template, the GF will automatically re-focus and account for any difference in thickness.
I then turn off the cut layer and tun on all the engraving and send it to print.
As long as I never move the position of the artwork on the App dashboard, it lines up dead on every time. I’ve done this many times and it’s never failed. My rational in doing it this way is that the focus shouldn’t change the position of the artwork. Wherever you position the artwork provides the X and Y coordinates for the printhead. The focus should only be adjusting the focal point of the laser. Thus, if you don’t move the artwork and only enable or ignore layers, the position stays the same.
Like I said above, perhaps I’m not aware of something and I’ve just been lucky. If so, I know there will be many folks in the GF community that have far more experience than I do that can explain or give better advice.
-John
After running the lid camera calibration I usually get spot on alignment right under the lid camera and using set focus.
If it’s super critical or a larger piece I can’t place under the lid camera then I’ll use either a jig or run a very low power score of the outer shape of whatever I’m cutting/engraving just enough to mark the masking. (depending on the exact project)
If you’d like, you can use the Camera Recalibrator to see if further improvement is possible. It will only make changes if it can make your camera more accurate; otherwise, it will exit without any changes. It takes about half an hour.
You’ll need a 12” x 20” piece of Proofgrade material with no markings or stickers. The feature was designed to be used with a flat piece of medium Proofgrade Draftboard, used upside-down (with the QR code side down). It may work with other materials that are the same size and use the same print settings as well, like Proofgrade plywood.
It prints a grid of markings, takes a picture, then measures its height in multiple locations. This data is used to make your camera more accurate for future prints.
Thanks for the suggestions all. I will definitely try set focus, which is a great tool I didn’t know about and see how that alone does. If no improvement, I will try the Camera recalibrator. I will try to find a sacrificial piece about the same size to experiment. Really appreciate the great suggestions.
Hi @typecase. I’m happy to hear that you were able to learn about the Set Focus function and will try the Camera Recalibrator that David mentioned. I’ll keep the thread open like David also said, and feel free to reach out if you run into any trouble with the steps. We’ll be here ready to help.
It’s been some time since there has been activity on this thread, so I’m going to close it. Should any additional questions or concerns arise, please don’t hesitate to start a new post or email us at support@glowforge.com.
