Laser camera not in sync


#1

It seems like the calibration of the laser and camera is a bit off. The laser cuts slightly to the right and below what the camera suggests, leaving a bit of guess work when printing multiple times on one sheet.

Has anyone encountered this before?


#2

Camera alignment is known to be a bit off at this point. They are considering anything up to 1/4" as normal at this point. You’ll have much better alignment if you cut towards the center of the bed.

They’ve said that alignment will improve significantly in future software updates as they update their vision software.


#3

There is also that the pre and post image are not the same. I’ve had things align perfectly when cutting that look different in post imaging.


#4

I first noticed this trying to center something in a circular piece of acrylic, and although it was centered in the GFUI, it was not once printed. That print was actually right underneath the camera.


#5

Yes, the original image on the bed is not a camera image. That freaked me out when I was engraving the second side of those tokens. 77 done on the first side and the camera image showed the image on the second side a solid 1/8" off, but all 1000 engraved perfectly.

I have seen a cut displaced from the image of the original file like this once though. Hasn’t happened again.


#6

One thing I’ve noticed is that precision of material thickness REALLY affects accurate alignment. I’ve had stuff be off because I cheated with a proofgrade default instead of actually measuring.


#7

I would try a few more on some scrap to see it is consistent.


#8

I do not have a 'forge yet (international :crying_cat_face:) but i have seen other threads about this.

I believe you will get better alignment if you aim to do your cut towards the centre rather than at the edges


#9

Yes, as I have placed items across the bed, it was far more accurate in the middle under the camera than at the extremes. This is a known issue with the image processing algorithms and such, and they are working on it. (Fisheye lens processing is always fun and interesting…or devastating and heartrending.)


#10

“alignment” is the term you want to use when searching for other people with this issue and the current work-around’s. It’s arbitrary, but it looks like the term most often used when discussing this problem.

Apparently there are some significant improvements that are still in the works (scanning material height before starting, for example). If I understood correctly, at the current state of the software, anything within 1/4" is within the currently expected error: Camera Alignment


#11

From that link, it also sounds like you can get better accuracy if you make sure the Glowforge is sitting completely flat (or more accurately, in exactly the same flatness as when it was calibrated at the factory) and everything else including the material to cut is as flat as possible (with consistent thickness).


#12

Apparently making the workspace file 20x12 improves precision, too.


#13

Also search for “Kentucky Windage”:


#14

that’s exactly what I thought when I saw the layers of my cuts not lining up when I hadn’t moved anything. With the bed size and the camera being centered they’d have had to use a fisheye type lens which always distorts on the outer edge.


#15

Thanks @tim1724, that’s right - we’re still improving our layout and alignment, so your print may appear offset from where you put it by up to a quarter inch. For the most accurate alignment results:

  • Use Proofgrade materials

  • Enter the thickness of the material if it’s not Proofgrade

  • Use material that is not warped or tilted

  • Place your design near the center of the bed

  • Reboot the machine if you see the alignment drifting

Also, if you wanted to place an engrave precisely in the middle of the circle you uploaded, you can try this:

  • Click “Add Artwork” button in the top left corner of the Workspace

  • Upload the design you want to engrave

  • Place the design inside of the circle

  • Click print to prepare a print that will engrave and cut in the same job

You can also combine your cut and engrave designs in a program like Inkscape, save it as an SVG, and upload it.

I hope this helps!


#16