Proofgrade settings not working

Yes GF definition of speed is not distance over time like it should be.
ipm = 4 + (cut - 100) * 153 / 400

100 is 4 ipm.
125 is 13.5625 ipm, so more than three times faster.
150 is 23.125 ipm, so nearly six times faster.

I’m surprised the cleaning instructions don’t have anything on cleaning the Red focus laser aperature and the other head camera.

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Thanks @mad_macs and @brokendrum!

@roy, would you do the cleaning and inspection that’s described here, please?

If you don’t find any damage, would you do a test print when you’ve finished? We included an extra piece of Proofgrade Draftboard with your materials shipment for troubleshooting. Please print the Gift of Good Measure on Proofgrade Draftboard and let us know the result.

Sure, I can do a cleaning earlier than necessary even though I doubt that’s the problem.

The only material I have had a problem with is this plywood. As I’m sure you know, plywood can vary tremendously. Proofgrade is supposed to fix that problem by being very consistent, plus Glowforge has said multiple times that the QR code on Proofgrade materials is supposed to give my Glowforge information about each individual piece of Proofgrade material to ensure optimum cutting. That is an issue when the QR code can’t be read, either because it’s out of camera range (as was the case here) or because it’s been cut off already. There is no way for me to supply the QR code or equivalent, only generic “Thick Maple Plywood”. That said, it does appear that you’re not actually doing anything different depending on the QR code, so maybe that claim is really “in the future…”

I’m not planning on doing a test cut on draftboard. As noted above, the problem has only occurred with this plywood, so that test would be meaningless.

In the interest of saving time, what will be the next step? Is there a recommended value besides 150/Full?

Also, where is the count of how many hours I’ve used my Glowforge? I’ve looked everywhere for it.

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I expect they have very detailed mapping of this one item (ruler) for intricate inspections for normalcy and any actual shifts within the machine would become apparent rather fast.
Up to you…

Yes Dan claimed every sheet had a unique barcode but I don’t think that is true. I think everybody sees the same PG settings and selecting with the drop down is the same as when it reads the barcode.

A simple test would be for a couple of people to post pictures of the barcode of the same material.

Every piece of maple ply I have had for the past year has had a slightly different code according to my QR reader.


Even within the same batch? I would have thought the differences were batch-specific.

Every one is different. Received a new shipment of 7 pieces of Medium Cherry Plywood on Wednesday.

QR codes ended in BKA, BJ+, BJ6, BJ7, BJ8, BJ9, etc…


Thank you for your reply.

Unfortunately, we don’t have a counter for how many hours of printing you’ve done, but I’ve passed your suggestion on to the team.

Regarding your Proofgrade material, it is possible that there is some warp that prevents the sheet of material from being completely flat. You can read about warped material here. If you haven’t already, could you check your material and let me know if it is flat?

I’m also curious, did you find that cleaning the unit made a difference with the cut through? And have you seen any issues with other materials since?

The material is completely flat. Even when my material is flat, I use strong magnets to hold it down just to be sure there is no shifting. Also, it was two different sheets, though they were received at the same time so may be part of the same production batch. My guess still is that plywood varies more than you think it does. Another possibility is that your speed calculation is inaccurate on curves. These cuts are about 90% curves.

I didn’t want to use my old blower so I ordered a new one, that will arrive tomorrow. I haven’t done any cutting since I posted this (not because I was avoiding it, I’ve just been busy with other things).

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Thanks for the update.

If you have a set of precision calipers or another means of precise measuring, could you measure the thickness of the sheets that weren’t cut all the way through. Then let me know the measurements you found.

Thank you.

I’ve never seen two sheets with the same barcode. I’m pretty sure they each have a unique identifier.

I haven’t seen any evidence that the identifiers are connected to different settings, however. But I haven’t looked closely at the settings that come up for each piece to see if they’re any different from the generic ones you get from the “choose a material” menu.

I wonder how the material thickness is set for the camera view. People say it doesn’t matter if it can’t read the barcode because you can select if from the list. Does that mean that all PG materials have the same nominal thickness or does the Barcode actually convey a measurement?

Has anybody compared a measured thickness to what the GFUI says? It takes a measurement for focus but that implies the thickness it uses for the camera is not very accurate. Has anybody tried measuring it and entering a more accurate value? Would that improve camera accuracy?

The QR code just reads as an identifying code for the material. The Glowforge then connects to a database over the internet to retrieve the settings for that material.

If the reports we’ve seen are correct that every individual piece of PG material (rather than each type of material) has a unique code, it’s possible (though highly unlikely, I would assume) that there may be some possibility for each piece to have its own settings with very precise thickness measurements.

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Since the machine only has 16 possible focus heights (0.0278" per step over a range of 0.417"), having a super precise measurement of the material thickness would seem to be unnecessary.

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Material thickness is also used to correct distortion from the camera, isn’t it? Precise data should make that process more accurate, maybe even to the point of making visual alignment in the GFUI feasible.

Certainly, and I agree that it could improve the visual alignment. I’m not sure what the variance is in the thickness from batch to batch, nor could I guess -how much- of an improvement it could make.

My comment was intended in respect to the issue the OP was having (i.e. inconsistent cuts). I don’t know if it would make much of a difference in that regard.

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It’s been a little while since I’ve seen any replies on this thread so I’m going to close it. If you still need help with this please either start a new thread or email