Proofgrade settings not working

I’m cutting Proofgrade Thick Maple Plywood and it didn’t cut through. This has happened before but it usually cut through everything but the backing paper. Now it’s not getting through the wood (like almost a full ply is uncut) and my pieces were unusable. The Proofgrade Cut ends up being 150/Full and the cut time is 0:34. I changed it manually to 125/Full [see below] and the cut time increased to 0:54. With 100/Full, the cut time was 2:59. That’s certainly non-linear.

I cut with 100/Full thinking I didn’t want to waste material with interim measures and the result was a thoroughly charred piece I can’t use. More wasted material. Next I tried 125/Full and it did cut all the way through but is still more charred than I would like.

In case it matters, the cuts are mostly curves, not straight lines.

What’s the solution? Is there a known correct setting?

I can send photos but I don’t want to post them publicly.

[UPDATE: Originally, I said 150/Full twice in my description above, but that was a typo. I corrected the middle setting I tested to 125/Full.]

Best to place the time zone and time of the cut attempts. It will help them narrow down which cuts to examine.

Only cuts I did today if they want to look at my logs. But the logs will tell them exactly what I said above.

I’m going to guess its a focus issue, based on char, with that speed. It should have gone through like butter. I would start with a cleaning of the lenses. Schmoo on a lens can cause some issues like this.

At 100, it was a completely clean cut. Also completely charred. Given that the scoring is perfect and I have had not had this problem with thinner hardwoods, I’m guessing it is a setting problem.

We are all using the same proofgrade settings.

I would go through a good cleaning of the critical points before going any further.

The lens cleaning parts are probably where any fast fix for you is.
It is possible your machine is faulting out I suppose, but the cleaning fixes most of these issues.

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That shouldn’t happen. If you select PG and then change the settings to manual you get to see what they are. The time shouldn’t change.

That was a typo. Thanks for catching. The speeds and times were for auto=150, 125, and 100. I have corrected that above.

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.