Automagic cuts not so auto

I finally received and fired up “Glowface” last week and despite a couple of hiccups have had decent luck so far.

This evening I was taking my first stab at a cut on some of the proofgrade maple plywood that came with the unit. The material was detected, and the cut lines showed the “will be automagically cut” in the app. The job completed but not all of the lines were cut all the way through the material. Some were very close, maybe within 1/32nd of an inch to completion. I noticed the material warped slightly upward as the job progressed, not sure if it was due to the heat or not. I thought the head would compensate for changes in height though. The uncut pieces were near the upper left corner and left center of the bed.

Anyone else seen this sort of behavior? Any recommendations on steps to debug the likely cause without another failed job? Cut a line straight across the bed and see if the edges fail to cut?

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This, most likely, was the cause of your problem. Double check your material when you put it into the Glowforge and anchor it down with strong magnets or make some of these,

very kindly shared to the community by @eljefe4, to hold your material flush to the bed. Even Proofgrade can sometime be slightly warped

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Particularly if you live in a high- humidity area. We have to compensate for the warp a bit, (slow down the cut speed by 10 points), or use those pins to hold it down really flat for cutting.

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If the material has a warp to it, pinning it flat puts stress in it, and the warp will cause it to move when the cut frees it.
Cutting is usually quick enough for thermal stress to be minimal, but engraving a larger area can deposit a lot of heat. Usually not a problem in wood because it is a good insulator, but marking metal with an engrave can heat it enough to be too hot to touch.

Unless I see a piece drop when a cut completes, I will usually hold the material from moving while I try to lift the cut with a piece of tape to see if it is free. If nothing has moved you can run the cut again.
There is a fine line for power to be just enough to cut through but not so much that flashback is a problem. The reports we have seen of incomplete cuts suggests a change, either in the power profile or some aspect of the material.
I suspect the latter because of all the effort glowforge has put into dialing the settings in, and for months across many sheets of material it had been perfect.

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Got a new habit and it seems to be working.
When I first put the material into the forge, I press on the middle.
If it does not have any give, I will flip it and press again.
Whatever side (if any) that has movement when pressed becomes the UP side.
A couple of magnets top and bottom until flattened and pressing movement has disappeared = Time To Vapor.

Ahh that’s cool. Got a new abbreviation.
TTV (time to vapor).
So --> it had a 12 minute TTV…
Or --> Setup to TTV, about one hour…
Love holding down the grass to make new paths, heh heh.

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Thanks everyone. I will make sure the material is flat on the next attempt.

Gotta burn to learn. Well, within reason I guess.

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I do it the other way. I find it easier to hold down edges that raise up than push the middle down with magnets because it’s hard to keep the magnets in the center out of the way of my project vs. the ones on the edge (since oftentimes I’m losing the edges anyway due to the available bed size).

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That’s my method also. I usually have the edge of those large disc magnets resting on and pinning the edges down. That also helps keep the material registered.

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I do it this way, too, except I use tape instead of magnets. Because I cut through the tape more times than I’m going to admit :slight_smile: And I don’t have magnets. Lol

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I prefer my tape-wrapped magnets for ease and speed, but my magnets are a little too tall for using with .44" cedar planks (which I have been using lately) so I tape those down.

Like @jamesdhatch, I find it easier to hold down edges that raise up than to push the middle down with magnets

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Followup:
I went through my pieces of pg maple ply and found a nice flat sheet to attempt another job. This wasn’t the same layout, but similar. This second piece did warp ever so slightly as the pieces were cut free, but I’m happy to report that all the cuts went through nice and clean.

In the interest of full disclosure, as it was cutting this second attempt I saw an incorrect, overlapping cut on one piece. At first I wondered if the software hadn’t handled it correctly but when I checked the source file, oops, there were the overlapping cut strokes plain as day. :blush: So I have to blame the fault in this job on operator error. It was just a single piece to adjust and re-cut at least, burning and learning.

Thanks again for the tips everyone. I’ll definitely be looking into some hold down technology.

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Some thoughts on warped material:

If your project allows you to cutting your material in half, doing so will reduce the amount of bow by about 75%.

Get a nice thick plate of Cast Tool & Jig Aluminum. You can clamp boards to the plate to help flatten them out. I’ve got some cheap 1/4 3ply underlayment that has flattened out nicely as a result of being clamped down to a plate of Aluminum I have left over from a 3D printing bed upgrade.

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I left the material in the box it arrived in for a while, probably not ideal. But I now keep the sheets on the floor under the table, bowed ones on the bottom, with a weight on the stack to suggest they straighten up and fly right.

I also conveniently had a couple of flat rare earth magnets taken from an old hard drive that were holding things to the fridge. They work perfectly for holding down the eighth inch material.

Thanks for catching the warp issue, @Xabbess.

@brucecooner, I’m glad you’re back on track. Here are some tips on how to reduce warp when storing your Proofgrade materials: https://glowforge.com/support/topic/troubleshooting/proofgrade

Happy printing!

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