I’m having a hard dialing in the settings. I can cut it just fine, and even got it pretty well dialed in to barely cut at 500/full, 250/90 or 200/70 [Pro], but I consistently get charring. Is this just the tradeoff with thinner material?
Char is generally no big deal, but it comes off on your fingers, like you just lost a fight with a pack of wild pencils. Trying to avoid that. If anyone has a setting to try that wont char it, I’m all ears. Maybe multiple passes at lighter power?
I haven’t tried material that thin but that’s quite an image.
The only general principle I have for attempting to minimize char is maximizing speed against the cut. The general notion is the fastest it can run with the lowest power that will pull off the cut. An aside on that may include 2 or more passes for even lower power against the material. Of course, YMMV, and materials impact it, too.
According to the great oracle (@dan was the one who told us this 
) you want to speed it up as fast as possible to reduce char, and use enough power to get through the material.
And I see Jason beat me to it. Chuckle!
Yeah so I started hot and fast. I went full power at 400/500 and it cut through with char. So then I did a run of 300-500 in 20 step increments at 100, and all produced char (unless it didn’t cut through). I think maybe this material may just be char-prone. I’ll update if I crack it.
I haven’t tried 1/32” myself, but my gut says full power at 750. That’s at least where I’d start.
750 is an engrave speed, not a cut. My cut settings only go to 500?
I suppose a hard enough engrave would cut. I’ll see what I can see.
EDIT: nope, duh, if I convert to engrave it’ll engrave the whole shape. Hmm.
Here’s a pic so far: 400/full (right) and 470/ full (left). Both charred badly.
I’ve not done 1/32 or birch, but my first gut on a cut for wood is always 500 speed and then tweak power.
You can cheat a bit and create a thin stroke straight line and then convert it to an outline and use engrave settings with higher power; effectively cutting the material.
That sounds tremendously slow in any kind of vertical line. It’d scan back and forth at whatever lpi, yes?
Doh! You’re right. That’s what I get for guessing.
people have been rattling things around in a box with a layer of salt to clean that up.
Not sure how effective for your problem but worth a shot.
I give the edges a quick wipe with an alcohol- or vinegar-soaked rag (to prevent swelling that water would impart).
Ah yeah, I forgot about the salt thing. I had a small salt container laying around to try it out, so lets see how it goes…
Not sure how long to shake it for, so tried it in 20 second intervals or so…
After about a minute of shaking, the char was reduced by probably 75%. I think this will work well enough. Thanks for the reminder on that salt trick!
If only I had a tumbler, it would let me salt it for ages. Maybe I’ll try to get the orbital sander rigged up to shake it? Sounds like a salt disaster waiting to happen though.
Now, does anyone have a handy tip for salt dust removal from wood…? 
Yes, it’s not the fastest in vertical lines, but at the higher engrave speeds it might not be too bad. I have not tried it (intentionally), but I have seen some folks in the forum talk about doing something like this–I can’t find one at the moment. At that thickness, you could probably go full speed on the engrave at just enough power to burn through and get something close to the same completion time as a straight cut; but, I’m just making assumptions.
Haven’t run it on a Glowforge, but I have cut a lot of the 1/32" and 1/64" on a 120W Trotec, and it’ll cut really well, but you want low power, very fast settings, and I’d recommend applying some laser-safe masking tape to both sides as well to prevent flashback and smoke marks. But if you don’t scorch it, you can get some really precise cuts with it:
If you’re cutting through at max speed/max power, my next step would be to reduce power to “100” (not full) and then down from there until you find where the threshold is. Also, make sure your material height/focus setting is right on - don’t just rely on the published wood thickness.
I posted the salt thing here a little while back, but I’m using it for thick chipboard. It cleans those cuts up in 20-30 seconds. Haven’t tried it with wood cuts.
I did exactly what you suggest on settings: find the threshold of power and speed where it barely cuts. I also started the whole thing with a pair of calipers to get the focus height dialed in exactly. In the end I think it’s a total fail for right now, and when my piece scaled down, the cuts were so close to each other that they caused the ply to smolder, ruining the pieces.
I tried color coding all the segments to define the order of cuts precisely to avoid overheating one particular area, it still got just a but too crispy. I’ll revisit this when I have more time, but for now I’m going to call it a bust. I might try again with 1/16".
I know GF has had this suggestion before, but they really really need to add a “test your material” template, where you can define thresholds and make automated tests.
Something like:
Action type: Cut
High power: 100
Low power: 100
High speed: 500
Low speed: 300
Number of steps: 10
And voila, it makes a set of circles (or squares, or whatever) with the power and speeds interpolated. Scale as you see fit and zap away.
If they even just made it possible to do “select all, set to 220/full” it would make my jobs way easier [I typically have 3 or 4 cut operations that must be done in order in each job]. The UI has a long way to go to be really dialed in for people who have specific needs. I hope they get around to UI improvements soon, but as @Dan says, they don’t release software timelines.
I have some 0.5mm walnut and I run it through at full speed and around 25-40% power. (It varies somewhat on different pieces of veneer.) Your birch is thicker, so I’d probably use 50% power as a starting point, then adjust up or down as needed.
Since it’s so thin, wouldn’t a heavy score act like a light cut?
Maybe try adjusting score settings to get the cut behavior you want?
I don’t have my unit yet, so this is pure conjecture.
John
