I’ve got the 45 watt model. Was wondering if anyone might have a recommendation for what 1/4 birch plywood settings might be to cut and engrave with? Also anyone have any cautions? This is some plywood from the woodcraft store where apparently others in my area source for laser projects and things, hopefully the glue won’t be a problem, we’ll see. But anyway would love any tips or recommendations. Still pretty new at all this.
I’m going to shift your post to Beyond the Manual so I can give you a starter number:
I’d start with power = Full, Speed = 140
Do a test cut, and if it doesn’t make it all the way through, drop the speed to 135.
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The inner plies probably have some voids and knots. The voids can kick up a good flame and increase flash back (because you get through quicker) and the extra dense spots can prevent you from making it through. Though if local folks are having good luck with it in their lasers, you’re probably mostly fine. Though what they consider “good luck” might be different than what you might hope for.
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I’ve had great (but unofficial) luck starting with the PG settings and adjusting the pews as needed. 
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Not likely. The OP said it was Birch from Woodcraft. They almost only sell Baltic Birch (not standard Birch) plywood. That’s manufactured without knots or voids. It’s (until PG) the go-to plywood for lasers.
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I second what @Jules said for the cut. I’m working with Woodpeckers Baltic Birch 1/8 and 1/4 (more often the 1/8). I need to revisit my 1/4" engrave settings now that I’ve done a few more jobs on the thinner ply. You’ll be able to get away with a faster cut if the board is absolutely flat and flush with the honeycomb, but here’s what I have in my notes that you could toy with.
1/4" BB
CUT | Full Power, Speed 140, Focus 0.23, 1 pass
ENGRAVE | Full Speed, Full Power, 270 LPI
1/8” BB
CUT | Full Power, Speed 170-200 (if warped) … 230 (IF absolutely flat)
ENGRAVE | Full Speed, Power 75, 340 LPI
ENGRAVE | Full Speed, Power 80, 270 LPI
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I use Baltic Birch from a couple of wood sources. And the 1/4" stuff often has sections that are more dense in the middle. I’d say maybe one in 4 or 5 sheets will have these areas.
I use 140 speed with full power, and 2 passes. This will cut through 99% of the stuff I use. The second pass is often just for those areas. Even then, I often have to score and cut a few lines using an exacto blade. And that does not work very well. I find I recut maybe one in 6 or 7 sheets.
I’m going to use up the rest of my 1/4" stock and then stop buying it. If I need something 1/4" I’ll cut two 1/8" sheets and glue them together. It’s just as fast and makes a nicer cut.
Perhaps it’s just supplier I have.
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Both are spot on. I find the 1/4" far more variable between suppliers. Best luck has been Woodcraft. Amazon is spotty.
Taking 2 1/8" panels does take longer - twice the cutting plus glue-up, but it’s often a really good way to go.
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For me it’s not twice the cutting, since I have to do 2 passes for the 1/4", but just one pass for the 1/8". So the cutting time is about the same.
The gluing will take a little longer, but not much. And I won’t have to recut some of my sheets. I think overall, using 2x 1/8" will save me time.
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100% behind Woodcraft as a supplier of all things wood. I have spent a lot of allowance there over the years. (Some may say unreasonable).
We have several in the area. Hopefully you will also.
It is a wood workers candy store though, so plan on some time wandering around if you head there and are into making wooden things.
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Thanks for mentioning! (You too @jamesdhatch!) I didn’t know of that store and there happens to be one 6 miles from my house; nice. I’ll be checking them out.
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I was using similar settings and getting spots that would not burn through but lately have found that if I set the focus a little lower, somewhere around .210, I have far greater success cutting 1/4 BB. Rarely am I reaching for the exacto to release pieces now.
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Depending on your use case, you might try using registration holes to align your layers.
Here’s an extreme case, about 12 layers of 1/8" flawlessly (and easily) aligned with dowels. It’s a pure friction fit, no glue was used. Just a matter of getting your holes the right size with some trial and error.
That being said, there are ways to cut 1/4" ply, again, trail and error and testing will be the best plan here. Searching the forum will yield lots of discussions. I just searched ‘1/4" settings’ and got lots of hits, but #1 is here:
Seems like a dead bullseye? Generally, I find that whatever I’m doing isn’t new, we have a pretty avid base here and we’ve tried a LOT of stuff… searching almost always finds something.
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You just saved me so much frustration!!! THANK YOU!
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I use 1/4 baltic birch from my local maker space so it is pretty nice.
So far my best settings are Full power and anywhere from 125 to 115 speed.
I am focusing at .25 so I am going to try what everybody is saying here and focus down a little lower at.23
I mimicked the thick Proofgrade settings of .208”, which works well.
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Thanks for the info. I’m curious about setting the focus height. I thought the “scanning your material” phase is the head coming over and using autofocus to set the focus? Does anyone know what the relationship is between the the focus height we set and what the autofocus is doing?
It seems like from what I’m reading in this thread that the height we enter is what the machine uses, (And I don’t know what the autofocus is doing, if anything?)… Am I correct?
Also, does anyone know if when you select 2 or three passes, does the focus point change between passes? It would be sweet to have the focus go deeper so you could cut through much thicker material? ie lower the focus by 1/8 each pass, and cut through 1/2" of material in 4 passes?
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Currently, it does not. It is an advertised feature that should appear some time in the future.
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Thanks Scott, I’ll look forward to that. Do you know why we input a focus distance and it also scans? Does one or other take priority? If I want to cut through thick in multiple passes, can I manually set the focus for say 3 or 4 different operations and have it use my focus settings over whatever the scanning part is doing?
The focus entry on the “Material Thickness” is to control the lid camera de-warp. It also pre-populates the manual focus settings for all the operations.
If you leave the manual focus setting the same as the material thickness, it will use the results from the “scanning” step during the print. This is the auto-focus feature.
If you change the manual focus to something different, it will use the value you entered.
Yes. If the focus value in the operation is different than the focus value in the material thickness, it will override the auto-focus.
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