Cutting problem birch plywood with GF pro

I cut birch plywood with GF pro. But it didn’t work…
Is this because of the wood? or my manual settings?
Speed: 175
Power: Full
Birch plywood: 1/6




Unless things have changed, support only assists with proofgrade materials.

Non-proofgrade plywood is designed to be cut with a saw blade. Therefore, the manufacturer doesn’t care about inconsistencies in glue, wood, etc… across a sheet, much less a lot. This means a laser setting that works in one spot will not work in another spot. I have found some cheap big box DIY plywood that cuts very consistently, but even then about .5% of a given cut line will not go all the way through and I have to use a utility knife to finish it.

First off all material needs to be very flat on the laser’s bed. Slight warps in the material means the material is being cut by a different part of the cone-shaped laser beam. Therefore less power is being applied. Along the same lines if your set focus height is wrong, you won’t be getting the full power of the beam on your material. If your material is flat and your focus height is correct and if this happens on proofgrade you have a laser problem. Otherwise, you have a typical non-proofgrade plywood problem. You can slow down your speed, up your speed and do two passes, or accept that one of the benefits of a cheap material is you can waste more of it.

4 Likes

I agree with @caribis2, but you’re pretty close… could be as simple as cleaning everything.
Since wood is, by nature, inconsistent and ply tends to be really inconsistent, the question generally isn’t wood vs. settings. It’s about matching a specific piece of wood to the right settings. Before removing a piece from your GF, always check to see that it has cut through. If not, you can always hit it again with a lighter pass,

3 Likes

Hi, I moved this to beyond the manual so it won’t get shut down too soon.

From your photo it looks like clean your lenses and drop the speed by the next minimum step and you will be at the best you can do.

That is the thing about non proofgrade woods, you will have to choose between a bit of over cut and a bit of not cut due to inconsistently.

1 Like

My settings for Baltic birch are slower than that, I think, and I have to do two passes to get through 1/4". You have to do some experimenting with non-PG materials. This test strip can be very helpful:

https://community.glowforge.com/t/has-anyone-been-cutting-0-37-0-40-material/28605/11

1 Like

Birch or Baltic birch? Not the same thing.

2 Likes

For that level of detail you might be better off using a different type of plywood, like poplar-core with hardwood veneer. Even Baltic birch varies quite a bit more than it’s supposed to (I’ve found glue pockets and voids in grades that supposed to be zero-defect), even from nominally-decent suppliers (I think there are manufacturers that are cheating and the average wholesaler/retailer doesn’t appear to actually check the product).

1 Like

This is birch

I’m not using birch ply wood but Maple plywood 1/4".

That’s not why I reply but it’s because I can confirm the glue (and what not) inconsistency of the NON PG materials, wood in particular.

Started cutting ago (2wks) with 168/full. As I’m cutting my way through sheets I need to adjust my settings and I’m currently cutting on 150/Full.
Apart from that I’m using masking tape with a apparently stronger glue then on the PG sheets.
This seems to influences the “through” cut and it looks like there is a "caramelized layer afterwards. and seems to prevent breaking loose of waste and object.

Assume you’ve cleaned your optics in that time? If you’re doing a lot of plywood two weeks can be easily long enough that you need to clean. If you haven’t read the “cleaning your machine” page, it’s a must-read.

2 Likes

Hands up! NO Never thought that 2weeks might be time to clean as per the first 3 sections of the cleaning instructions / guide. Thanks for pointing that out!

First run, after cleaning, will be on initial setting of 168/Full for cutting 1/4" maple plywood to see what a difference that will be.

Tata

1 Like

Time between cleans is really subjective. It depends a lot on what you’re doing – what materials you’re using, and how hard you’re hitting them. Some materials are straight up filthy (stamp rubber) and others have very little impact on the machine (etching tile or glass).

Cutting plywood is (in my experience) on the dirty side. Engraving lots of wood at high power is also filthy, but species and whatnot matters a great deal. Padauk leaves orange residue everywhere. Walnut engraves fairly clean. The list is as long as you can imagine, you just have to find what works for you.

6 Likes

Wow, Cleaning did improve cut depth. Not that I have been cutting 40 hours over the last 2 weeks but it never occurred it could make that big a difference.

Tried the “the old settings” on the same sheet for which I had to adjust settings, it cuts it far better.

Thanks

7 Likes

Yeah don’t forget to clean the lid camera too. A dirty camera can keep you from even being able to cut – if the GF can’t figure out alignment, you’re sunk.

Amazon (and others) sells 100 packs of those Zeiss wipes, if you search the forum you can see much discussion about cleaning intervals and techniques, but I find the wipes are really easy. I’m still on my first box.

1 Like

250 zeiss wipes cheap at Sams club too.

1 Like