For GF, that is (If I had a kilowatt-class laser I’d be all over the steel or titanium).
I’ve been thinking probably baltic birch, maybe in phenolic-clad, but really not sure. Might be acetal (but spendy), might even be acrylic if you could get away from the cracking and brittleness. Some of the other plastics aren’t really laserable.
Experts?
Guess it depends on the desired structural properties. Plywood is great for low weight and decent strength with plenty of give. Acrylic is very strong but very little give, but is pretty high in weight. Acetal will be my go to for things that need strength and good wear resistance.
I’ve lasered Delrin for structural parts. Spendy but strong and not brittle like acrylic. Others?
Ive used birch ply for scaffolding, but I will weld together a steel frame if I need something really rigid. What are you making?
I would say it depends on your application really.
Acrylic would be fine in a low stress environment. Once you start cycling it, you will probably experience cracking. This would be good for cases and storage.
Delrin/acetal is a good material to work with, has high strength and low wear, but as you said its expensive. This is really good for parts that see high stress, such as gears, but can also easily be used for supports as well.
Plywood and hard woods are great. They have really good strength/weight ratios, and are usually cheaper than the above options. Woods are really good when weight is a big concern, but are also great for other structures because they can handle quite a bit of stress.
What application are you looking at, or is this more of a general question?
Have to second this. It’s all about what property you want? Stiffness, toughness, slipperiness, waterproof, precision, weight, heat resistance/cold-shrinkage, abrasion resistance, paintability, etc
According to this site: https://www.pololu.com/docs/0J24/3 ABS and PETG are also laser cut and they are good engineering materials. People on this forum have said ABS melts badly though but Pololu seems to disagree.
I look forward to materials that I can 3D print and then laser engrave or perhaps trim accuately. So far my list is acrylic, PETG, ABS and acetal.
PETG is great. I use E3D Edge (PETG) which is incredibly tough and strong (almost as tough as nylon, but way stiffer)
I’m thinking (just for the heck of it, mostly) about making furniture, like some of those CNC chair and table designs. But not solid. So a leg, for example, might be two flat profile pieces connected by an edge piece and maybe some internal ribs, all glued up. I had sorta been thinking 1/4" and 1/8" ply because I’m comfortable with that from woodworking. But it would be fun to do other things if possible. If acrylic would crack under cycling that’s right out, alas (even though it would be really pretty). But hmm, ABS or PET if they worked OK.
I think I have a good handle on smaller structural bits, e.g. for parts of machines.
PETG is stiff? My experience has been the opposite, but maybe my comparisons are wrong. I’ve found PLA to be significantly stiffer (although obvious not as tough).
I believe he said that it was stiffer than nylon. Based on my experiences with both, I’d agree.
Yep, PLA is stiff, but of course mechanically is useless for any serious load or abrasion. I was comparing to Nylon, which is insanely tough, but also very flexible.
PETG has around a 32000psi modulus, PLA is 51000psi, while Nylon 910 has a 73000psi modulus. Tensile strength is 7700psi for PETG, PLA is 7300psi and about 8100psi for Nylon 910. The key difference is that nylon (and mostly PETG) have those numbers while 3D printed, while for PLA it is only when injection molded.
One nice feature of plywood is that it is so easy to make multiple layer laminates. The areas that need stiffness can be reinforced with a few extra layers. Since we will be laser cutting we can make complex glued up ribs and gussets without worrying about how hard they are to cut.
And since wood has a long history of being used in things like this, you can also put protective finishes on the outside. One of my dreams is to use (partly) ply that’s thin enough to bend just a little (e.g for a seat) and then throw a bunch of poly on so it doesn’t just wear right through.
Injection moulded glass filled nylon parts are also very stiff and tough, but I haven’t tried 3D printing it yet. E3D say it doesn’t extrude very evenly, which is not surprising.
I agree. You can also make cuts/engraves on the back of it to decrease your minimum bend radius.
I imagine (although don’t know) whether that reduces the interlayer adhesion. Nylon, unlike most other plastics, bond via hydrogen-bonding, so the layers stick insanely well (which is why 3D printed nylon is as strong as IM nylon basically) and I worry that glass weakens it. On Thomas’s review of bridge (I use 910 instead which I like better) vs. a composite nylon:
vs
Thank you for getting me to convert from bridge to 910. Yes, much better.
I don’t like the idea of fibers in the filament either, I would think that the strongest 3d printed parts you could make would be to print a shell and put glass or carbon fiber inside that shell.
I am also really interested in making simple furniture. My dream is to just shove 1/4" ply through my Pro, over and over, until I have a pile of wood shapes that I can screw together into something useful.
I can’t recall the brand name but we have some thin ply(less than an 1/8") that is used for boat building, its super flexible but once you glue up a couple layers it’s really strong