Advice needed on materials...

[rlemay 1]

Hey all, I'm pretty new to printing.  I've been sticking pretty much with PLA and ABS up to this point.  I'm working on a prototype which will have a steel tube frame.  I've thought about welding the joints together but some of the joints are going to be at odd angles and will make for difficult welds.  So, I thought, why not just print out some connectors for the tubes?  My question is, what is the strongest material I can print with my ulitmaker 2+.  I'd like it to bear as much weight as possible just to see if my idea will work.  If it does work, I'll eventually get the parts CNC'd out of steel or aluminum.  Any thoughts?

[krys 206]

Hi there,

I am no materials expert or structural engineer, but from what I have read and played with here are some thoughts that might help:

Nylon is super strong (tensile), but has some flex (like ABS), is super slipy, can be hard to get to stick to the bed and warps. But if you have solved ABS, then maybe it would work for you. Check our the Taulman stuff. They are several kinds, all for industrial use. I've used Bridge to good effect.

Polycarbonate is also insanely strong, but warps, is crazy difficult to get to stick to the bed and requires higher temperatures. 260C is a *minimum*! Also watch out for weak layer adhesion. I am still experimenting with this stuff myself, and it is driving me a bit batty. But YMMV.

Lastly, if you want rigid and strong, you can get excellent results with PLA or even better PLA/PHA (Colorfabb). This stuff is easy to print. Just use thicker walls (more shells), higher infill (but not 100%, it does not buy you anything) and print slower for better layer adhesion (I think). I saw @gr5 recently comment about PLA being plenty strong. He seems to know his stuff!

I do not know if this is a good example or not, but I have built a standing height electronics workbench from some cheap wood (it was a closet shoe shelf), ABS pipe for legs (PVC would have been better, wood or aluminum would have been even better) and 3D printed connectors for all of it. Flat plates to hold the wood slats together, fasteners to mount the wood to the top of the legs and t-junctions to hold the cross-braces. All in PLA/PHA and they are all holding just fine even after months of use of the desk and weight on it. ... I did make sure, however, when printing that all the stress points would not be along layer boundaries, as that is the weakness of all FDM printing.

So for your prototyping tests, why not just see how far you can go with PLA. Then get fancy later?

Oh, and I have seen videos of people doing various break tests of filament materials. Maybe check those out too.

Anyway, I am no expert, and YMMV, but I hope this gives you some ideas. Good luck!

[gr5 2,005]

I really need a diagram but if you are making say a geodesic dome then I would go for Nylon but as Krys says - it takes a while to learn how to do it right. For example you will need to enclose your printer, lower fan speed and do some weird stuff to get it to stick! Also you'll want to bake it before printing. Try taulman bridge - the easiest nylon I think maybe? Actually Taulman might have one even easier - I forget.

[rlemay 1]

Hi there,

I am no materials expert or structural engineer, but from what I have read and played with here are some thoughts that might help:

Nylon is super strong (tensile), but has some flex (like ABS), is super slipy, can be hard to get to stick to the bed and warps.  But if you have solved ABS, then maybe it would work for you.  Check our the Taulman stuff.  They are several kinds, all for industrial use.  I've used Bridge to good effect.

Polycarbonate is also insanely strong, but warps, is crazy difficult to get to stick to the bed and requires higher temperatures.  260C is a *minimum*!  Also watch out for weak layer adhesion.  I am still experimenting with this stuff myself, and it is driving me a bit batty.  But YMMV.

Lastly, if you want rigid and strong, you can get excellent results with PLA or even better PLA/PHA (Colorfabb).  This stuff is easy to print.  Just use thicker walls (more shells), higher infill (but not 100%, it does not buy you anything) and print slower for better layer adhesion (I think).  I saw @gr5 recently comment about PLA being plenty strong.  He seems to know his stuff!

I do not know if this is a good example or not, but I have built a standing height electronics workbench from some cheap wood (it was a closet shoe shelf), ABS pipe for legs (PVC would have been better, wood or aluminum would have been even better) and 3D printed connectors for all of it.  Flat plates to hold the wood slats together, fasteners to mount the wood to the top of the legs and t-junctions to hold the cross-braces.  All in PLA/PHA and they are all holding just fine even after months of use of the desk and weight on it.  ... I did make sure, however, when printing that all the stress points would not be along layer boundaries, as that is the weakness of all FDM printing.

So for your prototyping tests, why not just see how far you can go with PLA.  Then get fancy later?

Oh, and I have seen videos of people doing various break tests of filament materials.  Maybe check those out too.

Anyway, I am no expert, and YMMV, but I hope this gives you some ideas.  Good luck!

 

Fantastic info. Thanks so much. I've read a decent amount about carbon fiber reinforced nylon and some say it can be as strong as steel. I read about Markforged products and they were actually printing weight bearing auto parts. But your'e right, I should probably push the limits on PLA and see if I need to upgrade. I was really just hoping to not have to CNC metal parts because that can get expensive. Thanks again for the info!

[avogra 68]

Try taulman bridge - the easiest nylon I think maybe?  Actually Taulman might have one even easier - I forget.

 

They claim that the new Alloy 910 is stronger and easier to print than Bridge. But I haven't heard of anyone who actually tried it, so no idea, how it is different.

[rlemay 1]

Awesome. I've just ordered some Alloy 910. Bridge looks very flexible which isn't what I'm looking for.

Here's a pretty good video showing the difference in the two.

 

[gr5 2,005]

mark forged prints very very strong. They have a good process. But it's limited in 2 directions. Still it's pretty amazing. That's a very specialized printer.

[rlemay 1]

mark forged prints very very strong.  They have a good process.  But it's limited in 2 directions.  Still it's pretty amazing.  That's a very specialized printer.

 

I thought they had created a filament, maybe fiberglass reinforced that could be printed in a standard FDM process, but I could be completely wrong.

[gr5 2,005]

It kind of defeats the purpose when you cut up the fiberglass or carbon fibers much smaller than the .4mm nozzle size.

[JohnFox 25]

I have just tried the Alloy 910. Not easy but I got workable parts out of it.

I had to drop the temp to 245C to stop it from charring, then printed slow and at 105% flow rate. The spool it comes on is VERY small, only 50mm diameter, so the coil doesn't go in the Bowden tube very well. I uncoiled it, put it in the oven at 50C for 10mins and it 'relaxed' quickly. Not seen any obvious problems with water absorption.

Very strong and the parts have less friction than PLA. However you can't smooth the surfaces with wet and dry, unlike PLA or ABS.

 

 

Try taulman bridge - the easiest nylon I think maybe?  Actually Taulman might have one even easier - I forget.

 

They claim that the new Alloy 910 is stronger and easier to print than Bridge. But I haven't heard of anyone who actually tried it, so no idea, how it is different.

 

[avogra 68]

Sounds promising! I finally have to get some too. 245°C is exactly what I used for Bridge What did you use for bed adhesion?

[JohnFox 25]

I simply used PVA glue, ( Prit Stick ) and a brim, the brim seems to be important.

Anyone any ideas for 'finishing' Nylon prints, sanding doesn't seem to work well.

[Artiz 27]

mark forged prints very very strong. They have a good process. But it's limited in 2 directions. Still it's pretty amazing. That's a very specialized printer.

 

I bought one of those Markone's as my first printer... totally useless and so specialised that it could only print the carbon filament if your model was longer than about 6" and even then the software would not tell you if it was or was not going to print the carbon... sometimes it would/sometimes it wouldn't... hopeless printer of the worst kind because of how hyped it was... and of course how beautiful looking it is... now add to that it's hefty price & proprietary filaments and you have yourself a 'fool's printer' to match no other... luckily enough I got mine back to the seller before my 14 days grace was up... exchanged it for a UM2 and never looked back... no owner will ever tell you how useless they are either as they would just end up looking like the mug that they truly are after spending more than £5000 on a brick.

Edited September 7, 2016 by Guest