I’ve printed probably 5 kilos worth of prints with a lot of success, but exclusively PLA. I’d like to branch out to a new material. Should I start with ABS or TPU?
Petg or Tpu
Fear ABS and ASA like your worst nightmare
TPU.
ABS is a beautiful filament, but it’s somewhat similar to PLA in its properties.
TPU I fun to play with and its flexibility offers different properties than PLA
IMO having the ability to do TPU is way more versatile than going to another rigid structural filament.
ABS/ASA is just “pla but more impact resistant”.
TPU is “haha funny squishy wait this turns into a living hinge?” and opens up a TON of print opportunities.
I had a lot more fun trying out TPU (both high and low durometers) than switching to any other kind of filament. Whatever you print basically becomes shockproof l, is squishy/bendy, and you can chuck it across a room full-force with no problems. Super fun.However, TPU is happiest with a direct drive extruder. High durometer (95a) TPU’s are fine, but not optimal, in bowden extruders, while low durometer (Ninjaflex) straight up won’t print right thru a bowden. So keep your type of printer in mind when shopping for spools of test filament.
I would try PETG. It doesn’t need an enclosure.
No
ABS needs an enclosure for anything above around 10 layers. Even a room closed with it warm and no one inside is not enough to save an ABS print. Just the air from the moving tool head and the bed are enough to disturb a print and cause layer separation. An IKEA Lack table and a garbage bag over it is enough of an enclosure to count and get most prints alright. It stinks though.
TPU will have holes and look terrible unless you print out of a filament drier. You can dry the stuff a lot and print for around 45 minutes with it in open air before it will absorb enough moisture to start expanding steam in the melt zone and blowing holes in your print layers.
That enclosure might work for smaller ASA prints, but I needed a lot more insulation than a garbage bag to pull off larger prints.
Maybe I got lucky with TPU, but I didn’t run into any significant issues with humidity when I printed treads for wagon wheels over the course of two or three days.
Makes a huge difference with my junky TPU if it is dry or not.
I also have a massive stacked Lack (sp?) table with double legs. I put that stack with a MK3S+ into a 55 gallon trash bag and can print the entire build volume. The thing is, it has to be totally sealed off well and no traffic in the room that might disturb the thing in the slightest. I won’t even open a door to the room. I also let the bed heat for longer before the print starts. Lastly, I must design for ABS specifically and am very conscious of layer thickness transitions. I look at all filaments and designs as an optimization exercise for materials and process kinda thing. I design everything I print. So my advice is an abstraction of what is possible under similar constraints. Most files people share are not very well designed for 3d printing, or for material specific requirements/optimizations. I don’t recommend printing other people’s stuff unless you are forced to for some reason.
The primary issue with ABS is how heat is soaked into top layer/bottom layer transitions near any side walls. In most cases, just make a tapered transition over a long area and remove any top layers in places like interior surfaces. Designing tops sections that are rounded or hollow is another key, along with no supports based designs. Using exposed 3d cubic infill is how I get around a lot of the top layer heat issues.
If anyone is actually wanting to print ABS a lot, obviously just get a Voron.
Makes a huge difference with my junky TPU if it is dry or not
I am happy to have gotten lucky with Overture 95A!
ASA/ABS
I design my own prints too, but I also have a 350mm x 350mm bed. My bed size has lead to some fairly large prints. My printer is a Voron and I originally built it with the stock acrylic enclosure. This was fine for smaller parts (say 150-175 mm and smaller), but despite keeping keeping corners rounded and avoiding rapid shape transitions I still had some prints pull themselves apart or pull the print bed up. Even on cylindrical and rounded rectangle prints, without a solid top or bottom. It wasn’t until I insulated my Voron that I was able to pull these larger prints off with a chamber temp of around 58 C.
Maybe I should try another material as so far I’ve been sticking with polymaker ASA because it’s cheap and prints decently. What are you using?
I’ve only gone through 2 rolls of the cheap Matterhackers house brand ABS and maybe a quarter roll of Prusa ASA. My primary curiosity was if ABS/ASA is an effective alternative to Prusament PC Blend. In my experiments, my primary use for ABS/ASA is for refinishing and polishing. I’m super familiar with ABS in pro auto body work I was doing before RepRap was even a thing. I actually specialized in plastics and small repairs in addition to airbrush and graphics work as a painter; liked the art, but work out of used car lots paid the bills.
I only made a little disk sander thing out of a box fan motor with a housing constrained by print bed dimensions, also some dremel drill press tooling, and some BB30 bicycle parts.
The disk sander thing was not very useful overall. The level of integrated design was extreme and impractical in most cases, but it proved to me that I could technically do it. That largely helped me avoid the desire to build a Voron. Plus I spent years huffing ABS fumes already. The bicycle stuff showed me that PC blend is still quite a bit better at holding a load in the real world. I designed a couple of parts with threads that hold the bearings in tension on the spindle of the bike crank. I’m certainly not in race shape any more, but I am still quite hard on bike stuff. Plus bikes are a great test bed as leg forces are unbalanced, the vibration is inconsistent, contaminants are random, and UV exposure is harsh.
Anyways, the prusament ASA doesn’t have as many issues as MH ABS, but the difference is not huge. If I was going to do automotive class finishing, that is the only time I would go out of my way to use ABS/ASA. I could make it perfect on another level entirely than anything else I have played with.
I’ve dabbled in both automotive work and home renovation. Anyone who can do auto body work or interior finishing work well deserves way more credit than they usually get, so big kudos. I am pretty solid at the mechanical bits, but when it comes to finishing/painting things are a lot more difficult for me.
Print finishing is something I’ve thought about a few times now, but most of my prints are functional and live a pretty hard life. A bit of texture from layer lines and other imperfections is the least of their concerns. That said, I have sanded ASA some and it sands amazingly well. I could see getting it pretty smooth without too much effort and then either using a solvent based or finishing based method. Of course, if your print has a lot of fine detail this is going to be a massive PITA.
You can totally build a Voron anyway! I suggest magnetic panels, which makes popping the top super easy if you want to print PLA. I’ve run PLA, PETG, TPU, and ASA through mine. I have an under bed carbon filter that does a pretty good job with fumes.
Agree on bike parts being a good print test bed. I’m impressed that anything held up with pedal loads, there’s a lot of force there.
My main motive for sticking with ASA is its easily attainable high volumetric flow. I can easily swing 30 mm^3/s on my Rapido without having to jack up temps. Between this, Core-XY motion, and input shaping prints are way faster than my old i3 clone. PETG is quite a bit slower. PLA can be fast, but it’s also somewhat brittle.
Thanks. The main thing with paint is to be absolutely obsessive about the prep details and sanding. I’ve trained two apprentices. The hardest thing to defeat is one’s internal expectations of time. It is only right and ready when it is perfect even when redoing that primer for the fifth time feels like murder and the issue is only the size of a dime, it simply does not matter. That dime will cost two days to fix when it shows through, and that knowledge must come first. I told everyone that ever worked for me, “sand it until you think you are done, then take a break, come back, and acknowledge you are finally halfway done. Then repeat this until I cannot find a single issue with the panel.”
The cool thing about ABS and ASA is that you can sand it to a polish. Just treat it like a metal polish job but use automotive polishes instead of rouge like for metals. There are usually no inclusions from the print lines in my tests and it polishes to a remarkable finish that looks like extra shiny Lego’s. In fact, if you take a fully polished part and break it, you will likely find that the surface is changed for nearly a millimeter down. It happens even when the polish is done meticulously by hand with no buffer to heat up the surface. I’m not entirely sure what is happening with that one, but based on how it sounds and feels I bet there are better mechanical properties as well.
From my time around automotive racing, polished ABS/ASA feels like parts that are finished to reduce stress risers like how pistons and rods feel different after a similar polishing operation. I haven’t tested it, but that is how the parts felt to me. That might be one to try out, even with mechanical and functional prints. If you happen to snag some sandpapers, it only takes a sheet of 600 or 800, as a baseline where this has removed absolutely everything below regardless of what was below, then use 1500 to knock this down. Finally, toothpaste can nearly replace an automotive compound. No joke I have used it on cars in a pinch with a heavy cut pad. For a mirror it will take an intermediate cutting stage before the final polish. For something like a print that is already sitting at 1500 grit, toothpaste will get more shine than a typical new Lego. Just use an old sock and let the compound do the work just like with a buffer and pad.
The little Proxxon pen sander is also a must have device for print sanding in general. It is worth the spend. You only really need the sander without the power supply though. The supply is the scam. Just clip the wire and add a DC barrel jack to any old 12v 1A wall wart. Their sandpaper is really high quality and worth it, but some decent double sided tape will work to make your own. You can also make your own sandpaper holders to get into awkward places.
I don’t know that I could actually finish a Voron build now. That is the real underlying truth of it. I am physically declining and my up time is very limited over the last coupe of years. That has kinda quashed my EDA and circuit etching projects too, sadly. Even my riding is suffering. I did 26m every day for ~8 years after the broken neck and back, but now 16m every 2-3 days is all I can do and still sleep 4-6 hours at most. It is what it is… “Ya get what ya get and ya don’t pitch a fit.”
Thanks for taking the time to type out that reply, it packed a ton of information. I think you’re under selling the eye and the technique necessary to sand well. I’ve done some DIY auto-body and paint work and I really struggled to know when I had sanded well enough. Yeah, I knew I needed to sand more, but I had no idea where to focus my efforts and couldn’t easily distinguish a high spot that needed to get knocked down vs low spot that needed to get filled. Building that skill to the point of it being intuitive seems like something that would take a decent amount of practice or a great coach.
I hadn’t considered polishing ASA. I’m somewhat tempted to give it a go. The hardest thing for me would be figuring out how to sand large curved surface in such a way that doesn’t result in lots of obvious flat spots. I can absolutely see sanding/polishing making prints a bit stronger.
I’m sorry to hear about your physical condition and wish you as much additional recovery as possible. I totally get having very limited time with two younger kids in my house. I think all in the build took 4-5 months starting from printing parts, ordering a kit, and finishing assembly. Even though my kids are not new to me anymore, I don’t know that I’ve fully come to grips with the fact that I can’t complete projects as quickly as I once could and I should probably slow down my rate of project accumulation.
It really depends on what you’re looking for. Are you just looking to learn how to print new materials, or do you have specific requirements for a project?
If it’s the former, I’d say the easiest thing to try is PETG. It prints pretty reasonably on most printers though has stringing issues. It has different mechanical properties that make it suitable for other applications (for example, better temperature resistance and impact strength). It’ll be much less frustrating than trying to dial in ABS for the first time.
ABS and TPU are both a pretty large step up in difficulty, but are quite good for functional parts. If you insist on learning one of these, pick whichever one fits with your projects better. For ABS you’ll want an enclosure and a well ventilated room (IMO I wouldn’t be in the same room as the printer) as it emits harmful chemicals during printing.
I designed and printed a fender for my kid’s bike. It would be totally usable as a fender but he’s a savage so he broke the first one within 30 seconds of me installing it. Then I changed the design to add more support and that one lasted a full hour before he broke it off. So I’d like to print the same design again in a new material. I think either of these two would work, as they would put up with more abuse in different ways. one would be much harder and the other more forgiving.
I don’t love the idea of the toxic fumes. I don’t want to get an enclosure and the printer is in my home office off of my living room. I could crack a window and let it run overnight but that sounds inconvenient.
TPU will be nearly impossible for your kiddo to destroy. ASA/ABS are rugged, but if your print has thin surfaces it’s less strong in my experience than PETG.
I didn’t find TPU hard to print personally, just go slow and turn retraction way down or completely off. It will string pretty good, but most slicers have a setting to avoid crossing perimeters that will keep it in check. The only thing I would be wary of is ending up with a floppy print, so make sure the part has some structure.
