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PETG is slightly less strong than PLA - PETG has a bit of flex. I use PETG for raspberry pi cases because they get quite hot. Though having said that, PETG is f
by chewxy 6y ago
PETG is slightly less strong than PLA - PETG has a bit of flex. I use PETG for raspberry pi cases because they get quite hot. Though having said that, PETG is fast becoming my favourite thing to print with.
- dogma1138 6y agoPETG isn’t that great tends to deform less and shatter more, ASA is better if you need temperature resistance and is only slightly more expensive than PETG these days and it’s also much more machineable. PLA these days also has quite decent temperature resistance in filaments that were designed for that, but even the most generic stuff should be ok for most electronic applications there shouldn’t be a spot that goes over 45c her alone 60-70 where you really begin to see issue.
- ehnto 6y agoFor a portable device like this I would be worried about leaving it in the car if it's PLA. You can easily see 70c inside a car on a hot sunny day. That said, you can heat treat standard PLA to make it resistant to temperature.
- dogma1138 6y agoI wouldn’t leave a raspberry pi in a car that gets to 70c due to a very likely risk of damaging the BGA SoC and other soldered components.
- jrockway 6y agoThe SoC doesn't thermal throttle until 85C. It is not going to desolder from being inside a hot car.
- Damogran6 6y agoDoesn't PLA get dimensionally unstable with heat treating?
- ehnto 6y agoIt usually is yeah, but you can sometimes get good results. I think it depends a lot on the heat level against the specific print you are doing.
- StavrosK 6y agoPETG shatters more? Are you guys using colored PETG? Pure (transparent) PETG will buckle before it shatters, and is much stronger than PLA for me.
- tonyarkles 6y agoEven coloured PETG has been amazingly shatter resistant for me? I took a bad print and stuck it in a bench vice. It was long and skinny (maybe 3-4mm thick before the print failed), and it literally bent itself in half and did not snap.
- StavrosK 6y agoIt depends, pigment changes its properties. White Spektrum PETG tended to shatter a bit too easily for me (though still not more easily than PLA, I think).
- tonyarkles 6y agoHuh! Good to know! This was D3D in green. The only thing that's managed to break it so far is a drone clipping the ground with its landing gear at 40km/h, and the 3D printed piece was the perfect "weak link" to prevent a more catastrophic failure :)
- StavrosK 6y agoOh yes, engineering intentional weak links is an art of its own, when you don't want the more expensive components to break.
- tonyarkles 6y agoThe joke in engineering school was: "You may choose to design a specific weak link into your design; if you do not do so, one will be provided for you."
- Doxin 6y agoMy favorite PETG property is its sandability. You can sand down PETG way easier than PLA and it's not really any harder to print.
- Doxin 6y agoAlmost forgot to mention my second-favorite property, or more like a lack of a property: PLA tends to break over time. If you print a coat hook out of PLA it will fail sooner or later. Fractures just build up over time until it gives out. No such thing with PETG, it's either deforming or it isn't. none of this slowly deforming over time nonsense. And while I'm at it, my third favorite property: It's fairly bendy and springy! Even though it's less strong than PLA it's way less likely to break because of it. All in all my favorite 3d printing material so far.
- bradly 6y agoIsn't PETG much more durable than than PLA? PETG is less strong in the sense that is can flex, but it is much more impact resistant and less brittle than PLA I thoguht. Also, in something like a case with screw holes, even slightly too big screw will crack the case, while PETG will usually be okay. I could be wrong–I'm pretty new to 3D printing.
- vorpalhex 6y agoPETG isn't as hard as PLA and is less fragile, with minor flex. It's main downside is that it's a pain to glue without special glues as the usual suspects (cyanoacrylate, epoxy, etc) don't usually like to stick to it.
- chewxy 6y agoYa. Strength usually refers to static tensile strength, of which PLA scores pretty damn high. There's a YouTube channel called CNC Kitchen which does regular testing of filaments. He measures various kinds of strengths (tensile, compressive, impact, young's modulus etc). I highly recommend it. But when people say strength they usually mean static tensile strength.
- dekhn 6y agoYeah, I built a solar tracker that sits out in the sun. I originally printed with black PLA plastic. After a few hours of direct sunlight it melted! Now I print with PETG and that stuff is solid. I can't really tell the material properties differences between PLA and PETG (in terms of strength).
- chewxy 6y agoOuch. I found PLA to have less flex. PETG has a lot more flex. Also, what is the point of a solar tracker? We can all tell where the sun is...
- dekhn 6y agoI point a camera at the sun for long periods to take multiple exposures (goal is to watch a sunspot moving across the sun). People also use solar trackers to keep solar panels aligned with the sun. I thought PETG has a higher elastic modulus than PLA, but I haven't really tried it. I generally size my pieces to not flex, since that introduces error in the tracker.