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Slightly OT: how fragile are 3D printed things? Do they break easily? Do they feel fragile? The rods in thi design, might a person break them by accident? How a

Slightly OT: how fragile are 3D printed things? Do they break easily? Do they feel fragile? The rods in thi design, might a person break them by accident? How about intentionally?

ethan_smith 1y ago
The durability depends entirely on print settings (infill percentage, layer height), material choice (PLA, PETG, ABS), and load direction (perpendicular to layers is weakest), but properly printed PETG or ABS parts with 25%+ infill can be surprisingly robust for functional parts like telescope components.
wickedsight 1y ago
According to the description, the rods are aluminum. Printing rods this long is near impossible and if it was, they definitely wouldn't be rigid enough for this application. To answer your main question, it depends. There are many materials you can print with, they're strength can differ greatly. Some are very rigid, but somewhat brittle, others are less rigid, but also less brittle. Then it also depends on the design, the video[0] below is a great video on designing for 3d printing and the considerations needed for strength. Finally, print settings matter. Temperature can affect layer adhesion. Infill and wall count can affect strength and so can print direction (see video). 3D prints can be pretty strong though. I'm using 3d printed mounts to hang snowboards on my wall, for example. I've printed plenty of other stuff I really couldn't print by hand. And I'm only using FDM printing, with SLA and SLS printing even stronger parts can be printed. 0: https://youtu.be/mziT7KV-fRI https://youtu.be/mziT7KV-fRI
javchz 1y ago
Depends on the material and settings. But for example PETG it's as strong as a water bottle.
- filcuk 1y ago
  That can be a bit misleading, I feel. It depends on how well the layers are fused together, post-processing, or even the orientation of the print. At best, it can be nearly as strong as a water bottle, but I wouldn't expect it to be.
hengheng 1y ago
Really depends on what material you're pushing. PLA is not strong and doesn't like to warm up in the sun, Silk PLA (made to just look nice on the shelf) can even be brittle. But there are better materials. PETG is entirely reasonable, I store my pots and pans on PETG hooks and they're not oversized. The superior 3d printers can print ABS which is above any and all doubt. There are also specialized materials, such as carbon infused PETG, and there are engineering materials at 500€/kg with some interesting properties. But the gist is that PLA makes you go "this sucks, must be printed", and PETG makes you go "oh this is fine". Then there are resin printers that selectively UV cure a liquid to polymerize it. Last I tried that sticky goo it was awfully brittle and borderline unusuable. I heard it improved, but that's why resin printing is not everyday parts but figurines.
- ffaser5gxlsll 1y ago
  Regular PLA is actually stiffer than PETG/ABS, but it's more brittle (so has less impact strength) and a pure formulation has a lower softening temperature. It's generally not suitable for parts that go under the sun, unless it's some other formulation such as some HT-PLA variant, in which case it's actually a good choice for parts that need to be thin and stiff. Under most cases, you won't get the same inter-layer adhesion with ABS, so while you get better impact resistance, under most circumstances PETG will yield more durable parts that won't delaminate under the same stress conditions. For outside use under the sun, you should use it's cousin ASA. To respond to the OP.. 3D printed parts can be incredibly durable when printed correctly. The parts need to be designed for 3d-printing in mind, like most other manufacturing methods. A 1cm-thick 15% filled PLA slab that has been printed vertically might be easy to snap in half with two hands, but it becomes almost impossible to break with bare hands when printed horizontal, and requires a saw to be cut when filled to 50%+. And this using consumer-grade printers. I'm using 3d-printed parts for work and at home, some in use for almost 7 years at this point, and the only telltale sign is the layered look. The rods in the design are not 3d-printed, which makes sense (most plastics would be too flexible, and 3d-printing a rod is always more expensive).
  - terribleperson 1y ago
    You can get excellent inter-layer adhesion with ABS, if you crank temperature up and disable cooling. I print on a Mk3s in a photo tent and have had no trouble eliminating layer failures as an issue.
chantepierre 1y ago
The rods are heatshrink tubing wrapped-aluminum. I personnally have built a few partially 3d printed, or full 3d printed (except for a few hardware items and carbon fiber rods) telescopes – it all depends on print preparation skill, correctly drawing for 3d printing, and wise choice of material and print conditions.
alnwlsn 1y ago
If you've never FDM 3D printed anything before, you'll probably find it about on par with most other plastic objects in your life, even if it is technically weaker (for the most part). Most things aren't particularly fragile - print out a 1" cube in any material at default settings, and you'll be able to stand on it. You probably won't find a way to break it with your bare hands, short of pitching it into a concrete wall.
ajuc 1y ago
Haven't printed this telescope but I have printed some pretty big things for example a front rack for my wife's bike. It's on the 3rd version, the first one broke on small collision (the bike fell over while standing), the 2nd on a big collision (my wife hit a bus stop :/ ). The 3rd version survived several years of daily use including hauling stuff from the mall. The key is to split the design into parts that need to be strong in 2 axis and can be weak in the 3rd axis (to work around the layer adhesion problems). So you print 4 walls laying flat not standing vertically. That plus including rope or zip ties for elastic connections where needed - and you can make stuff that is plenty strong enough for most daily uses. I printed with PLA and PETG and both are ok - PETG is less stiff but handles direct sun better.

Slightly OT: how fragile are 3D printed things? Do they break easily? Do they feel fragile? The rods in thi design, might a person break them by accident? How about intentionally?

ethan_smith 1y ago

The durability depends entirely on print settings (infill percentage, layer height), material choice (PLA, PETG, ABS), and load direction (perpendicular to layers is weakest), but properly printed PETG or ABS parts with 25%+ infill can be surprisingly robust for functional parts like telescope components.

wickedsight 1y ago

According to the description, the rods are aluminum. Printing rods this long is near impossible and if it was, they definitely wouldn't be rigid enough for this application. To answer your main question, it depends. There are many materials you can print with, they're strength can differ greatly. Some are very rigid, but somewhat brittle, others are less rigid, but also less brittle. Then it also depends on the design, the video[0] below is a great video on designing for 3d printing and the considerations needed for strength. Finally, print settings matter. Temperature can affect layer adhesion. Infill and wall count can affect strength and so can print direction (see video). 3D prints can be pretty strong though. I'm using 3d printed mounts to hang snowboards on my wall, for example. I've printed plenty of other stuff I really couldn't print by hand. And I'm only using FDM printing, with SLA and SLS printing even stronger parts can be printed. 0: https://youtu.be/mziT7KV-fRI https://youtu.be/mziT7KV-fRI

javchz 1y ago

Depends on the material and settings. But for example PETG it's as strong as a water bottle.

filcuk 1y ago
That can be a bit misleading, I feel. It depends on how well the layers are fused together, post-processing, or even the orientation of the print. At best, it can be nearly as strong as a water bottle, but I wouldn't expect it to be.

hengheng 1y ago

Really depends on what material you're pushing. PLA is not strong and doesn't like to warm up in the sun, Silk PLA (made to just look nice on the shelf) can even be brittle. But there are better materials. PETG is entirely reasonable, I store my pots and pans on PETG hooks and they're not oversized. The superior 3d printers can print ABS which is above any and all doubt. There are also specialized materials, such as carbon infused PETG, and there are engineering materials at 500€/kg with some interesting properties. But the gist is that PLA makes you go "this sucks, must be printed", and PETG makes you go "oh this is fine". Then there are resin printers that selectively UV cure a liquid to polymerize it. Last I tried that sticky goo it was awfully brittle and borderline unusuable. I heard it improved, but that's why resin printing is not everyday parts but figurines.

ffaser5gxlsll 1y ago
Regular PLA is actually stiffer than PETG/ABS, but it's more brittle (so has less impact strength) and a pure formulation has a lower softening temperature. It's generally not suitable for parts that go under the sun, unless it's some other formulation such as some HT-PLA variant, in which case it's actually a good choice for parts that need to be thin and stiff. Under most cases, you won't get the same inter-layer adhesion with ABS, so while you get better impact resistance, under most circumstances PETG will yield more durable parts that won't delaminate under the same stress conditions. For outside use under the sun, you should use it's cousin ASA. To respond to the OP.. 3D printed parts can be incredibly durable when printed correctly. The parts need to be designed for 3d-printing in mind, like most other manufacturing methods. A 1cm-thick 15% filled PLA slab that has been printed vertically might be easy to snap in half with two hands, but it becomes almost impossible to break with bare hands when printed horizontal, and requires a saw to be cut when filled to 50%+. And this using consumer-grade printers. I'm using 3d-printed parts for work and at home, some in use for almost 7 years at this point, and the only telltale sign is the layered look. The rods in the design are not 3d-printed, which makes sense (most plastics would be too flexible, and 3d-printing a rod is always more expensive).
- terribleperson 1y ago
  You can get excellent inter-layer adhesion with ABS, if you crank temperature up and disable cooling. I print on a Mk3s in a photo tent and have had no trouble eliminating layer failures as an issue.

chantepierre 1y ago

The rods are heatshrink tubing wrapped-aluminum. I personnally have built a few partially 3d printed, or full 3d printed (except for a few hardware items and carbon fiber rods) telescopes – it all depends on print preparation skill, correctly drawing for 3d printing, and wise choice of material and print conditions.

alnwlsn 1y ago

If you've never FDM 3D printed anything before, you'll probably find it about on par with most other plastic objects in your life, even if it is technically weaker (for the most part). Most things aren't particularly fragile - print out a 1" cube in any material at default settings, and you'll be able to stand on it. You probably won't find a way to break it with your bare hands, short of pitching it into a concrete wall.

ajuc 1y ago

Haven't printed this telescope but I have printed some pretty big things for example a front rack for my wife's bike. It's on the 3rd version, the first one broke on small collision (the bike fell over while standing), the 2nd on a big collision (my wife hit a bus stop :/ ). The 3rd version survived several years of daily use including hauling stuff from the mall. The key is to split the design into parts that need to be strong in 2 axis and can be weak in the 3rd axis (to work around the layer adhesion problems). So you print 4 walls laying flat not standing vertically. That plus including rope or zip ties for elastic connections where needed - and you can make stuff that is plenty strong enough for most daily uses. I printed with PLA and PETG and both are ok - PETG is less stiff but handles direct sun better.