How durable are 3d printed objects?

Hello everybody, this is Reacher from Italy.
I'm thinking about buying my first 3d printer. It would be something like a Prusa I3.
I've seen a lot of things on thingiverse that I would like to print. I mean things like small plastic tools, smartphone covers, rc cars parts, spares and upgrades for the 3d printer etc...
Would it be possible to print everyday objects durable enough to withstand actual use? With a printer this cheap? (obviously after a correct set up and learning...)
Thanks in advance for any answer

Yes.

It can depend of what material you use, but even cheap abs and pla is extremely durable. For seriously strong stuff you can use petg, polyflex polymax and flexible materials.

But yes - parts are as good as commercially produced parts, in many cases stronger and lighter.

To a large extent for fdm machines it depends on the orientation you print them in.
So the same part can be printed in different orientations and one will be weak and break easily and the other will be strong, flexible and hard to break.

Getting really good 3d printed parts is as much an art as a science.

Yes i agree with curious abs and pla can be quite durable. If you want to use other materials check that the printer you are buying can actually take the material you want to print but a lot of cheaper 3d printers recommend either pla or abs or both.

It absolutely depends on the material AND the design.

And there are even more durable materials - it depends on the environment (temperature, humidity, pressure forces, acidity, rapid temperature changes) in which they need to perform.

Thanks for the answers. I wanted to know if these printers were suitable to produce usable parts. Now I think I'm gonna buy one soon.

On the subject, you guys think a PETG subframe could be designed to support 300+ lbs from 4 attachment points?

My original intent was to use internal aluminum tubing, but if I can make something that's totally printed, that would be great.

stick with the aluminium. cheaper and stronger.

You probably could make it from pet. But pretty sure aluminium would be cheaper and easier to use.

petg while stiff, is Nowhere near as stiff as aluminium. You would get way too much flex.

300lbs ?
what the hell are you making

A subframe for a motorcycle. I only weigh about 220, add another 10-15 lbs with gear, and then assume there will be bumps in the road.

I still intend to print the bulk of it, just reinforce it with aluminum. It will all be visible, and custom is cool. Plus I need to do up all sorts of brackets and stuff for wires, tail light, various electrical control bits, battery, and all that.

I see no problem just designing it with a channel all the way around to just drop in square aluminum tube from the bottom, then have the printed part just "sit" on top of it.

Reacher, yes, 3D printing has its strengths to create unique parts for end-use.
Mechanically it's about half as good in performance an injection molded part.
Even a cheap Wanhao printer can get you started to develop functional parts, with the right settings parts will come out great.

Avoid making 3D printed objects that will hold effort. 3D print parts seriously have creep issue, they will creep much faster than conventional injected mold.

Further, you can buy the best filament and still have shitty bonding issue. It's easy to screw around with ABS/PLA, if your controller board fail and print at low temperature, you are pretty sure parts will delaminate eventually.

I wouldn't ride a motorcycle whose frame was FDM printed in plastic. Hit one of those "bumps in the road" too hard and you're vulture meat. But maybe I'm just over-particular about my personal safety; you can do what you want...

Frame, no. Subframe, absolutely.

That's why the original intent was to brace it with tubing, so the weight is fully supported by the tubing and the rest is just for looks and holding light weight components in place.

you probably could get away with the petg - but just for cmmon sense I'd still use the aluminium reinforcement.
not worth taking risks with your life :-)

playing with the colorfabb xt/petg this afternoon

Motorcyclists are stupid though.

Well there is that.

I print mostly ABS which is plenty strong as long as I pay attention to two things:

Layer adhesion = printing at as high of temp as I can get away with and slightly over extruding.

Design = if I really need strength I'll divide a part in two pieces and print each at a different orientation and then glue the part together, the strength gain is sort of like what you get with plywood which is glued together at alternating grain patterns.

Well.... why not use 3D print as a sacrificial model. I would love to put carbon fiber tissue on it and resin vacuum it. You won't be able to argue with the results.

Quote:

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Originally Posted by Ama-fessional Molder

A subframe for a motorcycle. I only weigh about 220, add another 10-15 lbs with gear, and then assume there will be bumps in the road.

I still intend to print the bulk of it, just reinforce it with aluminum. It will all be visible, and custom is cool. Plus I need to do up all sorts of brackets and stuff for wires, tail light, various electrical control bits, battery, and all that.

I see no problem just designing it with a channel all the way around to just drop in square aluminum tube from the bottom, then have the printed part just "sit" on top of it.

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A couple of observations:
First, if you have a design payload of 250lbs, I think you need to design for 500-750 lbs minimum. That "bump" in the road could easily cause a 2G force making you weigh 500lbs for a moment.
FDM printing is inherently weak in certain directions as it is dependent on the tensile and shear strength of the interlayer bond, which is significantly less than that of most of the materials we use.
Tensile strength along the build's Z axis is almost non existent except for very large areas.
Compression directly along the build's Z axis will perform at or near the material specifications where directly supported, however, the beam strength (i.e. bending resistance between supports) is also reduced due the the weak interlayer bond.
IMO, FDM (at least with our hobby machines) is not suitable or safe for any kind of structural requirements in the ranges you need. It would be fine for enhancing the aesthetic appeal of an otherwise strong and well built aluminum structure that is properly designed to support all the loads.
Graham

Yeah, that's pretty much what I assumed.

It's the terminator/wolverine principle. Flesh is weak, indestructible interior alloy skeleton - much better :-)

Aardvark said orientation you print makes a huge difference. I can't stress that enough. Something so simple. Let's say I print a link in a chain and I print it standing up, bottom to top will be a far weaker link if I printed the the link laying flat on the print bed. Printing it laying flat will have the layers in the direction of the stress.