3D printed bushings

[The Wind Breezes]

So I have a 3d printer and have been printing some stuff in TPU which is basically 95A durometer polyurethane. I may print some bushings for the 1. Has anyone else on this forum done this? I know some people have tried it, but Google results are few and far between.

Here is a link to the filament I'm using, although I prefer to print in the colored versions:
https://www.amazon.com/HATCHBOX-TPU-.../dp/B01LVWK4L3

[ShocknAwe]

Rear subframe similar to akg would be interesting if the price was right.

[The Wind Breezes]

Material cost is not very high at all, the print time is the bigger issue although these aren't really precision parts by 3d printing standards so I can probably use as big a layer height as possible or even get a bigger nozzle for my extruder to decrease the time. Even so production volume would be low enough that these would just be for my personal use unless I get an army of printers! lol

OK, I looked up the AKG bushings...$270 for 8 individual pieces. I could do all that from one roll of filament easy.

Does anyone have dimensions on these bushings? If so I can make some in cad and start printing and we can get this experiment on the road!!

[d k]

Please keep us posted!

[Suprgnat]

I am concerned that the resulting material will not have the same homogeneity as have cast/extruded pieces.

Please test carefully.

[The Wind Breezes]

Yeah, that's always an issue with 3d prints. The TPU adheres layer-to-layer a lot better than anything else I've printed though.

How about this? If anyone gets me measurements for some bushings on the car, preferably rear subframe but I'll take any, I will send you a 3d print of that bushing you got me the specs for. Or alternatively I can 3d print something else cool for you, like an octopus, pangolin, tower of pi whatever you want within reason.

[fe1rx]

A 3-D printer strikes me as one of those "if the only tool you have is a hammer, then every problem looks like a nail" tools. Why make something that is readily available (urethane bushings) and better and more economically made with other technology (casting)?

I guess the problem is that after you have made an octopus, a pangolin and a tower of pi, what the heck do you do with one? Like an adjustable wrench, how can a tool that looks to be so useful, actually be so useless?

[The Wind Breezes]

Sounds like you're jealous and need a 3d printer. Well, we use the printer for prototyping at my work. It's amazingly useful for that. We've cut product development times hugely cuz previously we were getting SLAs made in china, then shipped over, then we would look at them and get another SLA made. The resolution on the FDM printer is good enough that we can do 99% of our prototypes on it, no need for resin cured prints.

Casting your own bushings isn't a terribly simple process. 3d printing them is. You spend 5 minutes in cad, 5 minutes telling the printer to make them, and wait a little while.

[WhatsADSM]

I own a printer as well but personally I would be a little worried about putting 3d printed parts in use in a structural setting like that. A failure of those bushings would be bad and personally wouldn't be worth my safety or the safety of others. Another point to note is that there is a need for a reasonably precise steel bushing as well which is what the fastener goes into.

[WhatsADSM]

Oh yea one last note. Assuming you have a reasonably capable printer setup you can also print POM (Delrin), but again not sure I am comfortable with any of this.

[tracer bullet]

Originally Posted by The Wind Breezes

Sounds like you're jealous and need a 3d printer.

With his shop and tools at his disposal, I wouldn't be surprised if he has one. Anyhow, at work, I have access to and use (for work) several varieties of 3D printing and completely agree with him. It's a good prototyping tool, and can make useful parts at times, but is in no way suited for making automotive bushings.

[The Wind Breezes]

Guys, if this happens, it's not going on some random car. It will go on MY car first, and I accept responsibility for whatever happens. I understand failure is a possibility.

Thanks for the info on Delrin filament. I hadn't considered that, and will order some to investigate how it prints.

I'm pretty comfortable with the strength / homogeneity of the printed TPU. It fuses a lot better than anything else I've printed with. For everyone complaining about those qualities, have you actually printed in TPU or are you basing your experience off printing in ABS / PLA / PETG?

[WhatsADSM]

Originally Posted by The Wind Breezes

Guys, if this happens, it's not going on some random car. It will go on MY car first, and I accept responsibility for whatever happens. I understand failure is a possibility.

Thanks for the info on Delrin filament. I hadn't considered that, and will order some to investigate how it prints.

I'm pretty comfortable with the strength / homogeneity of the printed TPU. It fuses a lot better than anything else I've printed with. For everyone complaining about those qualities, have you actually printed in TPU or are you basing your experience off printing in ABS / PLA / PETG?

Not to turn this into a 3d printer forum but really with an fdm (fff) printer nothing is truly isotropic. There are always voids in a part. PETG, PLA and TPU have similar layer adhesion in my experience. Better than abs certainly but it's still an fdm printer part, there are limitations.

FWIW this site did some experimentation and suggests PLA actually has the best layer adhesion of all the standard (non-exotic) materials:
https://www.3dhubs.com/knowledge-bas...rials-compared

If you do this. Again remember there needs to be a steel bushing used for the fastener I believe some other kits use steel rings where they face against the chassis as well. When you print the part you will want to print it on its sides with supports. This sucks because of the supports however it will place the z-lines parallel to the fastener and perpendicular to the forces that will want to rip them apart. Ideally do this with a dual extruder and PVA or HIPS support material to dissolve and still provide accurate print resolution.

My suspicion is that, honestly, it might actually work (I think people are just immediately dismissive here) but it is just to risky for me to do when there are great solutions out there for a reasonable cost already.

Edit: Here is a picture of the Whiteline kit. Note the required metal parts. Also note the price (under $160 for a kit to your door).
https://www.amazon.com/gp/aw/d/B00BED6TAW/

[WhatsADSM]

Well written article on FDM versus SLA printers when it comes to isotropy:
https://formlabs.com/blog/isotropy-in-SLA-3D-printing/

It's really a shame that the uv-resin world isn't nearly as supported as the filament world. Especially when it comes to engineering grade materials. Once the materials get there I will move to SLA (DLP). Would love an SLS machine as well but the cost/material choice just isn't there yet either.

[The Wind Breezes]

Yeah I understand about the metal insert. And I know even the TPU print isn't homogenous, I just think it may be "good enough" cuz it does fuse pretty well. We'll see, I guess.

Oh, I love the resin curing printers. Our business is seasonal and we've already spent a shitload of money this year so we can't budget it at the moment but now that we've proven how useful a FDM printer is I'm hopeful we can buy a UV cure printer in a few months. I'd like to get both laser and DLP ideally, but I'd probably go with laser first if I had to choose, just because of the flexibility and resolution.

[ianc]

Guys, if this happens, it's not going on some random car. It will go on MY car first, and I accept responsibility for whatever happens.

Unless the failure causes you to lose control and you take someone else out in the process. How you gonna rationalize that?

ianc

[The Wind Breezes]

Originally Posted by ianc

How you gonna rationalize that?

If you think your own driving is so flawless and safe as to justify that high horse, you're a liar or an extremely boring person. Really, God help us all if I'm driving that hard, that fast, around other people on public roads, bushing composition notwithstanding.

On a related note, I got some ABS prints shear tested yesterday for an unrelated business application by a professional lab using Instron equipment and the numbers were unexpectedly impressive. Really, that makes me more interested in getting these printed. I'm not super worried about the integrity under compression either...ask me about the TPU prints I ran over with my 10,000 lb forklift.

[ianc]

If you think your own driving is so flawless and safe as to justify that high horse, you're a liar or an extremely boring person

I'm asking you to consider the consequences of experimenting with parts whose failure might potentially be very damaging to others, not only yourself.

These little enforced vacations you keep periodically taking are not really teaching you much about how to play nicely with others, are they?

ianc

[fboutlaw]

As an engineer in a division that deals a lot with plastics, adhesives, process, etc. Please don't endanger yourself by using 3D printed parts as structural final goods. The whole point of different durometer bushings is to have one homogeneous structure with one property. 3D printing will give you one part with infinite different structural properties, the polymer chains won't fully link layer to layer, and you'll have something immensely unsafe. To fully form polymer chains, you need to mold the whole thing at once, and control the insert pressure, temperature, venting, and then control the cure profile to ensure that you've actually linked 95%+ of the polymer chains.

Buy engineered parts. Stay safe. You'll not only be a threat to yourself, but to others when your bearings break apart. That's where I draw the line.

There's only 1 3D printing company I know of (Carbon3D) that can actually make legitimate final goods due to their extraction method and custom polymers made for a continuous cure... but they are still sub-par to standard materials cast properly in a die.

Obviously this hits a nerve with me, as an engineer, and a BMW CCC instructor who's had many part failures at bad times. You're asking for trouble.

[The Wind Breezes]

Originally Posted by ianc

ianc

Your criticism is noted. If you really want to continue the discussion, you can private message me for my phone number and I'll be happy to talk to you. Continuing to serves no constructive purpose and is clogging up an otherwise interesting thread.

Originally Posted by fboutlaw

As an engineer you're asking for trouble.

Noted. As above, I'm available for discussion privately if you really care.

[Suprgnat]

Originally Posted by The Wind Breezes

Your criticism is noted. If you really want to continue the discussion, you can private message me for my phone number and I'll be happy to talk to you. Continuing to serves no constructive purpose and is clogging up an otherwise interesting thread.



Noted. As above, I'm available for discussion privately if you really care.

I'm confused. You start a discussion:

Originally Posted by The Wind Breezes

Has anyone else on this forum done this? I know some people have tried it, but Google results are few and far between.

but when the responses are generally negative, you want to take it private? Sorry, there is no upside to this idea. (At this date and time) 3-D printed bushings (at least the ones you propose) are a bad engineering decision. Negative ROI at best, someone suffering at worst.

I think fe1rx nailed it:

Originally Posted by fe1rx

A 3-D printer strikes me as one of those "if the only tool you have is a hammer, then every problem looks like a nail" tools.

Obviously, I'm very confused. Why did you start this thread, again?

[The Wind Breezes]

Originally Posted by Suprgnat

Obviously, I'm very confused. Why did you start this thread, again?

The notion that this is a bad idea has been raised more than once, and the same reason WHY it's a bad idea--3d prints not homogenous enough, in an extremely unlikely scenario someone could be hurt or killed if the bushings fail--has been promulgated over and over. If someone has new ideas, critical or positive, they are welcome in the thread. I understand the risks and consequences, and I'm not deterred. Rehashing the same old arguments when I've acknowledged them is not going to accomplish anything. That's why I asked them to take those discussions private: they've run their course, as far as I'm concerned, and a back-and-forth will do nothing for this thread.