18

I am woking on making solar panel mounts for the roof rack of my nissan xterra from TPU, since it can take a beating. Does any one have any experience with 3d-printed TPU threads? And how much stress before it can take before a bolt rips out? Also should i use teflon thread seal so the a bolt won't come loose?

you are viewing a single comment's thread
view the rest of the comments
[-] cmnybo@discuss.tchncs.de 14 points 7 months ago

I would through bolt the TPU and use a large washer on each side. Teflon lubricates the threads making it easier to turn. You want thread locker to keep a bolt from coming loose. Be careful with the thread locker since it eats many types of plastic.

[-] IMALlama@lemmy.world 9 points 7 months ago

Agree with all of this. Relying on the walls of TPU to hold threads in place doesn't seem like a great idea.

[-] Excrubulent@slrpnk.net 6 points 7 months ago* (last edited 7 months ago)

Yup, assuming the solar panels will be in the wind, potentially at highway speeds, absolutely do not rely on TPU threads for that. Threads rely on stiff material to transmit the forces from the angled faces of the thread into linear forces. Anything flexible will rip out very easily. It's shocking how fast a rubber material - even a firm rubber - gives up when real force is put onto it. It's like it's not even there.

The through bolt idea is pretty good. It should be easy enough to make a spool shape out of the TPU that will work as a shock absorber. Honestly even then I'd keep an eye on it to make sure it's not getting ripped up.

EDIT: I was curious how to quantify the difference, so I found this datasheet which shows the difference between the stiffness of rubbers, particularly polyurethane, which is what TPU is, and steel:

https://www.ansys.com/content/dam/amp/2021/august/webpage-requests/education-resources-dam-upload-batch-2/material-property-data-for-eng-materials-BOKENGEN21.pdf

You're looking for Young's modulus, which is 1.3 - 2.1 GPa for polyurethane, and 190-220 GPa for the various steels. Steel is hundreds of times stiffer. And for the threads to fail, they don't need to be damaged, just shift out of the way enough to slip past each other.

[-] jkrtn@lemmy.ml 2 points 7 months ago

Not to mention 3D threads will not be the right cross-section. It won't be face to face contact.

this post was submitted on 25 Mar 2024
18 points (90.9% liked)

3DPrinting

15527 readers
91 users here now

3DPrinting is a place where makers of all skill levels and walks of life can learn about and discuss 3D printing and development of 3D printed parts and devices.

The r/functionalprint community is now located at: !functionalprint@kbin.social or !functionalprint@fedia.io

There are CAD communities available at: !cad@lemmy.world or !freecad@lemmy.ml

Rules

If you need an easy way to host pictures, https://catbox.moe may be an option. Be ethical about what you post and donate if you are able or use this a lot. It is just an individual hosting content, not a company. The image embedding syntax for Lemmy is ![](URL)

Moderation policy: Light, mostly invisible

founded 1 year ago
MODERATORS