I have designed this model: enter image description here

My goal is to make it static, no vulnarable to shakes. The pitch is 40 mm with 4 revolutions. The dimensions of the 'wire' are 5x5 mm. Which settings for printing should I use to archieve hardness? I plan to make the wire 5x10 mm height, 4 walls, 0.28 layer height, 0.5 nozzle size. PLA. I don't know if this is overkill or it will be useless.

I hope you can give me suggestions about printing settings and model dimensions. I know that's spring design, which is made to be springy but I need it for other use.

Second design. Less springy, but not by much. My last hope is to print it horizontaly. enter image description here

  • $\begingroup$ Can you clarify the 5x5 and 5x10 figures? Is this cross section of the spring with planes through z axis? Which is z direction and which is radial? $\endgroup$ Oct 10 '20 at 21:11
  • $\begingroup$ Also, note that with the many bounraries in the polymer, printed springs other than coil springs are exceptionally weak. $\endgroup$
    – Trish
    Oct 10 '20 at 23:42
  • $\begingroup$ I added picture of the second design with 5x12 spiral. $\endgroup$ Oct 11 '20 at 2:44
  • $\begingroup$ What are you actually trying to do here? “Hardness” is not usually a spring characteristic. $\endgroup$
    – fectin
    Oct 11 '20 at 20:30
  • 1
    $\begingroup$ I'm trying to do this: aliexpress.com/item/627016197.html $\endgroup$ Oct 11 '20 at 20:45

If you want an helicoidal object which acts relatively rigid, you should pick a plastic which is very rigid to begin with. In the case of 3D printing, probably PLA is the best choice. Make it as thick as you can in all the directions where you have no constraints.

Still, it's an object which will be hardly printable without dissolving support material. You need a two material 3D printer if you want to get good results.

  • 1
    $\begingroup$ You might manage with Tree Support $\endgroup$
    – Trish
    Oct 12 '20 at 15:37
  • 2
    $\begingroup$ This answer is good for the question as asked, but possibly not for what OP actually needs. The clarifying comment that this is a vending machine auger indicates that ability to bend/compress by a few mm is unlikely to be a problem, and OP really should be asking about how to ensure it's not brittle/subject to breaking apart at the layers. $\endgroup$ Oct 12 '20 at 15:46
  • $\begingroup$ @Trish: Yes, tree support excels for things like this. Doing your own support structure would also be an option. I'd probably do it as an internal-threaded cylinder around the outside with sawtooth thread profile for the helix to rest on top of, with a few splits in it to make separation easy. $\endgroup$ Oct 12 '20 at 15:58

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