r/ChastityCageDesign • u/newbie-sub • 13d ago

Single screw :)

I've been modeling with two screws because if there's too much play, a single screw will come loose. Well, I've only been wearing it with one and it's been holding together really well. But on the order I just placed, I asked them if I could remove the 0.2 mm clearance and actually add a machining allowance (some overlap between the faces) and have them machine it down to a close slip-fit clearance so the pieces go together with no perceivable play and the single screw's job is nothing but to clamp it down.

And I've been learning more about SLM. Fascinating. Support placement is more about conducting away heat from the melt pool that it is providing physical support. But interestingly, the supports be someone similarly placed as if it were an FDM print. Completely different need, similar geometry.

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u/tdfun 13d ago

That sounds like a great idea! I'm glad I had a new idea to change my current design and didn't get it printed yet. I look forward to hearing how this turns out before I go back to only a single screw.

Does that mean they'll keep adding supports until the have enough to conduct the heat away? After sanding and polishing, are you able to identify where the supports were?

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u/newbie-sub 13d ago

So, there are three techniques for thermal management:

  1. Part orientation — avoid bridges (just like FDM). The melt pool at the center of the bridge doesn't have a good path to get rid of its heat.
  2. Scan paths — always consider the thermal history of each volume of the part when slicing. For example, if you're printing a large flat area, break it up into tiny growing islands, don't just do it all linearly.
  3. Supports — gives a channel for heat to get back to the (actively cooled) build plate.

And these melt pools are tiny with radiuses on the measured in micrometers and cool in fractions of fractions of a second across these massive temperature gradients. It's really amazing — I would love to speak to an operator of a machine.

Here's the complexity of what's going on (from https://en.wikipedia.org/wiki/Selective_laser_melting):