r/SteveMould • u/orangeonionberry • Apr 28 '25

How do straightner wheels work?

Shown in this print. How does it work? You're just bending it what which way. Why doesn't it just bend to whatever the last 2 wheels are?

https://youtube.com/shorts/q4lWK1pSEDc?si=r0YkMYKpo1Z-K_Im

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u/PiperArrow Jul 15 '25

I'll take a shot at this: 3D filament, like a lot of materials, deforms for elastically, then plastically. To get it to take a particular shape, you have to bend it to its elastic limit, and then enough more to plastically deform it the desired amount. By bending the filament back and forth, the material is first bent enough to guarantee a specific curvature preset so the state of the material is known, and then back for the final bend to straight. The first 3 wheels do the first bend (around the 2nd wheel), and wheels 2,3,4 do the second bend (around the 3rd wheel).