this post was submitted on 10 Jan 2024
3 points (100.0% liked)

3DPrinting

15595 readers
100 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: [email protected] or [email protected]

There are CAD communities available at: [email protected] or [email protected]

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
 

Why are 3D printers still stuck on stepper motors? Why haven't we transitioned to servo motors with encoder feedback for positioning?

Is it just too cost prohibitive for the consumer-level? We would be able to print a lot faster and more accurately if we had position feedback on the axes. Instead we just rely blindly on the stepper not skipping any steps when we tell it to move, hoping for the best.

you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] -1 points 10 months ago (1 children)

I disagree with all your points. What kind of servos are you talking about?

BLDC and AC servos maintain full torque at stop too, and have about 2-3× the torque of a stepper of similar size.

The only way a stepper can rival a servo for precision is with a high degree of microstepping, which is far from guaranteed positioning with open loop control.

I haven't directly compared response time between steppers and servos, but I would be extremely surprised if there's a significant enough difference to worry about. Most servo-controlled machines are larger and so are designed to accelerate slower than a printer, if that's what you mean. This is intentional because inertia is a thing you have to worry about, not because the servo reacts to command changes slowly.

There are valid reasons steppers are used on printers, but it's not because they have superior performance.

[–] [email protected] 1 points 10 months ago* (last edited 10 months ago)

BLDC and AC servos maintain full torque at stop too, and have about 2-3× the torque of a stepper of similar size.

Huh, this is true about BLDCs as well? I remember seeing in a video that BLDCs tend to have very poor torque output when stopped and especially when at low speeds (due to very low efficiency requiring too high currents for drivers to supply), whereas AC motors have a pretty much flat torque curve until they get fairly fast. I'd be interested to know if this is true.