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by Animats 3331 days ago
ShopBots, the big CNC routers, use big steppers with closed loop control, and get considerable power and speed out of a small motor without missing steps. Tormach CNC mills are stepper-driven without feedback; the motor is powerful enough and geared down enough that missing steps isn't a problem.

Steppers do consume full power when not moving, of course, so they're not favored for battery powered systems.

1 comments

The Tormach CNC actually uses a special driver that can detect missing step without feedback.
Shopbot has a closed loop stepper on some models [1], but Tormach says they don't.[2] Tormach just has a big enough stepper and enough gear reduction to avoid missed steps by brute force.

[1] http://www.shopbottools.com/mProducts/ShopBotdesign.htm [2] https://www.tormach.com/technical_questions.html