4 ms·
To be fair, most hobby CNC tools were opened looped until more tools came out that were BLDC + zero cross detection for speed control. That being said, stalling
by syntaxing 3y ago
To be fair, most hobby CNC tools were opened looped until more tools came out that were BLDC + zero cross detection for speed control. That being said, stalling your tool more or less means you’re just blindly cutting a part. Calculating the correct feed rate is absolutely essential for any router/milling operation.
- dheera 3y agoInstead of open loop calculations, why not just actually measure the current (or motor RPM) and do a feedback loop?
- syntaxing 3y agoMixture of motor technology, cost, and application. Take a dremel for instance, adding all these features cost money and most dremel users won’t care for it. Also certain motor technology makes it impossible to control in a meaningful fashion. If you stuck an encoder on a dremel, you’ll still have a lot difficulty maintaining the set RPM.
- dekhn 3y agothat doesn't give you step-level accuracy. Some systems do this- for example Prusa MK3 and newer don't have physical endstops, instead they monitor current. And FluidNC supports this but clearly points out you shouldn't use it for step-level accuracy.
- numpad0 3y agoSimple voltage control for spindle motors and open loop stepping motors for everything else is just precise enough and most cost effective for hobby machines. Closed loop is technologically superior but ultimately not necessary. (note: "sensorless homing" and sensorless BLDC are different things)