PP3DP, makers of the popular Up! personal 3D printer announced they’re upgrading their filament feeder in a significant way. Their original feeder involved a DC motor and mechanical switch, which limits the accuracy of prints as the DC motor takes a while to start up and spin down when electricity is applied. This means you’re not extruding immediately when you start printing and you don’t stop extruding when you should stop. The quality of the print suffers slightly because of this. However, the new version of the feeder will include not only a stepper motor to replace the DC motor, but also a micro switch. This should significantly improve the quality of prints.
Most of the personal 3D printer makers have now switched from DC to stepper motors for extrusion, and all have had terrific improvements in quality. We’d say this is now pretty much a standard if you want to sell a 3D printer.
Via PP3DP
The original dc motor was only used to prefeed the filament from the spindle into a tube so that he extruder motor (which has always been a stepper) did not have to try to pull the filament from the spindle. It was not a bowden extruder like in the ultimaker. The tube was only used as a mechanism to have a length of filament unrolled from the spindle. A stepper motor in this role doesn't have much advantage in this role, I'd think. Likely it was just easier to have the same motor used everywhere to simplify material sourcing/supply
The original dc motor was only used to prefeed the filament from the spindle into a tube so that he extruder motor (which has always been a stepper) did not have to try to pull the filament from the spindle. It was not a bowden extruder like in the ultimaker. The tube was only used as a mechanism to have a length of filament unrolled from the spindle. A stepper motor in this role doesn't have much advantage in this role, I'd think. Likely it was just easier to have the same motor used everywhere to simplify material sourcing/supply