Most 3D printers to this point are open loop. Stupid devices, if I send a code to move one unit forward I assume it happened. No encoders. They mark 1 axis limit by an endstop switch and assume the distance the opposite direction with a small safety margin. A new chipset out allows the noise in stepper motors to report back over a communication channel. The motor is able to tell if it had a problem and act accordingly. This is really just getting implemented on the 3D printer side. This is a slick low tech way to cope with this.
Stepper motors with actual encoders are Expensive > $150 per motor.
While 3D printers look like Laser cutters and CNC routers they can be worlds apart. One is additive manufacturing and the others are subtractive manufacturing. They can use motors, servos or stepper motors.
While I have been aware of stepper motors for a long time, I’ve just recently built a project using them and H-bridges.
In general there are some very different things going on with your “tool” . For a router we are switching a spindle on or off - Binary. With a laser you are usually using PMW to tell the Laser how much power to output. In a Printer Extruder you are pushing and pulling material back and forth constantly like a syringe to cause varied pressure during deposition.
On a 3D printer there is a test where you take a know quantity of material and use it all. You observe how far it goes and how fast, feed and speed, and adjust until you get the use of a know quantity over a know time and space.
All of these processes have 1 thing in common - gcode. Relative motion, speed and feed.
I will leave you with this. This is example is not a 3D printer but a use of 3D printing. An artist created his own extruder and made it work. He is using 3D printing as a medium for his art. I don’t know how he put together the software. It is one of my favorite 3D demos.
I have considered endstops on the Maslow but I think keeping it simple is best, I like it as it is. We measure, test adjust.
Thank you