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I'm making a plotter for drawing pcb designs on copper clad board.
I'm planning on using rails from a 3D printer for the 2D drawing plane and smaller vertical rails to raise and lower one of 4 pen holders.
The thinnest pen I'm using is 0.2mm, so that's the target resolution. Accuracy trumps speed in this application.

I'm going to use an ESP32 as the controller/WiFi.
My work area will be 400mm X 400mm.
I plan on writing the software myself.

Should I use continuous rotation servos or stepper motors and why, please?

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Either one will work. Servos are closed loop, you turn them on until they move to a position based on feedback from a sensor (usually encoder). Steppers are open loop, you provide steps and they move based on those steps (but you never really know if the motor got there, if an axis bound up the software would keep executing commands even if the motors were bound up.)

I would probably go with steppers, most software and controllers for axis control (with gcode) is built to work with steppers.

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  • \$\begingroup\$ Exactly what I was looking for. An encode can be as simple as a wheel with holes paired with a light and receiver, so I can add that to a stepper too? I plan to write the software for the esp32 in arduino and the computer driver in python. With me writing the software would your answer still be the same? I guess it's a question of accuracy and responsiveness. \$\endgroup\$
    – Mikeologist
    Commented Jul 2, 2021 at 19:56
  • \$\begingroup\$ Yes, encoders can be added to steppers, the problem is you then have to deal with the encoder input and not all axis control programs support closed loop with an encoder. But if you can find one with the capability then that works. I have only dealt with open loop control with axis control, and used encoder to verify the axis is moving but not to actually send the motor to a position. \$\endgroup\$
    – Voltage Spike ♦
    Commented Jul 2, 2021 at 19:58
  • \$\begingroup\$ Assuming both had encoders and software is not an issue, is there a merit of one over the other in this application? \$\endgroup\$
    – Mikeologist
    Commented Jul 2, 2021 at 20:00
  • \$\begingroup\$ Maybe, if you have microstepping and an encoder then you might get more resolution. It all depends on the accuracy of the stepper and encoder. \$\endgroup\$
    – Voltage Spike ♦
    Commented Jul 2, 2021 at 20:01
  • \$\begingroup\$ That's what I was looking for. I can choose a stepper motor, encoder, and stepper based on my resolution needs. Thanks for your time. \$\endgroup\$
    – Mikeologist
    Commented Jul 2, 2021 at 20:04

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