Yes and no: No, no one I'm aware of has tried using DC motors and cameras instead of steppers to control a printer.
But yes, industry uses optical technology in large CNCs all the time. Some homing switches are physical clicky switches, some are inductive proximity sensors, but an optical 'horseshoe' througbeam/fiberoptic sensor is the standard for highly repeatable sensor-based homing. Depending on your control system, homing to a hard stop by measuring motor torque can also be highly effective, then you don't even need switches.
I've personally worked on a number of CMMs (coordinate measuring machines, basically a CNC with a probe tip for checking that something was machined within tolerances instead of a spindle for actually cutting it) that use 90V DC motors and Heidehein glass scales for positioning. We calibrate them using laser interferometers; another optical technique - just with a single beam. Those same CMMs are being phased out across the industry in favor of optical measurement systems, just because they're faster.
Shane of the excellent "Stuff Made Here" Youtube channel recently made a big CNC painting robot that did optical tracking for a coarse positioning stage and used steppers for the local stage: https://youtu.be/osUTMnDFV30
But yes, industry uses optical technology in large CNCs all the time. Some homing switches are physical clicky switches, some are inductive proximity sensors, but an optical 'horseshoe' througbeam/fiberoptic sensor is the standard for highly repeatable sensor-based homing. Depending on your control system, homing to a hard stop by measuring motor torque can also be highly effective, then you don't even need switches.
I've personally worked on a number of CMMs (coordinate measuring machines, basically a CNC with a probe tip for checking that something was machined within tolerances instead of a spindle for actually cutting it) that use 90V DC motors and Heidehein glass scales for positioning. We calibrate them using laser interferometers; another optical technique - just with a single beam. Those same CMMs are being phased out across the industry in favor of optical measurement systems, just because they're faster.
Shane of the excellent "Stuff Made Here" Youtube channel recently made a big CNC painting robot that did optical tracking for a coarse positioning stage and used steppers for the local stage: https://youtu.be/osUTMnDFV30