in reply to %3rIPwlZ...

awesome thanks for the expert feedback @bobi!

One option to consider is some sort of pusher operated by a reciprocating metal ‘sawtooth’ of the correct pitch. This would give very precise incremental moves of the beam, with no risk of accumulated error.

i think i understand the concept, but i'm having trouble visualizing how this would operate in practice. is it possible to draw a diagram or is there a photo online of a similar concept? i realize i probably should have done this for my own conceptual model, but sounds like you got the idea.

This is low-tech and robust

this seems to rely on a custom part, the pusher chain. where would you find such a part? also is an air ram easy to find and use? that seems high-tech (at least in comparison to an electro-mechanical linear actuator that basically a motor plus a screw) but i'm new to everything here, i'll admit smart sensors and dumb motors are my default strategy. (%C4NTs6hbODYTK393SQK/EKbKDxdyIrWKen2+JhTgk4Q=.sha256)

How fast do you want this thing to go, and what is your max beam length?

not too worried about speed, as long as it's not terribly slow, as can parallelize if need be. initial max beam length is 2.4m (standard ceiling height), but eventually would want to produce longer beams.