Finally convinced that a belt-driven Z-axis wasn’t a good Idea because it didn’t hold its Z-position – and thus laser focus – firmly enough while positioning the toolhead… I’ve simplified the X-carriage plate and mounted the new BB-bearing, printed screw-driven, V1 stepper-slider. That, in turn, carries the Eleksmaker 2.5W laser module and danowar’s laser air-assist shroud that I’ve used with this laser module on several machines in the past.
The printed Z-axis slider assembly uses BBs for bearings and works surprisingly well…
The inexpensive (< $2) hobby stepper is hard to take seriously but with a simple unipolar to bipolar conversion actually works quite well for this application. The blue plastic cover is pried loose to expose the small PCB inside…
and the wide central trace is cut to disconnect the middle nodes of the two coils. The red wire is then snipped/removed from the 5-wire bundle…
and the four remaining wires rearranged in the connector to match the stepstick driver pinout… in this case, orange-pink is one coil, yellow-blue is the other.
The air-assist shroud gives a stronger air stream using a small radial fan and printed shroud…
The laser lens focal length (about 55mm) can be adjusted, if necessary, with the ridged nozzle
and fine-focus is acheived using Ryan’s focus script.
The two Charles Bronson image engravings and profile cuts used the exact same gcode file… before (right) and after (left) installing the air-assist shroud.
I’m pretty happy with this machine now and doubt I’ll make any more drastic changes… miniFR lives!
– David