New design for a CNC engraver/etcher/scratcher ... ???

santy wrote:

Oh, so Z axis only serves the purpose of probing the material. The rest is done via spindle output.

No and no, there is no Z axis, there is a pressure servo.

santy wrote:

I assume the Z output from the Gcode signal is script-converted into a S1 - S1000 signal to drive the pwm out.

Again no, although this works, it causes way to much vibration due to start/stop to change spindle speed.

santy wrote:

Can you post your files?

Of course, see the second post.

santy wrote:

Not sure how to handle the table flattening probe.

I have no idea what this is about? There is no probe and there is no flattening of granite/marble/glass material, they are flat, always.

Added this to printables.com , finally !
www.printables.com/model/876702-diy-cnc-...ng-logos-etc-o/files

I am not in the shop now, but in short, the "pressure" motor is
-a 3 phase BLDC motors with it's own electronic controller taken out of the old photocopiers,
-there are many versions and sizes of them,
-form 5 to 10 pins,
-all signaling is sinking type or "active low", meaning connect to ground to activate
-all have the pinout printed on the board,
-older ones are pure PWM while new ones require also a clock signal,
-some are single direction while some are bidirectional,
-and most of them can be easily used for this purpose/machine,
--The PWM ones require 5V, 12-24V and an inverted PWM signal
--The ones requiring clock signal have a self check feature, so mostly work with only 12-24V supply and one of the pins tied to ground, this pin will spin the motor for about 2 second and stop, and has to be disconnected and reconnected to spin again. This pin is used as inverted PWM but scaling must be set to about max 85-95% PWM to keep the controller from tripping and stopping the motor after 2 seconds.
--for inverting the PWM pin i use a single 220 OHm resistor and a single transistor, any NPN transistor works, resistor connected between base of transistor and PWM output from PC or Mesa board.
-
hackaday.io/project/5236-savin-c2020-teardown