Thanks for the replies —- More info
The project will be an electronic lead-screw for my Myford lathe.
This will develop in several distinct stages
- Rev counter and display. 60 tooth rotor and optical sensor on spindle using a mega for higher number of control button interrupts and digital pins using a mega
- Variable speed Leadscrew driver steppper driver to give a set speed for fine feed ( simple pulse calculation) using a uno
- Varying the speed of Leadscrew to be auto variable relative to the speed of spindle rotation thus staying constant per rev Using pulses from the spindle rotor and integrating this in the uno being used as the stepper pulse generator, fed with data from the mega
- Develop both input controls and display to give pitches for screwcutting and needing an accurate start pulse from an additional single spindle optical for consistent tool positioning for each cut
It is the screw cutting which needs the highly accurate pulsing The early development for a fine feed (typically 2 to 10 thou per spindle rev) will not need such a critical control, but Attaining this will be a crucial development task.
However, This is where the accurate pulse rate will be required, the 1642.6 Hz equates to cutting a pitch of 26 tip at 200 rpm, 3.33 Rev’s per second, with an 8 tip Leadscrew and a 200 stepper with 8 micro-steps. I.e the drive system will need 12.8 steps on the Leadscrew to move 1 thousandth of an inch, 26 tip equates to a pitch of 38.5 thou therefore needing 492.8 pulse steps per spindle rev to deliver
I have found many references to this type of system, but no real meat details
Tachometer and lcd driver circuits and sketches are common
At the moment, it is a question of overall strategy rather than circuits and sketches. No drivers or steppers have yet been researched except those I used for a CNC miller conversion These stages as outlined above and can be classed as sub-systems which will function in their own then integrated to work as a complete unit but the core is all about delivering accurate frequency of pulsing for the driver, resulting in the request about the possibility of using a tone for the pulse output