Upgrade Name: AC Spindle control
Description: Shield that allows turning an AC spindle on-off through gcode.
This is designed for an AC run Dremel-like tool so it doesn't allow spindle direction control. Since the pin that is used (Digital 10) in the stepper shield configuration can be used for PWM, this shield can support in the future spindle rotation speed control. Speed control is not supported currently by GRBL.
The shield is single sided to allow easy milling with the ShapeOko. Optionally the top side of the board can be used as an additional heatsink for the triac but it must be milled to isolate the main voltage from the circuit. The triac was put in a horizontal manner to save space and allow this to be stacked below the Stepper Shield. It also includes a screw terminal connected to the reset line to allow adding an external reset button to an enclosure.
Link to schematic and board in Eagle format, bill of materials, and optimized Gcode.
Forum discussions and examples
- http://community.carbide3d.com/t/can-you-control-router-power-using-gcode/3079/16 --- example from the Carbide 3D forums which shows an annotated image of the board and wiring details.
- Spindle Control
- PID Closed Loop Spindle Speed Control for Quiet Cut Spindle --- includes a graph showing non-linear nature
For single-speed routers/cut-out tools, some users have used a router speed control unit, such as the MLCS 9400 Standard Duty Router Speed Control to slow it down. Forum discussion: Re: DW660 Mods. Note that such units are simply a resistor which reduces the current, reducing torque --- only suitable for single speed motors. The VFDs actually tie into the electronic speed control, include a device to measure the current RPM, and will adjust current to maintain the desired RPM as torque requirements fluctuate when cutting.