Can i PWM a solenoid?

Community General Discussions
1

My CNC router (2D) tool lift function is controlled by a solenoid, which lifts the tool when powered, and releases the tool when not.

I have recently started using these nice little 0.2 mm tungsten carbide bits, however while machining a piece of copper plate the other day, the dropping of the tool onto the work piece caused the very fine bit to snap off. I was able to re set the tool height and use the now slightly shorter and therefore wider (1mm) bit.

My question to you is: is it feasible to use PWM to soften the lowering of the tool?

I dont imagine that i would be able to control tool height this way (i am considering one day removing the solenoid and replacing it with a tool lift servo to allow this), however if i was able to reduce the solenoid power from 12V down to 0V over one or two seconds, rather than instantly, the tool might not freefall as dramatically and stand a chance of penetrating the work piece without busting.

iirc, the solenoid is controlled by the original transistors, which i am switching using an arduino. There are some pictures on my "Franken CNC" "something else" post.

 

2

PWM & Solonoid

I see no reason why not. I am assuming that the tool “down” force is supplied by an electro/mechanical device. Could that force be lessened? Are you sure you can cut with .2mm tools?

3

It pulls it up under power,

It pulls it up under power, and i think down is on a spring, or just gravity (it has on and off, not up or down, if that makes sense)

i have just run a sketch that analog writes 0 - 255 in ±5 increments with a 30ms delay between each.

It cycles up and down,and while you can hear the PWM whine as it cycles through, it still just bangs, Up, Down, As before, if a little weaker

maybe ill take it apart some time and see if it can put a linear servo in instead