is there a way to get bobcad or mach3 to punch holes instead of drilling?
Ron Hess

Could easily get Mach to do that as all you would need to do is command a rapid Z move but as for making the code in BOBCAD, afraid I dont have a clue as I have never used it.
Hood

I tried  using mach for punching holes in foam but I was using an air solenoid controlling a linear slide to control the punch (annular cutter really) held in a collet.   Just a simple X/Y table with a brain that fired the output to the solenoid every time the Z DRO was less than zero, and retracted the solenoid when Z was greater than zero.  Worked pretty well actually but I ended up going to a heated cutter.

ASC
i would like to use a air cylinder to pierce light tin. what type on control valve are you using? i am new at this cnc so all the help you can offer would be a great help. is there any examples of how punching is accomplish? you mention to use brain,what is this and how would i use it?
Ron Hess

I just used a 24volt smc solenoid to fire the actuator down.  The actuator has a spring return.

Brains are similar to plc ladder logic, you give them a set of input conditions that control various outputs.  Check out the Mach tutorial videos for more info on how to set them up. 

My brain acted something like this:

If Z = Less than zero then turn relay output 1 on

If Z = Greater than zero then turn relay output 1 off