Constant Drilling Force

[mcfa001]

Has anyone setup a automated drilling machine that applies constant force during a drill operation.

I'm setting up a machine to do this and i'm contemplating setting up the drill feed axis on an air actuator to ensure the bit experiences constant force.

[underthetire]

Air does not work well. Since the tool will change loads, entering and exiting, you will get a build up of air pressure in the CYl that will release once the drill starts breaking through. This will jam the bit through once the tip penetrates the part. You need something less compressible. Think hydraulic, or air over oil.

Honestly, now days, it may be cheaper to use a stepper motor with something like arduino to control it.

[mcfa001]

i am familiar with the arduino boards as i currently use them to control transportation robots.

How would you control the constant torque on the stepper. from my limited knowledge i thought steppers required step and direction instrustions and you vary the speed by changing the step pulse. Is the torque related to the input voltage on the stepper?

[underthetire]

I believe it would be input current. Voltage would give you speed. I'm a servo guy, not much with steppers.

[keebler303]

Why does the force matter? A stepper wil give you a constant feed which will be pretty close to a constant force.

Matt