Re: [CAD_CAM_EDM_DRO] Calculating mechanical forces

>
>
>In a message dated 8/1/2005 7:27:09 PM Eastern Daylight Time,
>johnatl@... writes:
>
>I'm looking for formulae for calculating the forces while machining
>various materials.
>For example, if I want to use roundways and linear bearings for my Y
>axis,
>and I want to cut mild steel with a 2" fly cutter at some SFPM, and
>some feed per revolution,
>I want to find the force on the Y axis. That way I can find the size
>parts I need for
>a certain capacity and a certain life span.
>
>

The way I did this was to calculate the torque when spinning the cutter at
the appropriate SFPM for steel and consuming the motor's rated HP at
that speed. Then, I converted that torque to linear force at the radius of
the cutter. A 2" diameter fly cutter would presumably have a 1" tip radius
when set to exactly 2" dia, making the calculation easy. With HSS and
mild steel,
you run about 100 SFPM, or 190 RPM at 2" dia. Assuming a 1 Hp motor,
this would deliver a torque of [550 ft-Lb/sec / ((190/60)(rev/sec) * 2
Pi) ] =
27.6 Ft-Lb = 332 in-Lb. So, at a radius of one inch, the force on the
cutter tip
would be 332 Lbs! Think your round ways and linear bearings can keep the
machine within it's tolerances with 332 Lbs of force? Well, maybe you
have a
smaller motor.

Jon