Re: [CAD_CAM_EDM_DRO] Re: More on servo motor selection

From: <ym_wong@...>

> However, this does raise a question.. how does the spindle horsepower
> come into the equation? Can someone elaborate on that?

Power requirement for milling -

hpc = cim/K

Where:
hpc = horsepower at cutter
cim = metal removal rate in cubic inches per minute
K = a factor reflecting the efficiency of the metal cutting operation

The K factor for Aluminum is 2.5 - 4.0, depending on grade.

Using the before mentioned 1.5 cu. in./min, and the high end of
K factor for Aluminum, we get :

hpc = 1.5 / 4.0 = .375 or
3/8 horsepower at the cutter.
Due to losses within the machine, 1/2 hp is indeed a good starting point.

Now, to move the table by itself, not accounting for any cutting, you need
to
calculate the forces required.
I have an Excel spreadsheet that you can just plug you variables into for
this.
If anyone is interested, I can post it.
I would have done so earlier, but figured
everyone's already been through this before me.

After you've done that, you need to calculate the tangential forces of the
cutter
resultant from its being applied to the material.

I tend to over-calculate these forces so that I don't come up short later
on.

Hope that helps,

Weyland