The speed of the stroke varies according to where you are in any given
revolution. At the ends of the stroke the speed is zero (it's reversing).
Maximum speed occurs in the center of the forward and reverse stroke (at
90 and 270). At those points the speed of the stroke is equal to the
rotational speed of a circle who's speed is 22/7 ths (pi) times the length
diameter of the stroke times the number of revolutions every minute.

I wish I had one!

edd

natarajan ayyavu wrote:

Dear Sirs:

We have installed a Gear Shaping machine (model: similar to Lorenz
LS400). We would like to operate at 20 mpm cutting speed while cutting
internal splines. The intruction manual says:
cutting speed = pi * stroke length * strokes per minute / (1000)

(note, here stroke length = spline length + approach + over travel)

I do not understand why greek pi (value = 3.1428) presents in this
formula
when the cutter does not follow a circular motion. Here the cutter
follows a reciprocatory movement and shifted for relief by about 0.5mm
away from cutting surface. To my understand, I think the formula must
have been
cutting speed = 2 * stroke length * strokes per minute / (1000)

Can anyone explain why "pi" is considered in the formula.

Awaiting your help

with best regards

N. Ayyavu