In article ,
natarajan ayyavu wrote:
:
: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)

For suitable units (stroke length in mm, cutting speed in meters/min),
the formula in the manual gives the _peak_ cutting speed for a cutter
whose velocity varies sinusoidally. The formula you suggest would be
correct for a cutter whose velocity was constant during the stroke and
with an instantaneous reversal at each end.

--
Bob Nichols AT interaccess.com I am "rnichols"