end mill cut - how

I just can't figure this out and I'm sure someone has done this before.
Assume you have a flat faced endmill and the the corners have a radius (not
a ball nose). The end mill is plunged into the work piece (perpendicular to
a flat surface) and as it is plunging it is traversing. The endmill is
always perpendicular to the origainal flat surface. I hope I'm just in brain
fade here and the answer is painfully obvious.

 

Perhaps the answer is obvious.....but the question isn't.

 

What does the path look like? If it is straight or a simple arc this
can be done with moderate difficulty using a sweep with additional
guide curves.

 

Alan,

The fillets on the sides of the cutter aren't a real problem, using a
sweep with a profile that matches the cross section of the cutter should
do it. The way I would do it would be to make a planar 2D path to drive
the traverse and a projected curve used as a guide curve to drive the
plunge. This will keep the sweep section perpendicular to the path,
which is what it sounds like you want.

One of the problems with trying to simulate cutter paths in SW is the
fact that you can't create features which self intersect. A cutter path
done as a cut sweep will defintely overlap if you're clearing a face,
but may be ok if you're just maching a groove or something.

The tough part with something like this is actually the flat bottom face
of the cutter. If the cutter is ramping down so the axis is parallel to
Z at all times, the bottom of the cut will be kind of scalloped. The
face cut by ramping is not flat because the bottom of the cutter is
parallel to the top of the workpiece, not angled at the angle of the
ramp. This isn't impossible to make in SW, but it's difficult enough to
hardly be worth the bother.

good luck

 

I believe this part has the correct geometry for the type of machining
you are doing.

http://www.vidanay.com/Dave/EndMill.SLDPRT

SWX2006 SP4.1

Dave

 

Correction. The first model was not correct. I have revised and
uploaded again.

If you already downloaded, try again.

Dave

 

Alan,
You have not asked a complete question. What is the actual shape
(path) of the milled slot that you are looking for?
The factors here are: the speed and depth of the plunge, versus the
speed of the table traverse. The two extremes are: all plunge, no
traverse yields a round milled (drilled) hole, the diameter of your
cutter. (very much like the demonstration by Dr. Salvador). Small depth
plunge, all fast traverse, yields a flat milled slot, the width of
your cutter, the depth of your plunge, with fillets equal to the size
of the radii ground at the corners of the milling cutter. The radius,
or angle of the "milled slot" that you are looking for can be
calculated with trigonometry and calculus.

G. De Angelis
De Angelis Tool
www.deangelistool.com

 

Anything other than the two extremes of cutting condition stated by G.
De Angelis
results in a trough with a curved bottom regardless of the path shape
provided that any combination of plunge and traverse is present.
Remember, the back edge of the cutter is always gouging the area where
the traverse path just came from. The radius and depth of the curved
bottom in the trough increases as plunge rate overtakes traverse rate
until the curve becomes the full cutter diameter (ie a hole).
,