Re: Contour Machining, was Optimizing cutting paths

> Date: Sat, 01 Sep 2001 08:50:51 -0000
> From: rab@...
>Subject: Re: Contour Machining, was Optimizing cutting paths, was
>Traveling Salesman
>
>Thanks for the info Fred, your description of the treatment of
>islands is good.
>
>When I've tried to produce a contoured pocket from a series of offset
>toolpaths, the problem arose as to what to do when the toolpath meets
>up with or overlaps itself. Seems to need a way of automaticaly
>detecting and removing the redundant portions of the toolpath.
>

Your observation is correct. The offset curve function in Vector automatically trims any potentially overlapping lines into a nodal point or arc, depending on the nature of the tight spot. It has unlimited lookahead for interference conditions, so that if you had a barbell or hourglass shaped part, it will offset the ends and eliminate any parts of the curve from the waist or "bar" part where the cutter would cut the opposite wall if it cut either side as required. There is no question about cutting a 1/2 inch wide slot with a 5/8 cutter. No tool path can be generated with the offset function.


Because an offset will also arc around a sharp corner, I have had great success in using first a radius, in the wrong direction, then a diameter from the generated offset in the opposite direction to create a contour (either the inside or the outside) for inlay purposes. It immediately solves the problem of having to notch corners with a chisel, as there are none left. Even complex curves forming a point-like or hooked contour will end with a radius no smaller than the size of the cutter. I've been using and studying Vector intensely for over 6 years, and I just stumbled onto this while preparing for one of our classes earlier this year.

It may interest some to know that we first offered a set of three Vector training tapes for Vector version 2.02 to Bobcad in Florida ( who were distributing Vector at the time) in fall of 1997.


Best Regards, Fred Smith- IMService
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