I think I've discovered a "glitch" in which I can't see that there is anything wrong with my part, but the Solid Sweep fails to produce the correct geometry. The material is a 50 mm cylinder in which I wish to revolve a cutter around to produce a helical spiral groove with a decreasing radius as it moves along the part.
About the only thing I can see that might glitch up Solidworks is that the cutter ends up overlapping itself at the begining - which in real life is not a problem because the cutter just ends up passing over an area that already has material removed.
The problems I see are as follows:
This is at the start of the sweep. The arrow indicates a double-line which should not be there. The circled area looks like an area where SolidWorks just "gave up" and decided not to do anyhting for a revolution.
A section view of the part should reveal the profile of the cutter, should it not? In this image you can see the area circled does not match the profile of the tapered end mill - the upper surface is curved.
This is the end of the sweep. This geometry does not make sense... It looks like a mess.