Freesteel Blog » Scallop bisector flowers

Scallop bisector flowers

Monday, April 27th, 2009 at 2:28 pm Written by:

Just to prove I’m doing a little bit of work on this, here’s what I get from scallop bisectors when I give a bisection angle of 5 degrees and a stepover (distance the bisector extends close to the previous scallop contour) of 20% of the stepover.


The little flower in the top left hand corner looks like this:


While in Matienzo I met someone who actually runs machine tools and cuts parts using CAM software of the kind I write.

He wants only smooth passes everywhere, so he’s not particularly excited by choss like this showing up as a result of running the algorithms — whereas I am.

I say:

“Look, it’s made all these amazingly wiggly contorted self-enclosing paths when I put in these inappropriate numbers — and it didn’t crash or hang!”

You can take for granted that the code is reliable. What makes it reliable is that it’s built to work in all these nasty knotted-up cases first, not just the smooth pretty ones. That’s my style. I find that if the worst case is taken care of, then the easy stuff follows without effort.

I’ve seen geometric coding approached from the other direction — do the easy stuff first, and try to generalize it to the harder cases. You get results faster, and can learn as you go along, but it’s not easy to argue that it’s going to fail. But it does, so there’s no need to argue about it now.

The machinist also told me that his customers wouldn’t allow him to use this scallop machining because it left marks at the sharp corners that couldn’t be polished out.

We couldn’t agree on whether these marks were from the rapid changes in direction, or the excess material that’s left there which would be removed by these scallop bisectors.

I guess some cutting trials are now necessary to prove this.

Leave a comment

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <blockquote cite=""> <code> <em> <strong>