DonW
R.I.P.
Its sort of a pain. You have to draw just a bunch of circles and join them together otherwise arcs want to make a tight corner that obviously a round tool cant cut. If that makes any sense.
So a keyhole consist of two big circles to make the slot, one little circle to make the end of the slot and another circle for the bolt head end. Then you join all the intersections and delete the un needed arcs. Then of course you cant use drill points on a cnc router, you have to use a tiny 1/8 mill and cut the #7 hole for the 1/4 20 bolts in a circle instead plunging like you would with a regular mill. The oring grooves are another issue. You cant cut on a line you cut inside it or outside it. The cam will see it as a pocket rather than a groove so the grooves have to be third drawing. So basicly it takes 3 files to make one flange. Then you have to edit the TAP file so the cutter goes the other directions otherwise the acrylic burns and melts. Before you can do any cutting there needs to be a fixture file because the acrylic need to sit in a pocket because there is no place for the vacuum chuck to hold it down after its been turned into a ring with holes. Since your changing the shape you need a second fixture for the bottom part of the flange. Since your doing a fixture change you need a fixture pocketed and indexed for the first two fixtures. Once you have all these files put together and the fixtures made you can make a 10" flange in about 5 minutes. This is one of the reasons one off cnc work is so expensive.
Don
