Thursday, November 5, 2015

Cutting Angles With Millie

I mentioned yesterday that I was rewriting my angle cutting program to do diagonals in gcode instead cutting a series of horizontal steps.  The result left something to be desired.

The stripes are not cosmetic.  I used a ball nose mill, and yet the other 45 degree angle was from a square end mill: actually smoother.


Will said...

It's not clear to me what you are trying to do.
A ball end mill is intended to impart a radiused cut, either between two angled surfaces to eliminate stress risers, or a groove, like fluting a gun barrel to lighten it and add a bit more surface area for cooling.

Clayton Cramer said...

I was trying to cut a diagonal, and I had been led to believe by a friend that a square end mill would leave steps. It doesn't.

Will said...

There are specialty milling bits that have different profiles. You may find one with a beveled edge, or a taper, to match the angle you need.

The common method would be to mount the part so it can be milled flat, or angle the head, if that isn't possible. Another option would be to mount the part so the cut would be vertical, so it could be done with the side of the bit. This would be done better if you could align it with the X or Y axis, so you don't have to deal with the possible inaccuracy's of your cnc angle plotting. Better finish, if nothing else. Well, that's if you can turn a bit that is large enough to have the needed bit length/extension.