I'm trying to come up with an efficient way to complete two operations in 304 stainless steel. The part is .250" thick, 1.5" wide, and close to 3" long, milled square on all six sides with a lot of detail work. It's a part my company produces in rather large numbers, and until I started looking for ways to improve the production, they had a guy make them on a manual Bridgeport. Most of it is a cakewalk, but the two operations that are stumping me are the following:
Top of the part: Two .125" wide grooves with radius bottoms that are 2" long and about .030" apart.
Bottom of the part: 1.944" radius with its center 1.874" off the part, located in the center of the long dimension and expanding the entire width.
I'll start with the bottom first. I've tried setting the part on its side and plunging both a boring bar and a fly cutter down to cut the radius, but I couldn't keep my cutting edge from chipping and dying. Speeds and feeds had no effect on the tool life, so I assume the interrupted cut and inconsistent pressure is the issue. I'm thinking about laying it down flat and trying a G19 G03 arc subroutine with a ball endmill while stepping over, but I'm not sure about speeds and feeds.
For the slots on top, I'm thinking about a ball endmill with either a high feed ramp subroutine or a simple flat cut and step down sub, but not sure on the speeds and feeds there either because I haven't had the opportunity to work much with solid carbide tools and ball endmill chip loads specifically.
Didn't mean for the post to end up so long. Thanks for any insight you guys can provide. Oh, and I'll be doing the job on either my HAAS VF-2 or my VF-4.