I just wanted to share a few pictures of my latest project here in the ME shop. This is an aluminum fuselage bladder mold for the Design Build Fly team (DBF) here on campus. They will be laying up pre-preg carbon fiber sheets and clamping the two halves together under heat then inflating the bladder to maintain the features of the mold. They brought me $860 of aluminum and $350 worth of tooling.
The bottom mold was a lot of fun for the first 3". I was able to take a 2.75" depth cut with a 3/4" roughing ball end mill at 22.5 IPM and 0.1" step overs. Past 3" it gave me trouble since I had to reach down so far, ~3.8". Even a 1" ball end mill with a 4" length of cut presented issues with rigidity, but once the roughing was completed it went great.
For the finishing operation I used the Scallop 3D milling strategy with 0.007" stepovers, took about 23 hours to finish. It needs almost no finishing, right out of the mill.
The top half of the mold was much simpler, just because we only had to go to a max depth of ~2.5". I also used Scallop with 0.007" stepovers for the finishing on the top, took about 18 hours.
This also came out very nice, minimal finishing outside of the mill.