Surface finish after milling a mold ?

[Shizzlemah]

Hi guys. I am looking to mill a couple of molds for wax injection (investment casting) for a couple of personal projects.

How fine of a finish should I shoot for out of the mill, before polishing?

Currently I am using VisualMill which lets me specify a remaining 'scallop' height and finishing with a .125" ball end mill. I've run a few test cuts but I was wondering whats a reasonable amount to polish by hand? Cycle times are really going up as the finish gets finer.

I guess at what point is it faster to finish polish by hand than have an ultra-fine finish out of the machine?

[rjshreiner]

Remaining scallop height ....... Ask yourself some common sense questions. How are you planning to polish the mold? Is the grit size of the polish or sandpaper bigger than the scallop height that you are talking about. How will you polish to leave yourself a smooth finish and not just knock down the tips of the scallop along with the valleys. Would it be easier to post treat the wax with very controlled heat to smooth the wax before putting it in the slurry.