Mult. rough diameters controls the use of multiple roughing tools and is specified as a list of diameters separated by commas. The last diameter is also used for the finish pass. If you want FeatureMILL to select the tool to use for the final roughing pass, set the last Tool Diameter to 0.
Your Mult. rough diameter list should work its way gradually down to the desired finish tool. One way is to let the system pick the tooling initially, then set up your diameter list to work gradually toward the last value. If the system recommends a 0.125 inch endmill, set your Tool Diameter attribute to “1.0, 0.5, 0”.
By default, FeatureMILL creates one roughing and one finish pass for all of the milled features. If you use multiple roughing tools, FeatureMILL cuts all the parts of a feature that it is capable of cutting with the larger tool, and cuts only the remaining portions of the feature with the smaller tool. You do not have to manually create these separate regions. FeatureMILL automatically calculates them for you.
For cutting pockets or bosses, FeatureMILL automatically selects a single tool diameter for roughing and finishing. For a large feature with small corner diameters, this method results in a small tool cutting the middle of the pocket and wastes time. A better strategy uses a larger tool for the wide areas and a smaller tool for the tight corners.