Patent ID: 8142119
Filing Date: 2012-03-27
Classification: B23C,B23G,Y10T

Abstract:
1. A method of orbital milling using an orbital milling machine for cutting openings in a workpiece, said machine comprising: a tool holder being configured and disposed to receive and hold a milling tool therein; a milling tool comprising a shank portion and a cutting portion and having a central rotational axis; said milling tool being held in said tool holder by said shank portion; said tool holder comprising a drive mechanism to rotate said milling tool about said central rotational axis; said central rotational axis of said milling tool being spaced a distance from a second axis, said second axis being one of: a central axis of said tool holder and a central axis of a hole being cut by said milling tool to permit orbital milling; said cutting portion having a first end joined with said shank portion and a second end disposed opposite said first end; and said cutting portion comprising: at least one roughing cutting edge disposed at said second end; a plurality of finishing edges disposed adjacent said first end; a plurality of semi-finishing edges disposed between said at least one roughing cutting edge and said finishing edges; said at least one roughing edge and said semi-finishing edges being connected and axially spaced apart by a first transition section; said semi-finishing edges and said finishing edges being connected and axially spaced apart by a second transition section; and the maximum diameter of said cutting tool at said semi-finishing edges being larger than the diameter of said cutting tool at said roughing cutting edges and smaller than the diameter of said cutting tool at said finishing edges; said finishing edges each comprising a substantial portion being curved; said method comprising the steps of: advancing said milling tool substantially axially into a workpiece to cut an opening therein; cutting the workpiece with said at least one rough cutting edge, and substantially simultaneously revolving said milling tool about the second axis in an orbital path; advancing said milling tool substantially axially further into the workpiece; cutting the workpiece with said at least one rough cutting edge and said semi-finishing cutting edges, and substantially simultaneously revolving said milling tool about the second axis in an orbital path; advancing said milling tool substantially axially yet further into the workpiece; cutting the workpiece with said at least one rough cutting edge and said semi-finishing cutting edges, and substantially simultaneously cutting a curved surface in the workpiece with said substantial, curved portion of each of said finishing edges and finishing the interior side surfaces of the opening with said finishing cutting edges, and substantially simultaneously revolving said milling tool about the second axis in an orbital path; and one of (A) and (B):