Apparatus and method for hybrid machining a contoured, thin-walled workpiece

A method of hybrid machining a workpiece, comprising the steps of:

• rotating a cutter made of an electrically conductive material and having a non-conductive abrasive material;
• electrically powering a turbine blade and the cutter with a power supply;
• circulating a coolant between the turbine blade and the cutter, the coolant containing one or more additives for increasing electrical discharge between the turbine blade and the cutter;
• positioning the turbine blade relative to the cutter at a first predetermined depth of cut;
• moving the cutter relative to the turbine blade in a roughing pass machining operation in which material is removed from the turbine blade at a relatively high rate using a high-speed electro-erosion (HSEE) process when the power supply provides a first differential electrical potential and the coolant circulates at a first flow rate and a first pressure;
• and
• moving the cutter relative to the turbine blade in a finish pass machining operation in which material is removed from the turbine blade using precision electro-grinding (PEG) process when the power supply provides a second differential electrical potential and the coolant circulates at a second flow rate and a second pressure, wherein the first pressure is in a range between about 100 psi to about 400 psi, and wherein the second pressure is less than about 200 psi.

A method of hybrid machining a workpiece, comprising the steps of:

• rotating a cutter, the cutter made of an electrically conductive material and having a non-conductive abrasive material;
• electrically powering a workpiece and the cutter with a power supply;
• circulating a coolant therebetween, the coolant containing one or more additives for increasing electrical discharge between the workpiece and the cutter;
• positioning the workpiece relative to the cutter at a predetermined depth of cut;
• moving the cutter relative to the workpiece to remove material from the workpiece in a roughing pass machining operation in which material is removed from the workpiece at a relatively high rate using a high-speed electro-erosion (HSEE) process when the power supply provides a first differential electrical potential and the coolant circulates at a first flow rate and a first pressure;
• and
• moving the cutter relative to the workpiece to remove material from the workpiece in a finish pass machining operation in which material is removed from the workpiece using precision electro-grinding (PEG) process when the power supply provides a second differential electrical potential and the coolant circulates at a second flow rate and a second pressure, wherein the first and second flow rates are in a range between about 5 gpm to about 50 gpm.