Rotary cutting tool with enhanced coolant delivery

Abstract

A rotary cutting tool includes a main body, a shank portion having a rearward end, and a flute portion having a forward end with one or more flanks. One or more connecting fluid holes are in fluid communication with a central fluid hole and terminates at a flank at the forward end of the cutting tool. One or more twisted fluid holes extend through a lobe in the flute portion and terminates at a flank at the forward end of the cutting tool. A cross-sectional shape of the connecting fluid holes and the twisted fluid holes is selected to provide enhanced delivery of fluid to the cutting edge. In one aspect, the rotary cutting tool is a modular drill and the flute portion has a pocket for holding a replaceable cutting insert.

1 . A rotary cutting tool, comprising:
 a main body;   a shank portion having a rearward end;   a flute portion having a forward end with one or more flanks, the flute portion having a plurality of flutes separated by lobes, the flute portion integral and adjacent the shank portion in an axial direction of the main body;   a central fluid hole extending along a central, rotational axis, RA, from the rearward end, through the shank portion, partly into the flute portion, and terminating at a predetermined distance, DT, from the forward end;   one or more connecting fluid holes in fluid communication with the central fluid hole and terminating at a flank at the forward end of the flute portion for supplying fluid to one or more cutting edges of the flute portion; and   one or more twisted fluid holes extending from the rearward end through the shank portion, through a lobe in the flute portion, and terminating at a flank at the forward end of the flute portion for supplying fluid to one or more cutting edges of the flute portion,   wherein a cross-sectional area of the central coolant fluid hole is larger than a cross-sectional area of one or more of the twisted fluid holes;   wherein the central coolant fluid hole has a non-circular cross-sectional shape; and   wherein each of the twisted fluid holes has non-circular cross-sectional shape.   
     
     
         2 . The rotary cutting tool of  claim 1 , wherein the one or more flutes are formed with a helix angle, HA, with respect to a center rotational axis, RA, of the rotary cutting tool. 
     
     
         3 . (canceled) 
     
     
         4 . A rotary cutting tool, comprising:
 a main body;   a shank portion having a rearward end;   a flute portion having a forward end with one or more flanks, the flute portion having a plurality of flutes separated by lobes, the flute portion integral and adjacent the shank portion in an axial direction of the main body;   a central fluid hole extending along a central, rotational axis, RA, from the rearward end, through the shank portion, partly into the flute portion, and terminating at a predetermined distance, DT, from the forward end;   one or more connecting fluid holes in fluid communication with the central fluid hole and terminating at a flank at the forward end of the flute portion for supplying fluid to one or more cutting edges of the flute portion; and   one or more twisted fluid holes extending from the rearward end through the shank portion, through a lobe in the flute portion, and terminating at a flank at the forward end of the flute portion for supplying fluid to one or more cutting edges of the flute portion,   wherein a cross-sectional area of the central coolant fluid hole is larger than a cross-sectional area of one or more of the twisted fluid holes, and   wherein one of the one or more connecting fluid holes and one of the one or more twisted fluid holes emerge in the flank at the forward end of the flute portion.   
     
     
         5 . A rotary cutting tool, comprising:
 a main body;   a shank portion having a rearward end;   a flute portion having a forward end with one or more flanks, the flute portion having a plurality of flutes separated by lobes, the flute portion integral and adjacent the shank portion in an axial direction of the main body;   a central fluid hole extending along a central, rotational axis, RA, from the rearward end, through the shank portion, partly into the flute portion, and terminating at a predetermined distance, DT, from the forward end;   one or more connecting fluid holes in fluid communication with the central fluid hole and terminating at a flank at the forward end of the flute portion for supplying fluid to one or more cutting edges of the flute portion; and   one or more twisted fluid holes extending from the rearward end through the shank portion, through a lobe in the flute portion, and terminating at a flank at the forward end of the flute portion for supplying fluid to one or more cutting edges of the flute portion,   wherein a cross-sectional area of the central coolant fluid hole is larger than a cross-sectional area of one or more of the twisted fluid holes, and   wherein the central fluid hole has a triangular cross-sectional shape, and wherein the one or more twisted fluid holes has a different non-circular cross-sectional shape than the central fluid hole.   
     
     
         6 . The rotary cutting tool of  claim 1 , wherein the central fluid hole has a triangular cross-sectional shape, and wherein the one or more twisted fluid holes are “D-shaped” in cross section. 
     
     
         7 . The rotary cutting tool of  claim 1 , wherein the rotary cutting tool comprises a drill. 
     
     
         8 - 14 . (canceled) 
     
     
         15 . The rotary cutting tool of  claim 4 , wherein the one or more flutes are formed with a helix angle, HA, with respect to a center rotational axis, RA, of the rotary cutting tool. 
     
     
         16 . The rotary cutting tool of  claim 4 , wherein the central fluid hole has a non-circular cross-sectional shape, and wherein the one or more twisted fluid holes have a non-circular cross-section shape. 
     
     
         17 . The rotary cutting tool of  claim 16 , wherein the central fluid hole has a triangular cross-sectional shape, and wherein the one or more twisted fluid holes are “D-shaped” in cross section. 
     
     
         18 . The rotary cutting tool of  claim 4 , wherein the rotary cutting tool comprises a drill. 
     
     
         19 . The rotary cutting tool of  claim 5 , wherein the one or more flutes are formed with a helix angle, HA, with respect to a center rotational axis, RA, of the rotary cutting tool. 
     
     
         20 . The rotary cutting tool of  claim 5 , wherein the one or more twisted fluid holes are “D-shaped” in cross section. 
     
     
         21 . The rotary cutting tool of  claim 5 , wherein the rotary cutting tool comprises a drill.