Drill systems with coolant delivery arrangements and methods

Abstract

There is provided a drill tool assembly for drilling metallic or other materials, comprising a holder having a mounting slot in which a cutting insert is positioned, and a through tool coolant supply system. The drilling tool system allows for the application of coolant to the rake surfaces of the cutting insert in a manner which facilitates enabling higher penetration rates while maintaining integrity of the cutting edges of the cutting insert. The drilling tool system comprises a holder having a rotational axis and mounting slot. A cutting insert with sides positioned adjacent the side surfaces of the mounting slot and cutting edges extending from the rotational axis is mounted in the slot. The insert includes rake surfaces adjacent the cutting edges that are positioned above the mounting slot. At least one coolant channel is disposed with at least one coolant outlet directed at the sides of the insert at a position below the rake surfaces. The coolant outlet is configured to disperse coolant in a curtain across the entire rake face of each cutting edge.

What is claimed is: 
     
         1 . A drilling system comprising,
 a holder having a rotational axis and first and second clamp arms with side surfaces forming a mounting slot,   a cutting insert with sides positioned adjacent the side surfaces of the mounting slot and cutting edges extending from the rotational axis of the cutting insert and rake surfaces adjacent the cutting edges, the cutting edges spaced from the top of the first and second clamp arms when the insert is mounted in the mounting slot,   wherein the holder comprises at least one coolant channel disposed through the first and second clamp arms with the at least one coolant channel oriented at an angle to one of the sides of the insert and having an outlet positioned below the rake surfaces of the insert, wherein liquid coolant supplied to the at least one coolant channel exits the outlet and is dispersed in curtain across the entire rake face of each cutting edge after the liquid coolant impinges on the side of the insert from the at least one coolant channel.   
     
     
         2 . The drilling system of  claim 1 , wherein the outlet of the at least one coolant channel is formed at the interface between the sides of the mounting slot and sides of the insert, to cause turbulence and fringing of liquid coolant out of the outlet to create larger dispersion of the liquid coolant. 
     
     
         3 . The drilling system of  claim 1 , wherein the outlet of the at least one coolant channel is formed to cause fringing left and right of the liquid coolant when exiting the at least one coolant outlet. 
     
     
         4 . The drilling system of  claim 1 , wherein the outlet of the at least one coolant channel is formed as a non-circular outlet that causes fringing left and right of the liquid coolant when exiting the at least one coolant outlet. 
     
     
         5 . The drilling system of  claim 1 , wherein the liquid coolant has reduced flow rate upon impinging the side of the insert that causes turbulence at edges of the outlet of the at least one coolant channel to increase fringing left and right of liquid coolant when exiting the at least one coolant outlet. 
     
     
         6 . The drilling system of  claim 1 , wherein the outlet of the at least one coolant channel is positioned to disperse liquid coolant toward a chip as it is formed at the cutting edge at the top of the rake surface to promote chip segmentation through thermal shocking of the chip at the rake surface by the directed liquid coolant. 
     
     
         7 . The drilling system of  claim 1 , wherein the outlet of the at least one coolant channel is formed to disperse liquid coolant toward a chip as it is formed at the cutting edge at the top of the rake surface to provide lubricity and coolant flow around the area adjacent the cutting edge, minimizing re-cutting of chips and causing evacuation of chips from the rake surface adjacent the cutting edge after segmentation of a chip during cutting. 
     
     
         8 . The drilling system of  claim 1 , wherein the outlet of the at least one coolant channel disperses liquid to impinge the fusion interface of the chip being formed at and just away from a cutting lip adjacent the cutting edge on the rake surface. 
     
     
         9 . The drilling system of  claim 1 , wherein the cutting edges are at a predetermined spaced distance from the outlets of the at least one coolant channel on each side of the insert. 
     
     
         10 . The drilling system of  claim 1 , wherein the coolant channel in each of the first and second clamp arms are supplied by at least one coolant supply channel formed through the holder, and the at least one coolant supply channel has a larger diameter than the at least one coolant channel in each of the first and second clamp arms such that the velocity of the liquid coolant increases as it is supplied to the at least one coolant channel in each of the first and second clamp arms. 
     
     
         11 . A drilling system comprising a holder having a rotational axis, a cutting insert attachable to the holder with cutting edges extending from the rotational axis at the top of the insert when attached to the holder, wherein the holder comprises at least one coolant channel extending toward each side of the insert with an outlet positioned to direct coolant at each of the sides of the insert at a position spaced from the cutting edges, wherein the coolant spreads on the side of the insert to impinge upon the interface between the chip of material being formed along the length of the cutting edge. 
     
     
         12 . The drilling system of  claim 11 , wherein the outlet of the at least one coolant channel is formed to disperse liquid coolant toward a chip as it is formed to minimize the re-cutting of chips and causing evacuation of chips from the cutting edge after segmentation of a chip during cutting. 
     
     
         13 . The drilling system of  claim 11 , wherein the coolant supply channels are dimensioned to supply a predetermined volume of liquid coolant and directed to disperse the volume of liquid coolant against the side of the insert at an angle to create the curtain of coolant. 
     
     
         14 . The drilling system of  claim 11 , wherein flow of coolant from the at least one coolant supply channel is directed from an offset position relative to the cutting edge to promote and not disrupt the flow of chips from the cutting edges into flutes in the holder after they are formed. 
     
     
         15 . The drilling system of  claim 11 , wherein the at least one coolant channel for each side of the insert have outlets disperse the coolant directly onto the fusion boundary of a formed chip from an offset angle to the cutting edge. 
     
     
         16 . The drilling system of  claim 11 , wherein the outlet of the at least one coolant channel is formed to cause fringing left and right of the coolant when exiting the outlet. 
     
     
         17 . The drilling system of  claim 11 , wherein the outlet of the at least one coolant channel intersects the top of the side surfaces of the mounting slot. 
     
     
         18 . The drilling system of  claim 11 , wherein the position of the initial impingement of coolant on the sides of the insert from the outlets of the coolant channels is a distance from about 0.2 to 1 inch from a rake face formed adjacent each cutting edge. 
     
     
         19 . A drilling system comprising a holder having a rotational axis and chip evacuation flutes, a cutting insert with cutting edges extending from a rotational axis of the insert and rake faces adjacent the cutting edges, wherein the holder comprises at least one coolant channel to each side of the insert when mounted with the holder, with the at least one coolant channel having an outlet positioned to direct coolant at each of the sides of the insert below the cutting edges from a position offset from the flute formed in the holder to flow substantially flat across the face of insert to the cutting edge on each side of the insert, so that formed chips during cutting flow over top of the coolant flow and into the flute for effective discharge. 
     
     
         20 . The drilling system of  claim 19 , wherein the outlet of the at least one coolant channel is positioned adjacent the flute associated with each cutting edge at a predetermined spacing from the cutting edge.