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BECKER, Brian (7881 Harvest Lane, Chanhassen, MN, 55317, US)
JOHNSON, Cody (11215 49th Avenue North, Plymouth, MN, 55442, US)
MARUSICH, Troy, D. (8785 Darnel, Eden Prairie, MA, 55344, US)
BECKER, Brian (7881 Harvest Lane, Chanhassen, MN, 55317, US)
JOHNSON, Cody (11215 49th Avenue North, Plymouth, MN, 55442, US)
| CLAIMS WE CLAIM: 1. A coolant delivery system for directing coolant from a tool holder onto individual flutes of a cutting tool, comprising: a cutting tool having an outer diameter; a tool holder having a bore with an inner diameter; and a collar comprising: a nut portion having a plurality of through holes and a circumferential groove disposed on a back side of the nut portion; a cylinder portion having a bore and at least one groove on a side wall, an outer diameter of the cylinder portion being equal to the inner diameter of the tool holder, and an inner diameter of the cylinder portion being equal to the outer diameter of the cutting tool, whereby the cutting tool is received and retained by the collar, and the collar is received and retained by the tool holder; and wherein the through holes are in fluid communication with the circumferential groove of the nut portion and the groove of the cylinder portion, the groove of the cylinder portion is in fluid communication with a coolant source connected to a back end of the tool holder. 2. The system of claim 1, wherein each of the through holes of the nut portion corresponds to each of the flutes. 3. The system of claim 1, wherein the nut portion includes more through holes than number of flutes. 4. The system of claim 1, wherein the through holes of the nut portion of the collar extend at a certain angle with an axis of the collar. 5. The system of claim 1, wherein the through holes of the nut portion of the collar extend at different degrees towards the individual flutes. 6. The system of claim 1 , wherein the collar rotates with the cutting tool. 7. A method of delivering coolant from a back end of a tool holder onto individual flutes of a cutting tool, comprising: providing a collar having a nut portion and a cylinder portion; placing the cutting tool inside the collar; placing the collar inside the tool holder; placing the tool holder onto a spindle; rotating the spindle; and delivering pressurized coolant from the back end of the tool holder through the cylinder portion to the nut portion of the collar onto each of the flutes of the cutting tool. 8. The method of claim 7, wherein a nut portion includes a plurality of through holes and the circumferential groove disposed on a back side of the nut portion, a cylinder portion having at least one groove on a side wall, wherein the through holes are in fluid communication with the circumferential groove of the nut portion and the groove of the cylinder portion, the groove of the cylinder portion is in fluid communication with a coolant source connected to the back end of the tool holder. 9. The method of claim 8, wherein each of the through holes of the nut portion corresponds to each of the flutes. 10. The method of claim 8, wherein the nut portion includes more through holes than number of flutes. 11. The method of claim 8, wherein the through holes of the nut portion of the collar extend at a certain angle with an axis of the collar. 12. The method of claim 8, wherein the through holes of the nut portion of the collar extend at different degrees towards the individual flutes. 13. A method of cutting a workpiece material, the method comprising: providing a cylindrical body having a cross-sectional diameter and a longitudinal rotating axis, a plurality of teeth disposed on a circumference of the cylindrical body, each tooth having a cutting edge and separated by a flute; making a first tooth cut in the workpiece material by a first tooth of the plurality of teeth; transferring heat generated by the first tooth cut to a topmost surface of the workpiece material thereby allowing a second tooth to cut the workpiece material more easily; making a second tooth cut in the workpiece material by the second tooth while the topmost surface of the workpiece is still soft; providing a tool holder for holding the cylindrical body; and delivering pressurized coolant from a back end of the tool holder onto each of the flutes. |
CROSS-REFERENCE TO RELATED APPLICATIONfS)
The present utility patent application claims priority of U.S. Provisional Patent Application, Serial No. 61/118,166, filed November 26, 2008; subject matter of which is incorporated herewith by reference.
FIELD OF THE INVENTION
The present invention relates generally to a coolant delivery system. More particularly, the present invention relates to a coolant delivery system in a rotating cutting tool which effectively removes chips or swarf from cutting edges and flutes of the cutting tool.
BACKGROUND OF THE INVENTION In a material removal process, such as turning, milling, drilling, tapping and similar operations, material is removed in single or multiple sequences to achieve desired shape and size of a final part. Typically, material is removed by rotating a work piece against a cutting tool, or rotating a cutting tool against a work piece, depending on what type of process is used. The material removed during these processes is generally referred to as chips or swarf. It is known in the art that it is important to keep chips or swarf away from a cutting tool and especially from cutting edges of a cutting tool and/or flutes of a cutting tool. If chips or swarf are not removed properly, these chips or swarf could get clogged between two consecutive teeth and causing the cutting tool to rub against work piece without removing any material. This may result in damage to the work piece surface, breakage of the cutting tool, and/or even damage to a machine tool that rotates the cutting tool in some cases.
Effective application of coolant helps remove chips or swarf away from cutting surface. Coolant could be delivered by various mechanisms and at various flow rates and pressures. Most commonly used coolant discharge methods on a machine includes either or all of following: 1) flood coolant - discharge from around a spindle onto a tool at lower pressures; 2) through-spindle coolant - discharge from inside a spindle flowing out from sides onto a tool; and 3) through-spindle-through- tool - discharge where coolant is supplied through a spindle and through channels inside a tool onto a cutting edge of the tool. The latter two mechanisms offer delivery of coolant at higher pressures of the order from 200 Pounds/Square Inch (PSI) to 2000 PSI. Coolant flow rate can also be adjusted depending on type of coolant pump, but the coolant flow rate is generally in the order of 2 gallons-per-minute (GPM) to 50 gallons-per-minute. These individual methods have their own advantages and disadvantages. In through-spindle-through-tool arrangements, channels need to be made inside the tool material in certain predefined arrangement such that the coolant flows through these continuous hollow path channels and flows out at other end on to the desired area of the tool, thus making the tool body hollow. Examples of which can be found in U.S. Patent Nos. 4,669,933 and 4,795,292 issued to Dye wherein a chuck/tool holder includes continuous hollow path channels, and coolant flows from one end of the tool holder to the other end of the tool holder and onto the desired area of the tool. Similarly, U.S. Patent No. 7,134,812 issued to Beckington wherein a coolant collar assembly includes a tool holder (or referred to as "collar") having hollow path channels, and coolant flows from one end of the tool holder to the other end of the tool holder. This results in reduction in overall strength and rigidity of the tool, and increased tool cost. Also, this through-spindle-through-tool delivery method requires that each cutting tooth or flute have at least one coolant channel for sufficient availability of coolant and effective removal of chips with that coolant. However, there is a limitation on how many channels can be made so that overall performance of a tool is not affected. Therefore, there is a desire for an improved coolant delivery system in effectively removing chips or swarf from cutting edges and flutes of the cutting tool.
SUMMARY OF THE INVENTION
The present invention provides a coolant delivery system in a rotating cutting tool which effectively removes chips or swarf from cutting edges and flutes of the cutting tool. More particularly, the present invention provides a coolant delivery system which directs high pressure machining coolant from a back end of a tool holder onto individual flutes or teeth of a cutting tool whereby the coolant flows through axial grooves of a cylinder portion of a collar, into a circumferential groove in a nut portion of the collar, and onto each flute of the cutting tool through a plurality of holes on the face of the nut portion of the collar. In one embodiment of the present invention, a coolant delivery system comprises: a cutting tool having a longitudinal axis and a plurality of flutes disposed on the outside surface of the cutting tool, and the cutting tool being rotated around the longitudinal axis; a tool holder including a bore; a collar having a nut portion and a cylinder portion, the collar being disposed and retained within the bore of the tool holder, a back end of the cutting tool being disposed within a bore of the collar and retained by the nut portion of the collar, and the cylinder portion of the collar being disposed and retained within the bore of the tool holder; and wherein the cylinder portion of the collar includes a plurality of grooves for delivering pressurized coolant from the back end of the tool holder to the nut portion of the collar, and the nut portion of the collar includes a plurality of holes for delivering pressurized coolant from the collar to corresponding flutes of the rotating cutting tool.
Further in one embodiment of the present invention, each of the holes of the nut portion corresponds to each of the flutes. In another embodiment, the nut portion includes more holes than number of flutes.
Still in one embodiment of the present invention, the collar is made of any suitable material, preferably ferrous material, with an outer diameter equal to an inner diameter of the tool holder, and an inner diameter equal to an outer diameter of the cutting tool. The collar includes a plurality of grooves machined on the inner diameter in the length direction placed at a certain distance from each other. This distance could be the same or different between successive grooves. These grooves open into a circumferential groove on the inner diameter preferably located at the end which is closer to the cutting edge.
In an alternative embodiment, the collar has a circular circumference groove and a plurality of holes located on the front end face of the collar opening into the circular circumference groove. The holes can be made at a certain angle with an axis of the collar or straight at 90 degrees. The number of holes can be the same as number of flutes or teeth or higher. After a cutting tool is inserted into the collar, the collar secured into a tool holder, coolant flowing from through the spindle is channeled through the circular groove into the holes.
The present invention also provides a method of delivering coolant from the back end of a tool holder onto flutes of a cutting tool. The cutting tool is placed inside a collar. Through spindle pressurized coolant coming from the back end of the tool holder is delivered from the circumferential groove of the collar onto each of the flutes of the cutting tool.
It is noted that the size of the holes depend on desired pressure at given coolant flow rate as the pressure depends on the diameter or cross-sectional area of the hole. It is also noted that the holes are preferably circular in shape, but can be different shapes such as square or diamond or any other geometric shape that allows coolant discharge at the desired pressure.
Also, in operation, the collar rotates with the cutting tool, so that high pressure coolant is in fluid communication with the flutes. One of the advantages of the present invention is that tool strength and rigidity is not compromised, tool cost is not increased, and at the same time coolant is applied in an effective manner on each flute or cutting tooth to remove chips from cutting edges and flutes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a perspective view of one embodiment of a coolant delivery system, in accordance with the principles of the present invention.
FIG. 2 illustrates an enlarged perspective view of the coolant delivery system at a front end, in accordance with the principles of the present invention.
FIG. 3 illustrates a cross-sectional view of the coolant delivery system of FIG. 2 having a cutting tool in use.
FIG. 4 illustrates a front end view of the coolant delivery system of FIG. 2. FIG. 5 shows a perspective view of one embodiment of the coolant delivery system of FIG. 1 without a cutting tool and a collar mounted at a front end of the coolant delivery system, in accordance with the principles of the present invention.
FIG. 6 shows a side view of one embodiment of the cutting tool and the collar of the coolant delivery system of FIG. 1.
FIG. 7 shows a perspective view of one embodiment of the collar of the coolant delivery system of FIG. 1 having a nut portion and a cylinder portion.
FIG. 8 shows a side view of one embodiment of the collar of the coolant delivery system shown in FIG. 7.
FIG. 9 shows a perspective view of the cylinder portion of the collar shown in FIG. 7. FIG. 10 shows a bottom view of the nut portion of the collar shown in FIG. 7.
The above drawings and descriptions thereof are to be regarded as illustrative in nature and not restrictive. DETAILED DESCRIPTION
FIG. 1 illustrates one embodiment of a coolant delivery system 100, in accordance with the principles of the present invention. The coolant delivery system 100 includes a cutting tool 102, a tool holder 104, and a collar 106. As shown in FIGs. 1-4, the cutting tool 102 includes a longitudinal axis A and a plurality of flutes 108 disposed on an outside surface of the cutting tool 102. The cutting tool 102 is mounted on a spindle (not shown) and rotated around the longitudinal axis A. The tool holder 104 includes a bore 110. The collar 106 includes a nut portion 112 and a cylinder portion 114. The collar 106 is disposed and retained within the bore 110 of the tool holder 104. A back end of the cutting tool 102 is placed within a bore 118 of the collar 106 and retained by the nut portion 112 of the collar 106. The cylinder portion 114 of the collar 106 is disposed and retained within the bore 110 of the tool holder 104.
FIGs. 5-10 illustrate one embodiment of a coolant delivery system 100. As shown, the cylinder portion 114 of the collar 106 includes a plurality of grooves 120a, 120b for delivering pressurized coolant from a back end 117 of the tool holder 104 to the nut portion 114 of the collar 106. The groove 120a is a cut-through slot extending along the side wall of the cylinder portion 114, and the groove 120b is shorter than the groove 120a and is a cut-through slot extending along the side wall of the cylinder portion 114. It will be appreciated that the cylinder portion 114 may include additional grooves to deliver coolant from the back end 117 of the tool holder 104 to a front end 124 of the nut portion 112. Also, it will be appreciated that the size and shape of the grooves 102a, 102b can be varied without departing from the scope of the present invention. The nut portion 112 of the collar 106 includes a plurality of holes 122 for delivering pressurized coolant from the collar 106 to corresponding flutes 108 of the rotating cutting tool 102. In one embodiment, each of the holes 122 of the nut portion
112 corresponds to each of the flutes 108. In another embodiment, the nut portion 112 includes more holes 122 than the number of flutes 108.
As shown in FIG. 3, the hole 122 of the nut portion 112 is a through hole in fluid communication with a circumferential groove 126 (see FIG. 10) disposed on the back side 128 of the nut portion 112. The coolant flows from the back end 117 of the tool holder 104, through the grooves 120a, 120b of the cylinder portion 114 of the collar 106, to the circumferential groove 126 on the back side 128 of the nut portion 112 of the collar 106, then flows from the circumferential groove 126, through the holes 122, and onto the flutes 108 of the cutting tool 102. As shown in FIG. 4, the cutting tool 102 mills into a work piece 130, and the coolant is directed to the flutes 108 of the cutting tool 102. Under high pressure and flow rates, the coolant flows to cutting edges of the cutting tool 102 whereby chips or swarf from the drilling/cutting/milling process are removed from the cutting tool 102. As a result, the flutes or cutting edges of the cutting tool 102 are not clogged by the chips or swarf during the drilling/cutting/milling process.
It is appreciated that the collar is made of any suitable material, preferably ferrous material, with an outer diameter equal to an inner diameter of the tool holder, and an inner diameter equal to an outer diameter of the cutting tool. As discussed before, the collar includes a plurality of grooves, such as 120a,b, machined on the inner diameter in the length direction placed at a certain distance from each other. This distance could be the same or different between successive grooves. These grooves open into a circumferential groove, such as 126, on the inner diameter preferably located at the end which is closer to the cutting edge.
It is also appreciated that different embodiments of a collar can be used without departing from the scope of the present invention. In one embodiment, the through holes 122 can be made at a certain angle with an axis of the collar or straight at 90 degrees. The number of through holes 122 are the same as number of flutes or teeth or higher. After a cutting tool is inserted into the collar and the collar is secured into a tool holder, coolant flowing from the spindle is channeled through the circumferential groove into the through holes. Coolant is discharged from the through holes onto the flutes of the cutting tool.
Further, it is appreciated to those skilled in the art that the size of the through holes depend on desired pressure at given coolant flow rate as the pressure depends on the diameter or cross-sectional area of the through hole. It is also appreciated that the holes are preferably circular in shape, but can be different shapes such as square or diamond or any other geometric shape that allows coolant discharge at the desired pressure.
In operation of one embodiment of the present invention, the collar rotates with the cutting tool, so that high pressure coolant is in fluid communication with the flutes. These and other features of the present invention will become apparent to those skilled in the art from the following detailed description, wherein it is shown and described illustrative embodiments of the invention, including best modes contemplated for carrying out the invention. As it will be realized, the invention is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present invention.