JP2010105096A - Cutting tool of chip recovery type - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool of a chip recovery type capable of improving stability in machining and efficiency of chip recovery and eliminating restrictions on machining due to a shape of tool as required. <P>SOLUTION: In this cutting tool, a body part 11 includes a shank 14 being integral with a part 13 of effective cutting edge length, a stop hole 15 extended up to a section in front of the part of effective cutting edge length is provided inside the shank 14, a chip groove 16 at the outer periphery of the part 13 of effective cutting edge length is communicated with the stop hole 15, and the chips produced after cutting by a cutting edge 12 are sucked or fed under pressure by air stream, are taken into the stop hole 15, and are discharged to the outside through the stop hole 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotary cutting tool such as a ball end mill, and more particularly to a chip recovery type cutting tool that enables forced recovery of chips through an air flow inside a main body.

  As a conventional example of the above-mentioned cutting tool having a function of forcibly collecting chips, there is one disclosed in Patent Document 1 below. In the cutting tool unit (ball end mill) disclosed in the same document, a cutting tool having a cutting edge and a chip groove serving as a chip pocket is attached to a cylindrical holder by shrink fitting, and between the chip groove and the holder. A suction path is formed, and cutting is advanced while suctioning and collecting chips scraped by the cutting edge through the suction path.

JP 2008-173705 A

  The cutting tool unit disclosed in Patent Document 1 uses a cutting tool having a main body portion that does not change in diameter over its entire length, and increases the length of the main body portion of the cutting tool to some extent. Is inserted into the hole of the holder, and the insertion portion is tightened with the holder by shrink fitting to maintain the connected state of the two.

  In this cutting unit, since the connection between the holder and the main body of the cutting tool depends only on the frictional force of the fitting portion between them, there is a problem in the holding stability of the main body by the holder, and the thrust force is applied to the cutting tool. There is a possibility that the main body part may come off from the holder in the processing to which is added.

  Further, the insertion amount of the main body portion with respect to the holder is not stable, and the insertion amount may vary due to slipping during use. For this reason, there is a concern that the machining accuracy is lowered when the tool after the insertion amount variation is used under the same conditions as before the insertion amount variation.

  In addition, since the length of the main body inserted into the holder is long, the length of the suction path between the chip groove and the holder is inevitably long, the suction resistance increases, the suction efficiency decreases, Recovery efficiency decreases.

  In addition, the holder may become an obstacle and be subject to processing restrictions.

  An object of the present invention is to make it possible to improve the stability of machining and improve the efficiency of chip recovery, and to make it possible to eliminate machining restrictions due to the shape of the tool as needed.

In order to solve the above-mentioned problems, the present invention improves the rotary cutting tool provided with a cutting edge at the tip of the main body and a chip groove corresponding to the cutting edge on the outer periphery of the effective blade length of the main body. The main part of the tool includes a shank formed integrally with the effective blade length part, and the effective blade length part extends from the rear end of the shank toward the front end side of the main part inside the shank. A blind hole parallel to the open shaft center is provided at the rear end of the shank that extends to
The chip groove is communicated with the blind hole, and the chip scraped by the cutting blade is placed on the air stream by passing an air flow from the front end side to the rear end of the main body through the chip groove and the blind hole connected to the chip groove. It was taken in the said blind hole, and it was made possible to discharge | emit outside from this blind hole.

  In this cutting tool, it is preferable that the main body portion is composed of a cutting blade, a chip groove, a head portion having the shank, and a shank remaining portion, and the head portion is connected to the shank remaining portion so that the head portion can be replaced.

  In a two-blade cutting tool, the chip groove is arranged symmetrically about the center of rotation, and two strips are provided in the head portion. The groove width in the cross section perpendicular to the axis of the chip groove is 0.6D-0 .8D is also effective.

  In addition, this invention can be utilized suitably for the ball end mill provided with the ball blade.

  The chip recovery type cutting tool of the present invention is formed by integrally forming a cutting edge, a chip groove and a shank, and providing a blind hole inside the shank integral with the cutting edge and the chip groove, and an effective blade of the main body in the blind hole. Since the chip groove formed on the outer periphery of the long part is communicated, the chip cut by the cutting blade is put on the air flow by passing the air current through the chip groove and the blind hole inside the shank leading to the chip groove. It can be taken in and discharged to the outside through this blind hole.

  In the structure of Patent Document 1, the passage area of the chip discharge path is reduced by inserting a cutting tool into the hole of the holder, whereas the tool of the present invention forms a blind hole just before the effective blade length. As a result, the passage area of the portion constituted by the blind hole of the chip discharge passage can be increased as compared with the structure of Patent Document 1, and the increase in airflow resistance (decrease in the intake efficiency) is suppressed, and the chip is recovered. Increases efficiency.

  With this structure, the head portion can be integrated with the shank. Even when the head part is independent from the shank remainder, it can be added to the shank remainder with a structure that is constrained in the axial direction, and the stability and processing accuracy of the head can be improved by increasing the holding stability and positional accuracy of the head part. Improvements can also be made.

  Furthermore, since the head portion includes an integral shank, it can be avoided that the shank diameter is larger than the diameter of the effective blade length portion, and processing restrictions due to the shank (holder) becoming an obstacle can be eliminated. .

  Embodiments of a cutting tool according to the present invention will be described below with reference to FIGS. 1 to 4 show examples of application to a ball end mill. This chip recovery type cutting tool 1 is composed of a head part 10 and a shank remaining part 2.

  The head portion 10 is formed of a cemented carbide or a material whose surface is coated with a hard material. The head portion 10 has a cutting edge 12 on the outer periphery of the front end of the main body portion 11. The cutting edge 12 of the illustrated tool is a ball blade having a substantially ¼ circle, and the two blades are arranged symmetrically about the center of rotation.

  The main body portion 11 includes a shank 14 (that is, the tip side portion of the shank) integrated with the effective blade length portion 13 behind the effective blade length portion 13, and the shank 14 is provided inside the shank 14. A blind hole 15 is provided in parallel with the axial center extending from the rear surface to the front side of the effective blade length portion 13 toward the distal end side of the main body portion 11. The blind hole 15 is open to the rear end of the shank 14.

  A chip groove 16 corresponding to each cutting edge 12 is provided on the outer periphery of the effective blade length portion 13. The illustrated chip groove 16 is a torsion groove, and the inner diameter thereof is a through hole provided at the center of the shank remainder. Is equal to the inner diameter of 3. The chip grooves 16 are formed to a position where they can be cut through the end walls of the blind holes 15, and the chip grooves 16 are communicated with the blind holes 15.

  As shown in the figure, the tool provided with two strips on the head portion 10 with the chip grooves 16 arranged symmetrically about the center of rotation has an effective diameter of the tool as D, and the groove width W of the chip grooves 16 in the cross section perpendicular to the axis is 0.6D. When set to ˜0.8D, the passage area of the chip discharge path can be sufficiently secured while maintaining the required strength of the main body 11. The chip discharge path is a passage constituted by the chip groove 16 and the blind hole 15.

  This head portion 10 is connected to the tip of the shank remaining portion 2 to form a chip recovery type cutting tool 1.

  The shank remainder 2 is made of a steel material that is less expensive than the cutting tool material, and has a through hole 3 in the axial center. In the illustrated shank remaining part 2, a large-diameter cylindrical part 6 is connected to the rear of the small-diameter cylindrical part 4 via a taper part 5, and a head part 10 is connected to the tip of the small-diameter cylindrical part 4.

  It is preferable that the shank remaining portion 2 has an outer diameter at the tip equal to the outer diameter of the effective blade length portion 13 of the tool because processing restrictions by the shank remaining portion 2 can be avoided.

  The head portion 10 and the shank remaining portion 2 are connected to each other by making the outer diameter and inner diameter of the shank 14 included in the head portion 10 and the distal-side small-diameter cylindrical portion 4 of the shank remaining portion equal to each other, and the rear end and the distal end of both are V-shaped. Butting is performed in a fitted state, and the butted portion is brazed and joined.

  Other connection structures such as screw connection, shrink-fit connection, and bayonet fitting connection can also be employed. (Cross-sectional area) can be secured widely, which is preferable.

  The chip recovery type cutting tool configured as described above is used while being held by a main spindle of a processing machine or a tool holder set on the main spindle in the same manner as a normal rotary cutting tool. At this time, the through hole 3 of the shank remaining part 2 is communicated with the dust collecting chamber via the main shaft and the tool holder, the through hole 3 of the shank remaining part 2, the blind hole 15 communicated with the hole, and the chips communicated with the blind hole 15 An air flow from the front end of the main body 11 toward the rear portion is passed through the groove 16, and chips generated during the processing are loaded on the air flow and taken into the blind hole 15, discharged from the blind hole 15 to the outside, and collected in the dust collecting chamber.

  The airflow generated in the shank and in the chip groove can be generated by suction or air blowing. Since the illustrated tool is an end mill, it is suitable for chip collection by suction, but when air injection to the periphery of the processing part is allowed, the injected air is discharged through the inside of the shank 2, Pumping recovery can also be performed.

  Although the above description has been given by taking a ball end mill as an example, in the present invention, chips are forcibly recovered using an air flow, so a square end mill having a plurality of cutting edges at the tip of the head piece, a radius end mill, It can also be applied to drills. FIG. 6 shows an example thereof, in which the head portion 10 provided with the drill blade 17 is connected to the tip of the shank remaining portion 2.

An evaluation test was conducted to confirm the effect of the present invention.
The cutting tool used for the evaluation was a ball end mill (invention product) having the structure shown in FIG. 1 having a tool effective diameter D = φ10 mm and a blind hole and through-hole inner diameter d = φ9 mm. This is a comparative ball end mill in which a cutting tool (effective diameter is the same as the invention product) provided with a chip groove on the outer periphery is inserted into the tip of the hollow shank and fixed by shrink fitting. In the test, cutting was performed under the following conditions, and at that time, chips were sucked and collected by a dust collector, and the collection state was examined.
Work Material: Carbon-Cutting Conditions-
Cutting speed Vc: 157 m / min
Feed per blade fz: 0.125 / blade Cutting depth ap: 3 mm
Cutting width ae: 3 mm
Down cut Dry cutting Dust collection power: Invention 1.6kW
Comparative product 1.7kW

  As a result of this test, it was confirmed that the inventive product can perform stable processing and chip recovery superior to the comparative product.

The side view which shows embodiment of the chip collection type cutting tool of this invention Side view of the position of the cutting tool of FIG. Front view of the cutting tool of FIG. The perspective view of the part of the front-end | tip part of the cutting tool of FIG. The expanded sectional view of the part along the AA line of FIG. The side view which shows other embodiment of the chip collection type cutting tool of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chip collection type cutting tool 2 Shank remainder 3 Through-hole 4 Small diameter cylindrical part 5 Tapered part 6 Large diameter cylindrical part 10 Head part 11 Main body part 12 Cutting edge 13 Effective blade long part 14 Shank 15 Blind hole 16 Chip groove 17 Drilling blade D Effective diameter d of tool Internal diameter W of blind hole and through hole Groove width

Claims (3)

A cutting edge (12) was provided at the tip of the main body (11), and a chip groove (16) corresponding to the cutting edge (12) was provided on the outer periphery of the effective blade length (13) of the main body (11). A rotary cutting tool, wherein the main body (11) includes a shank (14) formed integrally with the effective blade length (13), and the main body from the rear surface of the shank to the inside of the shank (14). A blind hole (15) parallel to the open axis is provided at the rear end of the shank extending toward the front end of the shank extending to the front of the effective blade length (13),
The chip groove (16) communicates with the blind hole (15), and the chip groove (16) and the blind hole (15) connected to the chip groove (16) are cut by passing an air flow from the front end side to the rear end of the main body. A chip recovery type cutting tool in which chips cut by a blade (12) are placed in the airflow, taken into the blind hole (15), and discharged from the blind hole (15).   The main body (11) is composed of a head portion (10) having the cutting blade (12), the chip groove (16) and the shank (14), and a shank remaining portion (2), and the shank remaining portion ( The chip recovery type cutting tool according to claim 1, wherein the head portion (10) is connected to 2) so as to be replaceable.   The chip groove (16) is arranged symmetrically about the center of rotation, and two pieces are provided in the head portion (10). The groove width (W) in the cross section perpendicular to the axis of the chip groove (16) is D as the effective diameter of the tool. The chip recovery type cutting tool according to claim 1 or 2, which is set to 0.6D to 0.8D.

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