JP3025251U - End mill with twisted fluid supply hole - Google Patents

Abstract

(57) Abstract: In an end mill with a twist supply hole manufactured by twist extrusion molding, a spiral groove due to the twist extrusion molding is not left on the outer peripheral surface of the shank portion. An extrusion molding die 78 for molding a tool material 72 having twisted fluid supply holes 64a, 64b is provided with a spiral guide projection 74 for extruding while turning a tool material 84. Although it is provided in 76, a small diameter spiral groove erasing portion 88 is provided at the tip of the extrusion molding die 78 so that the spiral groove due to the guide projection 74 does not remain on the outer peripheral surface of the tool material 72. An end mill is manufactured using the tool material 72. The tool material in which the spiral groove due to the guide projection 74 remains on the outer peripheral surface may be removed by the depth of the spiral groove by cutting or grinding after temporary sintering.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 TECHNICAL FIELD The present invention relates to an improvement of an end mill with a twisting fluid supply hole in which a twisting fluid supply hole is provided by twist extrusion molding.

[0002]

[Prior art]

 (a) A blade having a spiral groove and an outer peripheral blade formed along the spiral groove and a shank are integrally provided on a cylindrical tool material, while (b) a paste-shaped tool When manufacturing the tool material by twist-extruding a raw material, a twisting fluid supply hole twisted with the same lead in the same twisting direction as the twist groove is provided so as to vertically pass through the blade portion and the shank portion. End mills with twisted fluid feed holes have been proposed. The end mill described in Japanese Utility Model Publication No. 7-5936 is an example thereof. In the twist extrusion molding, (c) a guide protrusion that is helically twisted in the same twist direction as the above-mentioned twist groove is formed in a cylindrical shape. Torsional extrusion equipped with an extrusion molding die provided on the peripheral surface and (d) a core that is helically twisted in the same twisting direction as the above-mentioned twist groove that is fixedly arranged inside the extrusion molding die. It is designed to be performed by using a molding device, and the tool material is provided with a twisting fluid supply hole by the core as the tool material is advanced while rotating in the extrusion molding die by the guide projection. Cemented carbide is used as the raw material for tools.

FIGS. 5 to 7 show an example of such a conventional end mill 10 with a twisted fluid supply hole (hereinafter, simply referred to as end mill 10). The end mill 10 has a cylindrical shank portion 12 and a pair of outer peripheral surfaces. And a blade portion 16 provided with the spiral grooves 14a and 14b, and is integrally formed by using a tool material 49 (see FIG. 8) made of a cemented carbide having a cylindrical shape. Outer peripheral blades 18a and 18b are formed on the blade portion 16 along the above-mentioned twisted grooves 14a and 14b, and bottom blades 20a and 20b are provided at the tip of the blade portion 16. Further, the shank portion 12 is formed with a flat portion 22 for a side lock screw for fixing the end mill 10 to the holder. 5 is a front view seen from the direction perpendicular to the axis, FIG. 6 is a rear end view seen from the shank portion 12 side, and FIG. 7 is a front end view seen from the blade portion 16 side.

The end mill 10 is provided with a pair of twisted fluid supply holes 24a and 24b extending vertically from the rear end of the shank portion 12 to the tip of the blade portion 16, and the flank surface 26a of the bottom blades 20a and 20b. , 26b. These twisted fluid supply holes 24a, 24b are twisted with the same lead in the same twisting direction as the twisted grooves 14a, 14b, and are shifted in phase by about 90 ° with respect to those twisted grooves 14a, 14b. It is formed parallel to the twisted grooves 14a, 14b so as not to open in the twisted grooves 14a, 14b. Further, on the outer peripheral surface of the shank portion 12, a pair of spiral grooves 28a, 28b is formed continuously with the above-mentioned twisted grooves 14a, 14b on the spiral winding of these twisted grooves 14a, 14b.

Here, when manufacturing the end mill 10, as shown in FIG. 8, for example, a pair of spiral guide protrusions 29 corresponding to the spiral grooves 28a and 28b are formed into a cylindrical shape. An extrusion molding die 44 provided on the inner peripheral surface 36 and a pair of twisted fluid supply holes 24a, 24b, which are fixedly positioned inside the molding inner peripheral surface 36 of the extrusion molding die 44, are twisted in the same manner. Torsional extrusion including a core 46 and an extrusion punch 40 for extruding a paste-like tool raw material 48 in which a cemented carbide powder contained in the raw material accommodation hole 38 and a binder are kneaded into an extrusion molding die 44. The apparatus 42 first forms a cylindrical tool material 49 having spiral grooves 28a, 28b on the outer peripheral surface and twisted fluid supply holes 24a, 24b inside. Next, after cutting the tool material 49 with the entire length of the end mill 10, the spiral grooves 28a and 28b in the blade portion 16 are ground along the spiral grooves 14a and 14b with a diamond grindstone or the like, and the flat portion is cut. The end mill 10 is manufactured by processing 22, the outer peripheral blades 18a and 18b, the bottom blades 20a and 20b, and the like. The size and number of the guide projections 29 are determined so that at least the extrusion of the tool raw material 48 can be extruded while spirally turning during extrusion molding.

As shown in FIG. 9, for example, the end mill 10 is held by a holder 32 by pressing a side lock screw 30 against the flat portion 22, and is mounted on a spindle such as a machining center (not shown). It is then used for cutting graphite electrodes. The holder 32 is provided with a flow passage 34 for supplying a fluid such as cutting fluid or air, and the fluid is made to act on the rear end surface of the end mill 10 at a predetermined pressure by a built-in pump or the like. As a result, the fluid is discharged from the tip of the blade portion 16 through the twisting fluid supply holes 24a, 24b, and also passes through the spiral grooves 28a, 28b from the tip of the shank portion 12 toward the blade portion 16 side. It is made to discharge toward.

Since the end mill 10 is integrally formed of cemented carbide, it has high wear resistance even in the cutting process in which powdery chips such as graphite are generated. To be In addition, since the compressed air or the like is discharged from the tip of the blade portion 16 by the twisting fluid supply holes 24a and 24b, the discharge property of the chips is excellent, and the breakage of the end mill 10 due to the chips is also excellent. It is avoided. Further, since spiral grooves 28a and 28b are provided on the outer peripheral surface of the shank portion 12 and compressed air or the like is discharged from the tip of the shank portion 12 toward the blade portion 16 side, the twisted fluid supply holes 24a and 24b are provided. The chips discharged on the upper surface of the workpiece or on the table by the compressed air supplied to the tip of the blade portion 16 are radiated from the vicinity of the end mill 10 by the compressed air discharged from the spiral grooves 28a and 28b. It becomes possible to observe the processed shape satisfactorily by visual inspection, and the problems such as chips entering the guide surface and promoting wear are eliminated. In particular, the compressed air or the like discharged from the spiral grooves 28a and 28b is uniformly discharged around the end mill 10 by the rotation of the end mill 10, so that a blind spot or There is an advantage that a shadow is not generated and the discharge position thereof completely follows the movement of the end mill 10.

Since the twisted fluid supply holes 24a, 24b are formed by twisting with the same lead in the same twisting direction as the twisted grooves 14a, 14b from the rear end of the shank portion 12 to the tip of the blade portion 16, Even if the tip of the blade portion 16 is ground again, the opening positions of the twisting fluid supply holes 24a and 24b are always kept at the same position, and the chip discharge operation by compressed air etc. can be stably obtained and the twisting It is possible to regrind and use it until the position where the grooves 14a and 14b are removed.

[0009]

[Problems to be solved by the device]

 However, in such an end mill with a twisted fluid supply hole, if cutting processing is performed without supplying fluid such as compressed air from the spiral groove existing on the outer peripheral surface of the shank portion, the cutting powder will enter the spiral groove. When foreign matter such as foreign matter enters the holder, it may get caught between the outer peripheral surface of the shank and the inner peripheral surface of the holder when it is attached to or detached from the holder, or the outer peripheral surface or inner peripheral surface of these may be scratched. There was a problem that the accuracy deteriorated, causing tremor. Also, when gripping the shank part with multiple gripping claws like a collet, some gripping claws are located on the spiral groove and a sufficient gripping action cannot be obtained, and the end mill rotates around the axial center during cutting. There is a risk that it will rotate relative to each other or will slip out in the axial direction due to the axial component force acting on the outer peripheral blade.

Further, in recent years, when machining aluminum or the like, high-efficiency machining in which an end mill is rotated at high speed has come to be performed. In that case, the fluid supplied from the spiral groove of the shank portion is scattered by centrifugal force. In addition to the inability to obtain the action of removing chips, the problems such as the working environment being deteriorated due to scattered cutting fluid have come to occur. In addition, even if you want to supply a large amount of cutting oil, etc. to the cutting part at the tip of the blade such as digging, grooving, pocketing, etc., a part of it will flow out from the spiral groove, so a sufficient amount of fluid will not flow. It was difficult to supply.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a spiral groove remaining on the outer peripheral surface of the shank portion in an end mill with a twist supply hole manufactured by torsion extrusion molding. It is to solve the above-mentioned various problems caused by.

[0012]

[Means for Solving the Problems]

 In order to achieve such an object, the first invention provides (a) a tool material having a columnar shape in which a blade portion provided with a spiral groove and an outer peripheral blade formed along the spiral groove and a shank portion. On the other hand, (b) When manufacturing the tool material by twist-extruding a paste-shaped tool material, the twisted fluid supply hole twisted in the same twist direction as the twist groove in the same lead. In the end mill with a twisted fluid supply hole, which is installed so as to vertically pass through the blade portion and the shank portion, (c) the outer peripheral surface of the shank portion has no spiral groove resulting from the twist extrusion molding. And

In a second invention, (a) a blade portion provided with a spiral groove and an outer peripheral blade formed along the spiral groove, and a shank portion are integrally provided on a cylindrical tool material. (b) An extrusion molding die in which a guide projection, which is spirally twisted in the same twisting direction as the above-mentioned twist groove, is provided on the cylindrical inner peripheral surface of the molding, and is fixedly positioned inside the extrusion molding die. In addition, when a paste-like tool raw material is twist-extruded to manufacture the tool material by a twist extrusion molding apparatus equipped with a core that is helically twisted in the same twist direction as the twist groove, In an end mill with a twisted fluid supply hole, in which a twisted fluid supply hole twisted with the same lead in the same twisting direction as the twisted groove is provided so as to extend vertically through the blade portion and the shank portion, (c) the shank The outer peripheral surface of the portion is characterized in that there is no spiral groove due to the guide projection.

According to a third aspect of the invention, in the end mill with a twisted fluid supply hole according to the second aspect of the invention, there is a spiral groove due to the guide projection on the outer peripheral surface of the tool material after the twist extrusion molding. After the tool material is pre-sintered, the outer peripheral portion of the tool material is removed by the depth of the spiral groove, so that the spiral groove does not exist on the outer peripheral surface of the shank portion. Characterize.

According to a fourth aspect of the present invention, in the end mill with the twisted fluid supply hole of the second aspect, whether the inner diameter of the inner peripheral surface of the extrusion is the same as the inner diameter of the guide projection at the tip of the extrusion die. By making the diameter smaller than that, there is provided a spiral groove erasing part in which the guide projection is eliminated, and the spiral groove due to the guide projection is not left on the outer peripheral surface of the tool material. It is characterized by being

A fifth invention is the end mill with a twisted fluid supply hole according to any one of the second invention to the fourth invention, wherein the tool material is made of cemented carbide and the paste-like tool material is made of cemented carbide. It is characterized by containing a powder and a binder.

[0017]

[Effect of device]

 In such an end mill with a twisted fluid supply hole of the present invention, since there is no spiral groove due to the torsional extrusion molding on the outer peripheral surface of the shank portion, the presence of the spiral groove prevents foreign matter such as chips from being caught. It eliminates problems such as jamming, runout, extraction due to reduced gripping action, fluid scattering due to high-speed rotation, and insufficient supply of fluid such as cutting fluid to the blade tip. In addition, since the twisting fluid supply hole is formed by twist extrusion molding, the twisting fluid supply hole can be compared to, for example, when a rod material provided with a linear fluid supply hole is twisted and deformed by heat. An end mill with supply holes can be manufactured easily and inexpensively.

In the third invention, since the cylindrical tool material having the spiral groove on the outer peripheral surface is pre-sintered, the outer peripheral portion of the tool material is removed by the depth of the spiral groove. The spiral groove can be relatively easily removed by cutting or grinding. In the fourth invention, a small-diameter spiral groove erasing portion is provided at the tip of the extrusion molding die, and the spiral groove caused by the guide projections is not left on the outer peripheral surface of the tool material. It can be manufactured in numbers.

Further, in the fifth device, since the tool material is made of cemented carbide, by using a paste-like tool material containing a powder of cemented carbide and a binder, twist extrusion molding is applied to apply the invention. End mills with twisted fluid feed holes can be conveniently manufactured.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Here, the twist groove provided in the blade portion is formed so as not to interfere with the twist fluid supply hole previously provided in the cylindrical tool material. It is formed by shifting phases. It is desirable that the same number of twisted fluid supply holes are provided corresponding to the twisted grooves, that is, the outer peripheral blades, but if at least one twisted fluid supply hole is provided regardless of the number of outer peripheral blades, a temporary effect can be obtained. In the torsion extrusion molding, the tool raw material is pushed forward while rotating, and the size and number of the guide projections of the extrusion molding die are determined so that the tool raw material is extruded while spirally turning during extrusion molding.

The spiral groove resulting from the guide projection of the extrusion molding die can be removed by temporarily sintering the tool material as in the third invention or by twisting extrusion as in the fourth invention. It is desirable to remove it at a stage, but it can be removed with a diamond grindstone or the like even after sintering the tool material. After the twist extrusion molding, you can remove the spiral groove by performing normal extrusion molding that reduces the outer diameter of the tool material so as not to crush the twisted fluid supply hole. The method of removal is appropriately determined. The spiral groove of the tool material that serves as the blade portion can be removed, for example, by forming a twist groove, so at least the spiral groove that serves as the shank portion may be removed.

Further, the end mill with twisted fluid supply hole of the present invention is preferably made of cemented carbide as in the fifth invention, but twist extrusion molding of powder high speed tool steel, ceramics, cermet, etc. is possible. It may be made of any other material.

An embodiment of the present invention will be described below in detail with reference to the drawings. 1 to 3 show an example in which the present invention is applied to a ball end mill, in which the ball end mill 50 has a cylindrical shank portion 52 and a blade portion provided with a pair of spiral grooves 54a, 54b on the outer peripheral surface. 56, and is integrally configured using a tool material 72 (see FIG. 4) made of a cemented carbide having a cylindrical shape. Peripheral blades 58a and 58b are formed on the blade portion 56 along the spiral grooves 54a and 54b, and arcuate bottom blades 60a and 60b are provided at the tip of the blade portion 56. 1 is a front view seen from the direction perpendicular to the axis, FIG. 2 is a rear end view seen from the shank portion 52 side, and FIG. 3 is a front end view seen from the blade portion 56 side.

The ball end mill 50 is provided with a pair of twisted fluid supply holes 64a and 64b extending vertically from the rear end of the shank portion 52 to the front end of the blade portion 56, and allows the bottom blades 60a and 60b to escape. The surfaces 66a and 66b are opened. These twisted-fluid supply holes 64a and 64b are twisted by the same lead in the same twisting direction as the twisted grooves 54a and 54b, and the phase is about 90 ° with respect to these twisted grooves 54a and 54b. It is formed parallel to the twisted grooves 54a and 54b so as not to open in the twisted grooves 54a and 54b.

Here, the tool material 72 is molded by, for example, a twist extrusion molding device 70 shown in FIG. The twist extrusion molding device 70 is configured substantially in the same manner as the twist extrusion molding device 42 of FIG. 8, and has a spiral shape with substantially the same lead in the same twist direction as the twist grooves 54a and 54b and the twist fluid supply holes 64a and 64b. A pair of twisted guide projections 74 are provided on the cylindrical inner peripheral surface 76 of the extrusion molding die, and the extrusion molding die 78 is fixedly disposed inside the inner peripheral surface 76 of the extrusion molding die. Extrusion molding of a paste-like tool raw material 84 obtained by kneading a pair of cores 80 twisted in the same manner as the twisted fluid supply holes 64a and 64b, a cemented carbide powder contained in a raw material accommodation hole 82, a binder and the like. An extrusion punch 86 for extruding into 78 is provided. At the tip of the extrusion molding die 78, the inner diameter dimension of the molding inner peripheral surface 76 is gradually reduced to be substantially the same as the inner diameter dimension of the guide protrusion 74, and the guide protrusion 74 disappears. 8 are provided. Therefore, unlike the tool material 49 molded by the twist extrusion molding apparatus 42 of FIG. 8, the tool material 72 molded by the twist extrusion molding apparatus 70 has a spiral groove formed on the outer peripheral surface thereof due to the guide projection 74. Does not remain. Since the core 80 is provided up to the tip of the extrusion molding die 78 and also exists inside the spiral groove erasing portion 88, even if the tool material 72 is crushed into a small diameter, the twisting fluid supply hole 64a, 64b is not crushed. Further, the size and number of the guide projections 74 are determined so that the tool raw material 48 is extruded while spirally swirling at least during extrusion molding.

The method for manufacturing the ball end mill 50 from the tool material 72 is substantially the same as the method for manufacturing the end mill 10, for example, after cutting the tool material 72 with the full length dimension of the ball end mill 50, the blade portion 56. The ball end mill 50 is manufactured by grinding the twisted grooves 54a and 54b with a diamond grindstone or the like and processing the outer peripheral blades 58a and 58b and the bottom blades 60a and 60b. The shank portion 52 remains the tool material 72. Since the base end portion of the blade portion 56 has a smaller diameter than the shank portion 52, the outer peripheral portion is removed to a desired diameter dimension by grinding or the like before or after processing the spiral grooves 54a and 54b.

In the ball end mill 50 of this embodiment as described above, since there is no spiral groove due to the torsional extrusion molding on the outer peripheral surface of the shank portion 52, foreign matters such as chips due to the existence of the spiral groove. It eliminates the problems of biting, runout, ejection due to reduced gripping action, fluid scattering due to high-speed rotation, and insufficient supply of fluid such as cutting fluid to the blade tip. Further, since the twisted fluid supply holes 64a and 64b are formed by the twist extrusion molding, compared with the case where the rod material provided with the linear fluid supply holes is twisted and deformed by heat, The tool material 72 and the ball end mill 50 can be manufactured easily and inexpensively. In particular, in this embodiment, a small diameter spiral groove erasing portion 88 is provided at the tip of the extrusion molding die 78 so that the spiral groove due to the guide projection 74 does not remain on the outer peripheral surface of the tool material 72. Therefore, it can be manufactured in the same number of steps as the conventional one.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the extrusion die 78 is provided with the spiral groove erasing portion 88 to form the tool material 72 having no spiral groove. After temporarily sintering the tool material 49, the outer peripheral portion of the tool material 49 may be removed by cutting or grinding to remove the spiral grooves 28a and 28b by the depth of the spiral groove.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the ball end mill 50 has been described, but the present invention is applicable to not only the square type end mill 10 as shown in FIG. 5 but also other end mills. Can be applied.

Further, in the above-mentioned embodiment, the two-blade ball end mill 50 having the two spiral grooves 54a and 54b has been described, but the present invention can be applied to a single-blade or an end mill having three or more blades. .

Further, in the above-described embodiment, the twisted fluid supply holes 64a and 64b, which are twisted in a spiral shape, are provided over the entire length of the ball end mill 50, but for convenience of extrusion molding, the rear end side of the shank portion 52 is provided. Part of the ball end mill 50 may have a straight line shape parallel to the axis of the ball end mill 50.

Although not illustrated one by one, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a front view showing an example in which the present invention is applied to a ball end mill.

FIG. 2 is a rear end view of the ball end mill of FIG.

FIG. 3 is a front end view of the ball end mill of FIG.

FIG. 4 is a schematic cross-sectional view of a torsion extrusion molding apparatus for molding the tool material of the ball end mill of FIG.

FIG. 5 is a front view showing an example of a conventional end mill with a twisted fluid supply hole.

6 is a rear end view of the end mill of FIG.

7 is a front view of the end mill of FIG.

8 is a schematic cross-sectional view of a twist extrusion molding apparatus for molding the tool material of the end mill of FIG.

9 is a front view showing a state where the end mill of FIG. 5 is attached to a holder.

[Explanation of symbols]

50: Ball End Mill (End Mill with Twisted Fluid Supply Hole) 52: Shank Part 54a, 54b: Twisted Groove 56: Blade Part 58a, 58b: Peripheral Blade 64a, 64b: Twisted Fluid Supply Hole 70: Twisted Extrusion Molding Device 72: Tool Material 74: Guide projection 76: Molding inner peripheral surface 78: Extrusion molding die 80: Core 84: Tool raw material 88: Spiral groove erasing portion

Claims (5)

[Scope of utility model registration request] 1. A blade part having a spiral groove and an outer peripheral blade formed along the spiral groove and a shank part are integrally provided on a cylindrical tool material, while a paste-shaped tool material is used. When manufacturing the tool material by twist extrusion molding, a twisting fluid supply hole twisted with the same lead in the same twisting direction as the twisting groove is provided so as to vertically pass through the blade portion and the shank portion. In the end mill with a twisted fluid supply hole, the outer peripheral surface of the shank portion does not have a spiral groove resulting from the twist extrusion molding. 2. A blade portion having a spiral groove and an outer peripheral blade formed along the spiral groove and a shank portion are integrally provided on a cylindrical tool material, while the same twist as the spiral groove. Spirally twisted in the same direction as the guide projection provided on the cylindrical inner peripheral surface of the molding, and a spiral in the same twisting direction as the spiral groove fixedly positioned inside the extrusion molding die. When a paste-shaped tool raw material is twist-extruded by a twist extrusion molding device including a core that is twisted like a core to produce the tool raw material, the core leads the same lead in the same twist direction as the twist groove. In an end mill with a twisted fluid supply hole, which is provided so that a twisted fluid supply hole twisted by a vertical path passes through the blade portion and the shank portion, the guide protrusion is provided on the outer peripheral surface of the shank portion. Twisting the fluid supply hole with an end mill, characterized in that there is no helical groove due to. 3. The spiral groove resulting from the guide projections is present on the outer peripheral surface of the tool material after the twist extrusion molding, and the spiral groove is formed only by the depth of the spiral groove after the tool material is pre-sintered. The end mill with a twisted fluid supply hole according to claim 2, wherein the spiral groove does not exist on the outer peripheral surface of the shank portion when the outer peripheral portion of the tool material is removed. 4. The extruding die has a distal end portion in which the inner diameter of the inner molding surface is equal to or smaller than the inner diameter of the guide projection so that the guide projection disappears. The end mill with a twisted fluid supply hole according to claim 2, wherein the spiral groove erasing portion is provided so that the spiral groove due to the guide projection does not remain on the outer peripheral surface of the tool material. 5. The torsion fluid supply hole according to claim 2, wherein the tool material is made of cemented carbide, and the paste-like tool material contains cemented carbide powder and a binder. With end mill.