JP2008229764A - Rotating tool and machining method - Google Patents

Abstract

A rotary tool that can be used for micromachining, has a sufficient strength or hardness, is unlikely to be broken or worn, and can form a machining surface with high flatness and a machining method. I will provide a.
In a rotary tool A having a shaft body provided with a cutting edge 11 and cutting the work material B with the cutting edge by rotating the shaft body, the shaft body is brought into contact with the work material and ground. A grinding surface 14 is provided. After cutting the work material by the cutting edge, at least a part of the processed surface formed on the work material by the cutting edge is ground by the grinding surface.
[Selection] Figure 1

Description

  The present invention relates to a rotary tool and a processing method.

 Conventionally, processing of high-hardness materials has been performed by grinding with a grindstone, but in recent years, materials for tools with excellent wear resistance have been developed, and high-hardness materials can be processed by using such materials for tools. Possible tools have been proposed.

  A rotary tool such as an end mill or a ball end mill is known as one form of a tool for processing such a high hardness material. In this rotary tool, a cutting edge having a required shape is provided at the tip of a substantially cylindrical shaft body, and the workpiece is cut with the cutting edge by rotating the shaft body.

  In a rotary tool equipped with a cutting edge, a so-called flank is provided immediately after the rotation direction of the cutting edge that rotates together with the shaft body. It is comprised so that parts other than a cutting blade may not contact a work material (for example, refer patent document 1 or patent document 2).

  In other words, the flank is such that the distance of the rotating shaft body from the rotation axis is smaller than the distance from the rotation axis to the tip of the cutting edge, and the so-called clearance angle is the size of the rotary tool. It is determined in consideration of the relative feed speed with respect to the work material.

  Briefly described with reference to the drawings, as shown in FIG. 7, the rotary tool a is provided with a cutting edge 110 at a tool tip 100 at the tip of a cylindrical shaft body, and the cutting blade 110 that rotates together with the shaft body. A flank 120 is provided immediately after the rotation direction. In general, the tool tip 100 is made of a high hardness material, and is bonded and fixed to a base metal 100 ′ made of a metal material having excellent toughness by an adhesive means such as brazing.

  The rotary tool a is moved relative to the work material at a predetermined feed speed while rotating the shaft body to cut the work material. The cutting may be performed while moving the rotary tool a with respect to the fixed work material, or the cutting may be performed while moving the work material while fixing the rotary tool a. Cutting may be performed while moving both the rotary tool a and the rotary tool a.

  When cutting the work material with the rotary tool a, as shown in FIG. 8A, the cutting edge 110 rotating together with the shaft body is pressed against the work material b, and the work material is shown in FIG. 8B. As described above, the cutting blade 110 is rotated along with the rotation of the shaft body, and the work material b is cut by feeding the rotary tool a relative to the work material b. For convenience of explanation, in FIG. 8B, chips generated by cutting with the rotary tool a are omitted.

Since the flank 120 is provided in the tool tip 100 at the tip of the shaft body, even if the rotary tool a is sent in the cutting direction while rotating the shaft body after cutting by the cutting edge 110, FIG. As shown in FIG. 8 (d), the cutting tool 110 is rotated once while the rotating tool a is sent without causing the interference of the rotating tool a contacting the work material b, and a new work material b is obtained. Cutting is going to be done.
JP 2005-014202 A Japanese Utility Model Publication No. 63-047818

  As described above, in the rotary tool, the shaft body provided with the cutting edge is provided with the flank so that cutting can be performed without causing interference between the work material and the rotary tool. As the shaft portion of the surface portion becomes thinner, the strength and rigidity of the cutting edge portion are reduced, and there is a problem that breakage and wear tend to occur on the cutting edge.

  In view of such a current situation, the present inventors conducted research and development of a rotary tool that can be used for micromachining, and that does not easily cause breakage or wear by having sufficient strength or hardness, The present invention has been achieved.

  In the rotary tool of the present invention, in a rotary tool having a shaft body provided with a cutting edge and cutting the work material with the cutting edge by rotating the shaft body, the shaft body is brought into contact with the work material for grinding. A grinding surface was provided.

  Moreover, the grinding surface was provided immediately after the rotation direction of the cutting blade rotating with the shaft body. Thereby, it is not necessary to form a flank on the shaft body, and it is possible to prevent the strength and rigidity of the shaft body from being lowered, so that breakage and wear of the cutting edge can be suppressed.

  Moreover, the grinding surface was provided in the shape of the circumferential surface which becomes equal distance from the rotating shaft of a shaft body. Accordingly, the work material can be continuously ground by the grinding surface, and the surface roughness can be reduced by flattening the processing surface by this continuous grinding.

  Further, at least the cutting edge and the grinding surface of the shaft body were made of a polycrystalline diamond sintered body or a cubic boron nitride sintered body. Since the polycrystalline diamond sintered body and cubic boron nitride sintered body are materials with extremely high strength and hardness, they are suitable for forming a tool used for micromachining. It is suitable for producing a fine tool of 1.0 mm or less, and an extremely high-quality rotary tool can be obtained by forming all of the tool tip with these.

  Further, in the processing method of the present invention, in the processing method of cutting a work material with a rotary tool having a shaft body provided with a cutting edge, the shaft body is provided with a grinding surface for abutting and grinding the work material. After cutting the work material with the cutting edge, at least a part of the processed surface formed on the work material with the cutting edge is ground with the grinding surface. Furthermore, the feed speed and / or rotation speed of the rotary tool with respect to the work material is adjusted, and the flank of the rotary tool having a clearance angle is used as a grinding surface.

  According to the present invention, the rotary body is provided with a grinding surface that is ground in contact with the work material on the shaft body provided with the cutting edge so that the work material and the rotary tool do not interfere with each other. Rather than providing a flank on the shaft of the rotary tool, a grinding surface is provided on the shaft, the rotary tool is brought into contact with the work material, and the work piece is ground on the grinding surface by rotating the shaft. it can.

  Therefore, it is possible to prevent the shaft body from being thinned by eliminating the need to form a flank on the shaft body, and to prevent the strength and rigidity of the shaft body from being lowered. Can be suppressed.

  In the rotary tool and the processing method of the present invention, in the rotary tool that is capable of cutting the work material by providing a cutting blade on the rotating shaft body, a grinding surface is provided for grinding the shaft body in contact with the work material, The work surface can be ground by rotating the grinding surface as the shaft rotates.

  That is, the rotary tool is provided with a cutting means for cutting the work material with the cutting edge and a grinding means for grinding the work material with the grinding surface. Therefore, in the cutting process of the work material, the cutting and grinding can be performed while being distributed to the cutting means and the grinding means, and the local load acting on the rotary tool can be reduced. Alternatively, in the state where the same local load is applied as when only the cutting edge is provided, the working efficiency can be improved by the amount of grinding by the grinding surface.

  The cutting edge provided on the shaft body only needs to be able to cut the work material. For example, as shown in FIG. 1A, a part of the peripheral surface of the tool tip portion 10 of the columnar shaft body. By flattening, a flat surface 13 can be provided, and one edge portion of the flat surface 13 where the flat surface 13 and the peripheral surface of the tool tip 10 intersect can be used as the cutting edge 11. Here, the flat surface 13 is a so-called “rake surface”. The rake face is not limited to the flat face 13 and may be a concave face with a recessed central part, and is covered at the intersection of the peripheral surface of the tool tip 10 and the rake face. The rake face may have any shape as long as an edge capable of applying a shearing force to the cutting material is formed.

  Further, the tool tip portion 10 provided with the cutting edge 11 has the entire peripheral surface as a grinding surface 14.

  In particular, the grinding surface 14 is provided in the shape of a circumferential surface that is equidistant from the rotation axis of the shaft body. Accordingly, as shown in FIG. 1A, the rotary tool A rotates the shaft body to cut the work material B with the cutting edge 11, and also processes the work material B exposed by cutting with the cutting edge 11. The grinding surface 14 provided on the tool tip 10 can be brought into contact with the surface.

  Moreover, the rotary tool A can grind the work material B with the grinding surface 14 by being sent relative to the work material B in the cutting direction while rotating the shaft body.

  While the rotary tool A is in contact with the work material B with the grinding surface 14, the rotation of the shaft body and the rotation tool A being fed to the work material B cause the rotation tool A to move to FIGS. The work material B can be ground as shown in FIG.

  In addition, when the work material is cut intermittently with the cutting edge as in the conventional example shown in FIG. 8, the cutting edge has a circular trajectory because it rotates together with the shaft body. After cutting with the tool, a continuous concave recess is formed on the work surface of the work material, and the surface roughness of the work surface is increased. By grinding the work material B, as shown in FIG. 1, the surface roughness of the work surface after grinding of the work material B can be reduced, and the flatness of the work surface can be improved.

  In particular, when the grinding surface 14 at the tool tip 10 is provided in a circumferential surface that is equidistant from the rotation axis of the shaft body, the work material B can be continuously ground by the grinding surface 14, and this continuous By rough grinding, the processed surface can be flattened to reduce the surface roughness. Moreover, the rotary tool A can be easily formed. Of course, a processed surface curved by the circumferential surface of the grinding surface 14 is formed in a portion near the feed direction of the processed surface after grinding by the grinding surface 14.

  In FIG. 1 (d), reference numeral 20 denotes a region to be ground of the work material B removed by grinding with the grinding surface 14. The work material B is removed by the amount of the ground region 20. In addition, the cutting amount of the work material B when the work material B is cut with the cutting edge 11 can be reduced. Therefore, the stress acting on the cutting edge 11 and the tool tip 10 during cutting by the cutting edge 11 can be reduced, and breakage and wear of the cutting edge 11 can be suppressed.

  Further, since the work material B is removed by an amount corresponding to the grinding region 20, the amount of protrusion of the protrusion formed on the work surface when the work material B is next cut with the cutting edge 11 is reduced. The surface roughness of the processed surface can be reduced. Here, the protrusion formed on the machining surface is cut off by rotating the rotary tool A relative to the work material B while the shaft rotates by the rake face of the rotary tool A. This is caused by the shift of the cutting start position by the blade 11 in the feed direction of the rotary tool A.

  The grinding surface 14 is not limited to the case where the grinding surface 14 is provided on the entire peripheral surface of the tool tip 10, but may be provided only at least somewhere behind the cutting edge 11 rotating with the tool tip 10.

  In particular, when the grinding surface 14 is provided immediately after the rotation direction of the cutting edge 11, it is not necessary to form a flank immediately after the rotation direction of the cutting edge 11, and the tip of the tool is formed along with the formation of the flank. Since the portion 10 can be prevented from becoming thin, the strength and rigidity of the tool tip portion 10 can be improved.

  In addition, when the grinding surface 14 is provided immediately after the rotation direction of the cutting edge 11, the cutting edge 11 can be firmly supported by the absence of the flank, so that the cutting edge 11 is broken or worn. Can be suppressed.

  Further, since the machined surface formed on the work material B by the cutting edge 11 can be immediately ground by the grinding surface 14, the machined surface can be a ground surface with a clean finished surface rather than a poorly finished cutting surface. And the appearance can be improved.

  In addition, when providing the grinding surface 14 partially in the surrounding surface of the tool front-end | tip part 10, in order to prevent that the surrounding surface of the tool front-end | tip part 10 in which the grinding surface 14 is not formed interferes with the workpiece B In addition, it is desirable to provide a clearance surface that is not in contact with the work material B on the peripheral surface of the tool tip 10 where the grinding surface 14 is not formed.

  In such a rotating tool A, when the tool tip 10 is composed of a polycrystalline diamond sintered body (hereinafter referred to as “PCD”) or a cubic boron nitride sintered body (hereinafter referred to as “CBN”). Can provide not only a rotary tool A with high workability of a high hardness material but also a crystal grain boundary on the surface of a polycrystal PCD or CBN as a grinding surface. Therefore, in the rotary tool A made of PCD or CBN, the rotary tool A having the grinding surface can be formed by forming only the rake face for forming the cutting edge 11.

  In FIG. 1, the tool tip 10 is integrally formed of PCD or the like. The high strength and high hardness characteristics of materials such as PCD and CBN can be suitably used as a tool when performing micromachining on the order of several μm, ensuring sufficient strength even when the diameter of the tool tip 10 is 1 mm or less. It will be possible. In particular, the structure in which the strength is ensured by devising the tool shape as in the present invention can provide a finer tool.

  In particular, when the tool tip 10 is formed with PCD, CBN, or the like, the grinding performance can be adjusted by adjusting the size of the crystal grain boundary. It is desirable to increase the boundary, and when importance is attached to the finished state of the processed surface, it is desirable to reduce the crystal grain boundary.

  In addition, as for the grinding surface, the surface of PCD or CBN may be subjected to electric discharge machining, shot blasting or the like as necessary to adjust the uneven shape of the grinding surface. Moreover, the surface roughness of the processed surface ground by the grinding surface can be further reduced by aligning the heights of the protrusions in the concavo-convex shape.

  By using the rotary tool A configured as described above, various kinds of processing can be performed on the work material B made of a high hardness material.

  In addition, in order to perform cutting with the cutting edge of the rotary tool and further continuously grind on the grinding surface, it is desirable to form the rotary tool as described above, but it has a clearance angle as in the past. Even in a rotary tool in which a flank is formed, by adjusting the rotational speed of the rotary tool and / or the feed speed of the rotary tool, the flank can be brought into contact with the work material after cutting with a cutting edge. Therefore, if the contact surface, that is, the flank surface is made grindable, similar processing can be performed.

  Further, the rotary tool A is not limited to the case where one cutting edge 11 is provided at the tool tip 10 as shown in FIG. 1, but the tool tip of a shaft body having a cylindrical shape as shown in FIG. Two cutting edges 11 'and 11' may be provided on 10 'by providing a rake face by two planes parallel to each other of the first flat surface 13'-1 and the second flat surface 13'-2.

  In this case, as shown in FIG. 2, by adjusting the ratio of the rake face area S where the rake face is formed in the tool tip 10 and the flank area T where the grinding face 14 is formed, Cutting amount and grinding amount can be adjusted.

  The number of cutting blades may be three or more. For example, as shown in FIGS. 3 (a) and 3 (b), a plurality of block bodies 15 "provided with cutting edges 11" It may be attached to a disc-shaped support plate 16 "provided at the tip of the body 10" to serve as a rotary tool.

  Here, as shown in the bottom view of FIG. 3B, the block body 15 ″ is a block body having a substantially one-eighth arc shape in the bottom view, and one end surface of the block body 15 ″ is In addition to the rake face 17 ", a grinding surface 18" is provided on the outer peripheral surface of the block body 15 ", and an edge formed by the rake face 17" and the grinding face 18 "is a cutting edge 11".

  The support plate 16 "is provided with fitting portions (not shown) that allow the block body 15" to be fitted and mounted at equal intervals, and in this embodiment, four block bodies 15 "are mounted. The block bodies 15 "mounted on the support plate 16" have their grinding surfaces 18 "positioned on the same arc.

  As a specific example, a shaft 30 having a substantially hemispherical tip with a diameter of about 50 μm at the tip is prepared as shown in FIG. A flat surface 33 having an angle of about 45 ° with respect to the rotation axis was formed at the tip of 30 by electric discharge machining, and a rotary tool having the flat surface 33 as a rake surface was formed.

  The flat surface 33 is not only for forming the cutting edge 31 as a rake face, but also for removing the center of rotation in the rotary tool. It is removed along with the formation.

  Since this rotary tool is made of PCD, the ground surface except for the edge portion of the outer peripheral edge of the flat surface 33 is a ground surface.

  Using this rotating tool, a concave prism of □ 0.4 mm × 0.2 mm was formed on a superalloy having a hardness of 2600 (25.2 GPa) Hv. Although some chips were found attached to the cutting edge 31, a concave prism could be formed without wear.

  In the present embodiment, only one flat surface 33 is provided on the shaft body 30 whose tip is hemispherical, but a plurality of flat surfaces 33 ′ may be provided as shown in FIG. 5, for example. In particular, when a plurality of flat surfaces 33 ′ are provided, it is desirable to arrange them on the peripheral surface of the shaft body 30 in a spiral shape.

  The flat surfaces 33 and 33 ′ provided at the tip of the tool at the tip of the shaft body 30 are provided for forming the cutting edge 31, and are not only formed as a flat surface but also in a concave shape, for example. It is good also as possible to form the cutting edge which consists of a sharp edge by forming.

  In the case of the tool shape shown in FIG. 4, the ratio between the rake face and the flank face changes according to the machining depth, that is, the distance from the tool tip, so the ratio between the cutting amount and the grinding amount changes for the reason described above. Therefore, when a plurality of flat surfaces 33 ′ are arranged in a spiral shape as in the tool shape shown in FIG. 5, a rake surface on the circumference appearing in a transverse section crossing the shaft body 30 at each distance from the tool tip, The ratio of the flank can be adjusted to be substantially constant. In addition, since cutting and grinding are performed in many smaller areas, the local load acting on the tool can be dispersed, and the intermittent interval of cutting can be shortened, so that the surface roughness of the machined surface can be further reduced. can do.

  Further, as shown in FIG. 6, a groove 35 may be formed in a spiral shape on the tool tip at the tip of the shaft body 30 to form a cutting edge 31 ". In this case, the groove 35 serves as a chip discharge path. As a result, it is possible to prevent chips from adhering to the grinding surface and reducing the grinding ability.

It is explanatory drawing of the cutting process by the rotary tool which concerns on embodiment of this invention. It is explanatory drawing of the rotary tool of other embodiment. It is explanatory drawing of the rotary tool of other embodiment. It is explanatory drawing of the rotary tool of an Example. It is explanatory drawing of the rotary tool of a modification. It is explanatory drawing of the rotary tool of a modification. It is explanatory drawing of the conventional rotary tool. It is explanatory drawing of the cutting process by the conventional rotary tool.

Explanation of symbols

A Rotating tool B Work material
10 Tool tip
13 Flat surface
11 Cutting edge
14 Grinding surface
20 Grinding area

Claims (6)

In a rotary tool having a shaft body provided with a cutting edge, and cutting the work material with the cutting edge by rotating the shaft body,
A rotary tool comprising a grinding surface for grinding the work piece against the shaft body.   The rotary tool according to claim 1, wherein the grinding surface is provided immediately after the rotation direction of the cutting edge that rotates together with the shaft body.   3. The rotary tool according to claim 1, wherein the grinding surface is provided in a circumferential shape that is equidistant from a rotation axis of the shaft body.   The rotary tool according to any one of claims 1 to 3, wherein at least the cutting edge and the grinding surface of the shaft body are a polycrystalline diamond sintered body or a cubic boron nitride sintered body. . In a processing method of cutting a work material with a rotary tool having a shaft body provided with a cutting edge,
The shaft body is provided with a grinding surface to be ground in contact with the work material,
A processing method comprising: grinding at least a part of a processed surface formed on the work material by the cutting edge after the cutting of the work material by the cutting edge. 6. The machining method according to claim 5, wherein a feed speed and / or a rotation speed of the rotary tool with respect to the work material is adjusted, and a relief surface of the rotary tool having a relief angle is used as a grinding surface.

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