WO2014136575A1

WO2014136575A1 - Drill for composite material, and machining method and machining device using same

Info

Publication number: WO2014136575A1
Application number: PCT/JP2014/053870
Authority: WO
Inventors: 浩文嶋田
Original assignee: 福井県
Priority date: 2013-03-08
Filing date: 2014-02-19
Publication date: 2014-09-12
Also published as: JP2014172120A; JP5476590B1

Abstract

The purpose of the present invention is to provide a drill for composite materials that minimizes the fusing and solidifying of chips so that the chips rise during boring, and that makes it possible to bore without causing burrs or inter-layer peeling in a machined material. Provided is a drill (1) for composite materials that comprises a tip section having formed thereon a tip cutting blade (5), a tapered section (4) that connects with the rear end side of the tip section and that is formed to have a tapered shape, and a same-diameter straight section (3) that connects with the rear end side of the tapered section (4) and that forms a finished machined diameter that is the same or larger than the outer diameter of the rear end side of the tapered section (4). A chip discharge groove (6) that has a twisted spiral shape is formed on the outer periphery of the tapered section (4), and an outer peripheral cutting blade (7) is formed along the edge of the straight section (3) side of the chip discharge groove (6) and is set so that the boring diameter increases continuously.

Description

Drill for composite material and machining method and machining apparatus using the same

The present invention is particularly suitable as a through-hole drilling tool for composite materials such as CFRP (Carbon Fiber Reinforced Plastics) or CFRTP (Carbon Fiber Reinforced Thermoplastics) such as fiber reinforced composite materials represented by thermoplastic carbon fiber reinforced plastics. A suitable drill, more specifically, forming a so-called burr at the opening of the through hole in one drilling operation and forming a high-quality through hole that does not cause delamination or surface peeling on the through surface on the side of the through hole. The present invention relates to a drill for composite materials.

As a through-hole drilling process for fiber reinforced composite materials such as CFRP, a method using a straight carbide drill with a diamond coat is known. However, when through-hole processing is performed by this method, sharpness deterioration due to wear of the cutting edge is likely to occur, and therefore processing defects such as uncut fibers, burrs, and delamination occur.

As a method for suppressing burrs during drilling, for example, in Patent Document 1, a drill for FPC (Flexible Printed Circuits) processing is configured as follows. That is, at least the blade portion is formed of any one of cemented carbide, cermet, ceramics, ultra-high pressure sintered body, or a material coated with a hard coating. Further, the flank is formed by the second flank and the third flank, and the flank angle of the third flank is set to 33 to 50 °. Therefore, the length of the cutting edge on the outer peripheral side of the chisel blade is shortened to reduce the width of the chip generated by the cutting edge, thereby improving the chip discharging performance and causing the poor discharging performance. The burr | flash which becomes and can be suppressed.

In Patent Document 2, as a drill suitable for CFRP drilling, it has a shape having a prepared hole processed part for machining a prepared hole and a finished part, and the diameter difference between the finished part and the prepared hole processed part is set to 0.1 mm or more and 2 mm or less. A two-stage drill is disclosed.

In Patent Document 3, a front end portion on which a front end cutting edge is formed and a rear end side outer diameter that is formed to be connected to the rear end side of the front end portion and larger in diameter than the front end side outer diameter and the front end side outer diameter. It is possible to form a taper part formed in a tapered shape with a difference in diameter and a finishing diameter larger than the outer diameter on the rear end side of the taper part while being connected to the rear end side of the taper part. And a straight portion having the same diameter as the whole, and a peripherally cutting edge spirally twisted is formed on the outer periphery of the tapered portion so that the drilling diameter is continuously increased. Is disclosed.

Japanese Patent Laid-Open No. 2005-88088 JP 2008-836 A JP 2011-104766 A

Carbon fiber reinforced composite material, especially CFRTP, is lightweight and has high strength and rigidity, and is easy to mold, so it is widely used for automobile parts and notebook PC cases.

CFRTP generally has a structure in which sheets of carbon fiber impregnated with a thermoplastic resin material impregnated with hard and hard to cut are laminated in layers. Since the thermoplastic resin material has the property of softening at about 140 ° C., if the heat generation during drilling is not suppressed as much as possible, the chips softened by the heat generation will enter the through-hole entrance (opening on the drilling start surface side). To become solidified. In addition, the fibers come out and become easy to wind around the drill, and further cause processing defects such as generation of uncut parts, fluffing, and delamination due to a reduction in cutting ability due to cutting edge wear. Also, CFRTP, which has a layered structure, is likely to generate burrs at the through-hole entrance and through-hole exit (opening on the side opposite to the drilling start surface), and delamination occurs due to the thrust force during processing. Since it is easy, it is difficult for the drills disclosed in

Patent Documents

1 and 2 to perform drilling to a practically sufficient level. Here, the “thrust force” is a force applied in the direction opposite to the drill feed direction in drilling.

As shown in FIG. 10, the drill disclosed in Patent Document 3 drills by rotating clockwise when the twist direction of the helical chip discharge groove formed along the outer peripheral cutting edge of the tapered portion is right-handed. As used. Therefore, the cutting blade 200 is provided in the same direction as the drill rotation direction, and the cutting operation is performed in the tapered portion so as to go from the tip portion side of the chip discharge groove to the straight portion side. Then, the chips generated by the cutting operation move to the straight portion along the twist direction by the rotating action of the drill and are discharged on the shank side. In particular, in a fiber reinforced composite material using a thermoplastic resin material as a matrix, chips are welded to the chip discharge groove due to the influence of heat generated during the drilling process, or softened chips are discharged to the through hole inlet side and the through holes are formed. It is unavoidable that welding is performed around the opening.

The present invention has been made in view of the above problems, and suppresses welding and solidification so that chips are raised during drilling, and has high quality without causing almost any burrs or delamination on the workpiece. An object of the present invention is to provide a composite material drill capable of drilling through holes.

The composite material drill according to the present invention is a composite material drill for perforating a workpiece including at least a part of a fiber reinforced composite material, the tip portion having a tip cutting edge formed thereon, and the rear portion of the tip portion. A tapered portion formed in a tapered shape by being connected to the end side and having a diameter difference between the distal end side outer diameter and the rear end side outer diameter larger than the distal end side outer diameter; and the rear end of the tapered portion A straight portion that is formed on the same side so as to be able to form a finishing diameter larger than the outer diameter on the rear end side of the taper portion, and connected to the side. A spirally twisted chip discharge groove is formed on the outer periphery of the taper portion, and an outer peripheral cutting edge is formed along an edge of the chip discharge groove on the straight portion side, so that a continuous drilling diameter is increased. Is set by the outer peripheral cutting edge. Operation by rotating the drill to take place, characterized in that it induces the chips produced by the cutting operation to face the drilling direction in the chip discharge groove. Further, the tip cutting edge of the tip portion has a tip angle of 60 ° to 140 °, and the center portion of the blade surface protrudes 0.5 mm or more from the cutting blade surface in the axial direction. The taper angle between the outer diameter line in contact with the outer diameter on the front end side and the outer diameter on the rear end side and the center line of the drill shaft is set to 45 ° or less. The entire taper portion is formed in the shape of a round land drill having the same diameter so that the taper portion can be formed to have a diameter that is 0.01 mm to 0.1 mm larger than the outer diameter on the rear end side. The rake angle is set to 0 ° to 20 ° and the clearance angle is set to 5 ° to 20 °, and the chip discharge groove is formed with a twist angle of 60 ° or less. Furthermore, the tip portion, the taper portion, and the straight portion are integrated coaxially. Furthermore, the axial center of the tip part, the taper part, and the straight part is made to coincide with the rotational axis. Furthermore, a flow path is formed along the center axis of rotation in the tapered portion and the straight portion while opening at the distal end portion, and air or cutting oil flowing through the flow channel is ejected at the distal end portion. .

The machining method according to the present invention is a machining method for drilling a workpiece including at least a part of a fiber-reinforced composite material using the above-described drill, wherein the tip cutting edge and the taper portion of the tip portion A prepared hole is drilled in the workpiece by the outer peripheral cutting edge, and the formed prepared hole is subjected to finishing by the straight portion and drilled.

A machining apparatus according to the present invention includes a driving unit that holds the above-described drill and rotationally drives the central axis of the drill, and a supporting unit that supports a workpiece including at least a part of a fiber-reinforced composite material. And a moving means for relatively moving the drive means and / or the support means so as to drill the drill into the workpiece.

Since the drill for composite material according to the present invention is processed while expanding the diameter while keeping the cutting resistance low by performing the pilot hole machining with the tapered portion, burrs are unlikely to occur around the through-hole outlet, and the plate of the workpiece Thrust force applied in the thickness direction is also reduced. Therefore, when perforating a CFRTP having a laminated structure, the peeling force with respect to the laminated boundary surface is reduced, and delamination hardly occurs.

Further, a cutting operation is performed by the outer peripheral cutting edge by forming a spirally twisted chip discharge groove on the outer periphery of the tapered portion and forming an outer peripheral cutting edge along the edge on the straight portion side of the chip discharge groove. If the drill is rotated in this manner, chips generated by the cutting operation are guided in the chip discharge groove toward the drilling direction, and discharge to the peripheral portion of the through hole entrance is suppressed. Therefore, almost no chips stay in the peripheral portion of the through-hole inlet, and it is possible to suppress welding so that the chips rise. And, in the penetrated state, the chips are quickly discharged along the chip discharge groove from the through hole inlet toward the through hole outlet, so that almost no chips remain in the peripheral portion of the through hole outlet, and the through hole is opened. It is possible to perform processing with high drilling quality that suppresses welding and solidification so that chips are raised in the peripheral portion of the steel.

It is a side view regarding the embodiment concerning the present invention. It is a front view regarding the front-end | tip part of the drill shown in FIG. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 3 is a cross-sectional view taken along line BB in FIG. 1. It is an expanded sectional view regarding an outer periphery cutting edge. It is a side view regarding the modification of embodiment shown in FIG. It is explanatory drawing regarding the difference with the cutting action of the conventional straight twist drill and the drill of this invention. It is explanatory drawing regarding the machining method at the time of using the drill which concerns on this invention. It is an external appearance perspective view which shows an example of the machining apparatus using the drill which concerns on this invention. It is explanatory drawing regarding the cutting operation of the conventional drill.

Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

Embodiments according to the present invention will be described with reference to FIGS. FIG. 1 is a side view of an embodiment according to the present invention. FIG. 2 is a front view relating to the tip of the drill shown in FIG. 3 is a cross-sectional view taken along the line AA in FIG. 4 is a cross-sectional view taken along line BB in FIG. FIG. 5 is an enlarged cross-sectional view relating to the outer peripheral cutting edge of the drill shown in FIG. 1.

As shown in FIG. 1, the drill 1 according to the present embodiment is a right-handed, left-rotating drill, and is formed into a tip portion 5 that is a tip portion, a tapered portion 4 that has an outer peripheral cutting edge 7, and a round land drill shape. The straight portion 3 and the shank 2 are connected and integrated on the same axis.

The drill 1 is a two-blade drill, in which the straight portion 3 is connected to the tip of the shank 2, and the tapered portion 4 is connected to the tip of the straight portion 3 integrally. The taper part 4, the straight part 3, and the shank 2 are connected with a tolerance of coaxiality 0.01.

The taper portion 4 has a tapered shape formed by a difference in diameter between the front end side outer diameter D1 and the rear end side outer diameter D2, and the straight portion 3 is integrally connected to the rear end side. The straight portion 3 is formed to be equal to or larger than the outer diameter D2 of the taper portion 4 rear end side. A tip cutting edge 5 having a tip angle α1 is connected to the tip end side of the taper portion 4.

The tapered outer periphery formed from the front end side outer diameter D1 to the rear end side outer diameter D2 of the taper portion 4 is formed with two helically twisted chip discharge grooves 6. An outer peripheral cutting edge 7 twisted in a spiral shape is formed at the edge on the straight portion 3 side, and is set so that the perforation diameter continuously increases. The straight portion 3 is formed in an end mill shape in order to shape a portion left uncut by the tapered portion 4 which is a prepared hole processing portion.

As shown in FIG. 1, the tip cutting edge 5 which is the tip has a tip angle of 60 ° to 140 °, and the center portion of the blade edge surface protrudes 0.5 mm or more from the cutting blade surface in the axial direction, The

ridgelines

9 and 10 form a tip angle α1, and the tip angle α1 is set in a range of 60 ° to 140 °.

As shown in FIG. 1, chip discharge grooves 6 are continuously formed on the outer circumferences of the taper portion 4 and the straight portion 3 in a spiral shape with a twist angle α3 opposite to the drill rotation direction. The twist angle α3 of the chip discharge groove 6 depends on the size of the tip angle and the material of the workpiece, but it can be set to 60 ° or less in order to prevent the cutting edge from becoming too sharp and easily chipped. Preferably, the chips containing the fiber material of the composite material can be quickly discharged by setting the angle to 60 ° or less.

The outer peripheral cutting edge 7 of the tapered portion 4 that is the prepared hole processing portion is not provided with a margin 8 as shown in FIG. 3, and the rake angle α5 and the clearance with respect to the conical surface in contact with the land outer periphery of the tapered portion 4 are provided. Each angle α4 is set in the range of 5 ° to 20 °. And the outer periphery cutting blade 7 is helically twisted and formed so that the edge by the side of the straight part 3 of the chip discharge groove 6 may be followed.

As shown in FIG. 1, the taper angle α2 resulting from the diameter difference between the front end side outer diameter D1 and the rear end side outer diameter D2 of the taper portion 4 is set to 45 ° or less. When the taper angle α2 is greater than 45 °, the thrust resistance exceeds the rotational force, so that a large burr is generated and cannot be reliably removed at the straight portion. The length L1 from the front end side outer diameter D1 to the rear end side outer diameter D2 of the taper portion 4 is determined by the taper angle α2.

FIG. 4 is a cross-sectional view of the straight portion 3 when the BB cross section shown in FIG. 1 is viewed from the rear end side of the straight portion 3 toward the tapered portion 4. The straight portion 3 is formed in the shape of a round land drill, and is formed to have a finishing diameter D3 equal to or larger than the rear end side outer diameter D2 of the tapered portion 4, and preferably 0.01 to 0.1 mm larger. The axial centers of the tip cutting edge 5, the taper portion 4 and the straight portion 3 are aligned with the drill rotation axis, and the connecting portion between the taper portion 4 and the straight portion 3 has an outer diameter on the tip side of the straight portion 3 which is the taper portion 4. They are connected in a tapered or curved shape with a reduced diameter toward the rear end side outer diameter. The tip cutting edge 5, the taper portion 4, the straight portion 3, and the shank 2 are integrated with a tolerance of coaxiality 0.01.

When drilling is performed while the drill shown in FIG. 1 is rotated counterclockwise about the central axis (in the direction of the arrow in FIG. 1), the cutting edge of the outer peripheral cutting edge 7 faces obliquely downward with respect to the rotation direction. The chip to be cut is guided so as to move in the drilling direction while moving from the blade edge toward the center of the chip discharge groove 6. Therefore, chips are discharged and hardly stay in the peripheral part of the through hole entrance, and the welding and solidification is suppressed so that the chips rise. Then, after the drill has penetrated the workpiece, the chips are quickly discharged from the through hole outlet side along the chip discharge groove 6, so that the chips are hardly accumulated in the peripheral portion of the through hole outlet and the chips are welded. Solidification is suppressed and high-quality drilling can be performed.

The surface of the drill 1 body is covered with a coating 12 made of diamond, as shown in FIG. The coating 12 can be formed by, for example, a well-known CVD method or PVD method, and may be a DLC film. Drills specializing in the processing of composite materials such as fiber reinforced resin materials need to sharpen the cutting edge and improve sharpness. By using ultrafine cemented carbide material as the drill base material, the cutting edge radius can be reduced. Can be shaped small. In addition, when the cutting edge is sharpened, chipping and abrasion of the cutting edge tip are likely to occur. Therefore, by forming the coating 12 with nano diamond coating, the outer peripheral cutting edge has a good sharpness without increasing the diameter of the cutting edge radius. Can be maintained for a long time. Further, even when the sharpness is deteriorated due to wear of the blade edge or the like, since the burr generated during the drilling of the pilot hole can be effectively removed by the straight portion 3, high-precision drilling can be stably performed. .

The material to be drilled by the drill 1 is preferably a fiber reinforced composite material. Specifically, a thermoplastic carbon fiber reinforced plastic (CFRTP), a thermosetting carbon fiber reinforced plastic jar (CFRP), a glass fiber reinforced material. Examples thereof include a plastic cage (GFRP), a glass long fiber reinforced plastic (GMT) cage, a boron fiber reinforced plastic cage (BFRP), an aramid fiber reinforced plastic cage (AFRP, KFRP), and a polyethylene fiber reinforced plastic cage (DFRP). Such fiber reinforced composite materials include reinforcing fibers in a matrix resin, and various forms have been developed. For example, what is provided with the layer structure which aligned the reinforcing fiber which consists of a long fiber in a predetermined direction, and was laminated | stacked on multiple axes | shafts.

FIG. 6 is a side view of a modification of the embodiment shown in FIG. In this example, a flow path 11 is formed along the rotation center axis inside the tapered portion 4 and the straight portion 3 while opening at the tip cutting edge 5 which is a tip portion. By circulating air or cutting oil through the flow path 11, fluid such as air or cutting oil can be ejected from the tip portion. Although the flow path 11 shown in FIG. 6 has a straight shape, it can also have a spiral twisted shape. When the drill shown in FIG. 6 is drilled while rotating counterclockwise in the same manner as in FIG. 1, the cutting edge of the outer peripheral cutting edge 7 faces obliquely downward with respect to the rotation direction. Is guided in the drilling direction while moving toward the center of the chip discharge groove 6. Therefore, chips are not discharged and stayed in the peripheral portion of the through-hole inlet, and it is possible to suppress the welding and solidification so that the chips rise.

Then, by blowing air or cutting oil from the tip cutting edge 5 to perform drilling, chips in the chip discharge groove 6 are blown and scattered along the chip discharge groove 6 at a peripheral portion of the through hole entrance. Chips are discharged without stagnation. Further, chips are efficiently discharged without clogging the cutting surface with which the tip cutting edge 5 and the outer peripheral cutting edge 7 abut. Furthermore, since the drill body is cooled by the air or cutting oil jetted, it is effective when drilling a material that is easily softened by heat, such as a thermoplastic resin material. The drill shown in FIG. 6 is particularly effective when the processing time until penetration is long, such as when the workpiece is thick.

FIG. 7 is a diagram illustrating the difference in cutting action between a conventional straight twist drill and the drill of the present invention. FIG. 7A shows a cutting mechanism of a straight twist drill, in which a linear blade provided at the tip rotates in the rotation direction indicated by the arrow to cut in the axial direction, and is cut with a scissors. The same cutting action as in the case. FIG.7 (b) is explanatory drawing regarding the cutting action by the drill of this invention, and part B2 cuts similarly to the cutting action of a straight twist drill, but for inducing the outer periphery cutting edge provided in the taper part. It also plays a role in improving centripetality. Part B <b> 1 shows the cutting action by the outer peripheral cutting edge 7 of the taper part 4. The outer peripheral cutting edge 7 formed in the taper portion 4 has an arc shape when viewed from the axial direction, and is formed into a spiral shape and a tapered shape as a whole. Cutting by point contact is continuously performed on the material, generating powdery chips and contributing to reducing wear on the outer peripheral cutting edge. Further, the outer peripheral cutting edge has the same cutting action as that of cutting with a knife due to the inclination by the twist angle and the rotation of the cutting edge along the outer peripheral surface direction accompanying the drill rotation, and a sharp cutting edge is obtained. Further, since the outer peripheral cutting edge is spiral and formed in a tapered shape as a whole, the total extension of the cutting edge for expanding the diameter can be taken longer, which contributes to the improvement of the tool life. When the drill rotates in the arrow direction, the cutting edge of the outer peripheral cutting edge 7 faces obliquely downward with respect to the rotation direction, so that the cut chips move in the chip discharge groove 6 in the drilling direction. Be guided. As a result, the chips are prevented from being discharged from the through-hole inlet, and hardly stay in the periphery.

FIG. 8 is an explanatory diagram relating to a machining method when the drill according to the present invention is used. FIG. 8A shows a state immediately before the start of drilling, and the tip of the drill 1 is set so as to abut on the plate-shaped workpiece M vertically. The rotation direction of the drill 1 is set to a direction in which the outer peripheral cutting edge performs a cutting operation. Next, in FIG. 8 (b), while the drill 1 rotates, the tip cutting edge of the tip portion first bites the workpiece M (eg, fiber reinforced composite material), and the outer periphery of the taper portion is cut. Induction of diameter expansion with a blade. Next, in FIG. 8C, the taper portion enters the workpiece M while the drill 1 is rotated, and diameter expansion processing is performed by the outer peripheral cutting edge. At this stage, the prepared hole is machined without causing delamination and burrs in the machined portion, and the chips are guided in the chip discharge groove in the drilling direction and are hardly discharged to the peripheral part of the through hole inlet. Therefore, stable drilling with an outer peripheral cutting edge is performed without welding and solidifying so that chips are raised at the peripheral portion of the through hole entrance. Next, in FIG. 8D, the straight portion enters the workpiece while the drill 1 rotates, and finishing is performed. Then, after the straight portion is removed from the workpiece M while finishing, the drill 1 is pulled up and the drilling process is completed.

FIG. 9 is an external perspective view of a machining apparatus using the drill according to the present invention. The machining apparatus 100 includes a moving means including a XYZ three-axis movable mechanism by a ball screw mechanism or a linear motor mechanism and a five-axis mechanism to which a rotation mechanism around the X and Y axes is added. The Z-axis moving mechanism 101 supports the drill 104 attached to the spindle shaft 103 and moves it up and down. As the moving means, a ball screw mechanism or a linear motor mechanism is used. Further, the Z-axis moving mechanism 101 includes a drive source that rotationally drives the spindle shaft 103.

The XY axis moving mechanism 102 moves the installation table to the X axis, the Y axis, or the XY compound axis. As the moving means, a ball screw mechanism or a linear motor mechanism is used. A support tool 106 such as a vise or a restraining jig is disposed on the installation table, and a workpiece 105 made of a fiber reinforced composite material or the like is placed and fixed on the support tool 106. The XY axis moving mechanism 102 is driven by a ball screw mechanism or a linear motor mechanism.

Then, the Z-axis moving mechanism 101 and the XY-axis moving mechanism 102 are controlled to perform drilling while rotating the drill 104 with respect to the workpiece 105. In addition, as the support tool 106, what has the function to pinch | interpose from the thickness direction or surface direction of the workpiece 105 may be used. Further, the spindle axis may be arranged on the X axis or the Y axis.

As described above, in the present invention, the cutting resistance and the drilling are achieved by forming a drill in which the tip cutting edge of the tip portion, the outer peripheral cutting edge of the taper portion, the chip discharge groove, and the outer peripheral cutting edge of the straight portion are integrated. A fiber-reinforced composite material drill that reduces machining heat, suppresses chipping and solidification of chips around the through-hole inlet and through-hole outlet, and realizes high-precision drilling with almost no burr or delamination Is obtained.

1 ・・ Drill, 2 ・ Shank, 3 ・・ Straight part, 4 ・・ Taper part, 5 ・・ Cut tip cutting edge, 6 ・・ Cut discharge groove, 7 ・・ Cut edge, 8 ・・ Margin, 9, 10 ... Edge line of blade edge, 11 .... Flow path, 12 .... Coating, 100 ... Machining device, 101 ... Z axis moving mechanism, 102 ... XY axis moving mechanism, 103 ... Spindle axis, 104 ..Drill, 105 .. Workpiece, 106 .. Supporting tool, α 1 .. Tip angle, α 2 .. Taper angle, α 3 .. Torsion angle, α 4 .. Rake angle, α 5.

Claims

A composite material drill for drilling in a workpiece including at least a part of a fiber reinforced composite material, wherein the tip is formed with a tip end formed with a tip cutting edge and connected to a rear end side of the tip end portion. A tapered portion formed in a tapered shape with a diameter difference between a distal end side outer diameter and a rear end side outer diameter larger than the distal end side outer diameter, and connected to the rear end side of the tapered portion, and A straight portion formed entirely in the same diameter so that a finishing diameter larger than the outer diameter on the rear end side of the taper portion can be formed, and the outer periphery of the taper portion has a spiral shape A twisted chip discharge groove is formed, and an outer peripheral cutting edge is formed along an edge of the chip discharge groove on the straight portion side so that the perforation diameter is continuously increased. Rotate the drill so that the cutting action is performed by the cutting edge. It is to, composite material for drilling, characterized in that induces chips produced by the cutting operation to face the drilling direction in the chip discharge groove.
The tip cutting edge of the tip portion has a tip angle of 60 ° to 140 °, and the center portion of the blade surface protrudes 0.5 mm or more from the cutting blade surface in the axial direction. The taper angle between the outer diameter line in contact with the outer diameter on the front end side and the outer diameter on the rear end side and the center line of the drill shaft is set to 45 ° or less. Is formed in the shape of a round land drill having the same diameter so that it can be formed to a diameter larger than the outer diameter on the rear end side by 0.01 mm to 0.1 mm. 2. The drill according to claim 1, wherein a rake angle of 20 ° and a clearance angle of 5 ° to 20 ° are set, and the chip discharge groove is formed with a helix angle of 60 ° or less.
The drill according to any one of claims 1 and 2, wherein the tip portion, the tapered portion, and the straight portion are integrated coaxially.
The drill according to claim 3, wherein the axis of the tip, the taper, and the straight is aligned with the axis of rotation.
A flow path is formed along the rotation center axis in the tapered portion and the straight portion while opening at the distal end portion, and air or cutting oil flowing through the flow passage is ejected at the distal end portion. The drill according to any one of claims 1 to 4, wherein the drill is characterized.
A drilling tool provided with the drill according to any one of claims 1 to 5.
A machining method for drilling a workpiece including at least a part of a fiber-reinforced composite material using the drill according to any one of claims 1 to 5, wherein the tip cutting edge and the taper portion of the tip portion A machining method, comprising: drilling a prepared hole in the workpiece with the outer peripheral cutting edge and performing a finishing process on the formed prepared hole with the straight portion.
Drive means for holding the drill according to any one of claims 1 to 5 and rotationally driving about a central axis of the drill, and support means for supporting a workpiece including at least a part of a fiber reinforced composite material A machining apparatus comprising: a moving means for relatively moving the driving means and / or the supporting means so as to drill the drill into the workpiece.