JP2010260115A - Tool for drilling hole in fiber-reinforced composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tool for drilling a hole in a fiber-reinforced composite material, which can prevent burrs and exfoliation of a fiber layer even if a diameter of a hole to be worked is large and also suppress chattering vibration so as to efficiently obtain a worked hole with high quality. <P>SOLUTION: The tool for drilling a hole in a fiber-reinforced composite material is such structured that a blade 3a extending axially forward while inclining radially outward from a rotation center C is formed at the tip of a body 4, a cutting edge 7 is formed on the blade 3a but no cutting edge is present at the rotation center at the tip of the body, and the cutting edge 7 provided between the tip and the outermost periphery of the blade 3a is inclined toward a base end of the blade as coming from the tip of the blade 3a toward the outermost periphery. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tool for making a hole in a fiber reinforced composite material such as a fiber reinforced plastics (FRP) material containing a reinforcing fiber such as carbon fiber and a matrix resin.

  FRP, particularly CFRP (carbon fiber reinforced plastic), has a large specific strength and specific elastic modulus, and has recently been frequently used for aircraft and vehicle structures. When constructing a structure using such an FRP material, the FRP member is usually drilled and connected with bolts or rivets. For this reason, for example, an FRP is applied to a structure such as an aircraft part. To use the material, a lot of drilling is required.

  In the drilling of the FRP material, as shown in FIG. 12, problems of processing quality occur, such as fiber fluffing easily occurring at the exit part of the hole, and the FRP material having a laminated structure is likely to be peeled off between layers. Cheap.

  On the other hand, when the application is a structure such as an aircraft, high processing quality is required. Therefore, avoiding the quality problems described above is extremely important. In addition, high-strength CFRP materials, etc., cause the tool blade to wear faster, resulting in faster tool replacement in order to maintain the machining quality, leading to an increase in tool costs in the product cost. is there.

  In order to avoid such a problem, several improvement measures have been proposed so far. For example, in Patent Document 1 below, the twist groove of the drill is formed in the direction opposite to the normal twist direction (reverse twist), and the cutting edge at the tip of the drill is an intermediate portion between the inner peripheral side and the outer peripheral side. It has been proposed to form a V-shape that intersects with each other. This drill first creates a cutting form that pushes the fiber in the FRP with a negative rake angle by making the torsion groove counter-twist, while suppressing the vibration during processing by the V-shaped cutting edge shape By cutting, it is possible to suppress burrs and peeling at the edge around the hole. However, in the case of the method of Patent Document 1, since the load during processing is concentrated on the outer periphery of the drill cutting edge, wear and chipping are likely to occur in the same portion. Furthermore, since the edge of the hole is formed at the same time, especially when the cutting edge is damaged, the generated burrs and fluff cannot be removed any more, so that a good machining quality can be maintained. Is difficult.

  Therefore, the inventors have proposed a machining method that uses a ball end mill or a radius end mill as in Patent Document 2 to perform drilling by rotation around the main axis and feed movement in the axial direction, as in a normal drill. Thereby, the burr | flash around the hole of FRP material and suppression of peeling are possible, and a favorable processing quality is obtained. However, this method is very effective for a hole having a relatively small diameter. However, when the hole diameter exceeds 10 mm, the axial force that the tool exerts on the workpiece (workpiece). It has been found that (thrust force) tends to increase, and for this reason, even if a ball end mill is used, burrs and the like cannot be sufficiently suppressed. In addition, when drilling with a ball end mill, chatter vibration is also likely to occur. For this reason, if the hole diameter is large, further measures are required.

  In addition, it is thought that the thrust force increase in large-diameter hole processing can be avoided by using a tool with a small existence ratio in the radial direction of the cutting edge as in Patent Document 3, for example. Although this document does not mention such a thing, it is presumed that the effect of reducing the thrust force is included.

Japanese Patent No. 2699527 JP 2009-39810 A Japanese Patent Laid-Open No. 02-237707

  In the tool shape described in Patent Document 3, the cutting edge of the cutting edge is located closer to the outer periphery. In the case of this form, since the machining is performed from the vicinity of the hole edge of the final hole finish location, a large thrust force is initially applied to the same portion. For this reason, as shown in the schematic diagram of FIG. 13, there is a large difference in the pressure applied to the work material between the inside and outside of the hole finish (outside the hole edge where the pressing pressure is not applied to the outer periphery of the hole and the work material). Occurs, and peeling of the fiber layer occurs around the hole. This peeling will occur around the final machining diameter from the beginning, and the hole diameter will not increase any further, so it cannot be removed even in subsequent machining.

  This invention is a high-quality drilling tool for fiber reinforced composite materials, especially when the machining hole diameter is large, suppressing thrust force to suppress burrs and fiber layer peeling, and suppressing chatter vibration. An object is to realize and provide a drilling tool capable of efficiently obtaining a machined hole.

  In order to solve the above-described problems, the drilling tool of the present invention is formed with a blade portion extending radially outward from the rotation center of the main body portion tip and extending forward in the axial direction, and a cutting blade is formed on the blade portion. And there is no cutting edge at the center of rotation at the tip of the main body, and the cutting edge provided between the cutting edge and the outermost periphery of the blade part moves toward the outermost periphery from the cutting edge of the blade part. It is characterized by being inclined toward the end side (side closer to the shank).

  In this drilling tool, there is no cutting edge on the inner peripheral side of the cutting edge of the blade part, and the tool end face occupied by one cutting edge in the end face view (axial view) of the tip of the tool It is effective that the ratio of the length in view is 50% or less of the tool radius. Further, the tip angle is gradually or gradually decreased from the tip of the blade portion toward the outer periphery, and further, the tip angle on the outer periphery is 60 ° or less and the clearance angle of the cutting blade is 15 ° or more. Is desirable.

  In addition, a through-hole for suction collection and pressure discharge of chips is provided in the axial center of the tool, the cutting edge is made of a hard sintered body such as sintered diamond, or a cemented carbide. It is also advantageous to form a cutting edge portion by applying a diamond coating layer by a vapor phase growth method on the surface of the substrate to be formed, and polishing the blade edge after film formation.

  By making the tool for drilling fiber reinforced composite materials into a structure that does not have a cutting edge at the center of rotation at the tip of the main body, the machining allowance of the work material is reduced compared to machining with a normal drill, etc. It is possible to reduce the thrust force that greatly affects This is also advantageous when using an air-driven processing device with a small driving force. In addition, when cutting fiber-reinforced composite materials, chips become powdery and the working environment deteriorates. However, with this tool, the amount of chips can be reduced by reducing the machining allowance.

  This effect is particularly easily obtained when the ratio of the length in the radial direction in the tool end view occupied by one cutting edge is 50% or less of the tool radius. In addition, since there is no blade at the center of rotation, a large hole can be made in the axial center of the main body, and powdered chips can be sucked and collected or pumped and discharged using the hole as a discharge passage.

  In addition, by having a cutting edge that goes to the base end side of the blade part from the cutting edge to the outermost periphery between the cutting edge and the outermost periphery of the cutting edge, the final at the beginning of the hole penetration The hole is smaller than the machining diameter. And since a process diameter becomes large gradually from there, the effect like a finishing process is acquired. Moreover, at this time, the thrust force is also applied to the finishing allowance area, and after the cutting edge penetrates the work material, the machining area gradually narrows and the pressure applied to the fiber layer gradually decreases. The fiber layer is difficult to peel off.

  Therefore, large burrs and peeling are unlikely to occur when the tool starts to penetrate the work material. Once large burrs or delamination occurs during the hole penetration, there are many cases that cannot be removed even after finishing, and the tool of the present invention can obtain good machining quality by preventing this.

  Note that a tool that does not have a cutting edge on the inner peripheral side of the cutting edge of the cutting edge is highly effective in avoiding the problems of burrs and separation during hole penetration by reducing the thrust force, and when starting to penetrate the work material. The quality can be kept even better.

  In addition, since the tool whose tip angle is reduced from the tip of the blade portion toward the outer peripheral side has a shorter cutting edge length in the axial direction than a tool with a constant tip angle having the same tip angle on the outer periphery, Reduction of machining time and chatter vibration can be achieved.

  Furthermore, the above-mentioned finishing effect is particularly noticeable with a tool whose tip angle on the outer periphery is set to 60 ° or less. In addition, since the CFRP material has a particularly large elastic recovery amount, the finished surface of the hole is likely to come into contact with the flank of the tool. If this happens, the work quality may be degraded due to the friction of the flank, but those with a clearance angle of 15 ° or more correspond to the expected elastic recovery of the work material even when the work material is CFRP. The amount of flank clearance that can be obtained is secured, and the processing quality is less likely to deteriorate due to friction on the flank surface.

  In addition, in the tool of the present invention, the radial length of the cutting edge is shorter than that of a normal drill or end mill. Therefore, chatter vibration that is likely to occur when processing a particularly thin work material can be effectively suppressed.

  Furthermore, since the cutting edge is short, the cost of the tool can be suppressed even if an expensive blade material such as a sintered diamond material (PCD material) is brazed and used. A diamond coating tool is often used in the processing of CFRP material. However, when the film thickness of the coating layer is increased in order to improve the wear resistance, the roundness of the cutting edge becomes large and the sharpness is lowered. In the case of a general drill-like shape, it is difficult to sharpen the cutting edge by polishing, but since the tool of the present invention has a short blade length and a simple shape, the cutting edge is polished and sharpened after film formation. It is also possible. As a result, it is possible to provide a tool that has a long life and can perform high-quality processing.

The top view which shows the outline | summary of the 1st form of the drilling tool of this invention Side view of the drilling tool of FIG. (A)-(c) is a front view which shows the specific example of a blade shape Enlarged cross-sectional view of the cutting edge along the lines XX and YY in FIGS. 3 (a) to 3 (c) The top view which shows the outline | summary of the 2nd form of the drilling tool of this invention End view of the tip side of the drilling tool in FIG. The expanded sectional view of the principal part of the 3rd form of the drilling tool of this invention (A) The figure which shows the initial state of the drilling by the drilling tool of this invention, (b) The figure which shows the state which progressed to the middle of the drilling The figure which shows the side surface shape and planar shape of the work material which were hollowed by the hole processing by the drilling tool of this invention The figure which shows the property of the hole processed with invention product 6 of an Example The figure which shows the change of the thrust force measured in Example 2 Diagram showing burrs generated at the edge of a hole when a hole is machined in the FRP material with a normal tool Schematic diagram showing a state in which a thrust force acts on the fiber layer when a hole is machined in the FRP material with the tool of Patent Document 3.

  Embodiments of a drilling tool according to the present invention will be described below with reference to FIGS. 1 and 2 show an outline of almost the entire drilling tool of the first embodiment. This drilling tool is constructed by additionally machining a blade portion characterizing the present invention to a blade-type replaceable boring bit, and is provided at the head portion 2 provided at the tip of a steel-shaped circular shank 1, A cemented carbide blade 3 is detachably mounted.

  In this tool, the cutting tool 3 is fastened to the head portion 2 using the presser 5 and the clamp screw 6. However, even if the cutting tool having a mounting hole is directly fixed to the head portion 2 using the clamp screw. Of course, it is allowed to integrally form the main body portion 4 including the shank 1, the head portion 2, and the cutting tool 3.

  The cutting tool 3 of the illustrated tool is attached eccentrically from the central axis (rotation center) C of the main body 4, and the radial distance from the central axis C to the outermost periphery of the cutting part 3 a formed on the cutting tool 3. L is the radius of the machining hole. W in FIG. 3A is the blade width. The blade width W needs to consider the strength of the blade portion 3a and the like, but the value is preferably 50% or less of the tool radius.

  The tip shape (blade shape) of the blade portion 3a has several patterns as shown in FIG. This figure is a view of the blade portion 3a from the rake face side, and in the same way as defined by a general drill, θ {Fig. 3 (c) is twice the angle represented by θ1, θ2}. The angle is the tip angle in the present invention.

  In the blade shape of FIG. 3A, the leading edge of the blade portion 3a is between the radially inner end and the outer end of the blade portion 3a, and both the outer peripheral side and the inner peripheral side with the leading edge as a boundary. There is a cutting edge 7. The cutting edge 7 provided between the leading edge of the blade portion 3a and the outermost periphery is inclined at an angle θ toward the base end side (side closer to the shank) of the blade portion as it goes from the leading edge of the blade portion 3a to the outermost periphery. The tip angle 2 × θ is determined by the inclination angle. The tip angle 2 × θ is preferably 60 ° or less in order to enhance the finishing effect.

  FIG. 3 (b) shows that the inner peripheral side of the blade portion 3a is processed so as to protrude to the foremost end, and the base of the blade portion becomes closer to the outermost side than the foremost end as the blade portion 3a moves from the foremost end to the outermost periphery. There is a cutting edge 7 inclined toward the end side. Further, in FIG. 3C, the tip angle is set in two stages of 2 × θ1 on the inner peripheral side and 2 × θ2 smaller than 2 × θ1 on the outer peripheral side. The blade shape of FIG. 3C can shorten the axial length of the cutting edge 7 while keeping the tip angle on the outer peripheral side the same as the shape of FIG. 3B where the tip angle is constant. Therefore, shortening of processing time and suppression of chatter vibration can be expected.

  The tip angle of the blade shape in FIG. 3C can be changed so that the tip angle gradually decreases from the inner peripheral side toward the outer peripheral side with the cutting edge 7 as a curved cutting edge. The tip angle of the outer peripheral portion is preferably 2 × θ2 of 60 ° or less.

  In any of the shapes, the cutting edge ridgeline viewed from the rake face side of the most advanced small region w of the blade portion 3a is allowed to be reinforced by chamfering or honing for countermeasures against defects. The cutting edge 7 is extended in the form which goes to the base end side of the blade part 3a from the strengthened cutting edge to the outer periphery. Here, when the chamfered surface is inclined on the inner peripheral side when viewed from the rake face side, for example, or rounded by the R honing process, strictly speaking, the inner periphery is more than the front edge of the blade part 3a. In this invention, about the form of FIG.3 (b), (c) which arrange | positions the inner peripheral side of the blade part 3a in the forefront of a blade part, there exists a micro length blade. The part is also regarded as the cutting edge of the cutting edge. The cutting edge 7 is given a clearance angle γ shown in the cross-sectional view of FIG. 4 in order to avoid contact with the finished surface after processing.

  In the present embodiment, the blade portion 3a is provided only on one side of the central axis C and the tool is in the form of a single blade, but a plurality of similar blade portions 3a are provided at a constant pitch in the circumferential direction with reference to the central axis C. It can also be configured as a two-blade tool having a symmetrical shape or a multi-blade tool having more than one blade. However, when processing fiber reinforced composite materials such as CFRP, the thrust force applied to each blade reaches a certain level even if the feed amount per blade is reduced and does not decrease below that. If this is done, the total thrust force increases, which may adversely affect the processing quality. Therefore, it is desirable to set the number of blades to 3 or less. The same applies to tools of other embodiments described later. Alternatively, a hard sintered body such as sintered diamond may be brazed to the replaceable cutting tool 3, and the cutting edge may be constituted by the hard sintered body.

  A second embodiment of the tool of the present invention is shown in FIGS. In the drilling tool of the second form, the shank 1 is formed of a steel pipe. The shank 1 has a part on the tip side removed to form a chip pocket 8. And the cutting tool 3 comprised by the cemented carbide or sintered diamond which has the above-mentioned cutting edge 7 is joined to the protrusion part which faced the chip pocket 8 of the front-end | tip of this shank 1 by brazing.

  In the tool of the second form, the outer peripheral surface of the shank 1 (the outer peripheral surface of the pipe) is placed on the inner peripheral side with respect to the radial outer end of the cutting edge 7 so that the shank 1 does not interfere with the work material during drilling. It arrange | positions and the inner peripheral surface (inner peripheral surface of a pipe) of the shank 1 is arrange | positioned on the outer peripheral side rather than the radial direction inner end of the cutting blade 7 conversely. In addition, it is not necessary to satisfy | fill the above relationships about the part which does not enter the inside of a processing hole at the time of a process on the base end side of a shank. Further, the tip of the shank 1 is also moved backward in the axial direction from the tip of the cutting edge 7.

In this tool, since the shank 1 is constituted by a hollow pipe, it is possible to forcibly collect and discharge chips by forcibly sucking and collecting chips by passing an air flow by suction or pressure feeding through a through hole 9 provided in the center of the shank 1. It is. In addition, although the front-end | tip of the blade part of this tool was made into the shape similar to FIG.3 (b), a front-end | tip shape like FIG.3 (a) and FIG.3 (c) may be sufficient. The material of the blade 3 may be a brazed hard sintered body such as sintered diamond in addition to the cemented carbide.

  Next, a third embodiment is shown in FIG. Since the tool shape and the like of the third embodiment are the same as those of the first embodiment, the illustration is omitted. In the third embodiment, the cutting tool 3 is formed by applying a diamond coating layer 3c by vapor phase growth to a cemented carbide base material 3b.

  The diamond coating layer 3c is rounded and blunted as the film thickness increases, and this causes deterioration of the processing quality. Therefore, the cutting edge of the cutting edge 7 after film formation as shown in the cross-sectional shape of FIG. It is good to use after carrying out the grinding | polishing process (process which removes the dull part of a chain line) which sharpens. As for the base material, it is desirable to use a Co binder amount of 8% or less in order to ensure the adhesion of the coating layer.

  Further, if the thickness of the diamond coating layer 3c is too thin, the wear resistance is lowered and the effect of the polishing treatment is difficult to be obtained. Therefore, it is recommended that the thickness is generally 10 μm or more. As a polishing method, there are a method using a diamond grindstone, and a method of pressing a stainless steel rod or a CFRP material rotated at high speed.

The performance evaluation test of the tool of this invention was conducted. The evaluation test will be described below.
The drilling tool used for the evaluation is the one described in the first embodiment. The tool shank is S12F-CKBR-16 made by Sumitomo Electric Hardmetal, and the tool that can be replaced is KBMXR0311-05. did. The material of the blade is JIS K20 class cemented carbide.

  The radial distance L {see FIG. 1 (a)} from the central axis C of the main body to the outermost periphery of the cutting edge is 6 mm, and a hole of φ12 mm is processed. The blade width W {refer to FIG. 1 (a)} is 2 mm, and the ratio of the length in the tool end view to the tool radius of the cutting edge is 50% or less (1/3). Further, the cutting edge ridge line at the forefront of the blade portion is chamfered in a region w of about 20 μm in the hole radial direction (blade width direction) as viewed from the rake face side as a measure against a defect.

  Table 1 shows the specifications of the prepared inventive tool. Inventive product 1 has the blade shape of FIG. 3 (a), and the radial center portion of the blade width of 2 mm protrudes most forward in the axial direction. Inventive products 2 to 5 have the blade shape of FIG. 3 (b), and the inner periphery of the blade portion protrudes most forward in the axial direction. The invention product 6 has a two-stage tip shape as shown in FIG. 3C, and has an inner peripheral tip angle 2 × θ1 = 90 ° and an outer peripheral tip angle 2 × θ2 = 40 °.

  As a comparative product, a general twist drill was prepared. An uncoated two-blade drill made of JIS Z20 class cemented carbide of φ12 mm, with a tip angle of 140 ° and a helix angle of 30 °.

  The work material is a plate material of carbon fiber reinforced plastics (CFRP), and eight unit layers having carbon fibers are joined in the in-plane direction, and the total thickness is 2.78 mm. The CFRP material was drilled in the thickness direction. The processing conditions at that time are through-hole processing under a dry condition with a cutting speed of 100 m / min, a feed amount per tooth fz = 0.025 mm / tooth.

  FIG. 8 shows an initial state of processing and a state during processing. The hole outer peripheral portion is grooved to form a circle, and the inner peripheral portion is cut out as shown in FIG. 9 from the processed portion. Such processing can be realized because the processing target is a fiber reinforced composite material in which chips become powdery, and the hole depth is particularly large in work materials that generate continuous chips such as metal. If so, there is a high possibility of clogging. Table 1 shows the maximum length of burr (fluff) generated at the hole exit of the first hole and the thrust force per blade as evaluation of the processing result.

  As can be seen from Table 1, the inventive product is superior to the comparative product (conventional drill) in both processing quality and thrust force. With respect to the tip angle on the outer periphery, the inventive products 5 and 6 of 60 ° or less are good with small burrs. A hole 11 machined into the work material 10 with the invention 6 having the best machining quality and thrust force is as shown in FIG. Further, it can be seen that the thrust angle is particularly small when the clearance angle is 15 ° or more, and it is desirable that the clearance angle is 15 ° or more because the effect of reducing the thrust force is remarkably brought out.

  Next, the verification result of the influence of the ratio of the length of the cutting edge in the tool radial direction in the tool end view will be described. The drilling tool used is the second form of FIGS. 5 and 6, the shank is formed of a steel pipe having an outer diameter of φ13.8 mm, and a K-type cemented carbide cutting tool is brazed to the tip thereof. . A distance L from the central axis of the main body to the radially outer end of the cutting edge is 7 mm, and a hole of φ14 mm is made. The blade shape was the type shown in FIG. 3B, and the tip angle θ was 60 ° and the clearance angle γ was 15 °.

  A hole was made in the same work material under the same conditions as in Example 1 by changing the ratio of the length of the cutting edge of the tool in the tool end view in the tool radial direction. In addition, the wall thickness of the pipe constituting the shank is 0.4 mm smaller than the blade width, and the inner circumference of the pipe is arranged outside the radial inner end of the cutting blade to prevent interference with the work material during machining. The structure is to avoid.

  FIG. 11 shows the measurement results of the thrust force in processing using this tool. As described above, when the ratio of the length of the cutting edge in the tool radial direction in the tool end view exceeds 50%, the thrust force tends to increase rapidly.

  In order to verify the effect of forced discharge of chips, the same tool as in Example 2 with a cutting edge length ratio in the tool end view set to 1/3 of the tool radius was used. A 12 mm CFRP material was drilled.

  Here, a comparison was made between normal drilling and chip suction through the spindle of the machining center. As a result, in the former normal processing mode, the maximum burr at the processing hole exit was about 0.6 mm, but in the latter mode in which chips are sucked and collected, the burr was suppressed to about 0.2 mm.

  Especially in processing that increases the plate thickness, chips are likely to accumulate in the circular groove before the hole penetrates, and residual chips adversely affect the processing, and burrs are likely to occur during hole penetration, but chips are processed by suctioning the chips. This eliminates the adverse effects on the machine and makes it possible to stably maintain high machining quality.

  Next, the result of evaluating the influence of the blade material is shown. This evaluation was performed by the same φ12 mm drilling test as in Example 1. A drilling tool in which sintered diamond is brazed to the tip of a cemented carbide cutting tool to form a cutting edge, and a diamond coating layer is applied on a cemented carbide substrate as in the third embodiment, and thereafter The drilling tools with sharpened cutting edges after polishing were compared.

Both tools had a tip angle θ = 60 ° and a clearance angle γ = 15 °. The material of the sintered diamond is DA2200 made by Sumitomo Electric Hardmetal. The diamond coating layer had an average particle size of diamond particles of about 1 μm, and the coating layer thickness was about 15 μm. A cylinder created by scraping the CFRP material was applied to the vicinity of the cutting edge after film formation while rotating from the rake face side and the flank face side to polish the cutting edge. The base material of the cutting tool provided with the diamond coating layer is made of JIS K01 class cemented carbide.
Table 2 shows the thrust force and the maximum burr length in the first hole and the 30th hole.

  As can be seen from Table 2, the inventive products 7 to 9 are all good at the initial stage of processing, but the inventive cemented carbide product 7 is deteriorated in burr and thrust force due to wear in the processing of the 30th hole. Yes. On the other hand, invention products 8 and 9 employing a sintered diamond and a diamond coating layer as a cutting tool both maintain a good state even when the 30th hole is processed. The inventive product 10 in which the cutting edge of the diamond coat is not polished has a relatively large burr at the time of processing the first hole, and it is important to improve the sharpness of the cutting edge in order to improve the processing quality of the hole. I understand. In addition, since the cutting edge of the invention product 10 is sharpened from the initial stage due to wear over time, burrs at the 30th hole rather than at the 1st hole are reduced.

DESCRIPTION OF SYMBOLS 1 Shank 2 Head part 3 Cutting tool 3a Blade part 3b Base material 3c Diamond coating layer 4 Main body part 5 Presser 6 Clamp screw 7 Cutting blade 8 Chip pocket 9 Through hole 10 Work material 11 Hole w Cutting edge reinforcement processing area C Main part Center axis θ, θ1, θ2 1/2 of the tip angle
γ Clearance angle W Blade width L Distance from the central axis to the outer radial edge of the cutting edge (tool radius)

Claims (8)

  A rotary cutting type drilling tool used for drilling a fiber reinforced composite material including a reinforcing fiber and a matrix resin, and a blade portion (3a) extending axially forward outward in the radial direction from the rotation center of the tip of the main body (4) ) Is formed, a cutting edge (7) is formed on the blade portion (3a), and there is no cutting edge at the center of rotation of the main body portion, and the cutting edge and the outermost periphery of the blade portion (3a) A fiber-reinforced composite material, characterized in that a cutting blade (7) provided therebetween is inclined toward the base end side of the blade portion (3a) from the foremost end of the blade portion (3a) toward the outermost periphery. Drilling tool.   The fiber-reinforced composite material drilling tool according to claim 1, wherein the inner peripheral side of the blade portion (3a) is located at the forefront of the blade portion, and the cutting edge (7) exists only radially outward from the foremost portion. .   The fiber reinforcement according to claim 1 or 2, wherein a ratio of a length in a radial direction occupied by one cutting edge (7) is 50% or less of a tool radius in an end face view of the tip side of the tool. Drilling tool for composite materials.   4. The fiber-reinforced composite material drilling tool according to claim 1, wherein a tip angle (2 × θ, 2 × θ2) on the outer periphery is set to 60 ° or less.   The fiber reinforced composite material drilling tool according to any one of claims 1 to 4, wherein a clearance angle (γ) of the cutting edge (7) is 15 ° or more.   The fiber reinforced composite material drilling tool according to any one of claims 1 to 5, characterized in that a through hole (9) is provided in the main body (4) for rotating and collecting chips for suction or pumping and discharging. .   The fiber reinforced composite according to any one of claims 1 to 6, wherein at least a part of the blade portion (3a) is made of sintered diamond, and the sintered diamond is provided with a cutting blade (7). Material drilling tool.   The diamond coating layer (3c) synthesized by the vapor phase growth method was applied on the base material (3b) of the cemented carbide, and the blade portion (3a) subjected to the polishing treatment of the blade edge after film formation was provided. A drilling tool for a fiber-reinforced composite material according to any one of claims 1 to 6.