JP2013252588A - Quadruple angle drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quadruple angle drill that can prevent delamination or burr on end faces at an entrance side and an exit side of a hole by suppressing wear of a tool even when drilling in a high efficient cutting condition.SOLUTION: A quadruple angle drill has the relation of α1>α2>α3>α4, in which α1 is a first tip end angle that is formed by an opposite first cutting blade, α2 is a second tip end that is formed by an opposite second cutting blade, α3 is a third tip end angle that is formed by the opposite second cutting blade, and α4 is a fourth tip end angle that is formed by the opposite second cutting blade, when viewed in a cross section that passes a tool shaft, and is in parallel to the tool shaft.

Description

  The present invention relates to a quadruple angle drill suitable for machining of composite materials, particularly CFRP (carbon fiber reinforced plastic).

  In recent years, the main material used in aircraft manufacturing has changed from aluminum alloys to composite materials. Among the composite materials, CFRP (carbon fiber reinforced plastic, hereinafter referred to as CFRP) is particularly frequently used. Since CFRP has the property of having both lightness and strength, use in an aircraft can greatly contribute to weight reduction of the aircraft and improvement of fuel consumption.

  However, since CFRP improves the strength by adding carbon fiber to a plastic base material such as plastic, the wear of the tool progresses early during cutting, and delamination (peeling) occurs on the processed surface. And burr will occur. Therefore, it is very difficult to process as compared with a normal material, that is, a metal material or a resin material.

  In particular, when drilling a plate-like CFRP using a drill, delamination (burring) and burrs are likely to occur on the end surface on the inlet side of the hole and on the end surface on the outlet side of the hole. Further, as described above, when CFRP is machined, since the wear of the tool proceeds at an early stage, the cutting resistance increases, and delamination and burrs are more likely to occur. Therefore, in order to achieve the formation of a good machined surface and the improvement of the tool life, the cutting conditions have to be lowered, and the drilling of CFRP is a process that requires high cost.

  In order to solve such a problem, a drill used for drilling CFRP is disclosed in the conventional literature.

  Patent Document 1 relates to a triple angle drill having a first cutting edge, a second cutting edge, and a third cutting edge, and even when drilling FRP, cutting is properly performed to the end (outer peripheral edge). It is disclosed that the generation of delamination due to excessive progress of the drill can be suppressed, and a good hole quality can be obtained.

  Patent Document 2 relates to a fiber reinforced composite material drilling tool in which the cutting edge is divided into at least three parts in the radial direction, and the tip angle of each blade part gradually decreases from the rotation center side to the outer peripheral blade part. Therefore, it is disclosed that an increase in the length of the outermost peripheral blade portion can be suppressed, and the problem of reduction in machining efficiency due to the cutting blade becoming longer in the axial direction can be avoided.

  Patent Document 3 relates to a fiber reinforced plastic drill having a third cutting edge in which a clearance angle is provided in a margin of a drill having the first and second cutting edges, and the occurrence of fusion of the drilled portion. It is disclosed that high-precision drilling can be realized.

JP 2010-284783 A JP 2009-172708 A JP 2010-17817 A

  However, in the drilling of CFRP, which is the subject of the present invention, as described above, delamination (burring) and burrs on the machined surface, and a reduction in tool life in a cutting tool, that is, a drill, are major issues.

  Although the triple angle drill described in Patent Document 1 has a first cutting edge, a second cutting edge, and a third cutting edge, since the change in the tip angle of each cutting edge is large, There is a problem that the difference in cutting resistance between the blades becomes large, and delamination and burrs cannot be suppressed when drilling is performed under highly efficient cutting conditions.

  Similar to the triple angle drill described in Patent Document 1, the fiber-reinforced composite material drilling tool described in Patent Document 2 has a cutting edge divided into at least three parts in the radial direction, and the tip angle of each blade part is the center of rotation. It decreases in a stepwise manner from the outer edge to the outer edge, but since the change in the tip angle at each cutting edge is large, the difference in cutting resistance at each cutting edge increases, resulting in high-efficiency cutting conditions. Therefore, there is a problem that delamination and burrs cannot be suppressed when drilling is performed.

  The fiber-reinforced plastic drill described in Patent Document 3 has a very large tip angle of 10 ° to 90 ° at the second cutting edge, and therefore, delamination (peeling) easily occurs on the wall surface of the hole. There is a problem that a processed surface of a simple hole cannot be formed.

  The present invention solves these problems and suppresses the wear of the tool even when drilling is performed under highly efficient cutting conditions, so that the end surface on the inlet side of the hole and the end surface on the outlet side of the hole An object of the present invention is to provide a quadruple angle drill that can prevent delamination and burr.

  In order to solve the above problems, the present invention provides four linear cutting edges for each main cutting edge in order to suppress tool wear, delamination and burrs. A quadruple angle drill characterized in that a tip angle formed by a blade is gradually reduced from a tool axis side to an outer peripheral side.

  That is, the present invention is provided with a blade groove, a leading edge, a land, and a margin along the tool axis, and a linear first cutting edge, a linear second cutting edge, and a linear first cutting edge are provided on the tip side. A quadruple angle drill provided with a main cutting edge comprising three cutting edges and a linear fourth cutting edge, the first cutting edges facing each other when viewed in a projection view obtained by rotating a tool A first tip angle α1, a second tip angle α2 formed by an opposing second cutting edge, a third tip angle α3 formed by an opposing third cutting blade, and a fourth tip angle α4 formed by an opposing fourth cutting blade. Is a quadruple angle drill provided with a relationship of α1> α2> α3> α4.

  In the present invention, it is desirable to provide the first tip angle α1 in the range of 140 ° to 160 °.

  In the present invention, it is desirable to provide the second tip angle α2 in the range of 80 ° to 100 °.

  In the present invention, it is desirable to provide the third tip angle α3 in the range of 50 ° to 70 °.

  In the present invention, it is desirable to provide the fourth tip angle α4 in the range of 20 ° to 40 °.

  In the present invention, the first cutting edge is formed by a relief surface and a thinning surface of the first cutting edge, and the thinning surface is provided on the front side in the rotation direction with respect to the first cutting edge and the first cutting edge. It is desirable that the first cutting edge is formed so as to be connected to the rear end of the flank of the first cutting edge.

  According to the present invention, it is possible to suppress the occurrence of delamination and burrs that occur in the drilling of composite materials (especially CFRP) used as aircraft materials, and to form a good hole processing surface. Become.

  Furthermore, since the present invention provides four linear cutting edges per main cutting edge, it reduces the difference in cutting resistance that occurs between the respective linear cutting edges, and promotes early wear and tool life. It is possible to suppress the decrease. Therefore, highly efficient drilling in the composite material can be realized at low cost.

It is the figure which showed the external appearance of the drill of this invention. It is the figure which rotated the side view of the drill of this invention shown in FIG. 1 90 degrees in the rotation direction, and expanded. It is the figure which rotated the drill of this invention shown in FIG. 1 90 degrees in the rotation direction, and expanded the main cutting edge vicinity of the drill. It is the figure which expanded the main cutting edge vicinity of the drill of this invention shown in FIG. It is sectional drawing when the drill of this invention is seen with the projection view obtained by rotating a tool. It is a figure which shows the thickness of the chip | tip formed with each cutting edge when the drill of this invention is sent at a predetermined distance in the tool axis direction. It is a photography photograph of the processing surface when cutting length is 1680mm (the number of processing holes is 280 holes) by example 1 of the present invention. It is the picked-up photograph of the processed surface when the cutting length is 1680 mm (the number of processed holes is 280 holes) by the prior art example 2. FIG. It is a photography photograph of the processing surface when cutting length is 5040mm (the number of processing holes is 840 holes) by example 1 of the present invention. It is the picked-up photograph of the processing surface when the cutting length is 5040 mm (the number of processing holes is 840 holes) by the prior art example 2. FIG.

  Hereinafter, the quadruple angle drill of the present invention (sometimes referred to as the drill of the present invention) will be described with reference to FIGS.

  FIG. 1 is a view showing the appearance of the drill of the present invention. A drill 1 according to the present invention is provided with a blade groove 2, a leading edge 3, a land 4, a first margin 5 and a second margin 6 along a tool axis O, and a straight first cutting edge on the tip side. The quadruple angle drill is provided with a main cutting edge 7 composed of a linear second cutting edge, a linear third cutting edge, and a linear fourth cutting edge.

  FIG. 1 shows a straight shank drill in which the shank diameter D which is the diameter of the shank portion 8 and the blade diameter d which is the diameter of the blade portion 9 are the same, but the blade diameter d is larger than the shank diameter D. Even when it is provided small, the advantageous effects of the present invention can be obtained.

  FIG. 1 shows a quadruple angle drill having two blades. In the present invention, it is more desirable that the number of blades be 2 to 3 blades. Here, “the number of blades is 2 to 3 blades” means that 2 to 3 main cutting edges 7 are provided.

  FIG. 2 is an enlarged view of the drill of the present invention shown in FIG. The main cutting edge 7 in the drill of the present invention is connected to the tool axis O, connected to the first cutting edge 10 extending to the outer peripheral side, and the second cutting edge 10 connected to the outer peripheral end of the first cutting edge 10 and extending to the outer peripheral side. Connected to the outer peripheral end of the cutting edge 11 and the second cutting edge 11, connected to the outer peripheral end of the third cutting edge 12 extending to the outer peripheral side, and extended to the outer peripheral side. It is composed of a fourth cutting edge 13. The fourth cutting edge 13 is connected to the leading edge 3.

  The first cutting edge 10 in the present invention is a ridge formed by the flank 14 and the thinning surface 15 of the first cutting edge. Chips formed by the first cutting edge 10 during the cutting process pass through the thinning surface 15 and are discharged into the blade groove 2.

  The second cutting edge 11 in the present invention is a ridge formed by the flank 16 of the second cutting edge and the blade groove 3. Similarly, the third cutting edge 12 is a ridge formed by the flank 17 of the third cutting edge and the blade groove 3, and the fourth cutting edge 13 is the flank 18 of the fourth cutting edge and the blade groove 3. A ridgeline composed of

  The drill of the present invention is provided with the first cutting edge 10, the second cutting edge 11, the third cutting edge 12, and the fourth cutting edge 13, which are four linear cutting edges, per main cutting edge 7. Is a major feature. Thereby, it is possible to reduce a difference in cutting resistance generated between the respective linear cutting edges, and to suppress early progress of wear and a decrease in tool life. Therefore, highly efficient drilling in the composite material can be realized at low cost.

  FIG. 3 is an enlarged view of the vicinity of the main cutting edge of the drill by rotating the drill of the present invention shown in FIG. 1 by 90 ° in the rotation direction. As shown in FIG. 3, the fourth cutting edge 11 is connected to the leading edge 3, and the flank 18 of the fourth cutting edge is connected to the land 4, the first margin 5, and the second margin 6.

  FIG. 4 is an enlarged view of the vicinity of the main cutting edge of the drill of the present invention shown in FIG. As described above, the flank 18 of the fourth cutting edge is connected to the land 4, the first margin 5, and the second margin 6. Further, the thinning surface 15 in the drill of the present invention includes the blade groove 2, the first cutting edge 10, the end of the second cutting edge on the rear side in the rotational direction 16 and the flank 17 of the third cutting edge. It is provided so that the edge part of the rotation direction back side may be connected.

  FIG. 5 is a cross-sectional view of the drill of the present invention as seen in a projection view obtained by rotating a tool. In the present invention, when viewed in a projection view obtained by rotating the tool, the first tip angle α1 formed by the opposed first cutting edge and the second tip angle α2 formed by the opposed second cutting edge are opposed to each other. The third tip angle α3 formed by the third cutting edge and the fourth tip angle α4 formed by the opposed fourth cutting edge are provided in a relationship of α1> α2> α3> α4.

  FIG. 6 is a diagram showing the thickness of chips formed by the respective cutting edges when the drill of the present invention is fed at a predetermined distance in the tool axis direction. Moreover, FIG. 6 can also be said to be a diagram showing the thickness of the chips formed by the respective cutting edges when the drill is fed at a distance of one blade feed amount f. The hatched portion in FIG. 6 indicates the thickness of the chips formed when the drill is fed at a distance of one blade feed amount f.

  In the drill of the present invention, the tip angles α1, α2, α3, and α4 formed by the respective cutting edges are provided in a relationship of α1> α2> α3> α4. Therefore, as shown in FIG. The thickness of the chips (the width of the hatched portion when measured in the direction perpendicular to the respective cutting edges) can be gradually reduced toward the outer peripheral side.

  That is, the thickness t1 of the chips formed by the first cutting edge, the thickness t2 of the chips formed by the second cutting edge, the thickness t3 of the chips formed by the third cutting edge, The respective cutting edges 10, 11, 12, and 13 are provided so that the relationship with the thickness t4 of the chips formed by the fourth cutting edge is a relationship of t1> t2> t3> t4. . Therefore, as the cutting speed increases, delamination (peeling) and burrs are more likely to occur on the processed surface of the hole. (Peeling) and generation of burrs can be prevented. Since the thickness of the chips generated by the cutting process becomes smaller toward the outer peripheral side, the cutting resistance on the outer peripheral side can also be reduced. Therefore, even in a composite material that is generally said to be difficult to drill, highly efficient drilling can be realized.

  In the present invention, it is desirable to provide the first tip angle α1 in the range of 140 ° to 160 °.

  In the present invention, it is desirable to provide the second tip angle α2 in the range of 80 ° to 100 °.

  In the present invention, it is desirable to provide the third tip angle α3 in the range of 50 ° to 70 °.

  In the present invention, it is desirable to provide the fourth tip angle α4 in the range of 20 ° to 40 °.

  As shown in FIGS. 2, 4, and 6, in the present invention, the first cutting edge is formed by a relief surface and a thinning surface of the first cutting edge, and the thinning surface includes the first cutting edge, It is desirable that the first cutting edge is formed so as to be connected to the rear end 19 of the flank of the first cutting edge in the first cutting edge provided on the front side in the rotational direction with respect to the first cutting edge. This makes it possible to form a short first cutting edge 10 on the center side, and has four cutting edges for realizing highly efficient drilling as compared with the conventional triple angle drill having three cutting edges. A quadruple angle drill can be manufactured.

  Hereinafter, the present invention will be described in detail by the following examples, but the present invention is not limited thereto.

Example 1
Using Comparative Example 1 and Conventional Example 2, a comparison test was performed on the processed surface of the hole when the CFRP was cut due to the difference in the number of linear cutting edges provided on one main cutting edge.

  Example 1 of the present invention is a quadruple angle drill according to the present invention in which four linear cutting edges are provided for each main cutting edge as shown in FIG. 2, and the number of cutting edges is two, and the first tip angle α1. Was 148 °, the second tip angle α2 was 90 °, the third tip angle α3 was 60 °, and the fourth tip angle α4 was 30 °. Further, the blade diameter d is 6.375 mm, the shank diameter D is 7 mm, and the groove length L when the blade groove 2 is measured in the direction of the tool axis is 50 mm (L / d = 7.84 times). The overall length was 120 mm, the twist angle of the blade groove 2 was 30 °, the core thickness d1 was 1.38 mm, and the cutting edge 7 was further coated with diamond coat.

  Conventional Example 2 is a triple angle drill described in Patent Document 1 in which three linear cutting edges are provided for each main cutting edge, and the number of cutting edges is two, and the first tip angle α1 is 120 °. The second tip angle α2 was 30 °, and the third tip angle α3 was 6 °. Further, the blade diameter d is 6.375 mm, the shank diameter D is 6.35 mm, and the groove length L when the blade groove 2 is measured in the direction of the tool axis is 51 mm (L / d = 8.0 times). ), The overall length was 101 mm, the twist angle of the blade groove 2 was 0 °, the core thickness d1 was 1.47 mm, and the cutting edge 7 was further coated with diamond coat.

  The cutting conditions were such that the work material was CFRP and a plate material having a thickness of 6 mm was used. At a horizontal machining center, the through-holes with cutting speed of 5000 min-1 (cutting speed approx. 100 m / min), feed amount per rotation of 0.1 mm / rotation and drilling depth of 6 mm are processed in the depth direction. It was. Air blow was used during the cutting process.

  As an evaluation method, when the cutting length is 1680 mm and 5040 mm, that is, when the number of processed holes is 280 holes and 840 holes, the end face on the inlet side of the processed hole and the end face on the outlet side of the processed hole are observed with a microscope, respectively. The presence or absence of burrs was confirmed.

  As an evaluation standard, when the cutting length is 1680 mm and 5040 mm, that is, when the number of processed holes is 280 holes and 840 holes, delamination or burrs are generated on the end surface on the inlet side of the processed hole and the end surface on the outlet side of the processed hole. What did not exist was considered good. The evaluation results will be described with reference to FIGS.

  FIG. 7 is a photograph of the machined surface when the cutting length is 1680 mm (the number of machining holes is 280 holes) according to Example 1 of the present invention. As shown in FIGS. 7 (a) and 7 (b), no delamination or burrs occurred on the end face on the inlet side of the processed hole and the end face on the outlet side of the processed hole.

  FIG. 8 is a photograph of the processed surface taken when the cutting length is 1680 mm (the number of processed holes is 280 holes) according to Conventional Example 2. As shown in FIG. 8A and FIG. 8B, in the drilling process according to the conventional example 2, burrs were generated on the end face on the inlet side of the processed hole, which was defective.

  FIG. 9 is a photograph of the machined surface when the cutting length is 5040 mm (the number of machining holes is 840 holes) according to Example 1 of the present invention. As in the case where the cutting length is 1680 mm (the number of processed holes is 280 holes), as shown in FIGS. 9A and 9B, the end surface on the inlet side of the processed hole and the end surface on the outlet side of the processed hole are Since lamination (peeling) and burrs did not occur, it was good.

  FIG. 10 is a photograph of a processed surface taken when the cutting length is 5040 mm (the number of processed holes is 840 holes) according to Conventional Example 2. As in the case where the cutting length is 1680 mm (the number of processed holes is 280 holes), as shown in FIGS. 10 (a) and 10 (b), in the drilling according to the conventional example 2, the end surface on the inlet side of the processed hole Because burr was generated, it was defective.

  From the above, the quadruple angle drill of the present invention in which four linear cutting edges are provided for one main cutting edge is a conventional triple in which three linear cutting edges are provided for one main cutting edge. It can be said that the effect that delamination (burring) and a burr | flash do not generate | occur | produce with respect to an angle drill on the end surface of the entrance side of a processing hole and the end surface of the exit side of a processing hole is very high.

  By using the drill of the present invention, it is possible to suppress the occurrence of delamination and burrs, which occur during drilling of composite materials used as aircraft materials, and to form a good hole processing surface. It becomes. Furthermore, since the present invention can suppress the early progress of wear and the reduction of the tool life in the drilling of the composite material, it is particularly suitable for the drilling of CFRP.

DESCRIPTION OF SYMBOLS 1 Drill of this invention 2 Cutting groove 3 Leading edge 4 Land 5 1st margin 6 2nd margin 7 Main cutting edge 8 Shank part 9 Cutting edge 10 1st cutting edge 11 2nd cutting edge 12 3rd cutting edge 13 4th cutting Blade 14 Flank of first cutting edge 15 Thinning surface 16 Flank of second cutting edge 17 Flank of third cutting edge 18 Flank of fourth cutting edge 19 Rear end of flank of first cutting edge 20 Second Rear end of flank of cutting edge 21 Rear end of flank of third cutting edge α1 First tip angle α2 Second tip angle α3 Third tip angle α4 Fourth tip angle t1 Chip formed by first cutting edge T2 Thickness of chips formed by the second cutting edge t3 Thickness of chips formed by the third cutting edge t4 Thickness of chips formed by the fourth cutting edge D Shank diameter d Blade Diameter f 1 blade feed amount

Claims (6)

A blade groove, a leading edge, a land, and a margin are provided along the tool axis, and on the tip side, a linear first cutting edge, a linear second cutting edge, and a linear third cutting edge, A quadruple angle drill provided with a main cutting edge comprising a linear fourth cutting edge,
When viewed in a projection view obtained by rotating the tool, the first tip angle α1 formed by the opposing first cutting edge, the second tip angle α2 formed by the opposing second cutting edge, and the opposing third cutting edge are The quadruple angle drill is characterized in that the third tip angle α3 formed and the fourth tip angle α4 formed by the opposed fourth cutting edge are provided in a relationship of α1>α2>α3> α4.   The quadruple angle drill according to claim 1, wherein the first tip angle α1 is provided in a range of 140 ° to 160 °.   The quadruple angle drill according to claim 1 or 2, wherein the second tip angle α2 is provided in a range of 80 ° to 100 °.   The quadruple angle drill according to any one of claims 1 to 3, wherein the third tip angle α3 is provided in a range of 50 ° to 70 °.   The quadruple angle drill according to any one of claims 1 to 4, wherein the fourth tip angle α4 is provided in a range of 20 ° to 40 °.   The first cutting edge is formed by a flank and a thinning surface of the first cutting edge, and the thinning surface is provided on the first cutting edge and the first cutting edge on the front side in the rotation direction with respect to the first cutting edge. The quadruple angle drill according to any one of claims 1 to 5, wherein the quadruple angle drill is formed so as to be connected to a rear end of the flank of the first cutting edge.