JP6378493B2 - drill - Google Patents

Description

  The present invention relates to a drill used for drilling.

  In recent years, weight reduction of aircraft parts and automobile parts has been demanded for the purpose of improving fuel efficiency, and CFRP (carbon fiber reinforced plastic) has attracted attention as an alternative material for iron-based alloys and aluminum alloys. This CFRP is often provided as a plate material having a composite structure combined with a relatively viscous metal such as aluminum or titanium. As a plate material having such a composite structure, a composite plate in which a metal material is stacked on one surface of CFRP is used. In order to apply such a composite plate to various parts, it is necessary to drill holes for riveting or screwing, so it is conceivable to drill the composite plate with a drill for a metal material. However, when a conventional general drill is used, if a composite plate is perforated from the metal material side, delamination of CFRP caused by the fiber material occurs, and if a composite plate is perforated from the CFRP side, the metal material There is a problem that burrs occur.

  Therefore, as described in Patent Document 1, a double angle drill having a two-stage cutting edge has been developed as a drill for solving such problems. This double-angle drill has a wear resistance improved by coating with a diamond film, and can prevent delamination and burring to some extent. However, even if the double angle drill described in Patent Document 1 is used, delamination and burrs cannot be sufficiently suppressed. Therefore, as described in Patent Documents 2 and 3, a drill having a Sarae blade formed on the rear side of the leading blade has been developed. This drill is called a fishtail type and can reduce the occurrence of delamination and burrs. In particular, the drill described in Patent Document 3 can greatly reduce the occurrence of delamination and burrs because the Sarae blade is inclined toward the tip end of the drill to make the edge of the Sarae blade have an acute angle.

Japanese Utility Model Publication No. 06-075612 JP 2008-000836 A Special table 2009-502538 gazette

  However, the drill described in Patent Document 3 has a problem in that the angle of the edge portion of the Sarae blade becomes small, so that the Sarae blade is easily chipped and the tool life is shortened.

  Accordingly, an object of the present invention is to provide a drill having a high drilling quality and a long tool life.

  A drill according to the present invention is a drill coated with a diamond film, which is formed from a rotation center of a tip portion and tilts radially outward of the drill with respect to the axis of the drill, and a diameter of the leading blade Formed on the outer side of the drill and inclined toward the tip of the drill with respect to the direction perpendicular to the axis of the drill, and formed on the outer side in the radial direction of the Sarae blade and radially outward of the drill with respect to the axis of the drill And a finishing blade inclined to the surface.

  According to the drill of the present invention, a hole can be formed in the workpiece by cutting the workpiece with the leading blade. Since the Sarae blade inclined toward the tip of the drill with respect to the direction perpendicular to the axis of the drill is formed on the outer side in the radial direction of the leading blade, the hole opened by the Sarae blade is formed by the outer tip of the Sarae blade. , Scraped from its outer periphery. As a result, not only the occurrence of burrs but also the occurrence of delamination at the hole exit is greatly suppressed, so that the drilling quality is improved. In addition, since the finishing blade inclined to the radially outer side of the drill with respect to the axis of the drill is formed on the radially outer side of the Sarae blade, the angle of the edge portion of the Sarae blade can be increased. Thereby, since the chip | tip of a Sarae blade is suppressed, a tool life becomes long.

  In this case, the angle formed by the Sarae blade and the finishing blade may be an obtuse angle. Thereby, since the chip | tip of a Sarah blade is further suppressed, a tool life becomes still longer.

  ADVANTAGE OF THE INVENTION According to this invention, tool life can be lengthened, improving the quality of drilling.

It is a side view of the drill which concerns on embodiment. It is a partially expanded view of the drill shown in FIG. It is a figure for demonstrating the state at the time of punching a process target object. It is a figure for demonstrating the state at the time of punching a process target object. It is a figure for demonstrating the process in an Example. It is a photograph of the processed work in the 1st process of Experiment 1 (drilling from the aluminum plate side). It is a photograph of the processed work in the 2nd process of Experiment 1 (hole processing from the CFRP side). It is a photograph which shows the state of the drill before the experiment in Experiment 1. FIG. It is a photograph which shows the state of the drill after 360 hole processing in Experiment 1. FIG. It is a photograph which shows the state of the drill after the 500 hole processing in Experiment 1. FIG. It is a side view which shows the front-end | tip part of the drill of Comparative Examples 1-4.

  Hereinafter, a drill according to an embodiment will be described with reference to the drawings. The drill according to the present embodiment is a drill covered with a diamond film. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a side view of a drill according to an embodiment. As shown in FIG. 1, a drill 1 according to the present embodiment is formed in an elongated bar shape, and a drill body 3 is formed at a tip portion of a shank 2. The drill body 3 is formed with two twisted grooves 4, and a pair of cutting edges 5 are formed along the twisted grooves 4.

  The twist groove 4 is a part for discharging the cutting waste cut by the cutting edge 5. The twist angle of the twist groove 4 is not particularly limited. For example, by setting the twist angle to 30 °, the discharge efficiency of the cutting waste is increased.

  The pair of cutting edges 5 are formed symmetrically with respect to the axis A of the drill 1, and are each composed of a leading edge 6, a Sarah edge 7, and a finishing edge 8.

  The leading edge 6 is a cutting edge formed from the rotation center of the tip of the drill 1. The leading edge 6 is inclined outward in the radial direction of the drill 1 with respect to the axis A of the drill 1. Inclining radially outward of the drill 1 with respect to the axis A of the drill 1 means increasing the diameter from the tip end side (left side in FIG. 1) toward the rear end side (right side in FIG. 1) of the drill 1. Moreover, it is synonymous with inclining to the rear-end side of the drill 1 with respect to the direction (diameter direction of the drill 1) perpendicular to the axis A. The leading blade 6 is composed of a first leading blade 6a and a second leading blade 6b having different tip angles. The first leading blade 6a is formed on the tip side (left side in FIG. 1) of the drill 1 with respect to the second leading blade 6b, and the second leading blade 6b is formed on the radially outer side of the first leading blade 6a. ing. The tip angle θ1 of the first leading blade 6a is larger than the tip angle θ2 of the second leading blade 6b. The tip angle θ1 of the first leading blade 6a can be set to 120 °, for example, and the tip angle θ2 of the second leading blade 6b can be set to 30 °, for example. The length of the first leading edge 6a in the direction of the axis A of the drill 1 can be, for example, about 20% to 30% of the diameter of the drill 1, and in particular, about 25%. The length of the second leading edge 6b in the direction of the axis A of the drill 1 can be, for example, about 5% to 15% of the diameter of the drill 1, and in particular, can be about 10%.

  The Sarae blade 7 is a cutting blade formed on the radially outer side of the second leading blade 6b (the leading blade 6). The Sarae blade 7 extends from the second leading blade 6b to a position just before the outer peripheral surface 3a of the drill body 3, and is inclined toward the tip side of the drill 1 with respect to the direction perpendicular to the axis A. For this reason, the outer front end 7 a of the Sarae blade 7 in the direction perpendicular to the axis A is a position that protrudes most to the front end side of the drill 1 among the Sarah blades 7.

  The angle θ3 inclined to the tip side of the drill 1 with respect to the direction perpendicular to the axis A of the Sarah blade 7 is not particularly limited, but can be, for example, 0 ° <θ3 ≦ 20 °. It is preferable that ° <θ3 ≦ 15 °, and more preferably 0 ° <θ3 ≦ 10 °. By making this angle θ3 larger than 0 °, the outer tip 7a of the Sarah blade 7 can be protruded most toward the tip side of the drill 1. As a result, when the drill 1 is rotated to perforate the workpiece, the portion surrounded by the rotation locus of the outer tip 7a can be scraped off from the workpiece. On the other hand, by setting the angle θ3 to 20 ° or less, the workability when forming the Sarah blade 7 can be improved, and the strength of the Sarah blade 7 can be secured. Moreover, this effect can be further enhanced by setting the angle θ3 to 15 ° or less, and further to 10 ° or less. The length of the Sarah blade 7 in the direction of the axis A of the drill 1 can be, for example, about 5% to 15% of the diameter of the drill 1, and can be particularly about 10%.

  The inclination angle with respect to the direction perpendicular to the axis A is also called a centripetal angle. The centripetal angle is positive (plus) on the rear end side of the drill 1 with respect to the direction perpendicular to the axis A, and with respect to the direction perpendicular to the axis A. The tip side of the drill 1 is negative (minus). For this reason, the Sarae blade 7 has a negative centripetal angle. A drill having a negative centripetal angle is referred to as a fishtail drill.

  The Sarae blade 7 may be linear or curved as long as it is inclined toward the tip of the drill 1 with respect to the direction perpendicular to the axis A.

  The finishing blade 8 is a cutting blade for suppressing chipping of the edge portion 7 b of the Sarae blade 7, and is a cutting blade formed on the radially outer side of the Sarae blade 7 and continuously formed from the Sarae blade 7. is there. The finishing blade 8 is inclined outward in the radial direction of the drill 1 with respect to the axis A of the drill 1, and extends from the outer tip 7 a of the Sarae blade 7 to the outer peripheral surface 3 a of the drill body 3. Inclining radially outward of the drill 1 with respect to the axis A of the drill 1 means increasing the diameter from the tip side of the drill 1 toward the rear end side of the drill 1 and with respect to a direction perpendicular to the axis A. This is synonymous with tilting toward the rear end side of the drill 1. For this reason, the angle θ4 of the edge portion 7b of the Sarah blade 7 is increased by forming the finishing blade 8. The angle θ4 of the edge portion 7b refers to an angle formed by the Sarae blade 7 and the finishing blade 8.

  The angle θ4 of the edge portion 7b is not particularly limited. For example, the angle θ4 can be 120 ° ≧ θ4 ≧ 80 °, preferably 115 ° ≧ θ4 ≧ 85 °, and 110 ° ≧ θ4 ≧. More preferably, the angle is 90 °. By making this angle θ4 80 ° or more, chipping of the Sarah blade 7 can be suppressed. Moreover, this effect can be further enhanced by setting the angle θ4 to 85 ° or more, and further to 90 ° or more. In particular, by setting the angle θ4 to 90 ° or more, the angle (edge portion 7b) formed by the Sarah blade 7 and the finishing blade 8 becomes an obtuse angle, so that the chipping of the Sarah blade 7 can be significantly suppressed. On the other hand, the cutting ability of the finishing blade 8 can be maintained by setting the angle θ4 to 120 ° or less. Moreover, this effect can be further enhanced by setting the angle θ4 to 115 ° or less, and further to 110 ° or less. The length of the finishing blade 8 in the axis A direction of the drill 1 can be, for example, about 3% to 10% of the diameter of the drill 1, and in particular, about 5%.

  The finishing blade 8 may be linear or curved as long as it is inclined outward in the radial direction of the drill 1 with respect to the axis A of the drill 1. Further, since the finishing blade 8 is a cutting blade for suppressing chipping of the edge portion 7 b of the Sarae blade 7, the diameter of the drill 1 is larger than that of the first leading blade 6 a, the second leading blade 6 b and the Sarae blade 7. The width in the direction is narrow.

  In the drill body 3 configured in this way, at least the entire cutting edge 5 is covered with the diamond film 9. The diamond film 9 can be formed by, for example, a CVD method.

  Next, referring to FIG. 3 and FIG. 4, a processing object 10 in which a fiber reinforced composite material typified by CFRP and a metal material typified by aluminum are laminated using a drill 1 according to this embodiment. A state of punching will be described.

  FIG. 3 and FIG. 4 are diagrams for explaining a state at the time of drilling a workpiece. The workpiece 10 is a plate-like member in which an upper layer member 11 and a lower layer member 12 are laminated. The upper layer member 11 is configured by one of a fiber reinforced composite material typified by CFRP and a metal material typified by aluminum, and the lower layer member 12 is typified by a fiber reinforced composite material typified by CFRP and aluminum. It is composed of either one of the metal materials.

  As shown in FIGS. 3 and 4, when the drill 1 is rotated and pressed against the workpiece 10, the workpiece 10 is first cut by the first leading blade 6a and the second leading blade 6b. The workpiece 10 is cut by the Sarae blade 7 and the finishing blade 8.

  Here, if a sticky metal such as aluminum is perforated with a cutting edge having a small tip angle and a low thrust load, a cylindrical burr tends to occur at the hole outlet. On the other hand, when fiber reinforced composite materials such as CFRP are perforated with a cutting edge having a large tip angle and a large thrust load, delamination tends to occur.

  As shown in FIGS. 3A to 3C, the first leading blade 6 a and the second leading blade 6 b are gradually reduced in tip angle from the rotation center of the drill 1. Then, when cutting the workpiece 10 with the first leading blade 6a and the second leading blade 6b, first, the first leading blade 6a and the first leading blade 6a and the first leading blade 6a with a large tip angle and a relatively large thrust load are used. A hole formed in the first leading blade 6a and the second leading blade 6b is formed by the second leading blade 6b in which the center portion of the hole opened by the second leading blade 6b is formed and then the tip angle is small and the thrust load is relatively small. The outer diameter portion is formed. For this reason, the hole drilled in the workpiece 10 by the first leading blade 6a and the second leading blade 6b suppresses the occurrence of delamination at the hole outlet by opening the outer diameter portion by the second leading blade 6b. It is done. On the other hand, cylindrical burrs are likely to occur at the hole outlet.

  As shown in FIGS. 4A to 4C, the Sarah blade 7 is inclined toward the tip side of the drill 1 with respect to the direction perpendicular to the axis A, and has a negative centric angle. Therefore, the workpiece 10 is cut from the outer tip 7a. Thereby, since the hole opened by the Sarae blade 7 is scraped off from the outer peripheral edge by the outer tip 7a of the Sarae blade 7, not only the occurrence of delamination but also the generation of burrs at the hole outlet is greatly suppressed.

  And the outer diameter of the hole opened by the whole cutting blade 5 of the drill 1 is formed by the finishing blade 8. At this time, the finishing blade 8 is narrower in the radial direction of the drill 1 than the first leading blade 6a, the second leading blade 6b, and the Sarae blade 7, and has a very small machining allowance. Occurrence and delamination are suppressed.

  As described above, according to the drill 1 according to the present embodiment, the first leading blade 6a and the second leading blade 6b whose tip angles gradually decrease from the rotation center of the drill 1 cut the workpiece 10. The occurrence of delamination at the hole exit can be suppressed. Since the Sarae blade 7 inclined to the tip side with respect to the direction perpendicular to the axis A is formed on the radially outer side of the leading blade 6, the hole opened by the Sarae blade 7 is the outer tip of the Sarae blade 7. The outer peripheral edge is scraped off by 7a. As a result, not only delamination but also burrs are greatly suppressed at the hole exit, and the drilling quality is improved. Moreover, since the finishing blade 8 that is inclined radially outward of the drill 1 with respect to the axis A of the drill 1 is formed on the radially outer side of the Sarae blade 7, the angle θ3 of the edge portion 7b of the Sarae blade 7 is increased. can do. Thereby, since the chip | tip of the Sarah blade 7 is suppressed, a tool life becomes long.

  And when the angle | corner which the Sarah blade 7 and the finishing blade 8 make is an obtuse angle, since the chip | tip of the Sarah blade 7 is further suppressed, a tool life becomes still longer.

  The present invention is not limited to the above embodiment.

  For example, in the above embodiment, a composite plate in which a fiber reinforced composite material and a metal material are laminated is used as the processing object 10. However, the processing target is a single plate made of only the fiber reinforced composite material. There may be. In addition, a single board means the board comprised only with the fiber reinforced composite material, and the laminated board which laminated | stacked multiple fiber reinforced composite materials is also contained in this.

  Moreover, although the said embodiment demonstrated as what the one Sarahe blade 7 and the finishing blade 8 were formed in each cutting edge 5, the Saraje blade 7 and the finishing blade 8 are formed in each cutting edge 5 2 or more. It may be a thing.

  Moreover, in the said embodiment, although the leading edge 6 demonstrated as what was comprised by two cutting edges, the 1st leading edge 6a and the 2nd leading edge 6b, the leading edge 6 was comprised by one cutting edge. It may be constituted by three or more cutting edges.

  Next, examples of the present invention will be described. The present invention is not limited to the following examples.

Example 1
In Example 1, the drill 1 shown in FIGS. 1 and 2 was used. The drill 1 of Example 1 was formed of a cemented carbide, and the diamond film 9 was formed by a CVD method. In the drill 1 of Example 1, the outer diameter D is 6.375 mm, the twist angle of the twist groove 4 is 30 °, the tip angle θ1 of the first leading blade 6a is 120 °, and the tip angle θ2 of the second leading blade 6b. Is 30 °, the angle θ3 inclined to the tip side of the drill 1 with respect to the direction perpendicular to the axis A is 10 °, the film thickness of the diamond film 9 is 15 μm, and the range in which the diamond film 9 is formed is from the tip of the drill 1 20 mm.

(Experiment 1)
As shown in FIG. 5, a workpiece 20 in which three 6.35 mm thick CFRPs 22 were laminated on a 4 mm thick aluminum plate 21 was used as a workpiece. Further, a wear promoting work composed of 15 mm thick CFRP was used.

  And the drill 1 of Example 1 was mounted | worn with the vertical machining center made from FANUC, and the following 1st process, the 2nd process, and the 3rd process were repeated sequentially, and the experiment which drills a total of 500 holes was conducted.

[First step] 5 holes are formed in the workpiece 20 from the aluminum plate 21 side (see FIG. 5A).
[Second step] 5 holes are made in the workpiece 20 from the CFRP 22 side (see FIG. 5B).
[Third step] Cutting 60 holes in the workpiece for promoting wear The cutting conditions in the first step and the second step were dry machining, the rotation speed was 3200 min ⁻¹ , and the feed rate was 320 mm / min. The cutting conditions in the third step were dry machining, the rotational speed was 5000 min ⁻¹ , and the feed speed was 500 mm / min.

  6 is a photograph of the workpiece in the first step (drilling from the aluminum plate side) of Experiment 1, (a) after machining 1 hole, (b) after machining 355 holes, and (c) 495. It is a photograph after drilling. FIG. 7 is a photograph of the workpiece in the second step of Experiment 1 (drilling from the CFRP side), (a) after machining 6 holes, (b) after machining 360 holes, and (c) 500 holes. It is a photograph after processing. As shown in FIGS. 5 and 6, when drilling was performed from the aluminum plate 21 side, delamination of CFRP 22 was confirmed to be about 1.2 mm after 355 holes were processed, and about 1.5 mm after 495 holes were processed. None of them was a problem level. As shown in FIGS. 5 and 7, when drilling was performed from the CFRP 22 side, all burrs on the aluminum plate 21 were 0.4 mm or less, which was not a problem level after any drilling.

  FIG. 8 is a photograph showing the state of the drill in Experiment 1 before the experiment. FIG. 9 is a photograph showing the state of the drill after drilling 360 holes in Experiment 1. FIG. 10 is a photograph showing the state of the drill after processing 500 holes in Experiment 1. As shown in FIGS. 8 to 10, when the drill 1 was observed after 360 holes were drilled, no abnormal point was found. Further, when the drill 1 was observed after processing 500 holes, a slight peeling of the diamond film 9 and welding of aluminum were observed at the edge portion 7b of each Sarah blade 7, both of which greatly affected the drilling performance. It wasn't.

(Comparative Example 1)
In Comparative Example 1, as shown in FIG. 11A, a double-angle drill 40 in which only a first leading blade 41 and a second leading blade 42 having different tip angles were formed as cutting edges.

(Comparative Example 2)
In Comparative Example 2, as shown in FIG. 11B, a triple angle drill 50 in which only the first leading blade 51, the second leading blade 52, and the third leading blade 53 having different tip angles are formed as cutting edges. Was used.

(Comparative Example 3)
In Comparative Example 3, as shown in FIG. 11 (c), a candle type drill 60 in which only a cutting edge 61 curved between the rotation center and the outer front end on the drill rear end side is formed as a cutting edge. It was.

(Comparative Example 4)
In Comparative Example 4, as shown in FIG. 11 (d), the first leading blade 71 and the second leading blade 72 having different tip angles and the second leading blade 72 were formed radially outside as cutting edges. The fish tail type drill 70 formed only with the Sarae blade 73 and was used. That is, the fishtail drill 70 was the same as the drill 1 of Example 1 except that the finishing blade 8 was not formed.

(Experiment 2)
About the drill 1 of Example 1, the double angle drill 40 of the comparative example 1, the triple angle drill 50 of the comparative example 2, the candle type drill 60 of the comparative example 3, and the fish tail type drill 70 of the comparative example 4, the cutting edge strength and drilling The processing quality was evaluated. The following three items were evaluated as drilling quality. The first item is the processing quality when a hole is made in the workpiece for promoting wear produced in Experiment 1. The second item is the processing quality when a hole is made from the aluminum plate 21 side in the workpiece 20 produced in Experiment 1. The third item is the machining quality when a hole is made from the CFRP 22 side in the workpiece 20 produced in Experiment 1. The evaluation of the strength of the cutting edge was ○ for those in which no chipping occurred even after 500 holes were processed, and chipping did not occur until 210 holes were processed, but △ and chipped up to 210 holes were processed in which 360 chipping occurred. The thing which generate | occur | produced was set as x. The evaluation of the processing quality is as follows: ○ in which delamination and burrs hardly occur, △ in which delamination or burrs have occurred to the extent that they do not cause practical problems, and delamination or burrs to the extent that they are practically problematic. What occurred was marked as x. The evaluation results are shown in Table 1.

As shown in Table 1, in Comparative Examples 1 to 4, there was an evaluation of x, but in Example 1, all were evaluated as ◯. Further, in Comparative Example 4 without a finishing blade, the evaluation of the blade edge strength is △, whereas in Example 1 with a finishing blade, the evaluation of the blade edge strength is ◯. It has been found that the life is extended.

  DESCRIPTION OF SYMBOLS 1 ... Drill, 2 ... Shank, 3 ... Drill main body, 3a ... Outer peripheral surface, 4 ... Twist groove, 5 ... Cutting blade, 6 ... Leading blade, 6a ... First leading blade, 6b ... Second leading blade, 7 ... Sarae Blade, 7a ... outer tip, 7b ... edge portion, 8 ... finishing blade, 9 ... diamond film, 10 ... workpiece, 11 ... upper layer member, 12 ... lower layer member, 20 ... workpiece, 21 ... aluminum plate, 22 ... CFRP, 40 ... double angle drill, 41 ... first leading blade, 42 ... second leading blade, 50 ... triple angle drill, 51 ... first leading blade, 52 ... second leading blade, 53 ... third leading blade, 60 DESCRIPTION OF SYMBOLS ... Candle type drill, 61 ... Cutting blade, 70 ... Fishtail type drill, 71 ... First leading blade, 72 ... Second leading blade, 73 ... Sarae blade, A ... Axis, [theta] 4 ... Angle of the edge of the Sarae blade.

Claims (2)

A drill for drilling a fiber reinforced composite coated with a diamond film,
A leading edge formed from the center of rotation of the tip, and inclined radially outward of the drill with respect to the axis of the drill;
A Sarae blade that is formed on the radially outer side of the preceding blade and is inclined toward the tip side of the drill with respect to a direction perpendicular to the axis of the drill;
A finishing blade formed on the radially outer side of the Sarae blade and inclined to the radially outer side of the drill with respect to the axis of the drill;
Equipped with a,
The leading blade has a first leading blade and a second leading blade that is formed radially outside the first leading blade and has a tip angle different from the first leading blade,
The angle inclined toward the tip side of the drill with respect to the direction perpendicular to the axis of the Sarae blade is greater than 0 ° and not more than 20 °,
An angle formed by the Sarae blade and the finishing blade is 120 ° or less and 80 ° or more . The drill according to claim 1, wherein an angle formed by the Sarae blade and the finishing blade is an obtuse angle.