TW201518012A - Drilling tool and method for producing the same - Google Patents

Abstract

The present invention provides a drilling tool and method for producing the same, whose shank body does not rust easily with excellent usability even if the drilling tool is coated with hard coating in the high-temperature process and having higher characteristic property. The drilling tool is formed of the blade part (1) and the shank part (4). The blade part (1) has a spiral chip discharging groove (2) at the outer periphery of the tool body. The shank part (4) has a shank body (3) whose diameter on the base end side is greater than that of blade part (1). The blade part (1) is made of super hard alloy. The shank body (3) is made of stainless steel. A shank taper part (6) which is more tapering as it approaches the front end is formed at the front end of the shank body (3). At least the portion near the shank body of shank taper part (6) is made of stainless steel. At least the outer periphery surface (12) of blade part (1) and the shank taper part (6) portion which is made of stainless steel are coated with the hard coating, while the outer periphery surface of shank body (3) is not coated with the hard coating.

Description

Drilling tool and method of manufacturing same

The present invention relates to a drilling tool and a method of manufacturing the same.

In recent years, printed wiring boards (hereinafter referred to as PCBs) have been developed to be smaller, thinner, and lighter, and have been developed to have higher heat resistance and higher rigidity in order to improve reliability. Therefore, the resin composition of the glass cloth and the insulating portion becomes difficult to be formed, and it is easy to wear the drill (hereinafter referred to as a PCB drill) used for the drilling of the PCB, and this problem will be The accuracy of the hole position due to wear is deteriorated.

Here, various proposals have been made, for example, a drill bit coated with a hardened film for improving wear resistance as disclosed in Patent Document 1, which is required to further improve the above-described hole positional accuracy.

[Previous Technical Literature] [Patent Document]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2012-11489

In recent years, in the PCB drill, a so-called composite type drill having a blade portion made of a super-hard alloy member and a shank body made of an inexpensive stainless steel member has begun to become mainstream. Here, since the shank main body is clamped at the time of drilling, a certain degree of hardness is required to avoid wear and tear, and in many cases, a martensite-based stainless steel capable of quenching treatment is used.

The quenched treated Matian stainless steel may rust in a high temperature and high humidity environment. When the shank body is clamped in a rust state, the drill bit may be broken due to the sway of the blade during drilling. The accuracy of the hole position is deteriorated.

However, the quenched stainless steel of the field is known to be easily rusted when a heat cycle (heating and cooling) is applied to a high temperature.

On the other hand, when the hard surface film is coated on the blade portion, the abrasion resistance can be improved to suppress the deterioration of the hole position accuracy. However, since the hard film film is low in temperature when the film forming process is too low, the film property is generally lowered. Covered in a high temperature process.

Therefore, in the film forming process of the hard film, heat cycle of several hundred ° C is usually applied to the shank main body, and in the combined hard film coated drill bit, there is a problem that the shank main body is easily rusted.

The inventors of the present invention have studied the rust and hard film of the mashed stainless steel after quenching in order to solve the above problems, and as a result, have obtained knowledge that the above problems can be solved by the arrangement of the film and the working method. opinion.

The present invention has been developed in accordance with the above knowledge of the present inventors, and provides a drilling tool and a method of manufacturing the same, which is difficult to make a shank even if a hard film having a high film property is coated in a high temperature process. The body is rusted and excellent in practicality.

The gist of the present invention will be described with reference to the drawings.

A drilling tool comprising at least a blade portion 1 and a shank portion 4, the blade portion 1 being provided on the outer circumference of the tool body with one or a plurality of spiral chip discharge grooves from the tool front end toward the base end side 2. The shank portion 4 has a shank body 3 having a larger diameter than the blade portion 1 on the proximal end side, and the blade portion 1 is formed of a superhard alloy containing tungsten carbide and cobalt, and the shank body The third system is formed of stainless steel, and the front end side of the shank main body 3 is formed with a shank push-out portion 6 that is tapered toward the front end side, and at least the vicinity of the shank body of the shank push-out portion 6 is It is formed of stainless steel, and is characterized in that at least the outer peripheral surface 12 of the blade portion 1 formed of the above-mentioned superhard alloy and the portion of the shank push-out portion 6 formed of the stainless steel are covered with a hard film, and The outer peripheral surface of the shank body 3 is not covered with a hard film.

The drilling tool according to claim 1, wherein the hardness of the shank body 3 is 35 HRC or more by a C-scale Rockwell hardness test.

The drilling tool according to the first aspect of the invention, wherein the hard film comprises at least aluminum and chromium as a metal component, at least Nitrogen is contained as a non-metal component, and the film thickness of the hard film is 1 μm or more and 5 μm or less.

The drilling tool according to claim 2, wherein the hard film contains at least aluminum and chromium as a metal component, and at least nitrogen is used as a non-metal component, and the film thickness of the hard film is 1 μm or more. 5 μm or less.

The drilling tool according to any one of claims 1 to 4, wherein the inner surfaces of the tool front end faces 9, 10 and the chip discharge groove 2 are not covered with a hard film.

Moreover, a method of manufacturing a drilling tool is a method for manufacturing a drilling tool, the drilling tool comprising at least a blade portion 1 and a shank portion 4, the blade portion 1 being disposed outside the tool body One or a plurality of spiral chip discharge grooves 2 from the front end of the tool toward the base end side, the shank portion 4 having a shank body 3 having a larger diameter than the blade portion 1 on the proximal end side, the blade portion 1 is formed of a superhard alloy containing tungsten carbide and cobalt, and the shank main body 3 is formed of stainless steel, and the front end side of the shank main body 3 is formed with a shank that is tapered toward the front end side. The portion of the shank body of the shank pushing portion 6 is formed of stainless steel, and is characterized in that: before the tool body forms the tool front end faces 9, 10 and the chip discharge groove 2, at least The outer peripheral surface 12 of the blade portion 1 formed by the hard alloy and the portion of the shank push-out portion 6 formed of the stainless steel are coated with a hard film, and after the hard film is coated, the outer peripheral surface of the shank main body 3 is polished to form For the outer surface of the shank body 3 It has a state of covering a hard film.

The method of manufacturing a drilling tool according to claim 6, wherein the hardness of the shank body 3 is 35 HRC or more by a C-scale Rockwell hardness test, and the hard film contains at least aluminum and Chromium is a metal component and contains at least nitrogen as a non-metal component, and the film thickness of the hard film is 1 μm or more and 5 μm or less.

Since the present invention is constructed as described above, it is possible to provide a drilling tool and a method of manufacturing the same, which is capable of rusting the shank body and having excellent practicability even when a hard film having a high film property is coated in a high-temperature process. .

1‧‧‧blade

2‧‧‧Cutting drain

3‧‧‧Knife body

4‧‧‧Knife

5‧‧‧Connected components

6‧‧‧Knife handle push-out

7‧‧‧ Middle cylindrical part

8‧‧‧2nd push section

9‧‧‧First knife belly (tool front face)

10‧‧‧second knife belly (tool front face)

11‧‧‧ cutting edge

12‧‧‧ outer perimeter

13‧‧‧Relieving surface

A‧‧‧ realm

D1‧‧‧ tool outer diameter

D2‧‧‧ slotted outer diameter

Fig. 1 is a schematic side view showing the present embodiment.

Fig. 2 is an enlarged schematic explanatory view of the blade portion of the embodiment.

Fig. 3 is an enlarged schematic explanatory view showing a blade portion of another example.

Figure 4 is a photograph showing the results of the experiment.

Figure 5 is a photograph showing the results of the experiment and its schematic.

The function of the present invention is shown in the drawings and the preferred embodiments of the present invention are briefly described.

A portion formed of stainless steel in the shank pushing and lowering portion 6 is covered with a hard film, whereby rust of the stainless steel portion can be suppressed. Further, by grinding the outer peripheral surface of the shank main body 3 and forming a state in which the hard film is not covered, The rust of the shank body 3 can be suppressed.

[Examples]

Specific embodiments of the invention are described in accordance with the drawings.

The embodiment includes at least a blade portion 1 and a shank portion 4, and the blade portion 1 is provided on the outer circumference of the tool body with one or a plurality of spiral chip discharge grooves 2 from the tool front end toward the base end side. The shank portion 4 has a shank main body 3 having a larger diameter than the blade portion 1 on the proximal end side, and the blade portion 1 is formed of a superhard alloy containing tungsten carbide and cobalt, and the shank body 3 is formed. It is formed of stainless steel, and the front end side of the shank main body 3 is formed with a shank push-out portion 6 that is tapered toward the front end side, and at least the vicinity of the shank body of the shank push-out portion 6 is The stainless steel is formed, and at least the outer peripheral surface 12 of the blade portion 1 formed of the above-mentioned superhard alloy and the portion of the shank push-out portion 6 formed of the stainless steel are coated with a hard film, and the shank body 3 is The outer peripheral surface is not covered with a hard film.

In the present embodiment, as the shank body 3, a shank body having a C scale of Rockwell C scale and a hardness of 35 HRC or more is used. This is because the shank body 3 is clamped when the drill bit is drilled, so a certain degree of hardness is required to avoid wear and tear due to clamping, and the C-scale Rockwell hardness test is preferably 35 HRC or more.

Moreover, since the ultra-hard alloy is relatively expensive, the target is a combined drill, and the minimum required amount of superhard alloy can be used to form the PCB drill bit, thereby reducing the cost of the drill. Therefore, at least the shank body 3 is formed not to Stainless steel, and the joint position of the super-hard alloy and the stainless steel is placed as close as possible to the position of the blade portion 1, thereby being a niche in terms of cost. Therefore, among the joint members 5 provided between the blade portion 1 and the shank body 3, at least the portion near the shank body of the shank push-out portion 6 is preferably made of stainless steel. On the other hand, when the joint area of the cemented carbide and the stainless steel is too small, the joint strength becomes small, so a certain joint area is required.

In the present embodiment, the joint member 5 between the blade portion 1 and the shank body 3 is connected to the shank push-out portion 6 which is connected to the front end of the shank body 3 and is connected to the shank push-out portion 6 The intermediate cylindrical portion 7 at the end and the second push-out portion 8 connected to the front end of the intermediate cylindrical portion 7 are formed. The base end of the blade portion 1 is connected to the front end of the second push-out portion 8 (see Fig. 1). Further, the joint position (boundary A) of the cemented carbide and the stainless steel is disposed on the middle of the intermediate cylindrical portion 7. Further, the joint position of the cemented carbide and the stainless steel may be disposed on the way of the shank push-out portion 6 connected to the shank body 3.

Further, the hard film to be coated contains at least aluminum (Al) and chromium (Cr) as a metal component, and at least nitrogen (N) as a non-metal component, and the film thickness of the hard film is 1 μm or more and 5 μm or less.

Although a hard film containing at least aluminum and chromium as a metal component and containing at least nitrogen as a non-metal component is generally used as a tool film for cutting a steel material, it is still effective for drilling a PCB. Although such a hard film is coated to suppress abrasion of the tool base material during drilling, the film itself needs to have an appropriate thickness because it is worn at the same time as the processing, and preferably has a thickness of 1 μm or more. On the other hand, since the internal stress of the film becomes large and the film is easily peeled off when it is too thick, it is preferably 5 μm. the following.

Further, the inventors of the present invention carried out various modifications to the site to be coated to produce a hard film-coated PCB drill, and conducted a drill test on the PCB, and as a result, it was found that the hard film coated on the outer peripheral surface of the blade covered the PCB with a hard film. The wear resistance of the drill bit has a dominant influence.

As shown in Fig. 2, this embodiment is a so-called straight type two-blade two-slot drill.

Specifically, it is a back taper shape in which the outer diameter of the front end portion of the blade portion 1 is D1 (tool outer diameter D1) and is gradually reduced in diameter from the front end side toward the base end side. It is called a so-called in-line type drill. In the figure, reference numeral 12 is an outer peripheral surface of the blade portion 1. On the outer circumference of the tool body (blade portion 1), two spiral chip discharge grooves 2 are provided from the tool front end toward the base end side.

Further, a cutting edge 11 is formed on a cross-sectional line portion between the cut surface of the chip discharge groove 2 and the first blade 9 provided at the tip end of the tool. A second blade 10 is connected to the rear side of the first blade 9 in the tool rotation direction, and the tool nose faces 9 and 10 are formed by the first blade 9 and the second blade 10.

Although the inner surface of the tool front end faces 9, 10 and the chip discharge groove 2 may be covered with a hard film, in this case, it is necessary to coat the hard film after forming the chip discharge groove 2, and thereafter the shank body 3 is ground. On the outer peripheral surface, it is possible that the central axis of the blade portion 1 and the central axis of the shank body 3 are offset. When the central axis of the blade portion 1 and the central axis of the shank body 3 are offset, the blade portion 1 is shaken during drilling, which is related to the breakage or The accuracy of the hole position is deteriorated.

Therefore, in the present embodiment, the hard film is applied to the shank push-out portion 6 from the front end of the tool before the tool front end faces 9, 10 and the chip discharge groove 2 are formed, and thereafter, the outer peripheral surface of the shank body 3 is ground, and thereafter Tool front faces 9, 10 and chip discharge grooves 2 are formed. In this case, although the peripheral surface 12 is covered with a hard film on the blade portion 1, the drill tip is not covered with the hard film on the tool front end surface 9 and the inner surface of the chip discharge groove 2. Further, in the case where one portion of the shank pushing and pulling portion 6 is formed of stainless steel, it is only necessary to coat the stainless steel portion of the blade portion 1 and the shank pushing portion 6 with a hard film.

Hereinabove, the shape of the drill described above has been described for the sake of simplicity of description of the present invention, but the shape of the drill is not limited to the above.

For example, if another example of the present invention is shown in FIG. 3, it is an undercut type two-blade two-slot drill. In order to reduce the cutting resistance, it may be formed by a predetermined area on one side of the drill bit. A drill bit that relieves the surface to set the clearance.

In another example, specifically, the outer diameter of the front end portion of the blade portion 1 is D1 (tool outer diameter D1), and the base end side of the blade portion 1 is set to be smaller than the outer diameter D1 of the tool. A so-called grooving type drill having a groove diameter D2. Two spiral chip discharge grooves 2 from the tool front end toward the base end side are provided on the outer periphery of the tool body (blade portion 1), and the blade portion 1 is on the front side in the tool rotation direction of the chip discharge groove 2. At a position lower than the outer peripheral surface 12, a spiral relief surface 13 from the tip end of the tool toward the proximal end side is provided to form a gap.

Further, a cutting edge 11 is formed on a cross-sectional line portion between the cut surface of the chip discharge groove 2 and the first blade 9 provided at the tip end of the tool. A second blade 10 is connected to the rear side of the first blade 9 in the tool rotation direction, and the tool nose faces 9 and 10 are formed by the first blade 9 and the second blade 10.

In the other example, the hard coating is applied to the shank pushing and lowering portion 6 from the tip end of the tool before the tool front end faces 9, 10, the chip discharge groove 2, and the relief surface 13 are formed, and then the outer peripheral surface of the shank main body 3 is polished. Thereafter, the tool front end faces 9, 10, the chip discharge grooves 2, and the relief surface 13 are formed. In this case, the outer surface of the blade portion 1 is covered with a hard film, but the tool distal end faces 9, 10, the inner surface of the chip discharge groove 2, and the relief surface 13 are not covered with a hard film.

Even if the above-described structure is used to coat a hard film having a high film property in a high-temperature process, it is possible to achieve a hard film-coated drill bit which is less likely to rust.

In other words, the present inventors have coated a hard film on a combined drill having a shank main body 3 and a shank push-out portion 6 made of quenched treated mashed stainless steel, and produced on a stainless steel member. The rust was subjected to various studies, and it was found that the portion covered with the hard film was less likely to rust; and when the surface was polished after the end of the hard film coating process, the polished surface was less likely to rust. Although the mechanism for these phenomena is subject to future research, the former can be regarded as a hard film that prevents the intrusion of oxygen and does not easily rust the stainless steel, and the latter can be regarded as to remove the surface of the stainless steel after deterioration in the coating process. It is not easy to rust.

The present inventors have succeeded in the following two cases by using this phenomenon: the hard coating film is coated on the shank pushing portion 6, and the outer peripheral surface is polished by the shank main body 3 after the coating process (the result becomes the shank main body 3). A hard film having a high film property is coated on the blade portion 1 and the shank body 3 is less likely to be rusted. Further, although the shank pushing and lowering portion 6 is not a member that is clamped at the time of drilling, the rust portion continues to expand once it is rusted, so that the adjacent shank body 3 is also likely to rust. Therefore, there is a need to make the shank push-out portion 6 less likely to rust.

Since the present embodiment is configured as described above, the rust of the stainless steel portion can be suppressed by coating the hard portion of the shank pushing portion 6 formed of stainless steel. Further, by polishing the outer peripheral surface of the shank main body 3 and forming a state in which the hard film is not formed, the surface of the shank main body 3 which has been deteriorated in the coating process of the hard film can be removed, thereby suppressing the coating process. The rust of the shank body 3 is caused.

Therefore, in the present embodiment, even if a hard film having a high film property is coated in a high-temperature process, it is difficult to rust the shank body.

An experimental example demonstrating the effects of the present embodiment will be described.

The combination drill having a shank diameter of 3.175 mm, a drill length of 38.1 mm, a blade diameter of 0.3 mm, and a chip discharge groove length of 5.5 mm (the shank body and the shank body of the shank body are made of stainless steel) The superhard alloy drill having the structure of the present embodiment was coated (the temperature at the time of film formation: 500 ° C), and the AlCrN film was placed as a hard film in an environmental test chamber at a temperature of 40 ° C and a humidity of 95% for 48 hours, and investigated. Rusty condition of the shank body and its vicinity. The results of this experiment are shown in Figure 4.

The photograph of Fig. 4 is taken from the second push-out portion to the middle of the holder body.

In addition, in the fifth drawing, in order to easily understand the position of the rust position and the hard coat portion to be described later, a schematic view of each photograph is arranged on the right side of the photograph of FIG.

Although there are two places for photographing the push-out portion in Fig. 4, the push-out on the right side is the handle push-out portion. The right side of the shank push-out portion is the shank body, and the left side of the shank push-out portion is the intermediate cylindrical portion connecting the shank body and the blade portion. There is a second push-out portion on the left side of the middle cylindrical portion, and a blade portion on the left side.

Fig. 4(C) is an embodiment in which an AlCrN film is coated on the entire body of the shank body and the left side thereof by an arc ion plating method, and the shank body is not covered with a hard material. Membrane. Fig. 4 (A) and (B) are comparative examples, (A) is a drill which is not covered with a hard film, and (B) is an arc ion plating method from the tool front end side (not the handle is pushed and pulled) to the knife. A drill bit covered with an AlCrN film (a part of the stainless steel is partially exposed) on the way to the handle.

According to the experimental results in Fig. 4, it can be understood that the drill of (C) does not rust as much as the drill of (A). On the other hand, it can be understood that the drill of (B) is rusted from the shank to the shank body. Further, (B) is rusted in a part of the hard coating portion where the shank is pushed out and a part of the hard coating portion of the intermediate cylindrical portion. This can be regarded as first rusting at the portion of the shank that is not covered with the hard film, and the rust is extended to the hard coating portion of the shank and the hard coating portion of the intermediate cylindrical portion.

According to the above experimental results, it was confirmed that the shank body is less likely to rust even if the hard film is coated, according to the configuration of the present embodiment.

1‧‧‧blade

3‧‧‧Knife

4‧‧‧Knife

5‧‧‧Connected components

6‧‧‧Knife handle push-out

7‧‧‧ Middle cylindrical part

8‧‧‧2nd push section

A‧‧‧ realm

Claims (7)

A drilling tool comprising at least a blade portion and a shank portion, wherein the blade portion is provided on the outer circumference of the tool body with one or a plurality of spiral chip discharge grooves from the tool front end toward the base end side, the knife The shank has a shank body having a larger diameter than the blade portion on the proximal end side, and the blade portion is formed of a superhard alloy containing tungsten carbide and cobalt, and the shank system is formed of stainless steel. The front end side of the shank body is formed with a shank push-out portion that is tapered toward the front end side, and at least the vicinity of the shank body of the shank push-out portion is formed of stainless steel, which is characterized by at least The outer peripheral surface of the blade portion formed of the cemented carbide and the portion of the shank push-out portion formed of the stainless steel are covered with a hard film, and the outer surface of the shank main body is not covered with a hard film. The drilling tool according to claim 1, wherein the hardness of the shank body is 35 HRC or more by a C-scale Rockwell hardness test. The drilling tool according to claim 1, wherein the hard film contains at least aluminum and chromium as a metal component, and at least nitrogen is used as a non-metal component, and the film thickness of the hard film is 1 μm or more and 5 μm or less. . The drilling tool according to claim 2, wherein the hard film contains at least aluminum and chromium as a metal component, and at least nitrogen is used as a non-metal component, and the film thickness of the hard film is 1 μm or more and 5 μm or less. . A driller as described in any one of claims 1 to 4 In the tool, the inner surface of the tool and the inner surface of the chip discharge groove are not covered with a hard film. A method for manufacturing a drilling tool, which is a method for manufacturing a drilling tool, the drilling tool comprising at least a blade portion and a shank portion, the blade portion being provided with one or a plurality of outer circumferences of the tool body a spiral chip discharge groove from the front end of the tool toward the base end side, the shank portion having a shank body having a larger diameter than the blade portion on the proximal end side, the blade portion being super-containing tungsten carbide and cobalt Formed by a hard alloy, the shank system is formed of stainless steel, and the front end side of the shank body is formed with a shank push-out portion that is tapered toward the front end side, and at least the shank of the shank push-out portion The portion near the body is formed of stainless steel, and is characterized in that at least the outer peripheral surface of the blade portion formed by the cemented carbide and the shank push-out portion are formed before the tool body forms the tool front end surface and the chip discharge groove. The portion formed of the stainless steel is coated with a hard film, and after the hard film is coated, the outer peripheral surface of the shank main body is polished to form a state in which the outer surface of the shank main body is not covered with a hard film. The method for manufacturing a drilling tool according to claim 6, wherein the hardness of the shank body is 35HRC or more by a C-scale Rockwell hardness test, and the hard film contains at least aluminum and chromium as a metal. The component contains at least nitrogen as a non-metal component, and the film thickness of the hard film is 1 μm or more and 5 μm or less.