KR20080102432A - Method of removing hard coating film - Google Patents

Abstract

A hard coating film (30) is efficiently etched with a beam of krypton ions, which have a relatively large mass, in a step (S2) and then slowly etched with a beam of argon ions, which have a small mass, in a step (S3) as shown in Fig. 3. Thus, film removal can be carried out in a short time while minimizing influences (shape change and dimensional change) on the tool base (20). Since krypton and argon each is an inert gas, chemical corrosion of the tool base (20) and resultant surface embrittlement are nil even when the surface of the tool base (20) is exposed. When this tool base (20) is recoated with a hard coating film (30) to produce a regenerated hard-film-coated processing tool (12), the hard coating film (30) is adherent thereto at an excellent adhesion strength.

Description

Method of film removal of hard film {METHOD OF REMOVING HARD COATING FILM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film removal method for hard films such as TiAlN and TiCN, and more particularly to a method for film removal of hard films without damaging the main body as much as possible.

BACKGROUND ART A hard coat coating member is known in which a hard coat composed of carbides, nitrides, carbonitrides, or mutual solid solutions of metals of Group IIIb, Group IVa, Group Va or Group VIa of the Periodic Table is coated on the surface of the body. For example, in a processing tool such as an end mill, a tab, a drill, or a bite, the hard film is subjected to an ion plating method, such as an ion plating method, on a processing section on which at least a cutting edge is formed as a surface of a tool substrate (main body) composed of cemented carbide. A hard film coating processing tool coated by PVD (Physical Vapor Growth) method is proposed in Patent Document 1 and the like.

In such a hard coating member, it is considered to reuse the main body such as a tool base material by removing the hard coating when the hard coating is worn or damaged, or when a defective product occurs due to a poor coating during manufacture. . That is, the film is chemically decomposed by a wet method using a hydrogen peroxide solution or the like to remove the film from the main body.

Patent Document 1: Japanese Unexamined Patent Publication No. 2005-7555

Disclosure of the Invention

Problems to be Solved by the Invention

However, when the film is removed using a chemical reaction in this way, if the main body is partially exposed due to the film thickness variation of the hard film or the difference in the ease of peeling of the film, the exposed surface of the main body is also damaged by the treatment liquid. Therefore, when the hard film is completely removed, the surface of the main body may be partially roughened or vulnerable. For example, when the main body is made of cemented carbide, the surface of the WC particles are chemically eroded and the surface becomes brittle, and the shape of the cutting edge may be rounded or the diameter may be reduced. . When the hard film is recoated to such a body, the adhesion is impaired due to the weakening of the surface, and the original film performance (durability or wear resistance, etc.) is not obtained, or the cutting edge is rounded, resulting in a decrease in cutting performance. .

The present invention has been made in view of the above circumstances, and an object thereof is to allow the hard film to be removed without damaging the main body of the hard film covering member as much as possible.

Means to solve the problem

In order to achieve this object, the first invention is a hard film made of carbides, nitrides, carbonitrides, or mutually solid solutions of metals of Group IIIb, IVa, Group Va or Group VIa of the Periodic Table of Elements coated on the surface of the body. A hard film covering member, wherein the hard film is removed from the main body, wherein the hard film is removed from the main body by etching by irradiating an ion beam to the hard film.

According to a second aspect of the present invention, in the method of removing the hard film, the hard film is irradiated with an ion beam generated using an inert gas as a working gas.

The third invention is the method of removing the hard film of the second invention, comprising: (a) a first etching step of etching by irradiating the hard film with an ion beam generated using a first inert gas as a working gas; and b) a second etching step of converting the working gas into a second inert gas having an atomic weight smaller than that of the first inert gas to generate an ion beam, and irradiating the hard film to perform etching.

4th invention is a film removal method of the hard film of 3rd invention WHEREIN: (a) In the said 1st etching process, any one of radon, xenon, and krypton is used as said working gas, (b) said 2nd In the etching step, argon gas is used as the working gas.

5th invention is a film removal method of the hard film in any one of 1st invention-4th invention, The said main body is comprised from the cemented carbide. It is characterized by the above-mentioned.

6th invention is a film removal method of the hard film in any one of 1st invention-5th invention WHEREIN: The said hard film coating member is a hard film coating processing tool by which the said hard film is coat | covered at least in a process part, It is characterized by the above-mentioned. do.

Effects of the Invention

According to the film removal method of the hard film of 1st invention, since a hard film is removed from a main body by sputtering mainly by irradiating and irradiating a hard film with an ion beam, it is partially carried out by the film thickness deviation of a hard film, the film removal speed deviation, etc. Even if the surface of the main body is exposed beforehand, the weakening of the surface due to chemical erosion is suppressed, and the influence on the main body is reduced as compared with the case where the chemical reaction is removed from the main film, and the shape change and the dimensional change are also reduced. As a result, the main body can be reused as it is or only slightly processed. By recoating the hard coating, the hard coating member can be inexpensively regenerated, and the adhesion strength of the hard coating is improved, and the same original coating as the new product is improved. Performance (durability, wear resistance, etc.) is obtained.

In the second aspect of the present invention, since the hard film is etched by irradiating the hard film with the ion beam generated using the inert gas as the working gas, the hard film is mechanically removed only by the sputtering phenomenon by ion irradiation. Therefore, although the film removal rate is slow, even when the surface of the main body is exposed, there is no weakening of the surface due to chemical erosion to the main body, and the adhesion strength of the recoated hard film is further improved.

In the third invention, in the first etching step, etching is performed using a first inert gas having a relatively large atomic weight, whereby the hard film can be efficiently removed by the sputtering phenomenon of large mass ions, while the second etching step is performed. In the case of etching using a second inert gas having a relatively small atomic weight, the hard coating is gradually removed by the sputtering phenomenon of the small mass ions. Therefore, by setting their processing time appropriately, The film removal treatment time can be shortened while minimizing the dimensional change). In addition, in the 1st etching process and the 2nd etching process, since only the working gas may be switched basically, those 1st etching process and 2nd etching process are carried out in the state which kept the hard-film covering member in the predetermined etching process container. Can be carried out continuously.

In the fifth aspect of the present invention, since the main body is made of cemented carbide, when the film is removed by chemical reaction using hydrogen peroxide, the surface of the WC particles is chemically eroded, and the surface becomes brittle. By applying the present invention to remove the film, the effect of the present invention is remarkably obtained such that the weakening of the main body surface is suppressed to improve the adhesion strength of the hard film after recoating.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram explaining an example of the hard film removal apparatus which can implement the method of this invention preferably.

FIG. 2 is a view showing an example of a hard coating coating tool in which a hard film is removed by the apparatus of FIG. 1, (a) is a front view, and (b) is an enlarged cross sectional view of a blade surface portion coated with a hard film.

FIG. 3 is a flowchart for explaining a procedure for removing a hard film by using the hard film removing device of FIG. 1.

Fig. 4 shows the result of examining the durability of the hard coat coating tool in which the hard coat is removed from the tool base material according to the method of the present invention, and then the coating of the hard coat on the tool base is performed by conventional chemical treatment. It is a figure compared with what was regenerated (conventional method 1, the conventional method 2), or a new article.

Explanation of the sign

12: hard film coating processing tool (hard film coating member)

20: tool base (body)

24: blade part (processing part)

30: hard film

Step S2: First Etching Process

Step S3: Second Etching Process

Best Mode for Carrying Out the Invention

The present invention is preferably applied to cutting tools such as end mills, drills, taps and bites, or hard coating coating tools such as rolled dies, and the like. It can be applied to the removal of various hard coating members.

Cemented carbide is preferably used as the tool base material on which the hard film is coated. Other tool materials such as high speed tool steels may be used. In order to improve adhesiveness, predetermined pretreatment can be performed, such as roughening on the surface of a tool base material or forming another film as a base material. The same applies to the hard coat-covered semiconductor device.

The hard coat covering member is a hard coat composed of carbides, nitrides, carbonitrides, or mutual solid solutions of at least Group IIIb, Group IVa, Group Va or Group VIa metals of the periodic table, for example, TiAlN, TiCN, TiCrN, TiN, or the like. This coating may be applied to the case where other coatings such as diamond coating or DLC (Diamond-Like Carbon) coating are formed above or below the hard coating. In the case of having an underlayer such as a diamond coating, only a hard coat such as TiAlN may be removed by ion beam etching to leave the underlayer.

The hard film is preferably formed by, for example, a PVD method such as an arc ion plating method or a sputtering method, and may be formed by another film formation method such as a plasma CVD method. Although the film thickness of a hard film is suitably determined according to the kind of film etc., about 1-5 micrometers is suitable, for example. Various aspects are possible, such as a multilayer laminated film in which two or more types of hard films are laminated alternately.

The etching by the ion beam is preferably performed by relatively moving the ion beam gun and the hard coat coating member which emit the ion beam as necessary so that the ion beam is uniformly irradiated onto the hard coat. Portions other than the coating area of the hard film to be etched may be masked with a masking agent such as a photoresist.

The working gas is a source of ions generating an ion beam, and the working gas is ionized and irradiated to the hard film. In 2nd invention, although an inert gas is used as a working gas, ion beam etching can also be performed using gases other than an inert gas at the time of implementation of 1st invention. In this case, in the case of the hard film and the chemically active gas, the hard film is removed by the chemical reaction in addition to the sputtering phenomenon, which is damaged as compared to the case where the chemical reaction is mainly wet-detached with the chemical reaction as in the prior art. This is greatly suppressed.

Moreover, although a hard film can also be removed by ion beam etching only, it can also carry out in combination with another film removal technique. That is, in suppressing damage to a main body such as a tool base material, it is preferable to employ ion beam etching at least in the final stage of film removal, and after removing the hard film efficiently and roughly by another film removal technology, a working gas such as an inert gas is removed. Various aspects are possible, for example, to remove a hard film gradually by ion beam etching.

In the fourth invention, any one of radon, xenon, and krypton is used in the first etching process, and argon gas is used in the second etching process, and their atomic weight is radon> xenon> krypton> argon. In carrying out the third invention, various aspects are possible, such as using a xenon gas in the first etching step and using a krypton gas in the second etching step. In addition, inert gases include neon and helium, which are not suitable for the etching process of the present invention because of their low mass.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a schematic configuration diagram of a hard film removal apparatus 10 capable of removing a hard film according to the method of the present invention, wherein an ion beam etching apparatus is used, and the hard film coating processing tool 12 is etched by the chuck 14. On the rotary table 18 in the processing container 16, it is arrange | positioned concentrically with the center line S. FIG. The hard coat coating tool 12 corresponds to a hard coat coating member, and the drawing is for the case of an end mill. As shown in FIG. 2, the tool base 20 formed of a cemented carbide has a shank 22 and a blade ( 24) is integrally formed. The blade 24 has an outer circumferential blade 26 and a bottom blade 28 as cutting blades, and the surface of the blade 24 is hardened by a coating technique such as an arc ion plating method by a PVD method. The film 30 is coated. The hard film 30 is composed of carbides, nitrides, carbonitrides, or mutual solid solutions of metals of Group IIIb, Group IVa, Group Va or Group VIa of the Periodic Table of Elements. In this embodiment, TiAlN is formed in a single layer. In addition, the film thickness is about 3 micrometers in the range of 1-5 micrometers.

FIG. 2A is a front view of the hard coat coating tool 12 viewed from the direction perpendicular to the axial center, and FIG. 2B is an enlarged cross-sectional view of the surface portion of the blade 24 coated with the hard coat 30. Incidentally, the oblique portion in Fig. 2 (a) shows the hard coating 30, and the blade 24 coated with the hard coating 30 is disposed on the rotary table 18 in an upward position. This hard coat coating processing tool 12 is a used product in which the hard coat 30 is worn or damaged by use, or a defective product caused by a poor coating of the hard coat 30 at the time of manufacture, and the like. Although only one coating tool 12 is arranged concentrically with the turntable 18, it is also possible to arrange a plurality of hard film coating tools 12 in parallel with the center line S and to perform film removal treatment at the same time. have. The tool base material 20 corresponds to a main body, and the blade part 24 corresponds to a process part.

The hard film removal apparatus 10 of FIG. 1 etches and removes the hard film 30 with the ion beam emitted from the pair of ion beam guns 32a and 32b which have an ion generating source. The working gas supply device 40 is for supplying a working gas, which is a source of ions of the ion beam, to the ion beam guns 32a and 32b. In this embodiment, the atomic weight is smaller than that of the krypton gas and the krypton gas. Argon gas can be switched and supplied, and the krypton ion beam and the argon ion beam are alternatively fired from the ion beam guns 32a and 32b according to the type of working gas. The inside of the etching processing container 16 is decompressed by the vacuum pump 42. In this embodiment, while the vacuum degree becomes 0.1 kPa, the acceleration voltage of ions is 3.0 kPa. Further, the distance from the ion beam guns 32a and 32b to the hard coat coating tool 12 is about 200 mm, and the hard coat coat tool 12 has a load bias of 50 kV and 500 V by the bias power supply 44. (Bias) was to be applied, and the ion source current was 500 mA.

The rotary table 18 is rotationally driven at a predetermined rotational speed around the center line S by the rotary drive device 46 having an electric motor, a speed reducer, and the like. It is rotated (rotated) around the shaft center integrally with (18), and the ion beam is irradiated substantially equally to the whole circumference of the blade part 24. Moreover, the up-and-down moving table 48 is arrange | positioned above the rotating table 18, and the said ion beam gun 32a, 32b is arrange | positioned through the biaxial irradiation angle adjusting apparatus 34a, 34b, respectively, The attitude | position of the ion beam gun 32a, 32b with respect to the hard-film-coated tool 12, ie, irradiation angle, can be adjusted. The up-and-down movable table 48 further includes the ion beam guns 32a and 32b together with the irradiation angle adjusting devices 34a and 34b in accordance with the diameter dimension of the hard coat coating tool 12 to the hard coat coating tool 12. An access separation device is provided for accessing and separating.

The up-and-down moving table 48 is arranged in the up-down direction, that is, the rotary table 18 by an axial movement device 50 having a feed screw that is rotationally driven in a forward and backward direction by, for example, an electric motor. It is made to move linearly in the direction parallel to the axial center (center line S) of the fixed hard-film-coating tool 12. The rotary drive device 46 and the axial movement device 50 are respectively controlled by the electronic control device 52 having a microcomputer or the like, so that the hard coat coating tool 12 is rotationally driven around the shaft center. As the ion beam guns 32a and 32b are moved up and down, the ion beam is irradiated around the entire length of the blade portion 24 on which the hard film 30 is coated. Irradiation time of an ion beam is suitably determined according to the length dimension of the blade part 24, the film thickness of the hard film 30, etc. In addition, a masking agent such as a photoresist is formed in a portion other than the coating region of the hard film 30, that is, the shank 22, as necessary, and etching by the ion beam is prevented.

Next, the procedure of film-detaching a hard film 30 using such a hard film removal film 10 will be described according to the flowchart of FIG. 3. In step S1 of FIG. 3, after arranging the hard coat coating tool 12 on the rotary table 18, the vacuum pump 42 is used to reduce the inside of the etching process container 16 to about 0.1 kPa, for example. do. In step S2, the ion beam guns 32a and 32b are moved up and down while rotating the hard film-coated tool 12 around the axis by the rotation drive device 46 and the axial movement device 50, while the working gas The krypton ion beam is irradiated to the hard film 30 and etched by supplying krypton gas as the working gas from the supply device 40 to the ion beam guns 32a and 32b. Since the krypton gas is an inert gas, it does not cause a chemical reaction with the hard film 30 of TiAlN, and only the hard film 30 is mechanically removed based on the sputtering phenomenon by irradiation of krypton ions. Since it is relatively large at 83.80, the hard film 30 is efficiently removed by the sputtering phenomenon by mass krypton ion irradiation. In the etching process using the krypton ion beam, the hard film 30 is completely removed, for example, at a portion where the hard film 30 is correctly coated (film thickness is 3 μm), so that the surface of the tool substrate 20 is removed. It is carried out for a predetermined time (for example, about 20 hours) predetermined to end before exposure. However, in actual step S2, the surface of the tool base material 20 is partially exposed in accordance with the state of the hard film 30 or the like. This step S2 is a first etching process.

Subsequently, step S3 is performed to convert the working gas supplied from the working gas supply device 40 to the ion beam guns 32a and 32b from krypton gas to argon gas, thereby irradiating the hard coating 30 with the argon ion beam. Etch. Since the argon gas is an inert gas, it does not cause a chemical reaction with the hard film 30 of TiAlN in the same manner as in the step S2, and only the hard film 30 is mechanically removed based on the sputtering phenomenon by irradiation of argon ions. Since the atomic weight of argon is relatively small at 39.95, the hard film 30 is removed relatively slowly by the sputtering phenomenon by argon ion irradiation with a small mass. The etching treatment by the argon ion beam is performed for a predetermined time (for example, about 10 hours) in which the hard film 30 can be completely removed. This step S3 is a second etching process.

Thereby, a series of etching processes are complete | finished, and the tool base material 20 from which the hard film 30 was removed is taken out from the etching process container 16, and the outer peripheral edge 26 or the bottom edge 28 as needed is replaced. After grinding, the TiAlN hard film 30 is coated on the blade portion 24 using a coating technique such as an arc ion plating method, thereby regenerating as a hard film coating tool 12.

Here, in the present embodiment, the hard film 30 is irradiated with an ion beam to be etched, so that the hard film 30 is removed from the tool base 20 with sputtering as the main, and thus the film thickness of the hard film 30. Even if the surface of the tool substrate 20 is partially exposed by the deviation, the film removal rate deviation, or the like, the weakening of the surface due to chemical erosion is suppressed as compared with the case where the chemical reaction is filmed off mainly. The influence on the surface is reduced, so that the shape change and the dimension change are also reduced. Thereby, the tool base material 20 can be reused as it is or only slightly processed, and by recoating the hard film 30, the hard film covering member 12 can be regenerated at low cost, and the hard film 30 ), The adhesive strength is improved, and the same original coating performance (durability, wear resistance, etc.) as that of the new product is obtained.

In particular, in this embodiment, since an inert gas of krypton gas and argon gas is used as the working gas for generating the ion beam, it does not cause a chemical reaction with the hard film 30, but only by sputtering by irradiation of ions. The hard film 30 is to be mechanically removed. Therefore, although the film removal rate is slow, even when the surface of the tool substrate 20 is exposed, there is no fragility of the surface due to chemical erosion to the tool substrate 20, and the recoated hard film 30 The adhesion strength is further improved.

In addition, in the present embodiment, since the tool base material 20 is comprised of cemented carbide, when the film is removed by chemical reaction using hydrogen peroxide, WC particles in the surface layer portion are chemically eroded and the surface becomes brittle. The film removal is carried out by the sputtering phenomenon by the ion beam using an inert gas as the gas, so that the weakening of the surface of the tool substrate 20 is avoided, and the above-described effects such as the adhesion strength of the hard film 30 after recoating are improved. Remarkably obtained.

In this embodiment, the etching is performed using krypton gas in step S2 to efficiently remove the hard film 30 by sputtering of relatively large krypton ions, while argon gas is used in step S3. The hard film 30 is gradually removed by the sputtering phenomenon of the argon ions having a small mass, so that the treatment time is appropriately set so that the influence on the tool substrate 20 (shape change or dimensions The film removal treatment time can be shortened while minimizing the change). For example, step S2 is set to the processing time as long as possible in the range which the tool base material 20 is not exposed in the part (film thickness is 3 micrometers) in which the hard film 30 is correctly coated, and step S3 Is set to the minimum processing time necessary for completely removing the hard film 30 left in step S2.

In addition, in the said steps S2 and S3, only the working gas may be switched, and these steps S2 and S3 can be performed continuously in the state which hold | maintained the hard-film-coated process tool 12 in the etching process container 16. Moreover, as shown in FIG.

In addition, the present invention is directed to an end mill of a double blade having a tool diameter D = 10 mm coated with a film thickness of 3 µm with TiAlN as the hard coating 30 on the blade portion 24 of the tool substrate 20 made of cemented carbide. A total of four test specimens, which were regenerated according to the method and conventional methods 1, 2 and new, which were regenerated by the conventional method, were prepared and subjected to cutting under the following processing conditions to investigate the flank surface wear width VB (mm). As a result, the result shown in FIG. 4 was obtained. The test article according to the method of the present invention uses the tool substrate 20 obtained by subjecting the treatment time of the step S2 to 20 hours and the process time of the step S3 to 10 hours, and performing the film removal treatment as it is to form the hard coating 30. Recoated. The test articles of Conventional Methods 1 and 2 are each obtained by recoating the hard coating 30 on the tool substrate 20 removed by chemical treatment using hydrogen peroxide water.

<< processing condition >>

Tool Double Blade Carbide End Mills, φ10

Cutting speed 34.5m / min

Feed rate 0.03 mm / day

Cutting depth axial aa = 15 mm

Ar = 0.5 mm in diameter

Cutting emulsion air blow

Type of processing side (down)

Workpiece SKD61 (40HRC)

As is clear from the measurement results in FIG. 4, it can be seen that according to the method of the present invention, the flank surface wear width VB becomes about 1/2 compared with the conventional methods 1 and 2, and excellent wear resistance at the same level as a new product is obtained. . This is considered to be because the adhesive strength of the hard film 30 to the tool base material 20 is about the same as that of a new article, and the cutting performance excellent in the grade which the shape of the cutting edge of the outer peripheral blade 26 is the same as a new article is obtained. .

As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, This invention can be implemented in the aspect which added various changes and improvement based on the knowledge of those skilled in the art.

According to the film removal method of the hard film of the present invention, since the hard film is removed from the main body by sputtering as a main by irradiating and irradiating the hard film with the ion beam, chemical erosion by chemical erosion as compared with the case of film removal by the main film While the weakening of the surface is suppressed, the influence on the main body is reduced, and the shape change and the dimensional change are also reduced. As a result, the main body can be reused as it is or only slightly processed. By recoating the hard coating, the hard coating member can be inexpensively regenerated, and the adhesion strength of the hard coating is improved, and the same original coating as the new product is improved. Performance is obtained. That is, the present invention is preferably used when the hard coat of hard coat covering members such as end mills, tabs, drills, etc. is detached and the main body such as a tool base material is reused to regenerate the hard coat coat member.

Claims (6)

A hard coating member comprising a hard coating made of carbides, nitrides, carbonitrides, or mutual solid solutions of metals of Group IIIb, IVa, Group Va, or Group VIa of the Periodic Table of Elements, coated on the surface of the body. As a method of film removal from the main body, A hard film removal method of hard film, wherein the hard film is removed from the main body by etching by irradiating the hard film with an ion beam. The method of claim 1, The hard film removal method of the hard film characterized by irradiating the hard film with the ion beam produced | generated using an inert gas as a working gas. The method of claim 2, A first etching step of etching by irradiating the hard film with an ion beam generated using a first inert gas as a working gas; And a second etching step of converting the working gas into a second inert gas having an atomic weight smaller than that of the first inert gas to generate an ion beam, and irradiating the hard film to perform etching. . The method of claim 3, wherein In the first etching step, any one of radon, xenon and krypton is used as the working gas, In said 2nd etching process, argon gas is used as said working gas, The film removal method of the hard film characterized by the above-mentioned. The method according to any one of claims 1 to 4, And the main body is made of cemented carbide. The method according to any one of claims 1 to 5, The hard coat coating member is a hard coat coating tool, wherein at least a hard coat is coated on the processed portion.

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