JP4652446B2 - Hard film removal method - Google Patents

Description

  The present invention relates to a method for removing a hard coating such as TiAlN or TiCN, and more particularly to a method for removing a hard coating without damaging a main body as much as possible.

  Hard film coating in which a hard film made of a carbide, nitride, carbonitride, or mutual solid solution of a group IIIb, IVa, Va, or VIa metal of the periodic table of elements is coated on the surface of the main body Members are known. For example, in a processing tool such as an end mill, a tap, a drill, a cutting tool, etc., the hard coating is applied to a processing part provided with at least a cutting edge on the surface of a tool base (main body) made of cemented carbide. A hard film coating tool coated by a PVD (physical vapor deposition) method such as an ion plating method has been proposed in Patent Document 1 and the like.

In such a hard coating coated member, when the hard coating is worn or damaged, or when a defective product is generated due to a defective coating at the time of manufacture, the hard coating is removed to remove the main body such as a tool substrate. It is considered to be reused. That is, using a hydrogen peroxide solution or the like, the film is chemically decomposed by a wet method and removed from the main body.
JP 2005-7555 A

  However, when the film is removed using a chemical reaction in this way, if the main body is partially exposed in advance due to variations in the thickness of the hard coating or the ease of peeling of the coating, the surface of the exposed main body is exposed. Are also damaged by the treatment liquid, and when the hard coating is completely removed, the surface of the main body may become partially rough or fragile. For example, when the main body is made of cemented carbide, the WC particles in the surface layer are chemically eroded and the surface becomes brittle, and the cutting edge of the cutting edge is rounded and the diameter is reduced. May change. When such a main body is re-coated with a hard coating, the adhesion is lost due to the weakness of the surface, the original coating performance (durability, wear resistance, etc.) cannot be obtained, or the cutting edge is rounded. The cutting performance will decrease.

  The present invention has been made against the background of the above circumstances, and its object is to make it possible to remove the hard coating without damaging the main body of the hard coating covering member as much as possible.

  In order to achieve such an object, the first invention provides a hard material composed of a carbide, nitride, carbonitride, or mutual solid solution of a group IIIb, IVa, Va, or VIa group metal of the periodic table of elements. A method of removing a film from the main body, wherein the hard film is etched by irradiating the hard film with an ion beam. Is removed from the main body.

  The second invention is characterized in that in the method for removing a hard coating of the first invention, etching is performed by irradiating the hard coating with an ion beam generated using an inert gas as a working gas.

  According to a third aspect of the present invention, in the method for removing a hard coating of the second invention, (a) a first etching step of performing etching by irradiating the hard coating with an ion beam generated using the first inert gas as a working gas; (B) a second etching step in which the working gas is switched to a second inert gas having an atomic weight smaller than that of the first inert gas to generate an ion beam and irradiate the hard coating to perform etching; It is characterized by having.

  According to a fourth aspect of the present invention, in the method for removing a hard coating of the third aspect, (a) in the first etching step, any one of radon, xenon, and krypton is used as the working gas. In the second etching step, argon gas is used as the working gas.

  According to a fifth aspect of the present invention, in the method for removing a hard film according to any one of the first to fourth aspects, the main body is made of a cemented carbide.

  A sixth invention is the hard film coating processing tool according to any one of the first to fifth inventions, wherein the hard film coating member is a hard film coating tool in which the hard film is coated at least on a processed portion. It is characterized by that.

  According to the film removal method of the hard coating of the first invention, the hard coating is removed from the main body mainly by the sputtering phenomenon by irradiating the hard coating with an ion beam and etching. Even if the surface of the main body is partially exposed due to variations or variations in the film removal rate, surface weakening due to chemical erosion is suppressed as compared with the case where the film is mainly removed by chemical reaction. The influence on the main body is reduced, and the shape change and dimensional change are also reduced. As a result, the main body can be reused as it is or with a slight modification, and by recoating the hard film, the hard film coated member can be reproduced at low cost, and the adhesion strength of the hard film is improved. Original film performance (durability, wear resistance, etc.) similar to that of a new product can be obtained.

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

  In the third invention, in the first etching step, etching is performed using the first inert gas having a relatively large atomic weight, whereby the hard coating can be efficiently removed by the sputtering phenomenon of large mass ions, while the second etching process is performed. In the etching process, etching is performed using a second inert gas having a relatively small atomic weight, so that the hard film is gradually removed by the sputtering phenomenon of small mass ions. Therefore, the processing time is appropriately set. Thus, the film removal treatment time can be shortened while minimizing the influence on the main body (shape change and dimensional change). Further, in the first etching step and the second etching step, basically, it is only necessary to switch the working gas, so that the first coating step and the second etching step are performed while holding the hard film covering member in a predetermined etching processing container. Two etching processes can be performed continuously.

  In the fifth invention, since the main body is composed of a cemented carbide, when the film is removed by a chemical reaction using hydrogen peroxide, the surface WC particles are chemically eroded and the surface is fragile. However, by applying the present invention in which the film removal is performed mainly by the sputtering phenomenon by the ion beam, it is possible to suppress the weakening of the surface of the main body and to improve the adhesion strength of the hard coating after the re-coating. The effect of the invention is remarkably obtained.

It is a schematic block diagram explaining an example of the hard film removal apparatus which can implement suitably the method of this invention. It is a figure which shows an example of the hard film coating processing tool from which a hard film is removed with the apparatus of FIG. 1, (a) is a front view, (b) is an expanded sectional view of the surface part of the blade part coated with the hard film It is. It is a flowchart explaining the procedure at the time of removing a hard film using the hard film removal apparatus of FIG. After removing the hard coating from the tool base according to the method of the present invention, the result of examining the durability of the hard coating coated tool obtained by re-coating the hard base on the tool base is shown as follows. It is a figure shown in comparison with what was regenerated as a film (conventional method 1, conventional method 2) and a new product.

Explanation of symbols

12: Hard film coating processing tool (hard film coating member) 20: Tool substrate (main body) 24: Blade part (working part) 30: Hard film Step S2: First etching step Step S3: Second etching step

  The present invention is suitably applied to a cutting tool such as an end mill, a drill, a tap, a cutting tool, or a hard film coating processing tool such as a rolling die, but various devices such as a hard film coated semiconductor device coated with a hard film. It can be applied to the film removal of a hard film coated member.

  A cemented carbide is preferably used as the tool base material to be coated with the hard coating, but other tool materials such as high-speed tool steel can also be used. In order to improve the adhesion, a predetermined pretreatment such as roughening the surface of the tool substrate or providing another coating as a base can be performed. The same applies to the case of a hard film coated semiconductor device.

  The hard coating member is a hard coating made of a carbide, nitride, carbonitride, or mutual solid solution of at least group IIIb, IVa, Va, or VIa metals of the periodic table of elements, such as TiAlN, TiCN. TiCrN, TiN or the like may be coated, and the present invention can also be applied to the case where another film such as a diamond film or a DLC (Diamond-Like Carbon) film is provided on or below the hard film. When a base layer such as a diamond coating is provided, only the hard coating such as TiAlN can be removed by ion beam etching to leave the base layer.

  The hard coating is preferably provided by a PVD method such as an arc ion plating method or a sputtering method, but may be provided by another film forming method such as a plasma CVD method. The film thickness of the hard coating is appropriately determined depending on the type of coating and the like, for example, about 1 to 5 μm is appropriate. Various modes are possible, such as a multilayer laminated film in which two or more kinds of hard films are alternately laminated.

  Etching with an ion beam is desirably performed by relatively moving an ion beam gun that emits the ion beam and the hard coating covering member as necessary so that the hard coating is uniformly irradiated with the ion beam. The portions other than the hard film coating region to be etched may be masked with a mask agent such as a photoresist.

  The working gas is a source of ions that generate an ion beam. The working gas is ionized and irradiated onto the hard coating. In the second invention, an inert gas is used as a working gas. However, in carrying out the first invention, it is also possible to perform ion beam etching using a gas other than the inert gas. In that case, in the case of a chemically active gas with the hard coating, the hard coating is removed by a chemical reaction in addition to the sputtering phenomenon. Damage to the main body is greatly suppressed as compared to the case of filming.

  Moreover, although a hard film can be removed only by ion beam etching, it can also be performed in combination with other film removal techniques. That is, it is desirable to employ ion beam etching at least at the final stage of film removal in order to suppress damage to the main body such as a tool base material, and after efficiently removing the hard film with other film removal techniques, Various modes such as gradually removing the hard film by ion beam etching using a working gas such as an inert gas are possible.

  In the fourth invention, any gas of radon, xenon, and krypton is used in the first etching step, and argon gas is used in the second etching step, and the atomic weight thereof is radon> xenon> krypton. Since it is> argon, various aspects are possible in implementing the third invention, such as using xenon gas in the first etching step and using krypton gas in the second etching step. In addition, other examples of the inert gas include neon and helium. However, since the mass is small, it is not suitable for the etching process of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a hard film removal apparatus 10 that can remove a hard film in accordance with the method of the present invention, using an ion beam etching apparatus. 16 is arranged concentrically with the center line S on the turntable 18 in the same. The hard film coating processing tool 12 corresponds to a hard film coating member, and the figure is an end mill. As shown in FIG. 2, the tool base 20 made of cemented carbide has a shank 22 and The blade part 24 is provided integrally. The blade portion 24 is provided with an outer peripheral blade 26 and a bottom blade 28 as cutting blades, and the surface of the blade portion 24 is coated with a hard film 30 by a coating technique using a PVD method such as an arc ion plating method. ing. The hard coating 30 is composed of a carbide, nitride, carbonitride, or mutual solid solution of a group IIIb, IVa, Va, or VIa group metal in the periodic table of elements. In this embodiment, TiAlN is made of TiAlN. It is provided as a single layer, and its film thickness is about 3 μm within a range of 1 to 5 μm.

  2A is a front view of the hard film coating tool 12 as viewed from the direction perpendicular to the axis, and FIG. 2B is an enlarged cross-sectional view of the surface portion of the blade 24 coated with the hard film 30. . 2A represents the hard coating 30, and the blade 24 coated with the hard coating 30 is disposed on the rotary table 18 in a posture in which the blade 24 faces upward. The hard film coating tool 12 is a used product in which the hard film 30 is worn or damaged by use, or a defective product caused by a defective coating of the hard film 30 at the time of manufacture. Although only one tool 12 is disposed concentrically with the rotary table 18, it is also possible to dispose a plurality of hard film coating processing tools 12 in parallel with the center line S and perform film removal processing at the same time. The tool base 20 corresponds to the main body, and the blade portion 24 corresponds to the processing portion.

  1 removes the hard coating 30 by etching with an ion beam emitted from a pair of ion beam guns 32a and 32b having an ion generation 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 krypton gas and the atomic weight of the krypton gas are higher than those of the krypton gas. A small argon gas can be switched and supplied, and a krypton ion beam and an argon ion beam are alternatively emitted from the ion beam guns 32a and 32b according to the type of the working gas. The inside of the etching chamber 16 is depressurized by a vacuum pump 42. In this embodiment, the degree of vacuum (Pressure) is 0.1 Pa, and the acceleration voltage of ions is 3.0 kV. is there. Further, the distance from the ion beam guns 32a, 32b to the hard coating coating tool 12 is about 200 mm, and a load bias (Bias) of 50 kHz and 500 V is applied to the hard coating coating tool 12 by a bias power source 44. The ion source current value was 500 mA.

  The rotary table 18 is rotationally driven around the center line S at a predetermined rotational speed by a rotary drive device 46 having an electric motor, a speed reducer, and the like, and the hard coating coating tool 12 is also integrated with the rotary table 18 as an axis. It is rotated (rotated) around, and the ion beam is irradiated almost evenly on the entire circumference of the blade portion 24. Further, an up / down moving table 48 is disposed above the rotary table 18, and the ion beam guns 32a and 32b are respectively disposed via biaxial irradiation angle adjusting devices 34a and 34b. The attitude of the ion beam guns 32a and 32b with respect to the processing tool 12, that is, the irradiation angle can be adjusted. The vertical moving table 48 also has an ion beam gun 32a, 32b that approaches and moves away from the hard coating coating tool 12 together with the irradiation angle adjusting devices 34a, 34b in accordance with the diameter and the like of the hard coating coating tool 12. A device is provided.

  The vertical movement table 48 is vertically moved by an axial movement device 50 having a feed screw that is driven to rotate in both forward and reverse directions by, for example, an electric motor, that is, the axis of the hard coating coating tool 12 fixed to the rotary table 18 ( It can be linearly moved in a direction parallel to the center line S). Then, the electronic control device 52 having a microcomputer or the like controls the rotation drive device 46 and the axial movement device 50, respectively, and the hard film coating processing tool 12 is rotationally driven around the axis, and the ion beam guns 32a and 32b. Is moved up and down, the ion beam is irradiated to the entire circumference of the blade portion 24 coated with the hard coating 30. The ion beam irradiation time is appropriately determined according to the length dimension of the blade portion 24, the film thickness of the hard coating 30, and the like. Note that a masking agent such as a photoresist is provided on the portion other than the coating region of the hard coating 30, that is, the shank 22, as necessary, so that etching by an ion beam is prevented.

  Next, the procedure for removing the hard coating 30 using such a hard coating removal apparatus 10 will be described with reference to the flowchart of FIG. In step S1 of FIG. 3, after the hard film coating tool 12 is disposed on the turntable 18, the inside of the etching processing container 16 is depressurized to, for example, about 0.1 Pa by the vacuum pump. In step S2, the ion beam guns 32a and 32b are moved up and down while the hard film coating tool 12 is rotationally driven around the axis by the rotation driving device 46 and the axial movement device 50, while the working gas supply device 40 uses the working gas as the working gas. By supplying krypton gas to the ion beam guns 32a and 32b, the hard coating 30 is irradiated with the krypton ion beam for etching. Since the krypton gas is an inert gas, it does not cause a chemical reaction with the TiAlN hard coating 30, and the hard coating 30 is mechanically removed exclusively based on the sputtering phenomenon caused by the irradiation of krypton ions. Is relatively large at 83.80, the hard coating 30 is efficiently removed by a sputtering phenomenon caused by irradiation with a large mass of krypton ions. The etching process using the krypton ion beam is finished before the hard coating 30 is completely removed and the surface of the tool base 20 is exposed at the portion where the hard coating 30 is correctly coated (film thickness is 3 μm), for example. This is performed for a predetermined time (for example, about 20 hours). However, in the actual step S2, the surface of the tool base 20 is partially exposed depending on the state of the hard coating 30 or the like. This step S2 is a first etching process.

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

  As a result, the series of etching processes is completed, and the tool substrate 20 from which the hard coating 30 has been removed is taken out of the etching process vessel 16, and after the outer peripheral blade 26 and the bottom blade 28 are reground as necessary, When the blade portion 24 is coated with a hard coating 30 of TiAlN using a coating technique such as a plating method, the hard coating coating tool 12 is regenerated.

  Here, in this embodiment, since the hard coating 30 is removed from the tool base material 20 mainly by the sputtering phenomenon by irradiating the hard coating 30 with an ion beam and etching, the film thickness of the hard coating 30 is reduced. Even if the surface of the tool base 20 is partially exposed due to variations or variations in the film removal rate, surface weakening due to chemical erosion is suppressed as compared with the case where the film is mainly removed by chemical reaction. At the same time, the influence on the tool base 20 is reduced and the change in shape and change in dimensions are reduced. As a result, the tool base 20 can be reused as it is or with slight modification, and the hard coating member 12 can be regenerated at a low cost by recoating the hard coating 30. The adhesion strength is improved and the original film performance (durability, wear resistance, etc.) similar to that of a new article can be obtained.

  In particular, in this embodiment, since an inert gas such as krypton gas and argon gas is used as a working gas for generating an ion beam, it does not cause a chemical reaction with the hard coating 30 and is hard only due to a sputtering phenomenon caused by ion irradiation. The coating 30 is mechanically removed. Therefore, although the film removal rate is slow, even when the surface of the tool base 20 is exposed, the surface of the tool base 20 is not weakened by chemical erosion, and the adhesion strength of the recoated hard coating 30 is not. Is further improved.

  In the present embodiment, since the tool base 20 is made of a cemented carbide, when the film is removed by a chemical reaction using hydrogen peroxide, the WC particles in the surface layer portion are chemically eroded. Although the surface becomes brittle, the film removal is performed by a sputtering phenomenon by an ion beam using an inert gas as a working gas, so that the surface of the tool base material 20 is prevented from being weakened and hard after recoating. The above effects such as improvement of the adhesion strength of the coating 30 can be obtained more remarkably.

  In this embodiment, the hard coating 30 is efficiently removed by the sputtering phenomenon of a relatively large mass of krypton ions by performing etching using krypton gas in step S2, while argon gas is used in step S3. Etching is performed to gradually remove the hard coating 30 due to the sputtering phenomenon of a small mass of argon ions. By appropriately setting the processing time, the influence on the tool base 20 (shape change or The film removal processing time can be shortened while minimizing dimensional changes. For example, step S2 is set to a processing time as long as possible in a range where the tool base material 20 is not exposed in a portion where the hard coating 30 is correctly coated (film thickness is 3 μm), and step S3 is the hard time left in step S2. The minimum processing time that can completely remove the coating 30 is set.

  Moreover, since it is only necessary to switch the working gas in the above steps S2 and S3, these steps S2 and S3 can be continuously performed while the hard film coating tool 12 is held in the etching processing vessel 16.

Incidentally, a two-blade end mill with a tool diameter D = 10 mm, in which TiAlN is coated as a hard coating 30 with a film thickness of 3 μm on the blade portion 24 of the tool base 20 made of cemented carbide, was regenerated according to the method of the present invention. Prepare a total of four test products, the conventional method 1, the conventional method 2, and a new one that were regenerated by the conventional method, and cut the flank wear width VB (mm) by cutting under the following processing conditions. As a result, the result shown in FIG. 4 was obtained. The test article according to the method of the present invention was prepared by using the tool substrate 20 obtained by performing the film removal treatment with the treatment time of the step S2 being 20 hours and the treatment time of the step S3 being 10 hours. Re-coated. The test products of the conventional method 1 and the conventional method 2 are obtained by re-coating the hard coating 30 on the tool base 20 that has been removed by chemical treatment using hydrogen peroxide.
"Processing conditions"
・ Tool 2 flute carbide end mill, φ10
・ Cutting speed 34.5m / min ・ Feeding speed 0.03mm / blade ・ Incision Axial direction aa = 15mm
Radial direction ar = 0.5mm
・ Cutting fluid air blow ・ Processing type Side (down)
・ Work material SKD61 (40HRC)

  As is apparent from the measurement results of FIG. 4, according to the method of the present invention, the flank wear width VB is about ½ as compared with the conventional methods 1 and 2, and excellent wear resistance comparable to that of a new product is achieved. You can see that This is presumably because excellent cutting performance is obtained when the adhesion strength of the hard coating 30 to the tool substrate 20 is about the same as that of a new article, and the cutting edge shape of the outer peripheral blade 26 is about the same as that of a new article.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention implements in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

  According to the method for removing a hard coating of the present invention, the hard coating is removed from the main body mainly by a sputtering phenomenon by irradiating the hard coating with an ion beam, so that the chemical reaction is mainly removed. Compared to the case, the weakening of the surface due to chemical erosion 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 with a slight modification, and by recoating the hard film, the hard film coated member can be reproduced at low cost, and the adhesion strength of the hard film is improved. The original film performance similar to that of a new product can be obtained. That is, the present invention is suitably used when removing a hard coating of a hard coating covering member such as an end mill, a tap or a drill, and reusing the main body such as a tool base to regenerate the hard coating covering member. .

Claims (4)

Hard film in which a hard film made of a carbide, nitride, carbonitride, or a mutual solid solution of a group IIIb, IVa, Va, or VIa metal of the periodic table of elements is coated on the surface of the main body In the covering member, a method of removing the hard coating from the main body by irradiating the hard coating with an ion beam and etching,
Etching is performed by irradiating the hard coating with an ion beam generated using an inert gas as a working gas.
A first etching step of performing etching by irradiating the hard film with an ion beam generated using a first inert gas as a working gas;
A second etching step of switching the working gas to 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 coating to perform etching;
A method for removing a hard coating, comprising: In the first etching step, any one of radon, xenon, and krypton is used as the working gas.
The hard film removal method according to claim 3, wherein argon gas is used as the working gas in the second etching step. The said main body is comprised with the cemented carbide alloy. The film removal method of the hard film of Claim 3 or 4 characterized by the above-mentioned. The said hard film coating | coated member is a hard film coating processing tool by which the said hard film is coated by the process part at least. The film removal method of the hard film of any one of Claims 3-5 characterized by the above-mentioned. .

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