WO2025204342A1 - Blade edge protection member and coating film removal method - Google Patents

Abstract

A blade edge protection member used together with a coating film removal device for generating plasma in a vacuum container in which a cutting tool is disposed and subjecting the same to a plasma treatment using the plasma to remove a coating film formed on the surface of the cutting tool, said blade edge protection member comprising a plasma shielding part that is disposed in the vacuum container so as to cover the blade edge of the cutting tool and suppresses the incidence of plasma ions to the blade edge.

Description

Cutting edge protection member and coating removal method

The present invention relates to a cutting edge protection member that protects the cutting edge of a tool during plasma processing, and a coating removal method using the cutting edge protection member.

Conventionally, so-called coated tools exist, in which a coating is applied to the surface of a substrate made of tool steel or cemented carbide, thereby imparting additional properties such as wear resistance and heat resistance to the original properties of the substrate. With use, the coating formed on the surface of such tools wears and peels off, reaching the end of their lifespan. In the past, such used tools were often discarded without being reused, but in recent years, they have been recycled by completely removing the coating from the surface of used tools (de-coating) and then coating them again.

A coating removal device such as that shown in Patent Document 1 is known as an apparatus for using plasma to remove coatings from the surface of tools. This coating removal device is configured so that the workpiece, a drill, is placed on a disk-shaped stage installed inside a vacuum chamber, argon gas is introduced into the vacuum chamber, and an antenna installed outside the vacuum chamber generates inductively coupled plasma inside the vacuum chamber. A bias voltage is applied to the stage, causing positive ions in the plasma to be incident on the coating on the surface of the drill, thereby removing the coating.

Japanese Patent Application Publication No. 2023-004296

However, when using the coating removal device described above to remove coatings from cutting tools such as drills through plasma treatment, the sharp cutting edge may wear away faster than the coating on the tool surface, resulting in dulling of the cutting edge.

The present invention was developed to solve these problems, and its main objective is to suppress wear on the cutting edge of tools during film removal processing using plasma.

In other words, the cutting edge protection member of the present invention is used in conjunction with a coating removal device that generates plasma in a vacuum chamber in which a cutting tool is placed and uses that plasma to perform plasma processing to remove a coating formed on the surface of the cutting tool, and is characterized by having a plasma shielding portion that is placed in the vacuum chamber to cover the cutting edge of the cutting tool and that prevents ions in the plasma from reaching the cutting edge.

With this configuration, the cutting edge of the cutting tool is covered by the plasma shielding portion, preventing ions in the plasma from reaching the cutting edge, thereby reducing wear on the cutting edge during plasma processing.

The cutting edge protection member is attached to the tip of the cutting tool and is preferably configured so that, when viewed from the axial direction of the cutting tool, the plasma shielding portions and exposed portions that expose the surface between the cutting edges of the cutting tool to plasma are arranged alternately around the axis.
In this way, the cutting edge of the tool is shielded from the plasma by the plasma shielding portion while the surface between the cutting edges is exposed to the plasma, so that the film on the surface between the cutting edges can be removed while suppressing wear of the cutting edge of the tool.

It is preferable that the cutting tool is a drill, and the cutting edge protection member is formed so that the inner wall surface of the plasma shielding portion is inclined at approximately the same angle as the point angle of the drill.
In this way, the inner wall surface of the plasma shielding portion and the tip angle of the drill are inclined at approximately the same angle, so the plasma shielding portion can be fitted and attached to the tip of the drill, further suppressing the incidence of ions in the plasma on the cutting edge.

A specific configuration of the cutting edge protection member is one that is roughly cylindrical, and the exposed portion is configured by a groove formed on the side peripheral surface so as to open to the upper and lower surfaces.
In this way, ions in the plasma can be made incident on the surface between the cutting edges of the tool from above, the sides, and below, and the surface between the cutting edges can be efficiently delaminated.

The cutting edge protection member is preferably formed so that the grooves constituting the exposed portion correspond to the shape of the grooves between the cutting edges of the drill.
This makes it easier for ions in the plasma to flow into the drill grooves, allowing for more efficient film removal.

It is preferable that the cutting tool is a hob, and the cutting edge protection member has a shape in which the plasma shielding portion extends straight along the axial direction of the tool.
In this way, a plurality of cutting edges of the hob aligned along the axial direction can be collectively protected by a single plasma shielding portion.

In a specific embodiment of the cutting edge protection member, the plasma shielding portion is made of one or more materials selected from stainless steel, molybdenum, tungsten, and quartz.
These materials allow the plasma shielding portion to exhibit sufficient resistance to ion collisions and heat during film removal processing using plasma.

Furthermore, the coating removal method of the present invention is a coating removal method in which plasma is generated in a vacuum chamber in which a cutting tool is placed, and a coating formed on the surface of the cutting tool is removed by performing plasma treatment using the plasma, and is characterized in that a plasma shielding section is installed in the vacuum chamber to cover the cutting edge of the cutting tool and suppress the incidence of ions in the plasma on the cutting edge, and the coating on the cutting tool is removed.
Such a coating removal method of the present invention can achieve the same effects as the cutting edge protection member of the present invention described above.

The present invention, configured in this way, can suppress wear on the cutting edge of the tool during the film removal process using plasma.

1 is a vertical cross-sectional view schematically showing the configuration of a coating removal device according to an embodiment of the present invention; FIG. 2 is a top view schematically showing the configuration of the coating removal device of the embodiment. FIG. 2 is a top perspective view schematically showing the configuration of the cutting edge protection member of the embodiment. FIG. 2 is a top perspective view showing the configuration of the cutting edge protection member of the embodiment, with the structure of the underside thereof visible; FIG. 2 is a top view schematically showing the configuration of the cutting edge protection member of the embodiment. FIG. 2 is a cross-sectional view schematically showing the configuration of the cutting edge protection member of the embodiment. FIG. 10 is a top view schematically showing the configuration of a cutting edge protection member according to another embodiment.

Below, a coating removal device according to one embodiment of the present invention will be described with reference to the drawings.

<Device configuration>
The coating removal device of this embodiment removes a coating formed on the surface of a tool by plasma treatment using inductively coupled plasma.

Specifically, as shown in Figures 1 and 2, the coating removal device 100 comprises a vacuum vessel 1 that forms a processing chamber S that is evacuated and into which gas is introduced, an antenna 2 provided outside the vacuum vessel 1, and a high-frequency power supply 3 that applies high-frequency waves to the antenna 2. In this configuration, when high-frequency waves are applied to the antenna 2 from the high-frequency power supply 3, a high-frequency current flows through the antenna 2, generating an induced electric field within the vacuum vessel 1 and generating inductively coupled plasma. In this embodiment, the antenna 2 and the high-frequency power supply 3 that applies high-frequency waves thereto constitute a plasma source.

The tool T, which is the target of processing by the coating removal device 100 of this embodiment, is what is known as a coated tool, and is a tool in which a coating (also called a coating film) is formed on the surface of a substrate made of, for example, tool steel or cemented carbide. Specifically, the tool T is a cutting tool with one or more blades, such as a drill, hob, or end mill, and is particularly a cutting tool with a honed cutting edge. The tool T of this embodiment is a drill with multiple cutting edges.

The vacuum vessel 1 is, for example, a metal vessel. This vacuum vessel 1 is electrically grounded, and the processing chamber S inside it is evacuated by a vacuum exhaust device 4.

Plasma-generating gas is introduced into the vacuum chamber 1 through a gas supply port (not shown). This plasma-generating gas is, for example, a rare gas such as argon gas, a halogen gas, or a mixture of these, and may be changed as appropriate depending on the material of the coating to be removed.

As shown in Figures 1 and 2, the antennas 2 are arranged so as to face the side walls of the vacuum vessel 1. In this embodiment, two antennas 2 are provided so as to face each of a pair of opposing side walls of the vacuum vessel 1, but this is not limiting and the number of antennas 2 may be one or three or more. The antennas 2 in this embodiment are rod-shaped and are arranged upright along the axial direction (vertical direction) of the vacuum vessel 1.

One end of the antenna 2, the power supply end, is connected to the high-frequency power source 3 via a matching circuit 31, and the other end, the termination end, is directly grounded. The termination end may also be grounded via a capacitor, coil, or the like.

The high-frequency power supply 3 can pass a high-frequency current through the antenna 2 via a matching circuit 31. The frequency of the high-frequency current is, for example, the common 13.56 MHz, but is not limited to this and may be changed as appropriate.

This coating removal device 100 has a magnetic field transmission window W that allows the magnetic field generated by the antenna 2 to pass through. Specifically, the coating removal device 100 is equipped with a dielectric plate that covers an opening formed in the wall of the vacuum vessel 1 from the outside of the vacuum vessel 1, and this dielectric plate forms the magnetic field transmission window W.

The dielectric plate is a flat plate made entirely of a dielectric material, such as ceramics such as alumina, silicon carbide, or silicon nitride, inorganic materials such as quartz glass or alkali-free glass, or resin materials such as fluororesin (e.g., Teflon). A sealing member such as an O-ring or gasket is placed between the dielectric plate and the vacuum vessel 1, creating a vacuum seal between them.

The coating removal device 100 is equipped with a tool holder 5 that holds tools T within the vacuum chamber 1. This tool holder 5 is configured to hold multiple tools T and to rotate and move the multiple tools T within the vacuum chamber 1. Specifically, this tool holder 5 is equipped with a disk-shaped rotary table 51 that rotates within the vacuum chamber 1, and an actuator (not shown) that rotates the rotary table 51.

The rotary table 51 is provided near the bottom wall of the vacuum vessel 1. On the top surface of the rotary table 51, there are provided a plurality of (six in this case) holding portions 511 that hold tools T upright with their tips facing upward. The holding portions 511 are circular when viewed from the top and bottom, and are arranged so that they are rotationally symmetrical with respect to one another about the central axis of the rotary table 51. Each holding portion 511 holds a plurality of tools T in an arrangement that is rotationally symmetrical with respect to one another.

In this embodiment, the rotary table 51 rotates when the actuator is driven, causing the multiple tools T held by the multiple holders 511 of the rotary table 51 to rotate around the center of the rotary table 51 as the axis of rotation. Note that in this embodiment, each holder 511 itself is configured to rotate (spin on its own axis) on the rotary table 51.

The coating removal device 100 is equipped with a bias power supply 6 that applies a bias voltage to the tool holder 5. The bias voltage may be, for example, a negative DC voltage, but is not limited to this. This bias voltage controls the energy of positive ions in the plasma when they strike the coating on the surface of the tool T, thereby enabling control of the coating removal rate, etc.

With this configuration, when high frequency power is applied to the antenna 2 from the high frequency power supply 3, the high frequency magnetic field generated by the antenna 2 passes through the magnetic field transmission window W made of the dielectric plate 8 and is formed (supplied) inside the vacuum chamber 1. This generates an induced electric field in the space inside the vacuum chamber 1, generating an inductively coupled plasma. Then, by applying a bias voltage to the tool holder 5, positive ions in the plasma are incident on the coating on the surface of the tool T, thereby removing the coating formed on the surface of the tool T.

In the coating removal device 100 of this embodiment, in order to prevent wear on the cutting edge of the tool T during the coating removal process, a cutting edge protection member 7 is placed inside the vacuum chamber 1. The cutting edge protection member 7 covers the cutting edge of the cutting tool and includes a plasma shielding portion 71 that prevents ions in the plasma from entering the cutting edge.

In this embodiment, the cutting edge protection member 7 is cap-shaped and attached to the tip of the tool T. Specifically, as shown in Figures 3 to 5, the cutting edge protection member 7 has a generally cylindrical shape. The cutting edge protection member 7 includes a plasma shielding portion 71 that shields the cutting edge of the tool T from plasma, and an exposed portion 72 that exposes the surface between the cutting edges of the tool T to plasma. The cutting edge protection member 7 includes multiple plasma shielding portions 71 and exposed portions 72 (two in this example), and is configured so that the plasma shielding portions 71 and exposed portions 72 are arranged alternately around the axis when viewed axially.

The cutting edge protection member 7 has grooves formed on its side circumferential surface that open to the top and bottom, providing an exposed area. The grooves formed on the side circumferential surface of the cutting edge protection member 7 are shaped to correspond to the groove shape formed between the cutting edges of the tool T, which is a drill. Specifically, the cutting edge protection member 7 is configured so that, when the cutting edge protection member 7 is attached to the tip of the tool T, the surface formed by the grooves formed on the side circumferential surface is approximately flush with the rake face formed by the grooves on the tool T.

The plasma shielding portion 71 is formed by the area other than the grooves in the cutting edge protection member 7. The plasma shielding portion 71 is formed so that its inner wall surface facing the outer surface of the tool T is inclined at approximately the same angle as the tip angle of the tool T. When attached to the tip of the tool T, the distance between the inner wall surface of the plasma shielding portion 71 and the cutting edge of the tool T is preferably 0 mm or more and 10 mm or less, and more preferably 0 mm or more and 3 mm or less. In this embodiment, the inner wall surface of the plasma shielding portion 71 is in contact with the cutting edge of the tool T, more specifically, in surface contact.

At least the plasma shielding portion 71 of this cutting edge protection member 7, or the entirety thereof, is made of a material that exhibits sufficient ion bombardment resistance and heat resistance during plasma removal processing, and is made of, for example, one or more materials selected from stainless steel, molybdenum, tungsten, or quartz.

<Effects of this embodiment>
According to the film removal process performed by the film removal device 100 using the cutting edge protection member 7 of this embodiment configured as described above,
The cutting edge protection member 7 is attached to the tip of the tool T and is configured so that, when viewed from the axial direction of the tool T, plasma shielding portions 71 that shield the cutting edge of the tool T from plasma and exposed portions 72 that expose the surface between the cutting edges of the tool T to plasma are arranged alternately around the axis.Therefore, while the plasma shielding portions 71 shield the cutting edge of the tool from plasma, the surface between the cutting edges is exposed to plasma, so that it is possible to remove the film from the surface between the cutting edges while suppressing wear of the cutting edge of the tool.
Furthermore, since the inner wall surface of the plasma shielding portion 71 and the tip angle of the drill are inclined at approximately the same angle, the plasma shielding portion 71 can be fitted and attached to the tip of the drill, further suppressing the incidence of ions in the plasma onto the cutting edge.
Furthermore, the exposed portion 72 of the cutting edge protection member 7 is configured with grooves formed on the side surface so as to open to the upper and lower surfaces, and the grooves are formed to correspond to the groove shape between the cutting edges of the tool. Therefore, ions in the plasma can be made incident on the surface between the cutting edges of the tool T from above, the side, and below, and the surface between the cutting edges can be efficiently delaminated.

<Other Modified Embodiments>
The present invention is not limited to the above-described embodiment.
For example, although the cutting edge protection member 7 in the above embodiment is attached to the tip of the tool T, this is not limiting. In other embodiments, as long as the cutting edge protection member 7 has a structure including a plasma shielding portion 71 that covers the cutting edge of the tool T, the cutting edge protection member 7 may be attached to a portion other than the tip of the tool T, or may be installed in the vicinity of the tool T without being attached to the tool T.

In addition, while the cutting edge protection member 7 in the above embodiment is attached to the tool T, which is a drill, the cutting edge protection member 7 in other embodiments may be attached to a hob, which has multiple cutting edges arranged around its rotation axis and multiple rows of the cutting edges along the rotation axis direction. In this case, as shown in FIG. 7 , the cutting edge protection member 7 has, for example, a ring-shaped mounting portion 73 that is attached to the hub of the tool T, and the plasma shielding portion 71 may have a plate-like shape extending radially outward from the mounting portion 73 in a top view. In addition, the radial tip of the plasma shielding portion 71 may be bent in a hook shape to surround the cutting edge of the tool T in a top view. In this case, the plasma shielding portion 71 may extend straight along the axial direction of the tool T and have a shape that covers the multiple cutting edges arranged in the axial direction.

Furthermore, the coating removal device 100 in the above embodiment was a so-called external antenna type in which high frequency waves are applied to an antenna 2 provided outside the vacuum vessel 1 to generate plasma inside the vacuum vessel 1, but this is not limited to this. In other embodiments, it may be a so-called internal antenna type in which an antenna 2 is installed inside the vacuum vessel 1 to generate plasma.

Furthermore, in the above embodiment, plasma processing is performed using inductively coupled plasma, but this is not limited to this. In other embodiments, plasma processing may be performed using plasma generated by other methods, such as capacitively coupled plasma. In other embodiments, the plasma source does not have to be configured using an antenna and a high-frequency power source.

It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the invention.

The cutting edge protection member of the present invention can reduce wear on the cutting edge of a tool during a coating removal process using plasma.

100... Coating removal device 1... Vacuum container 7... Cutting edge protection member 71... Plasma shielding part T... Cutting tool

Claims (8)

The present invention is used together with a coating removal device that generates plasma in a vacuum chamber in which a cutting tool is placed, and removes a coating formed on the surface of the cutting tool by performing plasma processing using the plasma,
a cutting edge protection member disposed in the vacuum chamber so as to cover the cutting edge of the cutting tool, the cutting edge protection member including a plasma shielding portion that suppresses incidence of ions in the plasma onto the cutting edge; The cutting tool is attached to a tip end of the cutting tool,
2. The cutting edge protection member according to claim 1, wherein the plasma shielding portions and the exposed portions that expose the surface between the cutting edges of the cutting tool to the plasma are arranged alternately around the axis when viewed in the axial direction of the cutting tool. the cutting tool is a drill;
3. The cutting edge protection member according to claim 2, wherein the inner wall surface of the plasma shielding portion is formed so as to be inclined at an angle substantially the same as the point angle of the drill. It has a generally cylindrical shape,
4. The cutting edge protection member according to claim 3, wherein the exposed portion is formed by a groove formed on the circumferential side surface so as to open to the upper and lower surfaces. The cutting edge protection member according to claim 4, wherein the grooves constituting the exposed portion are formed to correspond to the shape of the grooves between the cutting edges of the drill. the cutting tool is a hob;
The cutting edge protection member according to claim 2 , wherein the plasma shielding portion has a shape extending straight along the axial direction of the tool. The cutting edge protection member according to claim 1, wherein the plasma shielding portion is made of one or more materials selected from stainless steel, molybdenum, tungsten, and quartz. 1. A coating removal method for removing a coating formed on a surface of a cutting tool by generating plasma in a vacuum chamber in which a cutting tool is placed and performing plasma treatment using the plasma, comprising:
A coating removal method for removing a coating from a cutting tool by installing a plasma shielding part in the vacuum chamber that covers the cutting edge of the cutting tool and suppresses incidence of ions in the plasma onto the cutting edge.