Plasma head and plasma generator

Abstract

This plasma head is equipped with: a cylindrical main body through which a processing gas to be made into plasma travels; a pair of electrodes which are stored in the main body, and form a plasma gas by discharging electricity into some of the processing gas; and a rectifier member which has a plurality of rectifier plates which convert the flow of the processing gas, which is introduced into the interior of the main body and supplied to the pair of electrodes, into a helical flow.

Description

Technical Field

[0001] This specification relates to a plasma head and a plasma generator.

Background Art

[0002] Conventionally, for example, plasma heads and plasma generators disclosed in Patent Document 1 and Patent Document 2 (hereinafter referred to as "conventional devices, etc.") are known. In the conventional devices, etc., a process gas (for example, air containing nitrogen gas, nitrogen gas, etc.) is supplied into the interior through an opening. The opening has a hole through which the process gas passes, and the hole is provided so as to be inclined obliquely. Thereby, the process gas passing through the opening flows spirally between the outer electrode and the inner electrode.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, the openings provided in the conventional devices described above have holes drilled in a disc at an angle to the axis of the disc. Therefore, in conventional devices, the process gas supplied from the upstream side must pass through the holes, and a large reduction loss occurs in the process gas passing through holes with a small flow path cross-sectional area. Consequently, in conventional devices, the flow velocity of the process gas decreases downstream of the opening, that is, between the outer electrode and the inner electrode, and as a result, the plasma gas irradiated onto the workpiece may not have the flow velocity necessary for processing. Therefore, in plasma heads and plasma generators, it is desirable to reduce the reduction loss of the process gas supplied to the electrodes in a spiral flow.

[0005] This specification aims to provide a plasma head and a plasma generator that can reduce the reduction loss of process gas supplied between electrodes by a helical flow. [Means for solving the problem]

[0006] This specification discloses a plasma head comprising: a cylindrical body through which a process gas to be plasma-converted; a pair of electrodes housed in the body that discharge into a portion of the process gas to create plasma gas; and a rectifier member having a plurality of rectifier plates introduced into the body and supplied to the pair of electrodes to cause the process gas to flow in a spiral.

[0007] This specification also discloses the technical idea of ​​changing "the plasma head described in claim 2 or 3" to "the plasma head described in any one of claims 2-4" in claim 5 of the original application. Furthermore, this specification also discloses the technical idea of ​​changing "the plasma head described in any one of claims 1-3" to "the plasma head described in any one of claims 1-7" in claim 8 of the original application. Furthermore, this specification also discloses the technical idea of ​​changing "the plasma head described in any one of claims 1-3" to "the plasma head described in any one of claims 1-8" in claim 9 of the original application.

[0008] According to this, the plasma head can reduce the reduction loss that occurs in the process gas supplied to the electrodes as a spiral flow by passing the process gas through a rectifier member having a rectifier plate. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram illustrating the overall configuration of the plasma generator. [Figure 2] This is a partial cross-sectional view illustrating the configuration of the plasma head. [Figure 3] Figure 2 is a perspective view illustrating the rectifier member provided in the plasma head. [Figure 4] Figure 2 is a top view of the rectifier member. [Figure 5] Figure 2 is a bottom view of the rectifier member. [Figure 6] This is a perspective view illustrating the rectifier plate and the first ring of the rectifier component. [Figure 7] This is a diagram illustrating the arrangement of the rectifier plates. [Figure 8] This is a perspective view illustrating the second ring of the rectifier member. [Figure 9] This is a perspective view illustrating the rectifier member related to the first modified example. [Figure 10] Figure 9 is a top view of the rectifier member. [Figure 11] Figure 9 is a bottom view of the rectifier member. [Figure 12] This is a perspective view illustrating the rectifier member related to the second modified example. [Figure 13] Figure 12 is a top view of the rectifier member. [Figure 14] Figure 12 is a bottom view of the rectifier member. [Figure 15] This is a diagram illustrating the plasma head relating to the third modified example. [Modes for carrying out the invention]

[0010] Hereinafter, the plasma head and the plasma generation device will be described with reference to the drawings. In this embodiment, a case where the plasma generation device is an atmospheric pressure plasma generation device will be illustrated and described.

[0011] 1. Overall Configuration of Plasma Generation Device 1 The plasma generation device 1 is a device for generating plasma under atmospheric pressure. As shown in FIG. 1, the plasma generation device 1 includes a plasma head 10, a power supply device 20, and a gas supply device 30. The plasma generation device 1 supplies electric power Ph to the plasma head 10 via a power cable 21 from the power supply device 20, and supplies a process gas Gs to be plasmaized via a gas pipe 31 from the gas supply device 30. Thereby, the plasma generation device 1 can irradiate plasma gas Gp from the plasma head 10. The plasma generation device 1 includes a control device 40 that comprehensively controls the operation of the plasma generation device 1 including the power supply device 20 and the gas supply device 30.

[0012] The plasma head 10 is attached to the tip of the robot arm 51 of the industrial robot 50. Here, the power cable 21 and the gas pipe 31 are attached along the robot arm 51. The robot arm 51 is an articulated robot in which two arm parts 511, 511 are connected in one direction. Then, the industrial robot 50 drives the robot arm 51 to move the plasma head 10, and performs an operation of irradiating the work W supported by the work table D with the plasma gas Gp. The irradiated plasma gas Gp can perform, for example, a modification treatment for modifying the surface of the work W from hydrophobic to hydrophilic.

[0013] The power supply device 20 generates, for example, high-frequency alternating current power supplied from a commercial power supply (not shown) to a pair of electrodes 12 of the plasma head 10 described later. Then, the power supply device 20 supplies the generated alternating current power as electric power Ph to the electrodes 12 (more specifically, the outer electrode 121 and the inner electrode 122) of the plasma head 10 via the power cable 21.

[0014] The gas supply device 30 pumps and supplies, for example, air or the like containing at least one of an inert gas such as nitrogen and an active gas such as oxygen as the process gas Gs. For this reason, the gas supply device 30 includes a tank (not shown) for storing the plasma gas Gp. Although omitted in the present embodiment, the gas supply device 30 can include a heater for heating the process gas Gs supplied to the plasma head 10 as necessary. In this case, the gas supply device 30 can supply, for example, only the process gas Gs heated by the heater to the plasma head 10, or can mix the unheated process gas Gs supplied from the tank and the process gas Gs heated by the heater and supply the mixture to the plasma head 10.

[0015] The control device 40 controls the operations of the power supply device 20, the gas supply device 30, and the industrial robot 50. Further, the control device 40 includes a display unit 41. The display unit 41 displays various information and the like in the plasma generation device 1.

[0016] 2. Plasma head 10 Next, the configuration of the plasma head 10 will be described. As shown in FIG. 2, the base end side of the plasma head 10 is fixed to the housing 60, and the tip end side is covered by the cover 70. An opening 71 for irradiating the plasma gas Gp generated by the plasma head 10 is provided below the cover 70.

[0017] Here, in the present embodiment, the case where one plasma head 10 is provided is illustrated. However, the number of plasma heads 10 is not limited to one, and a plurality of plasma heads 10 can be arranged and provided with respect to the housing 60. In the following description, as shown in FIG. 2, for example, the width direction of the housing 60 and the cover 70 is the X direction, the height (vertical) direction of the housing 60 and the cover 70 (that is, the axial direction of the plasma head 10 fixed to the housing 60) is the Y direction, and the direction orthogonal to the X direction and the Y direction is the Z direction.

[0018] The plasma head 10 generates plasma gas Gp by plasmaizing process gas Gs. The plasma head 10 then irradiates the surface of the workpiece W with the generated plasma gas Gp. The plasma gas Gp irradiated onto the surface of the workpiece W can perform various surface treatments on the surface of the workpiece W, such as modifying the surface of the workpiece W from hydrophobic to hydrophilic.

[0019] Here, the processing capacity for various surface treatments such as modification of plasma gas Gp is ​​generally said to be correlated with the flow velocity of the plasma gas Gp reaching the processing position on the workpiece W. In other words, in order to improve the processing capacity of plasma gas Gp, it is necessary to increase the flow velocity of the plasma gas Gp irradiated toward the workpiece W. In order to increase the flow velocity of plasma gas Gp, it is necessary to efficiently circulate the process gas Gs toward the electrode.

[0020] When plasma is generated from a process gas Gs, the process gas Gs is made into a helical flow and passed between electrodes, as in the conventional equipment described above. In conventional equipment, the process gas Gs is made into a helical flow by passing through inclined holes.

[0021] However, in conventional equipment, when the process gas Gs flows through the holes, a large reduction loss occurs due to the significant narrowing of the flow path cross-sectional area. As a result, in conventional equipment, the flow velocity of the process gas Gs flowing between the electrodes decreases, and therefore, the flow velocity of the plasma gas Gp that is generated and irradiated toward the workpiece W also decreases.

[0022] In this case, it is conceivable to increase the flow path cross-sectional area by increasing the diameter of the hole to be drilled, but there are limitations to the size of the hole due to the constraints of the drilling process. Therefore, when process gas Gs flows through a hole drilled to create a spiral flow, as in conventional equipment, the reduction loss, that is, the energy loss due to the narrowing of the flow path cross-sectional area as the process gas Gs passes through the hole, is large, making it difficult to increase the flow velocity of the plasma gas Gp irradiated toward the workpiece W.

[0023] Therefore, as shown in Figure 2, the plasma head 10 of this embodiment comprises a cylindrical body 11 through which the process gas Gs to be plasma-converted is conducted, a pair of electrodes 12 housed in the body 11 that discharge into a portion of the process gas Gs to form plasma gas Gp, and a rectifier member 13 having a plurality of rectifier plates 131 that supply the process gas Gs introduced into the body 11 to the electrodes 12 in a spiral flow.

[0024] The main body 11 is formed from, for example, a conductive metal. A conical nozzle 111 is attached to the tip end of the main body 11 in the axial direction. The nozzle 111 irradiates the workpiece W with plasma gas Gp, which is generated by plasmaizing process gas Gs. A gas pipe 31 is hermetically connected to the base end of the main body 11 in the axial direction, and process gas Gs is supplied from a gas supply device 30 by pressure through the gas pipe 31. In this embodiment, the main body 11 and the nozzle 111 also function as the outer electrode 121 of a pair of electrodes 12.

[0025] As described above, the pair of electrodes 12 includes an outer electrode 121 formed by the main body 11 and nozzle 111, and an inner electrode 122 housed inside the main body 11 and positioned towards the center of the main body 11. By discharging a discharge against the process gas Gs supplied between the outer electrode 121 and the inner electrode 122, the process gas Gs is plasma-converted to generate plasma gas Gp. Alternatively, instead of the main body 11 and nozzle 111 forming the outer electrode 121, it is also possible to form the outer electrode 121 separately on, for example, the inner circumferential surface of the main body 11 and nozzle 111. In this case, the main body 11 and nozzle 111 do not need to be made of a conductive metal.

[0026] Here, a power supply unit 20 is connected to each of the outer electrode 121 and the inner electrode 122 via a power cable 21. As a result, a power Ph, which is high-frequency AC power, is supplied to the outer electrode 121 and the inner electrode 122, and a voltage is applied. In this embodiment, the inner electrode 122 is supported by a rectifier member 13 fixed inside the main body 11, as will be described later.

[0027] As shown in Figure 3-5, the rectifier member 13 of this embodiment is disc-shaped and includes a rectifier plate 131, a first ring 132, and a second ring 133. As shown in Figure 6, the rectifier plate 131 is formed using a thin plate and one end is fixed to the outer circumferential surface of the first ring 132. As shown in Figure 7, the rectifier plate 131 is arranged in a helical shape, positioned at an angle θ with respect to the axis O of the first ring 132.

[0028] As shown in Figure 6, the first ring 132 has rectifier plates 131 fixed at equal intervals along the circumferential direction of its outer surface, and has an internal threaded portion 132a on its inner surface. As shown in Figure 2, the internal threaded portion 132a is screwed into the internal threaded portion 122a provided on the internal electrode 122. In this way, the first ring 132 supports the internal electrode 122, which is one of the pair of electrodes 12 that is positioned towards the center of the main body 11.

[0029] As shown in Figure 8, the second ring 133 is formed to have a larger diameter than the first ring 132. The second ring 133 is positioned concentrically with the first ring 132 and supports the other end of the rectifier plate 131 in the radially outward direction of the first ring 132. The rectifier plate 131, with one end fixed to the first ring 132, is assembled, for example, by press-fitting it into the inner circumference of the second ring 133. As a result, the rectifier member 13 of this embodiment has 10 flow paths 134 partitioned by the outer circumferential surface of the first ring 132, the rectifier plate 131 fixed at an inclination angle θ, and the inner circumferential surface of the second ring 133, as shown in Figure 3-5.

[0030] Furthermore, as shown in Figure 2, the second ring 133 is held and fixed by the support member 112 and the retaining member 113 housed in the main body 11. As a result, the rectifier plate 131 and the first ring 132 assembled to the second ring 133 are fixed to the main body 11, and the inner electrode 122, whose male threaded portion 122a is screwed into the female threaded portion 132a of the first ring 132, is also fixed to the main body 11.

[0031] Here, the process gas Gs is transformed into a spiral flow by the rectifier member 13, as will be explained with reference to Figure 2. In the plasma head 10, the process gas Gs is pressurized and supplied from the gas supply device 30 to the upstream side of the rectifier member 13 (upward in the Y direction in Figure 2). Once the process gas Gs is supplied, it flows downstream of the rectifier member 13 (downward in the Y direction in Figure 2) through the 10 flow channels 134 formed in the rectifier member 13.

[0032] As described above, in the rectifier member 13, the rectifier plate 131 is positioned at an angle θ with respect to the axis O. Therefore, the process gas Gs that has passed through the flow path 134 flows downstream of the rectifier member 13, that is, between the outer electrode 121 and the inner electrode 122, in a spiral flow toward the nozzle 111. At this time, the spiral-flowing process gas Gs flows while in contact with the outer electrode 121 and the inner electrode 122, causing the outer electrode 121 and the inner electrode 122 to discharge. As a result, at least a portion of the process gas Gs is converted into plasma, and the plasma gas Gp is ​​irradiated from the nozzle 111.

[0033] By the way, in order to suppress the decrease in the flow velocity of the plasma gas Gp, it is necessary to reduce the reduction loss when the process gas Gs passes through the rectifier member 13 and maintain the flow velocity. For this reason, the rectifier member 13 of this embodiment is arranged such that, for example, the rectifier plate 131 satisfies the three conditions described below.

[0034] First, as shown in Figure 2, the first flow path cross-sectional area S1 is defined as the flow path cross-sectional area when the process gas Gs pumped from the gas supply device 30 passes through the inside of the main body 11. Also, as shown in Figure 2, the second flow path cross-sectional area S2 (=Sc × 10) is defined as the sum of the flow path cross-sectional areas Sc of each flow path 134 formed by the rectifier plate 131.

[0035] In this embodiment, the flow straightening member 13 is arranged such that the flow straightening plate 131 is configured such that the flow straightening area ratio R (=S2 / S1) of the second flow path cross-sectional area S2 to the first flow path cross-sectional area S1 is 0.8 or more. By setting the flow straightening area ratio R to 0.8 or more, the flow straightening member 13 of this embodiment has a loss coefficient Ks that represents the reduction loss that occurs when the process gas Gs passes through the flow path 134 where the flow straightening member 13 changes from the first flow path cross-sectional area S1 to the second flow path cross-sectional area S2, which is 0.1 or less. Furthermore, by setting the flow straightening area ratio R to 0.8 or more, the flow straightening member 13 of this embodiment has a contraction coefficient Kh that is 0.7 or more due to the reduction loss that occurs when the process gas Gs passes through the flow path 134 where the flow straightening member 13 changes from the first flow path cross-sectional area S1 to the second flow path cross-sectional area S2.

[0036] In other words, the rectifier member 13 can form a flow path 134 through which the process gas Gs flows using a thin rectifier plate 131, so the narrowing of the flow path 134 can be reduced compared to, for example, when a hole formed by drilling is used as the flow path. In other words, when using the rectifier member 13, there are fewer processing constraints, so the resistance generated when the process gas Gs is made into a helical flow can be reduced compared to the resistance generated when a hole formed by drilling is used to make a helical flow.

[0037] In other words, by using the rectifier member 13 in the plasma head 10, the process gas Gs can be smoothly converted into a spiral flow, allowing it to flow towards the electrode 12 while suppressing a decrease in flow velocity. As a result, the decrease in flow velocity of the plasma gas Gp generated by passing between the electrodes 12 can be suppressed, and the plasma gas Gp can be irradiated from the nozzle 111 toward the workpiece W.

[0038] In this embodiment, the rectifier member 13 is configured such that the inclination angle θ when arranging the rectifier plate 131 is set to, for example, 5 to 55 degrees, more preferably 10 to 50 degrees, and even more preferably 15 to 45 degrees, so as to satisfy the above-mentioned conditions.

[0039] Furthermore, as shown in Figure 4, consider a flow straightening member 13 equipped with a helical-shaped straightening plate 131 on the outer circumferential surface of the first ring 132, and assume that the flow straightening member 13 is viewed from the side where process gas Gs is supplied to the flow straightening member 13 (i.e., upstream of the flow straightening member 13, for example, upward in the Y direction in Figure 2) in the direction of the axis O (Y direction) of the first ring 132. In this case, the area occupied by the helical-shaped straightening plate 131 is 90% or more of the annular flow path cross-sectional area through which the process gas Gs passes, formed by the outer circumferential surface of the first ring 132 and the inner circumferential surface of the second ring 133, assuming that the straightening plate 131 is not provided on the outer circumferential surface of the first ring 132.

[0040] In other words, in a flow straightening member 13 having helical-shaped straightening plates 131, the cross-sectional area of ​​the straight flow path 135 (shown by a dot pattern (dark color) in Figure 4) along the axis O direction (Y direction) of the first ring 132 is less than 10%. As a result, when the process gas Gs passes through the flow straightening member 13, most of the process gas Gs comes into contact with the helical-shaped straightening plates 131, thus generating a helical flow in the process gas Gs.

[0041] As can be understood from the above explanation, the plasma head 10 comprises a cylindrical body 11 through which the process gas Gs to be plasmaized is conducted, a pair of electrodes 12 (outer electrode 121 and inner electrode 122) housed in the body 11 and discharging a portion of the process gas Gs to create plasma gas Gp, and a rectifier member 13 having a plurality of rectifier plates 131 that are introduced into the body 11 and supplied to the pair of electrodes 12 (outer electrode 121 and inner electrode 122) to create a spiral flow of the process gas Gs.

[0042] According to the plasma head 10, a helical flow can be generated by the flow of process gas Gs through a flow straightening member 13 having a flow channel 134 formed by a flow straightening plate 131. In this way, by partitioning the flow channel 134 using a thin flow straightening plate 131, the flow channel cross-sectional area Sc of each flow channel 134 through which the process gas Gs flows can be increased compared to when holes are drilled.

[0043] This reduces the reduction loss that occurs when the process gas Gs flows through the rectifier member 13, and therefore suppresses a decrease in the flow velocity of the process gas Gs supplied to the pair of electrodes 12. As a result, a decrease in the flow velocity of the generated plasma gas Gp is ​​also suppressed, and the flow velocity of the plasma gas Gp irradiated toward the workpiece W can be increased. This allows the plasma head 10, in other words, the plasma generator 1, to improve its processing capacity for irradiating plasma gas Gp.

[0044] 3. First variation In the embodiment described above, the inclination angle θ of the rectifier plate 131 in the rectifier member 13 was set to be relatively small (i.e., the rectifier plate 131 was on the side parallel to the axis O, so to speak, the rectifier plate 131 was in an upright position). However, for example, when performing various surface treatments on a workpiece W, the amount of plasma gas Gp generated may be increased depending on the treatment content. In this case, the inclination angle θ of the rectifier plate 131 can be set to be larger (i.e., the rectifier plate 131 was on the side at an angle with respect to the axis O, so to speak, the rectifier plate 131 was in a horizontal position).

[0045] Figure 9-11 shows a case where the inclination angle θ of the first ring 132 of the rectifier plate 131 with respect to the axis O is larger than in the case of Figure 3-5 described above, in other words, the rectifier plate 131 is laid flat. In this case, compared to the embodiment described above, the flow path cross-sectional area Sc of each flow path 134 becomes smaller because the rectifier plate 131 is laid flat, resulting in a larger reduction loss. However, a strong helical flow can be generated by the process gas Gs that passes through. That is, in this case, because the process gas Gs is accompanied by a strong helical flow, the number of times the process gas Gs swirls before being irradiated from the nozzle 111 (number of swirls) increases. Consequently, in this case, the distance over which the process gas Gs contacts the outer electrode 121 and the inner electrode 122 becomes longer, making it possible to increase the proportion of process gas Gs that is plasma-generated, in other words, the amount of plasma gas Gp generated.

[0046] 4. Second variation In the embodiments and first modified examples described above, the number of rectifier plates 131 in the rectifier member 13, i.e., the number of flow channels 134 in the rectifier member 13, was set to 10. However, the number of rectifier plates 131, i.e., the number of flow channels 134 in the rectifier member 13, is not limited to the 10 mentioned above. For example, as shown in Figure 12-15, it is possible to increase it to 12. In the rectifier member 13, when the number of flow channels 134 is increased, the flow channel cross-sectional area Sc of each flow channel 134 becomes relatively smaller, but the reduction loss does not change because the second flow channel cross-sectional area S2 does not change.

[0047] However, as the number of flow channels 134 increases, the resistance acting on the process gas Gs as it passes through the flow channels 134 becomes relatively larger, which may result in a decrease in the flow velocity of the process gas Gs. Therefore, in order to compensate for the decrease in the flow velocity of the process gas Gs, i.e., the decrease in the flow velocity of the plasma gas Gp, for example, the size of the inclination angle θ is increased (i.e., the rectifier plate 131 is laid flat), and as described above, the number of times the process gas Gs swirls is increased, thereby increasing the amount of plasma gas Gp generated. This makes it possible to compensate for the decrease in the processing capacity of the plasma gas Gp.

[0048] Alternatively, the number of rectifier plates 131, i.e., the number of flow channels 134 in the rectifier member 13, can be reduced from 10, although this is not shown in the diagram. In the rectifier member 13, reducing the number of rectifier plates 131, i.e., flow channels 134, allows the flow channel cross-sectional area Sc of each flow channel 134 to be relatively increased. However, in the rectifier member 13, reducing the number of rectifier plates 131, i.e., flow channels 134, can make it difficult to generate a sufficient helical flow in the process gas Gs, especially if the inclination angle θ is small. Therefore, in the rectifier member 13, to generate a strong helical flow, it is necessary to relatively increase the inclination angle θ of the rectifier plates 131, as described above, and as a result, the reduction loss may be relatively large.

[0049] Based on this, when considering the balance between the magnitude of the reduction loss and the strength of the spiral flow (number of swirls) of the process gas Gs, for example, the number of rectifier plates 131 should be set to 6 or more and 14 or less, more preferably 7 or more and 13 or less, and even more preferably 8 or more and 12 or less. By setting the number of rectifier plates 131 in this way, a flow path cross-sectional area ratio R of 0.8 or more can be maintained, and the loss coefficient Ks can be set to 0.1 or less and the contraction coefficient Kh can be set to 0.7 or more.

[0050] 5. Third variation In the embodiments and modifications described above, the case in which the rectifier member 13 has a second ring 133, that is, the other end of the rectifier plate 131 is supported by the second ring 133, was explained as an example. However, the second ring 133 of the rectifier member 13 can be omitted if necessary.

[0051] If the second ring 133 of the rectifier member 13 is omitted, as shown in Figure 15, the rectifier plate 131 can be sandwiched between the support member 112 and the holding member 113 housed in the main body 11, thereby fixing the rectifier member 13 to the main body 11. Furthermore, with the rectifier member 13 fixed to the main body 11, the inner electrode 122 can be fixed by screwing the male threaded portion 122a of the inner electrode 122 into the female threaded portion 132a of the first ring 132. In this case, the flow path 134 is formed by the outer circumferential surface of the first ring 132 of the rectifier member 13, the rectifier plate 131, and the inner circumferential surface of the main body 11. Therefore, the same effects as in the above-described embodiment can be obtained in this case as well.

[0052] 6. Fourth variation In the embodiments, first and second modifications described above, the rectifier member 13 is formed by assembling the rectifier plate 131 and the first ring 132 as a single unit to the second ring 133. That is, in the rectifier member 13 described above, the second ring 133 is treated as a separate component. However, instead, for example, it is also possible to manufacture a rectifier member 13 with a complex shape by integrally molding the rectifier plate 131, the first ring 132, and the second ring 133 using well-known additive manufacturing techniques. In this case, the separate assembly of the rectifier member 13 can be omitted. [Explanation of Symbols]

[0053] 1...Plasma generator, 10...Plasma head, 11...Main unit, 111...Nozzle, 112...Support member, 113...Holding member, 12...Electrode, 121...Outer electrode, 122...Inner electrode, 122a...Male threaded part, 13...Rectifier member, 131...Rectifier plate, 132...First ring, 132a...Female threaded part, 133...Second ring, 134...Flow path, 135...Flow path, 20...Power supply unit, 21...Power cable, 30...Gas supply unit, 31...Gas distribution Tube, 40...Control device, 41...Display unit, 50...Industrial robot, 51...Robot arm, 511...Arm section, 60...Housing, 70...Cover, 71...Opening, Gs...Process gas, Gp...Plasma gas, θ...Inclination angle, O...Axis, S1...First channel cross-sectional area, S2...Second channel cross-sectional area, Sc...Channel cross-sectional area, R...Channel cross-sectional area ratio, Ks...Loss coefficient, Kh...Contraction coefficient, Ph...Power (AC power), W...Workpiece, D...Workpiece stand

Claims

1. A cylindrical body through which the process gas to be plasma-generated is conducted, A pair of electrodes housed in the main body discharges a portion of the process gas to form a plasma gas, A flow straightening member having a plurality of straightening plates that cause the process gas introduced into the main body and supplied to the pair of electrodes to flow in a spiral, Equipped with, The aforementioned rectifier member is A first ring supporting one of the pair of electrodes, which is positioned on the central side of the main body, A plasma head comprising: a rectifier plate, one end of which is fixed to the outer circumferential surface of the first ring, and which is arranged in a helical shape at an angle to the axis of the first ring.

2. The aforementioned rectifier member is The plasma head according to claim 1, further comprising a second ring concentrically arranged with the first ring and supporting the other end of the rectifier plate in the radially outward direction of the first ring.

3. When the rectifier member is viewed from the side to which the process gas is supplied, in the axial direction of the first ring, The area occupied by the aforementioned rectifier plate is, The plasma head according to claim 1 or 2, wherein the cross-sectional area of ​​the annular flow path through which the process gas passes is 90% or more, assuming that the rectifier plate is not provided on the outer circumferential surface of the first ring.

4. The aforementioned rectifier member is The plasma head according to claim 1 or 2, wherein the rectifier plate is arranged such that the ratio of the cross-sectional area of ​​a second flow path, which is the sum of the cross-sectional areas of the flow paths formed by the rectifier plate and through which the process gas passes, to the cross-sectional area of ​​a first flow path through which the process gas passes inside the main body, is 0.8 or more.

5. The aforementioned rectifier member is The plasma head according to claim 4, wherein the loss coefficient representing the reduction loss that occurs when the process gas passes through the channel from the first channel cross-sectional area to the second channel cross-sectional area is 0.1 or less.

6. The aforementioned rectifier member is The plasma head according to claim 4, wherein the contraction coefficient due to the reduction loss that occurs when the process gas passes through the channel from the first channel cross-sectional area to the second channel cross-sectional area is 0.7 or more.

7. The plasma head according to claim 1 or 2, wherein the number of rectifier plates in the rectifier member is 6 or more and 14 or less.

8. The plasma head according to claim 1 or 2, A power supply device that supplies power to the electrode, A gas supply device that supplies the process gas to the main body, A plasma generator equipped with [a specific feature / equipment].

9. The aforementioned power supply device is The plasma generator according to claim 8, wherein high-frequency alternating current power is supplied to the electrode.

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