Plasma processing apparatus

Abstract

To provide a plasma processing apparatus capable of ensuring insulation of a rotating cylinder portion.SOLUTION: A plasma processing apparatus 1 includes an inner electrode 100, an electrode holder 200, an outer electrode 400 formed in a cylindrical shape and surrounding the inner electrode and the electrode holder, an insulating pipe 500 arranged between the inner electrode and the electrode holder and the outer electrode and surrounding the inner electrode and the electrode holder, a rotating cylinder portion 600 made of an insulating material, formed in a cylindrical shape surrounding the outer electrode, and capable of rotating relatively to the outer electrode around the central axis AX of the inner electrode, and a drive mechanism 700 for rotating the rotating cylinder portion.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a plasma processing apparatus. [Background technology]

[0002] Conventionally, in a torch used for plasma processing of the surface of a workpiece such as a synthetic resin, it is known that the nozzle of the torch that irradiates plasma is rotated to accommodate the shape of the workpiece. For example, Japanese Patent Application Laid-Open No. 2001-68298 discloses a plasma nozzle including an electrode and a casing that can rotate relative to a support tube arranged around the electrode. The casing is made of metal, and when a voltage is applied to the electrode, an electric discharge occurs between the electrode and the casing. As the casing rotates about its axis, the plasma jet describes the generatrix of a cone and is irradiated onto the surface of the workpiece. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-68298 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the plasma nozzle described in JP 2001-68298 A, the casing that rotates relative to the inner electrode is electrically charged, so there is a risk of contacting this casing.

[0005] The object of the present disclosure is to provide a plasma processing apparatus that does not require electroconductive bearings (slip rings) or electric brushes for rotating an electrically charged casing, has a simple and inexpensive structure, and is capable of reducing the risk of contact with the rotating cylindrical portion. [Means for solving the problem]

[0006] A plasma processing apparatus according to one aspect of the present disclosure includes an inner electrode to which a voltage is applied, an electrode holder that holds the inner electrode, an outer electrode formed in a cylindrical shape and surrounding the inner electrode and the electrode holder, an insulating pipe that is disposed between the inner electrode, the electrode holder, and the outer electrode and surrounds the inner electrode and the electrode holder, a rotating cylindrical portion made of an insulating material and formed in a cylindrical shape surrounding the outer electrode, the rotating cylindrical portion being rotatable relative to the outer electrode around the central axis of the inner electrode, and a drive mechanism that rotates the rotating cylindrical portion. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a plasma processing apparatus capable of preventing contact with a charging portion and reducing the risk associated with contact with a rotating cylinder portion. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional perspective view of a plasma processing apparatus according to an embodiment of the present disclosure. [Diagram 2] 2 is a cross-sectional view showing a tip portion of a plasma processing apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will now be described with reference to the accompanying drawings, in which the same or corresponding components are designated by the same reference numerals.

[0010] 1 is a cross-sectional perspective view of a plasma processing apparatus according to an embodiment of the present disclosure. The plasma processing apparatus 1 is suitably used for surface modification of a workpiece, and is also suitably used for TIG welding.

[0011] As shown in FIG. 1, the plasma processing apparatus 1 includes an inner electrode 100, an electrode holder 200, a position adjustment member 250, a support 300, an outer electrode 400, an insulating pipe 500, a rotating cylinder portion 600, and a driving mechanism 700.

[0012] The inner electrode 100 has a shape that extends linearly. The inner electrode 100 is made of, for example, tungsten. A voltage is applied to the inner electrode 100 from a power source (not shown).

[0013] The electrode holder 200 holds the inner electrode 100. The electrode holder 200 has an inner holder 210, an outer holder 220, and a fin member 230.

[0014] The inner holding body 210 holds the inner electrode 100 while contacting the outer circumferential surface of the inner electrode 100. The inner holding body 210 has a shape extending along a direction parallel to the central axis AX of the inner electrode 100. The inner holding body 210 is made of, for example, copper. A slit extending in a direction parallel to the axial direction of the inner holding body 210 is formed at the tip of the inner holding body 210.

[0015] The outer holder 220 surrounds the inner holder 210. A tapered portion that gradually reduces in diameter toward the tip side is formed on the inner peripheral surface of the tip of the outer holder 220. Therefore, when the inner holder 210 is inserted into the outer holder 220, the tip of the inner holder 210 is pressed against the tapered portion of the outer holder 220 and is brought into pressure contact with the inner electrode 100. A female thread portion is provided at the base end of the outer holder 220.

[0016] The position adjustment member 250 is capable of adjusting the position of the inner electrode 100 with respect to the electrode holder 200. The position adjustment member 250 has an adjustment portion 252 and a knob 254.

[0017] The adjustment part 252 is movable in the axial direction relative to the outer holding body 220. Specifically, the adjustment part 252 is provided with a male thread portion that screws into a female thread portion provided at the base end of the outer holding body 220. The adjustment part 252 is capable of adjusting the relative position of the inner electrode 100 with respect to the electrode holding body 200 by adjusting the force that axially biases the inner holding body 210 relative to the outer holding body 220 (pushing force).

[0018] For example, when the adjustment part 252 is screwed into the outer holding body 220 with the tip part of the adjustment part 252 in contact with the base end part of the inner holding body 210, the tip part of the inner holding body 210 is urged toward the inner electrode 100 by the reduced diameter part of the outer holding body 220. As a result, the tip part of the inner holding body 210 is pressed against the inner electrode 100, and the relative position of the inner electrode 100 with respect to the electrode holding body 200 is determined.

[0019] Conversely, when the adjustment portion 252 moves away from the inner holder 210, the force exerted on the inner holder 210 by the reduced diameter portion of the outer holder 220 is released, making it possible to move the inner electrode 100 relative to the electrode holder 200, i.e., to change the relative position of the inner electrode 100 with respect to the electrode holder 200.

[0020] The knob 254 is connected to the base end of the adjustment portion 252. The knob 254 is connected to the base end of the adjustment portion 252 so as not to rotate relative to the adjustment portion 252. Note that the adjustment portion 252 and the knob 254 may be integrally formed from the same material.

[0021] The support 300 supports the electrode holder 200. The support 300 has a support plate 310, an insulating plate 320, a block portion 330, and an intervening member 340.

[0022] The support plate 310 is formed in a disk shape. The support plate 310 is made of a metal such as aluminum. However, the support plate 310 may be made of an insulating material.

[0023] The insulating plate 320 is disposed in an opening provided in the support plate 310. The electrode holder 200 is disposed so as to penetrate the insulating plate 320. The insulating plate 320 has a gas inlet portion 322 (described later).

[0024] The block portion 330 is fixed to the insulating plate 320 by a fastening member such as a screw. The block portion 330 is fixed to the insulating plate 320 from one side in a direction parallel to the central axis AX of the inner electrode 100. The block portion 330 is made of a conductive material. The electrode holder 200 is disposed so as to penetrate the block portion 330. Specifically, the inner peripheral surface of the block portion 330 is in contact with the outer holder 220.

[0025] The intervening member 340 is made of an insulating material and is interposed between the outer holder 220 and the insulating plate 320. As shown in Fig. 1, a recess 342 is formed on the outer circumferential surface of the intervening member 340. The recess 342 is connected in an annular shape around the central axis AX. The recess 342 forms a space S between the insulating plate 320 and the intervening member 340.

[0026] The outer electrode 400 is formed in a tubular shape, more specifically, in a cylindrical shape. The outer electrode 400 surrounds the inner electrode 100 and the electrode holder 200. The outer electrode 400 has an outer electrode body 410 and a power feed tip 420.

[0027] The outer electrode body 410 is fixed to the support 300 from the other side in a direction parallel to the central axis AX of the inner electrode 100. In other words, the block portion 330 and the outer electrode body 410 are fixed to the insulating plate 320 so as to sandwich the insulating plate 320 from both sides in a direction parallel to the central axis AX.

[0028] The power supply tip 420 is connected to the tip of the outer electrode body 410. The power supply tip 420 includes a tip surface 420a (see FIG. 2) that is located in the same plane as the tip portion 110 of the inner electrode 100 or that is located further ahead than the tip portion 110. The tip surface 420a is perpendicular to the central axis AX.

[0029] The insulating pipe 500 is disposed between the inner electrode 100 and the electrode holder 200, and the outer electrode 400. The insulating pipe 500 surrounds the inner electrode 100 and the electrode holder 200. The insulating pipe 500 is formed in a cylindrical shape. The insulating pipe 500 is made of ceramics or the like. The insulating pipe 500 is sandwiched from both sides in a direction parallel to the central axis AX by the power feed tip 420 of the outer electrode 400 and the intervening member 340 of the support 300.

[0030] A process gas (argon, air, etc.) is supplied into the insulating pipe 500 from a gas supply unit (not shown). The gas supply unit supplies the process gas to a gas inlet 322 provided in the insulating plate 320. A gas flow path connecting the gas inlet 322 to the space S is formed in the insulating plate 320, and a through hole is formed in the intervening member 340. Therefore, the process gas supplied from the gas supply unit flows between the outer holder 220 and the insulating pipe 500 through the gas inlet 322, the gas flow path, and the through hole of the intervening member 340.

[0031] The fin member 230 is a member for forming a swirling flow FL (see FIG. 2) around the inner electrode 100 by swirling the process gas supplied inside the insulating pipe 500. The fin member 230 is connected to the tip portion 222 of the outer holder 220. More specifically, the fin member 230 is fitted to the tip portion 222 of the outer holder 220 from the outer periphery of the tip portion 222. A plurality of spiral grooves are formed on the outer periphery of the fin member 230. The outer periphery of the fin member 230 may be in contact with the inner periphery of the insulating pipe 500 or may be spaced apart from the inner periphery of the insulating pipe 500. However, it is preferable that the outer periphery of the fin member 230 be in contact with the inner periphery of the insulating pipe 500. The fin member 230 is spaced apart from the outer periphery of the inner electrode 100.

[0032] The processing gas supplied to the inside of the insulating pipe 500 is turned into plasma in the vicinity of the tip 110 of the inner electrode 100. The insulating pipe 500 defines the position where the plasma is generated between the inner electrode 100 and the outer electrode 400. As shown in Fig. 2, the tip 110 of the inner electrode 100 is movable between a retracted position P1 where the tip 110 is flush with the tip surface of the insulating pipe 500 and a protruding position P2 where the tip 110 is flush with the tip surface 420a of the power feed tip 420. In other words, the electrode holder 200 holds the inner electrode 100 such that the tip 110 of the inner electrode 100 is movable between the retracted position P1 and the protruding position P2.

[0033] 1 and 2, the position of the tip portion 110 of the inner electrode 100 may be set to a position exposed from the insulating pipe 500. In the example shown in Fig. 2, the position of the tip portion 110 is set between the retracted position P1 and the protruding position P2.

[0034] The rotating cylinder part 600 is formed in a cylindrical shape surrounding the outer electrode 400. The rotating cylinder part 600 is rotatable relative to the outer electrode 400 around a central axis AX. The rotating cylinder part 600 is made of an insulating material. In this embodiment, the rotating cylinder part 600 has a rotating cylinder part main body 610 and a rotating nozzle 620.

[0035] The rotating cylinder body 610 is disposed around the outer electrode body 410. A bearing is disposed between the rotating cylinder body 610 and the outer electrode body 410. The rotating cylinder body 610 is made of, for example, polyether ether ketone (PEEK resin) or the like.

[0036] The rotary nozzle 620 is connected to the tip of the rotary cylinder main body 610 so as not to rotate relative to the rotary cylinder main body 610. The rotary nozzle 620 is a part that blows out a plasmatized swirling flow FL. As shown in FIG. 2, an opening (plasma blowout port) 620b of the rotary nozzle 620 may be eccentric with respect to the central axis AX of the inner electrode 100. The rotary nozzle 620 is made of, for example, polyether ether ketone (PEEK resin) or the like. As shown in FIG. 2, the rotary nozzle 620 has an opposing surface 620a that faces the tip surface 420a of the power feed tip 420.

[0037] 2, the rotating cylinder main body 610 may be formed with a supply flow passage 610a for supplying gas from the outside of the outer electrode 400 toward between the tip face 420a and the opposing face 620a. Alternatively, an annular groove may be formed in at least one of the tip face 420a and the opposing face 620a, and a seal member such as an O-ring may be provided in the groove.

[0038] The driving mechanism 700 rotates the rotating cylinder portion 600. The driving mechanism 700 includes a motor M and a power transmission unit that transmits the output of the motor M to the rotating cylinder portion 600. In this embodiment, the power transmission unit has a first gear 710 and a second gear 720. However, the power transmission unit may be configured with, for example, a belt, a pulley, a roller chain, a sprocket, or the like. Moreover, instead of the motor M, a power source that generates a rotational force, such as a gasoline engine, a diesel engine, or a rotating cylinder, may be used.

[0039] The motor M is fixed to the support plate 310. The output shaft of the motor M passes through the support plate 310.

[0040] The first gear 710 is connected to the output shaft of the motor M.

[0041] The second gear 720 is disposed so as to mesh with the first gear 710. The second gear 720 is disposed so as to surround the outer electrode 400. The center of rotation of the second gear 720 is located on the central axis AX.

[0042] 1, the rotating cylinder main body 610 of the rotating cylinder 600 has a receiving surface 612 that receives the second gear 720 in a direction parallel to the central axis AX. The second gear 720 is fixed to the rotating cylinder main body 610 by a fastening member B that applies an axial force to press the second gear 720 against the receiving surface 612.

[0043] In the plasma processing apparatus 1 described above, when a processing gas is supplied from a gas supply unit (not shown) to the inside of the insulating pipe 500, the processing gas passes through the grooves of the fin member 230 to become a swirling flow FL around the inner electrode 100 and is turned into plasma in the vicinity of the tip 110 of the inner electrode 100. Meanwhile, when the motor M of the drive mechanism 700 is driven, the rotating cylinder main body 610 and the rotating nozzle 620 rotate around the central axis AX relative to the inner electrode 100 and the outer electrode 400 via the first gear 710 and the second gear 720. Therefore, it becomes possible to irradiate a workpiece with plasma according to the shape of the workpiece, for example.

[0044] As described above, in the plasma processing apparatus 1 of this embodiment, the rotating cylinder portion 600 is made of an insulating material, thereby reducing the risk of contact with the rotating cylinder portion 600 and increasing safety compared to when the rotating cylinder portion 600 is made of a conductive material (metal, etc.).

[0045] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0046] [Aspect 1] an inner electrode to which a voltage is applied; an electrode holder for holding the inner electrode; an outer electrode formed in a cylindrical shape and surrounding the inner electrode and the electrode holder; an insulating pipe disposed between the inner electrode and the electrode holder and the outer electrode, and surrounding the inner electrode and the electrode holder; a rotating cylinder portion made of an insulating material and formed in a cylindrical shape surrounding the outer electrode, the rotating cylinder portion being rotatable relative to the outer electrode about a central axis of the inner electrode; a drive mechanism for rotating the rotating cylinder portion.

[0047] In this plasma processing apparatus, since the rotating cylinder part is made of an insulating material, the risk of coming into contact with the rotating cylinder part is reduced compared to when the rotating cylinder part is made of a conductive material (metal or the like).

[0048] [Aspect 2] a support body supporting the electrode holder and the outer electrode, The electrode holder is a holder body that holds the inner electrode and is disposed to penetrate the support; a block portion connected to a base end of the holder body, the block portion is fixed to the support from one side in a direction parallel to the central axis, 2. The plasma processing apparatus of claim 1, wherein the outer electrode is fixed to the support from the other side in a direction parallel to the central axis.

[0049] [Aspect 3] 3. The plasma processing apparatus according to aspect 2, wherein the insulating pipe is sandwiched between the outer electrode and the support body from both sides in a direction parallel to the central axis.

[0050] In this embodiment, the position of the insulating pipe is determined, and therefore the plasma generation position is effectively defined.

[0051] [Aspect 4] The drive mechanism includes: A motor; A first gear connected to an output shaft of the motor; A second gear arranged to mesh with the first gear, the second gear is disposed to surround the outer electrode, the rotating cylinder portion has a receiving surface that receives the second gear in a direction parallel to the central axis, 2. The plasma processing apparatus of claim 1, wherein the second gear is fixed to the rotating cylinder portion by a fastening member that applies an axial force to press the second gear against the receiving surface.

[0052] In this embodiment, the second gear is fixed to the rotating cylindrical portion by the fastening member, so that free rotation of the second gear portion relative to the rotating cylindrical portion is suppressed.

[0053] [Aspect 5] 2. The plasma processing apparatus of claim 1, wherein the electrode holder holds the inner electrode so that the inner electrode can move between a retracted position where a tip of the inner electrode is flush with a tip surface of the insulating pipe and a protruded position where the tip of the inner electrode is flush with a tip surface of the outer electrode.

[0054] [Aspect 6] The rotating cylinder portion is an opposing surface facing the tip surface of the outer electrode; 6. The plasma processing apparatus of claim 5, further comprising: a supply passage for supplying a gas from an outside of the outer electrode toward a gap between the tip surface and an opposing surface of the outer electrode.

[0055] In this aspect, by supplying gas to the supply flow path, the processing gas supplied between the inner electrode and the insulating pipe is prevented from passing between the tip surface and the opposing surface of the outer electrode and heading toward the outside of the outer electrode.

[0056] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0057] 1 plasma processing apparatus, 100 inner electrode, 110 tip portion, 200 electrode holder, 210 inner holder, 220 outer holder, 230 fin member, 250 position adjustment member, 252 adjustment portion, 254 knob, 300 support, 310 support plate, 320 insulating plate, 330 block portion, 340 interposition member, 400 outer electrode, 410 outer electrode body, 420 power supply tip, 420a tip surface, 500 insulating pipe, 600 rotating cylinder portion, 610 rotating cylinder body, 612 receiving surface, 620 rotating nozzle, 620a opposing surface, 700 driving mechanism, 710 first gear, 720 second gear, B fastening member, M motor.

Claims

1. an inner electrode to which a voltage is applied; an electrode holder for holding the inner electrode; an outer electrode formed in a cylindrical shape and surrounding the inner electrode and the electrode holder; an insulating pipe disposed between the inner electrode and the electrode holder and the outer electrode, and surrounding the inner electrode and the electrode holder; a rotating cylinder portion made of an insulating material and formed in a cylindrical shape surrounding the outer electrode, the rotating cylinder portion being rotatable relative to the outer electrode about a central axis of the inner electrode; a drive mechanism for rotating the rotating cylinder portion.

2. a support body supporting the electrode holder and the outer electrode, the electrode holder is fixed to the support from one side in a direction parallel to the central axis, The plasma processing apparatus according to claim 1 , wherein the outer electrode is fixed to the support from the other side in a direction parallel to the central axis.

3. 3. The plasma processing apparatus according to claim 2, wherein the insulating pipe is sandwiched between the outer electrode and the support body from both sides in a direction parallel to the central axis.

4. The drive mechanism includes: A motor; A first gear connected to an output shaft of the motor; a second gear arranged to mesh with the first gear, the second gear is disposed to surround the outer electrode, the rotating cylinder portion has a receiving surface that receives the second gear in a direction parallel to the central axis, The plasma processing apparatus according to claim 1 , wherein the second gear is fixed to the rotary cylinder portion by a fastening member that applies an axial force to press the second gear against the receiving surface.

5. 2. The plasma processing apparatus according to claim 1, wherein the electrode holder holds the inner electrode so as to be movable between a retracted position where a tip of the inner electrode is flush with a tip surface of the insulating pipe and a protruding position where the tip of the inner electrode is flush with a tip surface of the outer electrode.

6. The rotating cylinder portion is an opposing surface facing the tip surface of the outer electrode; The plasma processing apparatus according to claim 5 , further comprising: a supply passage for supplying a gas from an outside of the outer electrode toward a gap between the tip surface and an opposing surface of the outer electrode.

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