A method and mold for manufacturing a Faraday shielding tube for a radio frequency ion source

Abstract

The present invention provides a method and mold for manufacturing a Faraday shielding tube for a radio frequency ion source, the method comprising: making a circular plate substrate of a Faraday shielding tube; loading the circular plate substrate into a mold, and pressing and molding the Faraday shielding tube; demolding the pressed Faraday shielding tube from the mold; finally welding and molding the inlet and outlet water pipes and the side wall gaps by vacuum brazing to complete the manufacturing of the finished Faraday shielding tube. The Faraday shielding tube consists of two parts: the inlet and outlet water pipes and the cylinder body. The cylinder body is a three-layer structure with three oxygen-free copper cover plates. The internal waterway and "Z"-shaped seam are processed by a CNC machine tool, and then welded into a flat plate structure by diffusion welding, and then extended and extruded into a cylinder by a mold, and finally the inlet and outlet water pipes and the side wall gaps are welded and molded by vacuum brazing. The manufacturing method has high domestic technical maturity, high strength and good stability after molding, and diffusion welding does not have solder and does not have the problem of waterway clogging.

Description

Technical Field

[0001] The invention relates to the field of electronics, in particular to a method for manufacturing a Faraday shielding tube of a radio frequency ion source and a mold. Background Art

[0002] The neutral injection system is a key auxiliary device in tokamak physics experiments. Based on the neutral injection system, plasma heating, non-inductive current driving, and charging experiments can be carried out. The heating of high-current plasma has become the most important way of auxiliary heating in fusion. The ion source is a key component in the high-power neutral injection system. With the development of the neutral injection system, more and more research has been done on the high-current ion source. The indicators that the high-current ion source can achieve can basically determine the performance of the neutral beam injection system.

[0003] Among them, the radio frequency ion source is a commonly used ion source in the neutral injection system. The typical radio frequency ion source consists of a plasma generator and an accelerator. The basic working principle diagram is shown in the figure. The plasma generator includes a driving area for the generation of radio frequency plasma and an expansion area for plasma diffusion. It is mainly used to generate large-area plasma with uniform density, and uses a filtering magnetic field to reduce the electron temperature. At the same time, negative ions are generated by injecting cesium; the negative ion accelerator is used to extract negative ions from the plasma, deflect the extracted electrons, and then accelerate the negative ions to the required energy, and form an ion beam with certain optical properties.

[0004] In order to avoid the influence of arcing and electrical breakdown on the coil during beam extraction, the inner wall of the RF drive source is isolated by a 99.5% alumina ceramic insulation barrel. During the operation of the ion source, the sputtering of the plasma will cause the sputtered material to adhere to the extraction electrode, reducing the electrical insulation performance of the extraction electrode. If the RF power is very high or the ion source is running for a long time, the alumina ceramic barrel will be damaged. Therefore, a Faraday shield is designed in the ceramic barrel to effectively protect the ceramic barrel.

[0005] Since the Faraday cage shield has complex water channels inside for cooling the cage, the conventional manufacturing method currently uses electroplated copper. The main disadvantages of this structure are:

[0006] (1) Electrodeposition copper manufacturing technology requires special molds, which are expensive.

[0007] (2) Domestic electrodeposited copper manufacturing technology is not mature enough, with low yield and many defects, making it difficult to ensure product stability.

[0008] (3) The Faraday cage shielding tube made of domestically produced electro-deposited copper has poor strength and is difficult to meet the use requirements. Summary of the invention

[0009] The purpose of the present invention is to provide a method and a mold for manufacturing a Faraday shielding tube of a radio frequency ion source, so as to solve the shortcomings of the Faraday shielding tube, such as high cost, low yield and insufficient strength.

[0010] The technical solution adopted by the present invention to solve the technical problem is: a method for manufacturing a Faraday shielding tube of a radio frequency ion source, comprising the following steps:

[0011] Step 1, manufacturing a Faraday shield cylinder circular plate substrate; the circular plate substrate includes a three-layer structure;

[0012] Step 2: Loading a circular plate substrate into a mold to press-form a Faraday shielding tube;

[0013] Step 3, demoulding the pressed Faraday shield cylinder from the mold;

[0014] Step 4: Finally, the inlet and outlet water pipes and the side wall gaps are welded by vacuum brazing to complete the manufacturing of the Faraday shielding tube.

[0015] Furthermore, the circular plate substrate includes three oxygen-free copper cover plates, namely an upper cover plate, a middle cover plate and a bottom cover plate, which are processed with internal water channels and Z-shaped seams by CNC machine tools and are welded into a flat structure circular plate substrate by diffusion welding.

[0016] Furthermore, the upper cover plate is a flat plate with eight rectangular blades, and a water inlet pipe hole and a water outlet pipe hole are processed in the middle area.

[0017] Furthermore, the middle cover plate is a flat plate with eight rectangular blades, the rectangular blades correspond to the upper cover plate, and are processed by a CNC machine tool to form an "S"-shaped water channel and 64 "Z"-shaped gaps.

[0018] Furthermore, the bottom cover plate is a circular plate, and 8 water outlet channels are processed on the plate.

[0019] Furthermore, the step 2 specifically includes:

[0020] Install the mold on the press, test and debug the mold, and determine the position of the upper mold; press the positioning hole on the Faraday shielding cylinder circular plate substrate to place the Faraday shielding cylinder circular plate substrate; the preload cylinder is installed on the cylinder mounting seat, and the hydraulic station realizes the rising and falling action of the preload cylinder through the oil circuit interface, and transmits the action to the demolding guide rod through the demolding guide column. The upper demolding plate, the lower demolding plate and the mold frame support play a supporting role in the entire structure, and the guide column spring plays a buffering and shock-absorbing role; before the extension extrusion process, the upward movement of the preload cylinder will give the lower mold a preload pressure, and the Faraday shielding cylinder circular plate substrate will be tightened between the upper and lower molds; the press extrusion upper mold moves downward, and the extension die mouth will limit the deformation direction of the Faraday shielding cylinder circular plate substrate, and the extension is extruded into the sizing mold barrel to form a cylindrical shape.

[0021] Furthermore, the demoulding process in step 3 specifically includes:

[0022] Remove the upper mold press, and the hydraulic station moves the preload cylinder upward through the oil circuit interface. The action is transmitted to the demoulding guide rod through the demoulding guide column to push the Faraday shield cylinder upward and move it out of the lower mold to realize demoulding.

[0023] Furthermore, after being stretched and extruded into a cylinder through a forming die, the inlet and outlet pipes and the side wall gaps are welded by a vacuum brazing process.

[0024] The present invention also provides a radio frequency ion source Faraday shielding tube manufacturing mold, comprising: an upper mold, a lower mold, a demoulder, and a pre-tightening cylinder;

[0025] The lower die comprises an extension die opening and a sizing die cylinder;

[0026] The demoulding device comprises an upper demoulding plate, a lower demoulding plate, a demoulding guide rod, a demoulding guide column, a guide column spring, and a mold frame pillar. The upper demoulding plate and the lower demoulding plate are connected by a plurality of mold frame pillars; a guide column spring is sleeved on the periphery of the demoulding guide column; the demoulding guide rod is located in the middle of the plurality of demoulding guide columns;

[0027] The preload oil cylinder comprises an oil cylinder mounting seat, an oil circuit interface, and a preload oil cylinder;

[0028] The upper die is a Faraday shielding cylinder inner cavity structure, with an inverted arc at the lower end and a structure connected to a press machine on the upper end surface;

[0029] The lower die includes an extension die and a sizing die. The extension die is used to limit the deformation direction of the substrate. The extension die is an arc structure and its function is to prevent the workpiece from producing defective products due to excessive friction during extension deformation. The sizing die is used to shape the Faraday shielding tube according to the specified size.

[0030] Beneficial effects:

[0031] The present invention adopts diffusion welding and die extension extrusion molding process in the method of manufacturing the Faraday cylinder shielding cylinder. (1) The diffusion welding process is characterized in that the material to be welded does not melt, and relies on solid-phase diffusion at the atomic scale to form a firm welding interface, with high welding quality. Intermediate layer materials can be used to reduce the matching requirements of the surface to be welded. The welding process does not use solder, which can effectively prevent water channel blockage, and the welding raw materials can be strengthened in advance and have high strength after molding. (2) The die extension extrusion molding process is a purely physical means with good economy, operability, product stability and high yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the working principle diagram of the radio frequency ion source;

[0033] Figure 2This is the finished product picture of the Faraday shield;

[0034] Figure 3 It is the middle cover plate of the Faraday shield cylinder (expanded view);

[0035] Figure 4 This is an exploded view (expanded view) of the Faraday shield cylinder;

[0036] Figure 5 This is a schematic diagram of the Faraday shielding tube molding mold structure.

[0037] Among them: inlet and outlet water pipes 1, cylinder 2, "S" shaped water channel 3, upper cover plate 4, middle cover plate 5, bottom cover plate 6, upper demoulding plate 7, demoulding guide rod 8, lower demoulding plate 9, guide column spring 10, demoulding guide column 11, cylinder mounting seat 12, oil circuit interface 13, pre-tightening cylinder 14, mold frame support 15, sizing mold cylinder 16, extension mold mouth 17, Faraday shielding cylinder 18, upper mold 19. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0039] As shown in 2, the Faraday shield cylinder mainly includes two parts according to the structural characteristics: the inlet and outlet pipes 1 and the cylinder body 2;

[0040] like Figure 3 The middle cover of the Faraday shield cylinder of the present invention is shown as an expanded view: the middle cover is an oxygen-free copper plate with a wall thickness of 2.5 mm, including 8 rectangular blades, each blade is processed by CNC to form 8 "S"-shaped water channels 3, and the water channel section is 4 mm × 1.4 mm. Each blade water channel is connected in series to form a water channel, a total of 8, and finally gathered at the water inlet of the middle cover. The water inlet is a water pipe with an inner diameter of 12 mm and an outer diameter of 15 mm, and the water pipe is brazed. There is a "Z"-shaped gap with a gap of 1 mm in the middle of each "S"-shaped water channel 3, and there are 64 in total.

[0041] like Figure 4 As shown in the figure, the cylinder is a three-layer structure, specifically including: three oxygen-free copper cover plates, the upper cover plate is a 1mm thick flat plate with inlet and outlet holes processed on it, the middle cover plate is a 2.5mm thick plate with 3 "S"-shaped water channels and 64 "Z"-shaped gaps processed by CNC machine tools, and the bottom cover plate is a 3mm thick round plate with 8 outlet water channels processed on it, with a water channel section of 4mm×1.4mm. The water inlet and outlet holes of each layer of the cover plate are aligned and then welded into a flat plate structure by diffusion welding.

[0042] like Figure 5 As shown, the special forming die of the present invention is used to extrude the water inlet and outlet pipes and the side wall gaps, and finally the water inlet and outlet pipes and the side wall gaps are formed by vacuum brazing.

[0043] According to a preferred embodiment of the present invention, Figure 1-4 The dimensions of the cylinder 2 are: inner diameter 240mm, outer diameter 246mm, height 160mm, the cross-sectional dimension 3 of the water channel inside the cylinder wall is 4mm×1.4mm, 64 Z-shaped seams are evenly distributed on the cylinder wall, the height of the Z-shaped seam is 145, and the seam gap is 1mm. The manufacturing process is to use three oxygen-free copper cover plates, namely the upper cover plate 4, the middle cover plate 5 and the bottom cover plate 6, to process the internal water channel and Z-shaped seam through a CNC machine tool, and then to weld them into a circular plate substrate through diffusion welding, and to extend and extrude them into a cylinder through a special forming mold, and finally to weld the inlet and outlet pipes 1 and the side wall gaps by vacuum brazing.

[0044] Among them, the special extension molding mold for Faraday shield tube is as follows Figure 5 As shown, it includes an upper die 19, a lower die, a demoulder, and a pre-tightening cylinder;

[0045] The lower die includes an extension die opening 17 and a sizing die cylinder 16;

[0046] The demoulding device comprises an upper demoulding plate 7, a lower demoulding plate 9, a demoulding guide rod 8, a demoulding guide column 11, a guide column spring 10, and a mold frame support column 15. The upper demoulding plate 7 and the lower demoulding plate 9 are connected by a plurality of mold frame supports 15; the demoulding guide column 11 is covered with a guide column spring 10; the demoulding guide rod 8 is located in the middle of the plurality of demoulding guide columns 11;

[0047] The preload cylinder comprises a cylinder mounting seat 12 , an oil circuit interface 13 , and a preload cylinder 14 .

[0048] The core material of the upper mold 19 is preferably 718 mold steel, which is an inner cavity structure of the Faraday shielding tube 18, with an outer diameter of 240 mm, a height of 160 mm, a lower end inverted arc diameter of 2 mm, and an upper end surface provided with a structure connected to a press.

[0049] The lower die, the core material of which is preferably 718 die steel, includes an extension die 17 and a sizing die 16. The extension die 17 is used to limit the deformation direction of the substrate. The extension die is an arc structure and is used to prevent the workpiece from producing defective products due to excessive friction during extension deformation. The sizing die 16 is used to shape the Faraday shielding tube 18 according to the specified size.

[0050] According to an embodiment of the present invention, the Faraday shielding tube forming process comprises the following specific steps:

[0051] Install the mold on the press, test the mold and debug it, and determine the position of the upper mold 19. Press the positioning hole on the Faraday shielding cylinder circular plate substrate and place the Faraday shielding cylinder circular plate substrate. The preload cylinder 14 is installed on the cylinder mounting seat 12. The hydraulic station realizes the rising and falling action of the preload cylinder 14 through the oil circuit interface 13, and transmits the action to the demolding guide rod 8 through the demolding guide column 11. The upper demolding plate 7, the lower demolding plate 9 and the mold frame support 15 play a supporting role for the entire structure, and the guide column spring 10 plays a buffering and shock absorbing role. Before the extension extrusion process, the upward movement of the preload cylinder 14 will give the lower mold a preload pressure, and the Faraday shielding cylinder circular plate substrate will be tightened between the upper and lower molds. The press extrusion upper mold 19 moves downward, and the extension die mouth 17 will limit the deformation direction of the Faraday shielding cylinder circular plate substrate, and the extension extrusion into the sizing mold cylinder 16 will form a cylindrical shape.

[0052] Demolding process: remove the upper mold 19 press, the hydraulic station realizes the upward movement of the pre-tightening cylinder 14 through the oil circuit interface 13, and transmits the action to the demolding guide rod 8 through the demolding guide column 11 to push the Faraday shielding cylinder 18 upward and move it out of the lower mold to realize demolding.

[0053] Finally, the inlet and outlet water pipes 1 and the side wall gaps are welded by vacuum brazing to complete the manufacturing of the finished product.

[0054] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, and it should be clear that the present invention is not limited to the scope of the specific embodiments, for those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A method for manufacturing a Faraday shielding tube for a radio frequency ion source, characterized in that: The steps include: Step 1, making a Faraday shield cylinder circular plate substrate; the circular plate substrate includes a three-layer structure; the circular plate substrate includes three oxygen-free copper cover plates, namely an upper cover plate, a middle cover plate and a bottom cover plate, and the internal water channel and Z-shaped seam are processed by a CNC machine tool, and are welded into a flat plate structure circular plate substrate by diffusion welding; the upper cover plate is a flat plate with eight rectangular blades, and the middle area is processed with a water inlet pipe hole and a water outlet pipe hole; the middle cover plate is a flat plate with eight rectangular blades, and the rectangular blades correspond to the upper cover plate, and an "S"-shaped water channel and 64 "Z"-shaped gaps are processed by a CNC machine tool, and the bottom cover plate is a circular plate, and 8 water outlet water channels are processed on the plate; Step 2: Loading a circular plate substrate into a mold to press-form a Faraday shielding tube; Step 3, demoulding the pressed Faraday shield cylinder from the mold; Step 4: Finally, the inlet and outlet water pipes and the side wall gaps are welded by vacuum brazing to complete the manufacturing of the Faraday shielding tube.

2. The method for manufacturing a Faraday shielding tube for a radio frequency ion source according to claim 1, characterized in that: The step 2 specifically includes: Install the mold on the press, test and debug the mold, and determine the position of the upper mold; press the positioning hole on the Faraday shielding cylinder circular plate substrate to place the Faraday shielding cylinder circular plate substrate; the preload cylinder is installed on the cylinder mounting seat, and the hydraulic station realizes the rising and falling action of the preload cylinder through the oil circuit interface, and transmits the action to the demolding guide rod through the demolding guide column. The upper demolding plate, the lower demolding plate and the mold frame support play a supporting role in the entire structure, and the guide column spring plays a buffering and shock-absorbing role; before the extension extrusion process, the upward movement of the preload cylinder will give the lower mold a preload pressure, and the Faraday shielding cylinder circular plate substrate will be clamped between the upper and lower molds; the press extrusion upper mold moves downward, and the extension die mouth will limit the deformation direction of the Faraday shielding cylinder circular plate substrate, and the extension is extruded into the sizing mold barrel to form a cylindrical shape.

3. The method for manufacturing a Faraday shielding tube for a radio frequency ion source according to claim 1, characterized in that: The demoulding process in step 3 specifically includes: Remove the upper mold press, and the hydraulic station moves the preload cylinder upward through the oil circuit interface. The action is transmitted to the demoulding guide rod through the demoulding guide column to push the Faraday shield cylinder upward and move it out of the lower mold to realize demoulding.

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