A dodecagonal vacuum chamber manufacturing process for heavy ion cancer treatment device

Abstract

The application discloses a manufacturing process of a dodecagonal vacuum chamber for a heavy ion cancer treatment device, which comprises the following steps: 1) blanking; 2) chamber body forming; 3) reinforcing rib welding; 4) vacuum degassing; and 5) assembly welding forming. The pipeline section of the diode magnet vacuum chamber is dodecagonal and is assembled by five integral assembly weldings. The blanking selects a 1.5mm-thick 316L stainless steel sheet without warping deformation, the chamber body forming adopts die pressing forming, the symmetric half sections are pressed, and the edges are milled and cleaned after pressing, the welding seam is clean and free of oil stains, and the integral assembly welding is a 9-degree vacuum chamber; the reinforcing rib welding process adopts laser double-sided staggered intermittent welding; the 9-degree dodecagonal vacuum chamber prepared in step 3) is subjected to high vacuum degassing at 950 DEG C for 1h according to a vacuum degassing process; and the 9-degree dodecagonal vacuum chamber prepared in step 4) is five assembly formed. The vacuum chamber body adopts thin-wall stamping and laser deep penetration welding forming, is convenient to manufacture, and greatly reduces the manufacturing cost and welding difficulty.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of superconducting magnets, and particularly relates to a manufacturing process of a dodecagonal vacuum chamber for a heavy ion cancer treatment device. BACKGROUND

[0002] The synchronous ring dipole magnet dodecagonal vacuum chamber is a new type of vacuum chamber, which can reduce the air gap of the corresponding magnet and reduce the cost of the magnet and operation.

[0003] The dodecagonal vacuum chamber product structure and performance index are as follows:

[0004] 1. The vacuum pipeline product belongs to a super-high vacuum equipment part;

[0005] 2. The inner cross-sectional dimension of the pipeline is 203x60, and the wall thickness is 1.5mm;

[0006] 3. The reinforcing rib spacing is 24mm, and the rib thickness is 4mm;

[0007] 4. The vacuum pipeline material is 316L austenitic stainless steel, and the material performance should meet the drawing and technical requirements;

[0008] 5. The vacuum leakage rate is less than 5x10 -8 Pal / s, and the working vacuum degree is 5x10 -7 Pa;

[0009] 6. The vacuum pipeline belongs to a thin-walled vacuum device with a wall thickness of less than 2mm.

[0010] The reinforcing ribs are arranged on the outer wall of the vacuum chamber to ensure the stability of the external pressure, and the flange corrugated pipe is assembled at both ends. Since the conventional argon arc welding of the vacuum chamber has large welding deformation and low qualified rate of vacuum air tightness, the reinforcing ribs are brazed by using vacuum silver copper palladium filler metal, which is expensive. Therefore, related process research and development are needed, laser welding is used to improve the product quality and reduce the manufacturing cost. SUMMARY

[0011] The application provides a manufacturing process of a dodecagonal vacuum chamber for a heavy ion cancer treatment device, so as to provide a process for improving product quality and reducing manufacturing cost, and solve the problems of large welding deformation of the conventional argon arc welding of the vacuum chamber and high price of vacuum silver copper palladium filler metal brazing.

[0012] To this end, the application adopts the following technical scheme:

[0013] A manufacturing process of a dodecagonal vacuum chamber for a heavy ion cancer treatment device comprises the following steps:

[0014] 1) blanking: select the stainless steel sheet with flat surface and no warping deformation, cut according to the design size;

[0015] 2) chamber forming: according to the shape and specification of the dodecagonal vacuum chamber, use the corresponding mold to press form, press two symmetrical half sections, and then mill the edges and clean to ensure that the weld is clean and free of oil stains;

[0016] Weld the two half sections to form a vacuum chamber. The gap between the welds is less than 0.2mm when assembling. Laser deep penetration welding is used for single-sided welding and double-sided forming. After welding, straighten the shape;

[0017] 3) reinforcement welding: the reinforcement is a U-shaped sheet, the profile of the reinforcement groove is matched with the outer profile of the vacuum chamber, and the reinforcement is vertically clamped on the top and bottom surfaces of the vacuum chamber; There is a corresponding reinforcement on the left and right sides of the vacuum chamber, and the reinforcement is equally spaced along the length direction of the vacuum chamber;

[0018] The reinforcement welding process uses laser double-sided staggered intermittent welding. When assembling, draw reinforcement position lines on the outer surface of the vacuum chamber; and use a pressing tool to press and clamp the reinforcement, and a vacuum chamber core support inside the support tool to ensure welding strength and control welding deformation; The specific process is as follows:

[0019] ① Place the vacuum chamber pad flat on the welding platform, install the inside support tool, assemble the reinforcement according to the marked line position, ensure that the gap between the reinforcement and the vacuum chamber body is less than 0.2mm, and spot weld for fixation;

[0020] ② Adjust the position of the inside support tool, install the reinforcement position distance tool, and assemble the reinforcement from left to right to the two ends in turn, and spot weld for fixation;

[0021] ③ Turn over the vacuum chamber pad and place it flat on the welding platform, assemble the reinforcement according to steps ① and ②, and the outer profile of the reinforcement on the same section is butt jointed flat, and the butt joint is not more than 0.5mm;

[0022] ④ Check and confirm the position of each reinforcement and end plate, and start welding after ensuring that there is no error. Weld the tube body into shape, and spot weld the reinforcement joint surface from the melting point, and spot weld one place at each end;

[0023] ⑤ Weld the reinforcement using self-welding welding skip welding method, the welding length is not more than 50mm each time, and the next welding is carried out after the upper weld cools down to control the welding deformation; The distance is uniform, the weld is uniform and full, and there is no appearance defect;

[0024] 6. The tooling supports the vacuum chamber at both ends, the inner support tooling is loaded into the vacuum chamber at both ends, and is horizontally placed on the workbench. The dial indicator is used to align the upper plane of the vacuum chamber, with an error of ±0.1 mm. After compression, the angle of the end faces of the vacuum chamber is milled according to the drawing, so that the included angle between the two end faces and the axis of the vacuum chamber is 9°. The burrs, iron filings and other impurities are removed. After processing, the length and angle of the vacuum chamber are detected to ensure that they meet the requirements of the drawing;

[0025] 7. Leak detection: ensure that the leakage rate is less than 5*10-8 Pa.L / s;

[0026] 8. Cleaning: clean the surface stains and oil stains of the vacuum chamber. During the cleaning process, avoid knocking and scratching the inner and outer surfaces of the vacuum chamber, and avoid getting oil stains and stains. After cleaning, the vacuum chamber is wiped dry;

[0027] 4) Vacuum degassing: the vacuum chamber prepared in step 3) is degassed according to the vacuum degassing process;

[0028] 5) Splicing forming: select 5 vacuum chambers prepared in step 4), and sequentially splice and connect the 5 vacuum chambers. During splicing, a splicing tooling is used, the connecting plates are aligned, the misalignment is less than 0.5 mm, the flange corrugated pipes at both ends are assembled and welded, and argon arc welding is used for welding.

[0029] Further, the welding parameters of the laser deep penetration welding in step 2) are as follows: the laser welding power is not less than 600 W; the welding speed is not greater than 3.5 m / min; the scanning width is not greater than 1.2 mm; and the scanning speed is not less than 400 mm / min.

[0030] Further, the stainless steel plate in step 1) is selected to be a 1.5 mm thick 316L stainless steel plate, and laser cutting is used for blanking.

[0031] Further, during the vacuum degassing in step 4), the vacuum environment is heated to 950℃ for at least 1h.

[0032] The beneficial effects of the present application are as follows:

[0033] 1. The dodecagonal vacuum chamber body of the present application is formed by die pressing, and the symmetric half sections are pressed, which can improve the production speed and reduce the difficulty of chamber body forming and the cost of tooling manufacturing;

[0034] 2. The laser deep penetration welding process is used for welding the dodecagonal vacuum chamber body of the present application, single-sided welding is used for double-sided forming, the welding strength is increased, welding defects are avoided, the performance of the product is greatly improved, the first-time qualified rate of vacuum leak detection is 100%, and the product quality is improved;

[0035] 3. The twelve-sided vacuum chamber body reinforcing rib welding of the present application adopts laser double-sided staggered intermittent welding. When welding, a fixed distance clamping tool is used, the processing efficiency is improved by 3 times, the manufacturing cost is reduced by 40%, and compared with the original process, there is great improvement and promotion. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a structural schematic diagram of the 9° twelve-sided vacuum chamber of the present application;

[0037] Figure 2 is a schematic diagram of the mold pressing half-section vacuum chamber of step 1) of the present application;

[0038] Figure 3 is a structural schematic diagram of the half-section vacuum chamber of step 1) of the present application;

[0039] Figure 4 is a schematic diagram of the inner lining tool and reinforcing rib of the present application;

[0040] Figure 5 is a structural schematic diagram of the 5-puzzle vacuum chamber of the present application. DETAILED DESCRIPTION

[0041] The present application will be further described below in conjunction with the drawings:

[0042] A manufacturing process for a twelve-sided vacuum chamber for a heavy ion cancer treatment device, comprising the following steps:

[0043] 1) blanking: select a 1.5mm thick 316L stainless steel plate with flat surface and no warping deformation, and cut the blanking according to the design size using laser cutting.

[0044] 2) chamber body forming: according to the shape and specification of the twelve-sided vacuum chamber, use the corresponding mold to press forming, press two symmetrical half-sections (such as Figure 2 and 3 shown), after pressing, milling edge, cleaning, to ensure that the weld is clean and free of oil stains;

[0045] two half-sections are assembled and welded to form a vacuum chamber. The gap between the welds is less than 0.2mm when assembling, laser deep penetration welding is used for welding, single-sided welding double-sided forming, and welding is followed by straightening;

[0046] The welding parameters of laser deep penetration welding are as follows: laser welding power is not less than 600W; welding speed is not greater than 3.5m / min; scanning width is not greater than 1.2mm; scanning speed is not less than 400mm / min.

[0047] 3) reinforcing rib welding: the reinforcing rib is a U-shaped thin plate (such as Figure 4The profile of the inner groove of the reinforcing rib is adapted to the outer profile of the vacuum chamber, and the reinforcing rib is vertically clamped on the top surface and the bottom surface of the vacuum chamber; a corresponding reinforcing rib is arranged on the left side and the right side of the vacuum chamber, and the reinforcing ribs are equidistantly arranged along the length direction of the vacuum chamber;

[0048] The reinforcing rib welding process adopts laser double-sided staggered intermittent welding. The reinforcing rib position line is drawn on the outer surface of the vacuum chamber during assembly welding. A pressing plate tool is used to press and clamp the reinforcing rib, and an inner support tool is used in the core support of the vacuum chamber to ensure the welding strength and control the welding deformation. The specific process is as follows:

[0049] ① Place the vacuum chamber pad flat on the welding platform, install the inner support tool, and assemble the reinforcing rib according to the position line. Ensure that the gap between the reinforcing rib and the vacuum chamber body is less than 0.2mm, and spot weld for fixation.

[0050] ② Adjust the position of the inner support tool, install the reinforcing rib position distance tool, and sequentially assemble the reinforcing rib from left to right to the two ends, and spot weld for fixation.

[0051] ③ Turn over the vacuum chamber pad and place it flat on the welding platform. Assemble the reinforcing rib according to steps ① and ②. The outer profiles of the reinforcing ribs on the same section are butt jointed flat, and the butt joint is not more than 0.5mm.

[0052] ④ Check and confirm the positions of each reinforcing rib and end plate. After ensuring that there is no error, start welding. Weld the pipe body into shape. Spot weld the reinforcing rib joint surface. Spot weld one place at each end.

[0053] ⑤ Weld the reinforcing rib using the self-welding welding skip welding method. The welding length is not more than 50mm each time. After the upper section of the weld cools down, the next welding is performed to control the welding deformation. The distance is uniform, the weld is uniform and full, and there is no appearance defect.

[0054] ⑥ Support the two ends of the vacuum chamber with the tool, install the inner support tool in the two ends of the vacuum chamber, and place it horizontally on the workbench. Use the dial gauge to find the upper surface of the vacuum chamber. The error is within ±0.1mm. After pressing, mill the angles of the two end surfaces of the vacuum chamber according to the drawing, so that the included angles of the two end surfaces with the axis of the vacuum chamber are 9° respectively. Remove the burrs, iron chips and other impurities. After processing, detect the length and angle dimensions of the vacuum chamber to ensure that they meet the requirements of the drawing.

[0055] ⑦ Leak detection: ensure that the leakage rate is less than 5×10-8Pa.L / s.

[0056] ⑧ Cleaning: clean the surface stains and oil stains of the vacuum chamber. During the cleaning process, avoid scratching and scratching the inner and outer surfaces of the vacuum chamber, and avoid getting oil stains and stains. After cleaning, dry the vacuum chamber.

[0057] 4) Vacuum degassing: the vacuum chamber prepared in step 3) is degassed according to the vacuum degassing process. Heat to 950℃ under vacuum environment for at least 1h.

[0058] 5) Welding and forming: Select 5 vacuum chambers obtained in step 4), and connect the 5 vacuum chambers in sequence. When welding, use welding tooling to assemble and weld the connecting plates, align the connecting plates, and ensure that the misalignment is less than 0.5mm. Assemble the flange bellows at both ends and use argon arc welding.

[0059] Internal support fixtures, such as Figure 4 The inner lining fixture has the same outline shape as the vacuum chamber, but its dimensions are slightly smaller. After being inserted into the vacuum chamber, the inner lining fixture provides support, preventing the vacuum chamber from being deformed by pressure during welding, thus improving the machining accuracy of the vacuum chamber. The reinforcing rib positioning fixture is made of ordinary steel plate, horizontally positioned adjacent to the vacuum chamber. Grooves are equidistantly cut on the side of the steel plate adjacent to the vacuum chamber, with each groove corresponding to a reinforcing rib. The grooves are used to place the reinforcing ribs, thus providing positioning. The steel plate is fixed to the worktable by clamps. When the fixture supports both ends of the vacuum chamber, ordinary clamping components are used to lift the bottom surface of the vacuum chamber, fixing it before machining.

Claims

1. A manufacturing process for a dodecagonal vacuum chamber used in a heavy ion cancer treatment device, characterized in that, Includes the following steps: 1) Cutting: Select a flat stainless steel sheet without warping or deformation, and cut it according to the design dimensions; 2) Chamber forming: According to the shape and specifications of the dodecagonal vacuum chamber, use the corresponding mold to press and form two symmetrical half sections. After pressing, mill the edges and clean to ensure that the weld seam is clean and free of oil. The two half-sections are assembled and welded to form a vacuum chamber. The weld gap is less than 0.2mm during assembly. Laser deep penetration welding is used for welding, with single-sided welding and double-sided forming. The shape is corrected after welding. 3) Welding of reinforcing ribs: The reinforcing ribs are U-shaped thin plates. The outline of the inner groove of the reinforcing ribs is adapted to the outline of the outer vacuum chamber. The reinforcing ribs are vertically clamped on the top and bottom surfaces of the vacuum chamber. There are corresponding reinforcing ribs on the left and right sides of the vacuum chamber, and the reinforcing ribs are equidistantly arranged along the length of the vacuum chamber. The reinforcing rib welding process employs laser double-sided intermittent staggered welding. During assembly welding, the reinforcing rib position lines are marked on the outer surface of the vacuum chamber. A pressure plate fixture is used to clamp and hold the reinforcing rib, and a core support fixture is used inside the vacuum chamber to ensure welding strength and control welding deformation. The specific process is as follows: ① Place the vacuum chamber flat on the welding platform, install the inner support fixture, and weld the reinforcing ribs according to the marked positions, ensuring that the gap between the reinforcing ribs and the vacuum chamber body is less than 0.2mm, and fix them by spot welding; ② Adjust the position of the internal support fixture, install the reinforcing rib positioning fixture, weld the reinforcing ribs from the left and right sides to both ends, and spot weld them in place; ③ Flip the vacuum chamber flat and place it on the welding platform. Weld the reinforcing ribs according to steps ① and ②. The outer contours of the reinforcing ribs in the same cross section should be aligned and the misalignment at the joint should not exceed 0.5mm. ④ Check and confirm the positions of each reinforcing rib and end plate. After ensuring that there are no errors, start welding. Weld the tube body to form, self-melting weld the joint surface of the reinforcing rib, and spot weld one point at each end. ⑤ Welding of reinforcing ribs: Self-fusion welding with skip welding method is adopted. Each welding length shall not exceed 50mm. After the upper section of the weld has cooled, the next welding shall be carried out to control welding deformation. The spacing should be uniform, the weld should be uniform and full, and there should be no appearance defects. ⑥ The tooling supports both ends of the vacuum chamber. The inner support tooling is installed into both ends of the vacuum chamber and placed horizontally on the worktable. The dial indicator is used to align the upper plane of the vacuum chamber, with an error within ±0.1mm. After tightening, the angles of the two end faces of the vacuum chamber are milled according to the drawings, so that the angles between the two end faces and the axis of the vacuum chamber are 9°. Remove the burrs, iron filings and other impurities. After processing, check the length and angle dimensions of the vacuum chamber to ensure that they meet the requirements of the drawings. ⑦ Leak detection: Ensure leakage rate < 5 × 10⁻⁸ Pa·L / s; ⑧ Cleaning: Clean the surface of the vacuum chamber to remove dirt and oil stains. During the cleaning process, avoid bumping or scratching the inner and outer surfaces of the vacuum chamber, and avoid getting oil stains or dirt on it. Wipe the vacuum chamber dry after cleaning. 4) Vacuum degassing: The vacuum chamber obtained in step 3) is degassed according to the vacuum degassing process; 5) Welding and forming: Select 5 vacuum chambers obtained in step 4), and connect the 5 vacuum chambers in sequence. When welding, use welding fixtures to assemble and weld the connecting plates, align the connecting plates, and ensure that the misalignment is less than 0.5mm. Assemble the flange bellows at both ends and use argon arc welding.

2. The manufacturing process of the dodecagonal vacuum chamber for heavy ion cancer treatment device according to claim 1, characterized in that, The welding parameters for laser deep penetration welding in step 2) are as follows: laser welding power not less than 600W; welding speed not greater than 3.5m / min; scanning width not greater than 1.2mm; scanning speed not less than 400mm / min.

3. The manufacturing process of the dodecagonal vacuum chamber for heavy ion cancer treatment device according to claim 1, characterized in that, In step 1), the stainless steel plate is a 1.5mm thick 316L stainless steel plate, which is cut by laser cutting.

4. The manufacturing process of the dodecagonal vacuum chamber for heavy ion cancer treatment device according to claim 1, characterized in that, In step 4), during vacuum degassing, the gas is heated to 950°C for at least 1 hour in a vacuum environment.

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