Manufacturing method of large-size arc-shaped extremely-high vacuum cavity

Abstract

The invention provides a large-size arc-shaped extremely-high vacuum cavity manufacturing method, which belongs to the field of vacuum cavity processing, and comprises the following steps: removing hydrogen molecules in an extremely-high vacuum cavity raw material by using an extremely-high vacuum furnace; a numerical control machine tool is used for machining the vacuum bottom plate, the vacuum upper cover plate, the vacuum inner arc side plate and the vacuum outer arc side plate in sequence; the vacuum bottom plate, the vacuum upper cover plate, the vacuum inner arc side plate and the vacuum outer arc side plate are sequentially placed on a welding tool, spot welding and fixing are conducted through argon arc welding, and then external welding is conducted through laser welding to form an extremely-high vacuum cavity; carrying out leak detection on a welding seam welded by the extremely high vacuum cavity by using a helium mass spectrum leak detection method; and a laser tracker is adopted to measure the size of the extremely-high vacuum cavity, and the arc-shaped extremely-high vacuum cavity is manufactured. The invention aims to solve the problem that the arc-shaped extremely-high vacuum cavity is easy to leak in the prior art. The technical effects are that the phenomenon of air entrapment of the extremely high vacuum cavity is avoided, and the probability of leakage of the extremely high vacuum cavity is reduced at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum cavity processing, and in particular to a method for manufacturing a large-sized arc-shaped ultra-high vacuum cavity. Background Art

[0002] The completion of a new generation of high-intensity heavy ion accelerators has provided strong support for cutting-edge research in nuclear physics, materials science, and other fields. Capable of delivering pulsed heavy ion beams up to 4.25 GeV / u, these accelerators place stringent demands on the design of various systems. The high-precision ring spectrometer, a key component, is crucial for ion beam control and experimental applications. The high-precision ring spectrometer is composed of a variety of magnets, electronic cooling systems, dual time-of-flight spectrometers and other large experimental terminals. In order to meet the requirements of different experimental terminals for ultra-high vacuum environments, the ultra-high vacuum system design must be better than 1×10 -9 The high-precision annular spectrometer's diode iron high vacuum chamber is a large-scale arc-shaped structure with a thickness of more than 7 mm. It is usually manufactured by welding four plates together. The conventional welding process uses argon arc welding to form two inner welds and two outer welds. However, the traditional manufacturing method has significant problems. On the one hand, due to the excessive thickness of the sheet, the outer weld is difficult to penetrate, resulting in a gap inside the outer weld, causing gas entrapment. Gas molecules collide in the gap, resulting in the ultra-high vacuum system being unable to reach 1×10 -9 The design index of Pa affects the stability of the ion beam and the experimental accuracy. On the other hand, the manufacturing process cannot perform effective ultra-high vacuum leak detection on the two internal welds. If a leak occurs, subsequent repair welding is difficult to implement due to the complex structure and limited space, which increases the maintenance cost and scientific research time cost, and seriously restricts the overall performance of the high-current heavy ion accelerator. Summary of the Invention

[0003] The present invention provides a method for manufacturing a large-sized arc-shaped ultra-high vacuum cavity, which is used to solve the defects of the existing technology in the manufacture of ultra-high vacuum cavities, such as the air entrapment phenomenon and the easy leakage. The method can avoid the occurrence of air entrapment in the ultra-high vacuum cavity and effectively perform ultra-high vacuum leak detection on all welds at one time, thereby reducing the probability of leakage in the ultra-high vacuum cavity.

[0004] The present invention provides a method for manufacturing a large-scale arc-shaped ultra-high vacuum cavity, comprising: Hydrogen removal: Use an ultra-high vacuum furnace to remove hydrogen molecules from the raw materials of the ultra-high vacuum chamber; Parts processing: Use CNC machine tools to process the vacuum bottom plate, vacuum upper cover plate, vacuum inner arc side plate and vacuum outer arc side plate in sequence; Laser welding: Place the vacuum bottom plate, vacuum upper cover plate, vacuum inner arc side plate and vacuum outer arc side plate on the welding fixture in sequence, fix them with argon arc spot welding, and then use laser welding for external welding to form an ultra-high vacuum chamber; Ultra-high vacuum leak detection: Use helium mass spectrometry leak detection to detect leaks in the welds of ultra-high vacuum chambers; Dimension detection: A laser tracker is used to measure the dimensions of the ultra-high vacuum cavity, and the arc-shaped ultra-high vacuum cavity is completed.

[0005] In addition, the method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to the present invention may also have the following additional technical features: In some embodiments of the present invention, further comprising: Before performing ultra-high vacuum leak detection, the ultra-high vacuum flange is welded to the end of the ultra-high vacuum chamber using argon arc welding.

[0006] In some embodiments of the present invention, further comprising: Before ultra-high vacuum leak detection, the ultra-high vacuum cavity completed by laser welding is cleaned in ultra-high vacuum.

[0007] In some embodiments of the present invention, ultra-high vacuum cleaning is performed on an ultra-high vacuum cavity after laser welding, including: Rough wash to remove visible dirt; Ultrasonic cleaning in a weakly acidic water-based solution at 65°C for 15 minutes to remove oil; Place in a 65°C weak alkaline solution and ultrasonically clean for 15 minutes to neutralize; rinse repeatedly with flowing deionized water; Use high-purity nitrogen to dry the water stains.

[0008] In some embodiments of the present invention, the welding tool comprises: The bottom plate positioning fixture is provided with a waist groove and a limit groove, and waist grooves are provided on both sides of the limit groove; The pressing plate is installed on the base plate positioning fixture through the mold assembly.

[0009] In some embodiments of the present invention, mold assembly includes: The column is set between the pressure plate and the bottom plate positioning tooling; Screw rod: A screw rod is provided at each end of the column, one of the screw rods is connected to the pressure plate, and the other screw rod is connected to the base plate positioning tooling.

[0010] In some embodiments of the present invention, the welding tool further comprises: Positioning pin: when working, the positioning pin is inserted into the bottom plate positioning tooling.

[0011] In some embodiments of the present invention, further comprising: During the laser welding step, before using argon arc welding to fix it, a laser tracker and vernier caliper are used to perform an initial measurement of the size of the ultra-high vacuum cavity spliced ​​on the welding fixture to confirm that the size meets the requirements.

[0012] In some embodiments of the present invention, the method further comprises: fixing with argon arc spot welding; The welding position is wiped with alcohol to remove surface oil and oxide layer, and then laser welding is used to perform external welding to form an extremely high vacuum cavity.

[0013] In some embodiments of the present invention, forming an ultra-high vacuum chamber by external welding using laser welding includes: Set parameters for laser welding machine; Turn on the laser indicator light, adjust the robot to the center of the welding position, use a stainless steel plate for trial welding, and observe whether the weld has defects such as incomplete penetration, porosity, and thermal cracks after the trial welding; Determine final welding parameters; Laser welding is used to perform external welding to form an extremely high vacuum chamber.

[0014] In summary, the present application includes the following beneficial technical effects: the ultra-high vacuum chamber is formed by placing the vacuum bottom plate, vacuum upper cover plate, vacuum inner arc side plate and vacuum outer arc side plate in sequence on the welding tooling, fixing them with argon arc spot welding, and then using laser welding for external welding. The hydrogen removal setting can ensure that all external welds are welded through, avoiding the occurrence of gas entrapment in the ultra-high vacuum chamber. At the same time, since all the settings are external welding, all welds can be effectively tested for ultra-high vacuum leaks at one time, reducing the probability of leakage in the ultra-high vacuum chamber. Even if leakage occurs in the later stage, only the external welds need to be repaired, and the operating space is not restricted, reducing the maintenance cost and scientific research time cost, and ensuring the overall performance of the high-current heavy ion accelerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference numerals are used throughout the accompanying drawings to denote the same components. In the accompanying drawings: Figure 1 The flowchart of the method for manufacturing a large-sized arc-shaped ultra-high vacuum chamber according to some embodiments of the present invention is schematically shown.

[0016] Figure 2 A three-dimensional diagram schematically illustrates a welding tool for a method of manufacturing a large-sized arc-shaped ultra-high vacuum chamber according to some embodiments of the present invention.

[0017] Figure 3 A three-dimensional diagram of a bottom plate positioning tool 1 for a method for manufacturing a large-sized curved ultra-high vacuum chamber according to some embodiments of the present invention is schematically shown.

[0018] Figure 4 A three-dimensional diagram schematically illustrates a mold assembly 6 for a method for manufacturing a large-sized curved ultra-high vacuum chamber according to some embodiments of the present invention.

[0019] Figure 5 A partial enlarged view of part A of a welding tool in a method for manufacturing a large-sized arc-shaped ultra-high vacuum chamber according to some embodiments of the present invention is schematically shown.

[0020] Figure 6 A three-dimensional view of an ultra-high vacuum chamber manufactured by the method for manufacturing a large-sized arc-shaped ultra-high vacuum chamber according to some embodiments of the present invention is schematically shown.

[0021] Reference numerals: 1. Bottom plate positioning fixture, 2. Vacuum bottom plate, 3. Vacuum upper cover plate, 4. Vacuum inner arc side plate, 5. Vacuum outer arc side plate, 6. Mold assembly, 7. Press plate, 8. Nut, 9. Locating pin, 10. Locating hole, 11. Threaded hole, 12. Waist groove, 13. Column, 14. Screw, 15. Ultra-high vacuum flange, 16. Limit groove. DETAILED DESCRIPTION

[0022] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0023] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an", and "" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain", and "have" are inclusive and therefore specify the presence of the stated features, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0024] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0025] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," and the like. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "below" another element or feature would then be oriented as "above" or "above" another element or feature. Thus, the example term "below" may include both above and below orientations. The device may be otherwise oriented rotated 90 degrees or in other orientations and the spatially relative descriptors used herein are interpreted accordingly.

[0026] The cross-section of the diode iron vacuum chamber is a rectangular cross-section greater than or equal to 342 mm × 92 mm, with a wall thickness of more than 7 mm, a deflection angle of 18°, a deflection radius greater than or equal to 9500 mm, and a total length of more than 3.6 m. Typically, this large-scale arc-shaped vacuum chamber is made up of four plates. First, the bottom plate and the inner and outer arc side plates are assembled, and the two internal welds are completed using argon arc welding. The top plate is then covered and the remaining two welds are completed from the outside. On the one hand, due to the excessive thickness of the plate, the outer weld is difficult to penetrate, resulting in a gap inside the outer weld, causing gas entrapment. Gas molecules collide in the gap, resulting in the ultra-high vacuum system being unable to reach 1×10 -9 The design index of Pa affects the stability of the ion beam and the experimental accuracy. On the other hand, the manufacturing process cannot perform effective ultra-high vacuum leak detection on the two internal welds. If a leak occurs, subsequent repair welding is difficult to implement due to the complex structure and limited space, which increases the maintenance cost and scientific research time cost, and seriously restricts the overall performance of the high-current heavy ion accelerator.

[0027] In addition, it should be noted that the definition of ultra-high vacuum refers to a gas pressure below 10-7 Pa vacuum environment; large size refers to the horizontal or vertical scale usually above 1 meter.

[0028] like Figures 1 to 6 As shown, according to an embodiment of the first aspect of the present invention, a method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber is proposed, comprising: Hydrogen removal: Use an ultra-high vacuum furnace to remove hydrogen molecules from the raw materials of the ultra-high vacuum chamber; Parts processing: Use CNC machine tools to process the vacuum bottom plate 2, vacuum upper cover plate 3, vacuum inner arc side plate 4 and vacuum outer arc side plate 5 in sequence; Laser welding: Place the vacuum bottom plate 2, vacuum upper cover plate 3, vacuum inner arc side plate 4 and vacuum outer arc side plate 5 on the welding fixture in sequence, fix them with argon arc spot welding, and then use laser welding to perform external welding to form an ultra-high vacuum cavity; Ultra-high vacuum leak detection: Use helium mass spectrometry leak detection to detect leaks in the welds of ultra-high vacuum chambers; Dimension detection: A laser tracker is used to measure the dimensions of the ultra-high vacuum cavity, and the arc-shaped ultra-high vacuum cavity is completed.

[0029] In the above embodiment, it should be noted that the process of using an ultra-high vacuum furnace to remove hydrogen molecules from the raw materials of the ultra-high vacuum chamber specifically includes: placing the raw materials 316L and 316LN of the ultra-high vacuum chamber to be dehydrogenated into an ultra-high vacuum furnace after ultra-high vacuum cleaning; -3 Under the conditions of Pa, the dehydrogenation temperature is 900~950℃, and the dehydrogenation time is 1h / mm wall thickness. During the cooling process, the temperature zone of 900-600℃ must be quickly avoided for less than 15 minutes to avoid the formation of carbide precipitation.

[0030] Ultra-high vacuum cleaning includes: rough washing to remove visible dirt; then ultrasonic cleaning in a weak acidic water-based solution at 65°C for 15 minutes to remove oil; then ultrasonic cleaning in a weak alkaline solution at 65°C for 15 minutes to neutralize; repeated rinsing with flowing deionized water until there is no foam; and blowing dry water stains with high-purity nitrogen.

[0031] High-purity nitrogen refers to nitrogen with a purity between 99.99% and 99.9999%.

[0032] The vacuum bottom plate 2, the vacuum upper cover plate 3, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 are sequentially processed using a CNC machine tool. Specifically, the drawings of the vacuum bottom plate 2, the vacuum upper cover plate 3, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 are first imported into the CNC machine tool respectively, and then a 7 mm thick 316L stainless steel sheet that has been dehydrogenated is fixed on the CNC machine tool. Molybdenum wire is selected as the electrode wire material, with a diameter of 0.1-0.3 mm, a discharge power of 100-120 A, a pulse width of 4-8 μs, an impulse voltage of 90-110 V, and a wire speed of 0.5-5 m / s.

[0033] Then the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 are processed by a CNC bending machine or a CNC circular arc bending machine according to parameters such as deflection angle and radius.

[0034] After all parts are processed, a laser tracker is used to accurately measure the length, width, radius, angle, etc. of the vacuum bottom plate 2, vacuum upper cover plate 3, vacuum inner arc side plate 4 and vacuum outer arc side plate 5.

[0035] Furthermore, a CNC machining center is used to process the ultra-high vacuum flange 15 according to national standards. The material of the ultra-high vacuum flange 15 is 316LN.

[0036] Placing the vacuum bottom plate 2, the vacuum upper cover plate 3, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 on the welding tool in sequence specifically includes: first fixing the vacuum bottom plate 2 on the welding tool, then splicing the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 on both sides of the vacuum bottom plate 2 respectively, then splicing the vacuum upper cover plate 3 on the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5, and then using the welding tool to fix the welding positions to form four outer welds.

[0037] The method of fixing by argon arc spot welding is to use an argon arc welding machine to spot weld and fix the welding positions of the four outer welds.

[0038] Then, the method of using laser welding for external welding to form an extremely high vacuum cavity includes using a laser welder to fully weld the welding positions of the four external welds, grinding and electrochemically polishing all welds after welding, and using a hydraulic correction machine to mechanically correct the areas with relatively large deformation.

[0039] The laser tracker is used to measure the dimensions of the ultra-high vacuum chamber. Specifically, the width, height, deflection angle, deflection radius, flatness, and perpendicularity between the flange surface and the axis of the welded and leak-tested ultra-high vacuum chamber are measured. Except for angles that must be within ±0.1°, all other dimensions must be within ±0.5mm.

[0040] The technical effect achieved by the above embodiment is as follows: the ultra-high vacuum chamber is formed by placing the vacuum bottom plate 2, the vacuum upper cover plate 3, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 on the welding tool in sequence, fixing them with argon arc spot welding, and then using laser welding for external welding. The setting for hydrogen removal can ensure that all external welds are welded through, avoiding the occurrence of gas entrapment in the ultra-high vacuum chamber. At the same time, since all the settings are external welding, it is possible to effectively complete the ultra-high vacuum leak detection of all welds at one time, reducing the probability of leakage in the ultra-high vacuum chamber. At the same time, even if leakage occurs in the later stage, only the external welds need to be repaired, and the operating space is not restricted, reducing the maintenance cost and scientific research time cost, and ensuring the overall performance of the high-current heavy ion accelerator.

[0041] Optional, such as Figure 1 As shown, before performing ultra-high vacuum leak detection, the ultra-high vacuum flange 15 is welded to the end of the ultra-high vacuum chamber by argon arc welding.

[0042] In the above optional embodiment, it should be noted that an ultra-high vacuum flange 15 is welded to each of the two ends of the ultra-high vacuum chamber.

[0043] The helium mass spectrometry leak detection method is used to detect the welds of the ultra-high vacuum chamber. The helium mass spectrometry leak detection method is used to detect the position of the silver wire sealing ultra-high vacuum flange 15 and all welds. If the leakage rate value is less than 1×10 -8 Pa·L·S -1 It is considered qualified.

[0044] The beneficial effects of the above optional embodiments are: using argon arc welding to weld the ultra-high vacuum flange 15 to the end of the ultra-high vacuum chamber can ensure reliable welding of the ultra-high vacuum flange 15 and the ultra-high vacuum chamber, and reduce welding costs, thereby realizing the combination of argon arc welding and laser welding to maximize the sealing of the ultra-high vacuum chamber after welding while ensuring the convenience of welding and controlling the welding cost.

[0045] Optional, such as Figure 1 As shown, before the ultra-high vacuum leak detection, the ultra-high vacuum cavity completed by laser welding is subjected to ultra-high vacuum cleaning.

[0046] In the above optional embodiment, it should be noted that before the ultra-high vacuum leak detection, the ultra-high vacuum cavity is subjected to ultra-high vacuum cleaning after the ultra-high vacuum flange 15 is welded.

[0047] After the ultra-high vacuum chamber size test is completed, the ultra-high vacuum chamber is verified. A 400L sputtering ion pump and two titanium sublimation pumps are installed in the ultra-high vacuum chamber. After being kept at a high temperature of 250°C for 48 hours, the ultra-high vacuum chamber made of 316L as the main material of the chamber and 316LN as the flange and processed by laser welding can achieve an ultimate ultra-high vacuum of 8×10 -10 Pa, proving that this ultra-high vacuum chamber can avoid the occurrence of air entrapment and can complete the ultra-high vacuum leak detection work in one go, avoiding a series of problems caused by leak repair in the later stage.

[0048] The beneficial effects of the above optional embodiments are: through the ultra-high vacuum cleaning setting, debris and oil stains on the inner wall of the ultra-high vacuum chamber can be removed, reducing the pollution of the environment inside the ultra-high vacuum chamber caused by debris and debris, and ensuring the ultra-high vacuum performance of the ultra-high vacuum chamber.

[0049] Optional, such as Figure 1 As shown, the ultra-high vacuum cleaning of the ultra-high vacuum cavity completed by laser welding includes: Rough wash to remove visible dirt; Ultrasonic cleaning in a weakly acidic water-based solution at 65°C for 15 minutes to remove oil; Place in a 65°C weak alkaline solution and ultrasonically clean for 15 minutes to neutralize; rinse repeatedly with flowing deionized water; Use high-purity nitrogen to dry the water stains.

[0050] In the above optional embodiment, it should be noted that high-purity nitrogen refers to nitrogen with a purity between 99.99% and 99.9999%.

[0051] The beneficial effects of the above optional embodiments are: rough washing can quickly remove visible dirt on the surface and avoid large particles of impurities affecting subsequent cleaning and the performance of the ultra-high vacuum cavity. Ultrasonic cleaning with a weakly acidic water-based solution at 65°C uses the chemical reaction between acidic components and grease and the cavitation effect of ultrasonic high-frequency vibration. The dual effects effectively break down oil stains, so that the oil stains on the inner wall surface of the ultra-high vacuum cavity can be completely removed, reducing the pollution of the ultra-high vacuum environment by residual oil stains. The neutralization step with a weak alkaline solution can effectively neutralize the residual acidic substances to prevent them from corroding the ultra-high vacuum cavity materials, and further remove residual impurities. Flushing with flowing deionized water can take away the substances produced by the neutralization reaction and other residual impurities, and reduce the amount of residual ions. Finally, high-purity nitrogen is used to blow away the water stains to avoid the generation of water vapor by residual moisture and prevent it from volatilizing in the ultra-high vacuum environment and affecting the ultra-high vacuum degree. Through this series of cleaning processes, the impurity content in the ultra-high vacuum cavity can be greatly reduced, the cleanliness of the surface of the ultra-high vacuum cavity can be improved, and the ultra-high vacuum performance of the ultra-high vacuum cavity can be effectively guaranteed. Optional, such as Figures 2 to 6As shown, the welding tooling includes a base plate positioning tooling 1, a mold assembly 6 and a pressure plate 7. A waist-shaped groove 12 and a limit groove 16 are provided on the base plate positioning tooling 1. Waist-shaped grooves 12 are provided on both sides of the limit groove 16. The pressure plate 7 is installed on the base plate positioning tooling 1 through the mold assembly 6.

[0052] In the above optional embodiment, it should be noted that a plurality of mold assemblies 6 are connected to each side of the limiting groove 16 of the vacuum bottom plate 2, and all the mold assemblies 6 are connected to the bottom plate positioning tooling 1 by bolt connections. The multiple mold assemblies 6 on one side of the limiting groove 16 and the multiple mold assemblies 6 on the other side of the limiting groove 16 are arranged in a one-to-one correspondence, and a pressure plate 7 is connected between each corresponding two mold assemblies 6, and the shape of each mold assembly 6 is elliptical.

[0053] During operation, the vacuum bottom plate 2 is inserted into the limiting groove 16, the two waist-shaped grooves 12 are respectively located on both sides of the vacuum bottom plate 2, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 are respectively connected to the vacuum bottom plate 2 and after adjusting the position through the mold assembly 6, the vacuum upper cover plate 3 is spliced ​​with the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5, and then the pressing plate 7 is pressed onto the vacuum upper cover plate 3 and connected to the upper end of the mold assembly 6.

[0054] The processing method of the bottom plate positioning fixture 1 is to first use wire cutting to process the outer structure, and then use a large gantry milling machine for fine processing, and its processing accuracy can be controlled within 0.2mm.

[0055] The beneficial effects of the above optional embodiments are: the vacuum bottom plate 2 can be effectively limited by the setting of the limiting groove 16, and the waist-shaped groove 12 can leave a weld seam in the ultra-high vacuum cavity to facilitate subsequent spot welding.

[0056] Optional, such as Figures 2 to 6 As shown, the mold assembly 6 includes a column 13 and a screw 14. The column 13 is arranged between the pressure plate 7 and the base plate positioning tooling 1. A screw 14 is provided at each end of the column 13. One screw 14 is connected to the pressure plate 7, and the other screw 14 is connected to the base plate positioning tooling 1.

[0057] In the above optional embodiments, it should be noted that each mold assembly 6 includes a column 13 and two screws 14. The cross-sectional shape of the column 13 is elliptical. The column 13 is connected to the base plate positioning tooling 1 and the corresponding pressure plate 7 through the two screws 14.

[0058] The beneficial effect of the above optional embodiment is: through the elliptical setting of the column 13, the coordinated setting of multiple columns 13 can firmly clamp the vacuum bottom plate 2, the vacuum upper cover plate 3, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5, thereby ensuring the installation accuracy of the vacuum bottom plate 2, the vacuum upper cover plate 3, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5.

[0059] Optional, such as Figures 2 to 6 As shown, the welding tool further includes a positioning pin 9. During operation, the positioning pin 9 is inserted into the base plate positioning tool 1.

[0060] In the above optional embodiment, it should be noted that, specifically, a positioning hole 10 and a threaded hole 11 are further provided on the base plate positioning tool 1 , a positioning pin is inserted into the positioning hole 10 , and a screw rod 14 is screwed into the threaded hole 11 .

[0061] The vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 are both processed with steps with a depth of 7 mm and a width of 1.5 mm for placing the vacuum bottom plate 2 and the vacuum upper cover plate 3.

[0062] The vacuum bottom plate 2, the vacuum upper cover plate 3, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 are placed on the welding tool in sequence, including: the vacuum bottom plate 2 is placed on the positioning pin 9 and then placed on the limit groove 16 of the bottom plate positioning tool 1 and located between the two waist-shaped grooves 12, and then the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 are respectively connected to the vacuum bottom plate 2, and then the vacuum upper cover plate 3 is spliced ​​with the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5, and then the vertical position of the multiple elliptical mold assemblies 6 is adjusted. Column 13, use the coordinated action of multiple columns 13 and multiple screws 14 to adjust the accuracy of the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5, then install the pressing plate 7 on the screw 14 on the corresponding column 13 and fix it with gasket and nut 8 to make the vacuum upper cover plate 3 and the vacuum inner arc side plate 4 and the vacuum upper cover plate 3 and the vacuum outer arc side plate 5 tightly fit, so that the vacuum bottom plate 2, the vacuum upper cover plate 3, the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 are placed on the welding tool in sequence.

[0063] Before laser welding, the welding tooling is processed.

[0064] The beneficial effect of the above optional embodiment is that the stability and firmness of the ultra-high vacuum chamber placed on the bottom plate positioning tool 1 can be guaranteed by the provision of the positioning pins 9 .

[0065] Optional, such as Figure 1 As shown in the figure, in the laser welding step, before using argon arc welding to fix it, a laser tracker and a vernier caliper are used to perform an initial measurement of the size of the ultra-high vacuum cavity spliced ​​on the welding fixture to confirm that the size meets the requirements.

[0066] In the above optional embodiment, it should be noted that a laser tracker and a vernier caliper are used to perform an initial measurement of the size of the ultra-high vacuum chamber spliced ​​on the welding fixture to confirm that the size meets the requirements, including whether the angular accuracy of each component reaches ±0.1° and whether the cross-sectional size accuracy reaches ±0.5mm.

[0067] The advantages of the above optional embodiment include: using a laser tracker and vernier caliper for initial dimensional measurement before laser welding allows for precise control of the specifications of each part of the ultra-high vacuum chamber. This allows for timely detection of splicing errors, avoids rework due to dimensional discrepancies, and improves welding efficiency. It also ensures that the ultra-high vacuum chamber dimensions meet the requirements of the high-precision ring spectrometer, ensuring subsequent welding quality and ultra-high vacuum performance, and reducing the risk of performance defects due to dimensional issues.

[0068] Optional, such as Figure 1 As shown, after fixing with argon arc spot welding, the welding position is also wiped with alcohol to remove surface oil and oxide layer, and then laser welding is used for external welding to form an extremely high vacuum cavity.

[0069] In the above optional embodiment, it should be noted that the method for wiping the solder joint with alcohol is to use a cotton swab or non-woven cloth dipped in alcohol to fully wet the solder joint surface. Wipe in a circular motion to dissolve grease and rosin residue. Stubborn stains can be gently scrubbed with a soft brush, or repeated wiping 2-3 times.

[0070] The beneficial effect of the above optional embodiment is: by wiping the welding position with alcohol to remove surface oil and the setting of the oxide layer, the smoothness and high vacuum degree of the laser welding surface can be effectively ensured, thereby avoiding the occurrence of air entrapment during the laser welding process.

[0071] Optional, such as Figure 1 As shown, the use of laser welding for external welding to form an extremely high vacuum chamber includes: Set parameters for laser welding machine; Turn on the laser indicator light, adjust the robot to the center of the welding position, use a stainless steel plate for trial welding, and observe whether the weld has defects such as incomplete penetration, porosity, and thermal cracks after the trial welding; Determine final welding parameters; Laser welding is used to perform external welding to form an extremely high vacuum chamber.

[0072] In the above optional embodiment, it should be noted that the use of laser welding to perform external welding to form an ultra-high vacuum chamber specifically includes: The laser welding parameters were set to 6~8KW laser power, 0.8~2m / min welding speed, +2~+5mm defocus, argon shielding gas, and 15~30L / min flow rate.

[0073] Turn on the laser indicator light, adjust the robot to align with the center of the welding position, use stainless steel plate for trial welding, and observe whether the weld after the trial welding has defects such as incomplete penetration, porosity and thermal cracks. Specifically, turn on the laser indicator light, adjust the robot to align with the weld center corresponding to the welding position with an error of less than 0.1mm, use 7mm thick 316L stainless steel for trial welding, and observe whether the weld has defects such as incomplete penetration, porosity and thermal cracks. When the weld surface is smooth and without depressions, there is no undercut on both sides and the weld is fully welded, determine the final welding parameters.

[0074] Then, wipe the welding position with alcohol to remove the oil and oxide layer on the surface of the two weld positions of the vacuum upper cover plate 3, and import the 3D model of the ultra-high vacuum cavity fixed with argon arc spot welding after installation in the welding fixture into the CNC machine control system. Generate a path along the arc weld and avoid the position with the pressure plate 7. Set the clamping point at 5mm on both sides of each pressure plate 7 and the surface distance from the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 on the corresponding side of the ultra-high vacuum cavity is 15mm. After the setting is completed, formal welding is carried out. The protective gas should be turned on before welding, and the welding area should be purged 5s in advance. Start the laser and start welding after the power is stable.

[0075] For the places where there is a pressure plate 7 but was not welded the first time, the position of the pressure plate 7 is adjusted, and the welds on both sides are polished and cleaned. Then, the 3D model of the ultra-high vacuum chamber installed on the welding fixture and fixed with argon arc spot welding is imported into the CNC machine tool control system. A path is generated along the arc weld to avoid the position of the pressure plate 7. A clamping point is set at 5mm on both sides of each pressure plate 7 and the surface distance from the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 on the corresponding side of the ultra-high vacuum chamber is 15mm. After the setting is completed, formal welding is carried out. Before welding, the protective gas should be turned on, and the welding area should be purged 5s in advance. The laser should be started, and welding should be started after the power is stable. The welding of the two weld positions at the vacuum upper cover plate 3 is completed.

[0076] Then, the entire ultra-high vacuum chamber is taken out and turned over, and the position of the vacuum upper cover plate 3 is placed on the positioning pin 9, and then placed on the limit groove 16 of the bottom plate positioning tool 1 and located between the two waist-shaped grooves 12. The two weld positions of the upper cover plate are wiped with alcohol to remove surface oil and oxide layer. The 3D model of the ultra-high vacuum chamber fixed by argon arc spot welding after being installed on the welding tool is imported into the CNC machine tool control system, and a path is generated along the arc weld. The position with the pressure plate 7 is avoided. A clamp clamping point is set at 5mm on both sides of each pressure plate 7 and the surface distance from the vacuum inner arc side plate 4 on the corresponding side of the ultra-high vacuum chamber and the vacuum outer arc side plate 5 on the corresponding side is 15mm. After the setting is completed, formal welding is carried out. The protective gas should be turned on before welding, and the welding area should be purged 5s in advance. The laser is started and welding is started after the power is stable.

[0077] For the places where there is a pressure plate 7 but was not welded the first time, the position of the pressure plate 7 is adjusted, and the welds on both sides are polished and cleaned. Then, the 3D model of the ultra-high vacuum chamber installed on the welding fixture and fixed with argon arc spot welding is imported into the CNC machine tool control system. A path is generated along the arc weld, and the position with the pressure plate 7 is avoided. A clamping point is set at a position of 5mm on both sides of each pressure plate 7 and the surface distance from the vacuum inner arc side plate 4 and the vacuum outer arc side plate 5 on the corresponding side of the ultra-high vacuum chamber is 15mm. After the setting is completed, formal welding is carried out. Before welding, the protective gas should be turned on, and the welding area should be purged 5s in advance. The laser should be started, and welding should be started after the power is stable. The welding of the two weld positions at the vacuum bottom plate 2 is completed.

[0078] After welding is completed, all welds are ground and electrochemically polished, and areas with larger deformations are mechanically corrected using a hydraulic correction machine.

[0079] Furthermore, according to the processing drawings, the portion of the ultra-high vacuum chamber that is redundant at the location where the positioning pin 9 is installed is removed, and the two processed ultra-high vacuum flanges 15 are respectively welded to the two ends of the ultra-high vacuum chamber using argon arc welding to complete the welding.

[0080] The beneficial effects of the above optional embodiments include: Through parameter setting, trial welding, and parameter determination, the laser welding process can be optimized in advance. Trial welding can detect weld defects, avoid problems such as incomplete penetration and porosity caused by direct welding, and ensure the quality of external welding. Welding after finalizing the parameters can improve the welding accuracy and sealing of the ultra-high vacuum chamber, meeting the stringent ultra-high vacuum chamber requirements of high-precision annular spectrometers and ensuring the ultra-high vacuum performance and operational stability of the equipment.

[0081] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for manufacturing a large-scale arc-shaped ultra-high vacuum cavity, characterized in that: include: Hydrogen removal: Use an ultra-high vacuum furnace to remove hydrogen molecules from the raw materials of the ultra-high vacuum chamber; Parts processing: using a CNC machine tool to sequentially process the vacuum bottom plate (2), the vacuum upper cover plate (3), the vacuum inner arc side plate (4) and the vacuum outer arc side plate (5); Laser welding: placing the vacuum bottom plate (2), the vacuum upper cover plate (3), the vacuum inner arc side plate (4) and the vacuum outer arc side plate (5) on the welding fixture in sequence, fixing them by argon arc spot welding, and then performing external welding by laser welding to form an extremely high vacuum cavity; Ultra-high vacuum leak detection: Use helium mass spectrometry leak detection to detect leaks in the welds of ultra-high vacuum chambers; Dimension detection: A laser tracker is used to measure the dimensions of the ultra-high vacuum cavity, and the arc-shaped ultra-high vacuum cavity is completed.

2. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to claim 1, characterized in that: Also includes: Before the ultra-high vacuum leak detection is performed, an ultra-high vacuum flange (15) is welded to the end of the ultra-high vacuum cavity by argon arc welding.

3. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to claim 1, characterized in that: Also includes: Before ultra-high vacuum leak detection, the ultra-high vacuum cavity completed by laser welding is cleaned in ultra-high vacuum.

4. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to claim 3, characterized in that: The ultra-high vacuum cleaning of the ultra-high vacuum cavity completed by laser welding comprises: Rough wash to remove visible dirt; Ultrasonic cleaning in a weakly acidic water-based solution at 65°C for 15 minutes to remove oil; Place in a 65°C weak alkaline solution and ultrasonically clean for 15 minutes to neutralize; rinse repeatedly with flowing deionized water; Use high-purity nitrogen to dry water stains.

5. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to any one of claims 1 to 4, characterized in that: The welding tool comprises: A bottom plate positioning tool (1) is provided with a waist-shaped groove (12) and a limiting groove (16), and the waist-shaped groove (12) is provided on both sides of the limiting groove (16); A pressing plate (7), wherein the pressing plate (7) is mounted on the base plate positioning fixture (1) through a mold assembly (6).

6. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to claim 5, characterized in that: The mold assembly (6) includes: A column (13), the column (13) being arranged between the pressing plate (7) and the bottom plate positioning tool (1); Screw rod, a screw rod (14) is provided at each end of the column (13), one of the screw rods (14) is connected to the pressing plate (7), and the other screw rod (14) is connected to the bottom plate positioning tool (1).

7. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to claim 6, characterized in that: The welding tool also includes: The positioning pin (9) is inserted into the bottom plate positioning tool (1) during operation.

8. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to claim 1, characterized in that: Also includes: In the laser welding step, before the argon arc welding is used for fixing, a laser tracker and a vernier caliper are used to perform an initial measurement of the size of the ultra-high vacuum cavity spliced ​​on the welding fixture to confirm that the size meets the requirements.

9. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to claim 1, characterized in that: The fixing by argon arc spot welding also includes: The welding position is wiped with alcohol to remove surface oil and oxide layer, and then laser welding is used to perform external welding to form an extremely high vacuum cavity.

10. The method for manufacturing a large-scale arc-shaped ultra-high vacuum chamber according to claim 1, characterized in that: The method of using laser welding to perform external welding to form an ultra-high vacuum cavity includes: Set parameters for laser welding machine; Turn on the laser indicator light, adjust the robot to the center of the welding position, use a stainless steel plate for trial welding, and observe whether the weld has defects such as incomplete penetration, porosity, and thermal cracks after the trial welding; Determine final welding parameters; Laser welding is used to perform external welding to form an extremely high vacuum chamber.

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