A hemispherical shell and a processing method thereof

Abstract

The application belongs to a kind of shell processing method, aiming at the technical problems of low machining precision and easy deformation during the processing of hemispherical shell, provides a kind of hemispherical shell and its processing method, by optimizing the structure shape of raw material blank, the material blank consumption is reduced by about 10%, in the processing process, the clamping position is close to the processing position by optimizing the process clamping step, so that the machining process can increase the rough machining cutting amount, and the clamping positioning can be repeated, the positioning accuracy is improved, the production process is easy to operate, according to the material and cutting performance of the hemispherical part, by using the processing technology and tooling, the machining deformation of the hemispherical part is greatly reduced, and the qualified rate of batch production is effectively improved.

Description

Technical Field

[0001] This application pertains to a shell processing method, specifically relating to a hemispherical shell and its processing method. Background Technology

[0002] Gas cylinders are primarily used for storing liquid and gaseous media and bearing certain pressures to provide pressure and propulsion, making them widely used in pressure vessels for aerospace propulsion systems. Metal cylinders, mainly steel cylinders, were the most widely used in the early days. However, due to quality concerns, the choice of materials gradually shifted from steel to aluminum alloys. Currently, titanium alloy cylinders are a key research focus due to their advantages such as high strength, good corrosion resistance, ease of forming, and excellent weldability. Structurally, they range from annular and cylindrical to spherical cylinders. Because they rely on a metal shell to withstand gas pressure, their design and manufacturing processes are mature, resulting in long fatigue life, high reliability, and operating pressures ranging from several megapascals to tens of megapascals. Therefore, they are widely used in aerospace propulsion systems.

[0003] In existing gas cylinder manufacturing methods, roughing, semi-finishing, and finishing of raw material blanks are often affected by unstable clamping during the process, leading to compromised machining accuracy. This is especially true for thin-walled gas cylinders, which are prone to deformation due to their hollow internal structure, resulting in low yields. Similar problems exist when manufacturing hemispherical shells. Summary of the Invention

[0004] This application addresses the issues of low machining accuracy and easy deformation in the processing of hemispherical shells by providing a hemispherical shell and its processing method.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] Firstly, this application proposes a method for processing hemispherical shells, defining the circular opening of the raw material blank as the front;

[0007] The method includes:

[0008] The length of the raw material blank clamping section accounts for 14-18% of the total length of the raw material blank, and the diameter accounts for 55-60% of the total diameter of the raw material blank; the raw material blank includes a processing body and a clamping section coaxially connected to the rear end face of the processing body.

[0009] The clamping section is held in place, and the outer surface of the processing body is rough-machined.

[0010] Make a hole in the clamping section to obtain the axial hole of the clamping section;

[0011] The inner surface of the machining body is roughed by inner arc machining, and then the inner surface of the machining body and the inner surface of the axial hole of the clamping section are semi-finished and finished.

[0012] The front end face of the processing body is precision machined, and the front end of the outer wall of the processing body is machined to form a cylindrical surface.

[0013] The cylindrical surface is clamped, and the clamping section is removed, so that the processing body is formed into a hemispherical processing body;

[0014] After installing the support and positioning fixture inside the hemispherical processing body, the outer surface of the hemispherical processing body is precision machined to obtain the processed hemispherical shell.

[0015] Preferably, the support positioning fixture includes a stepped mandrel that is fixedly disposed thereon;

[0016] The front sidewall of the stepped mandrel abuts against the front end face of the hemispherical machining body, and the rear outer wall abuts against the inner wall of the axial hole of the clamping section. The front end of the stepped mandrel is used for clamping during machining.

[0017] Preferably, the stepped mandrel includes a first shaft segment, a second shaft segment, a third shaft segment, a fourth shaft segment, and a fifth shaft segment connected sequentially from front to back;

[0018] The first shaft segment is used for clamping during machining;

[0019] The outer diameter of the second shaft segment is larger than that of the first shaft segment. A limiting step is provided on the rear side wall of the second shaft segment. The limiting step penetrates the rear end face of the second shaft segment and abuts against the front end face of the hemispherical processing body.

[0020] The outer diameter of the third shaft segment is greater than the outer diameter of the fifth shaft segment;

[0021] The fourth shaft segment is frustum-shaped, and its large end is connected to the third shaft segment;

[0022] The outer wall of the fifth shaft segment abuts against the inner wall of the axial hole of the clamping segment.

[0023] Preferably, the support positioning fixture further includes a pressure cap; the stepped mandrel further includes a sixth shaft segment;

[0024] The sixth axis segment is connected to the rear end of the fifth axis segment, and the sixth axis segment is located outside the rear end of the hemispherical machining body;

[0025] The front end face of the pressure cap abuts against the rear end face of the sixth shaft segment, and the pressure cap is detachably connected to the stepped mandrel.

[0026] Preferably, the support positioning fixture further includes screws;

[0027] The screw connects the gland and the stepped mandrel axially.

[0028] Preferably, before rough machining the outer surface of the machining body, the process further includes:

[0029] The arc between the side wall of the clamping section and the rear end face is machined into an edge.

[0030] Preferably, the rough machining of the inner surface of the machining body includes the following machining parameters:

[0031] The depth of cut Ap is 0.5–1 mm, the cutting speed Vc is 300–400 r / min, and the feed rate F is 0.1–0.15 mm / r.

[0032] Preferably, the finishing of the front end face of the processing body includes using the following processing parameters:

[0033] The depth of cut Ap is 0.1-0.2 mm, the cutting speed Vc is 500-650 r / min, and the feed rate F is 0.06-0.1 mm / r.

[0034] Preferably, the finishing of the outer surface of the hemispherical machining body includes using the following machining parameters:

[0035] The depth of cut Ap is 0.1-0.2 mm, the cutting speed Vc is 550-650 r / min, and the feed rate F is 0.06-0.07 mm / r.

[0036] Secondly, this application proposes a hemispherical shell, which is processed using the above method.

[0037] Compared with the prior art, this application has the following beneficial effects:

[0038] This application proposes a method for machining hemispherical shells. By optimizing the structure and shape of the raw material blank, the amount of raw material used is reduced by approximately 10%. During machining, the process clamping steps are optimized to bring the clamping position close to the machining position, thereby increasing the roughing depth of cut, allowing for repeated clamping and positioning, improving positioning accuracy, and facilitating operation during production. Based on the material and cutting performance of the hemispherical part, this machining process and tooling significantly reduce the machining deformation of the hemispherical part, effectively improving the pass rate of batch production. The advantages are particularly pronounced for thin-walled hemispherical shells, effectively solving problems such as raw material waste, limited clamping positions during machining, poor repeatability, large and irregular machining deformation, and difficult operation during machining, thus avoiding high defect rates in batch processing. Furthermore, this invention can be combined with optimized machining parameters to achieve even higher precision and smaller deformation. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the raw material blank in the embodiments of this application;

[0041] Figure 2 This is a schematic diagram of the arc between the sidewall of the clamping section and the rear end face after machining into an edge in an embodiment of this application;

[0042] Figure 3 This is a schematic diagram of the axial hole of the clamping section in an embodiment of this application;

[0043] Figure 4 This is a schematic diagram of the hemispherical processing body in an embodiment of this application;

[0044] Figure 5 This is a schematic diagram of the support and positioning fixture installed inside the hemispherical processing body in an embodiment of this application;

[0045] Figure 6 This is a schematic diagram of the supporting positioning fixture in an embodiment of this application;

[0046] Figure 7 This is a structural comparison diagram of the existing clamping section of the raw material blank and the clamping section in this application.

[0047] Among them: 1-raw material blank, 2-clamping section, 3-processing body, 4-support and positioning fixture, 401-stepped mandrel, 402-first shaft section, 403-second shaft section, 404-third shaft section, 405-fourth shaft section, 406-fifth shaft section, 407-sixth shaft section, 408-pressure cap, 409-screw, 410-limiting step, 5-cylindrical surface, 6-axial hole of clamping section, 7-hemispherical processing body. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0050] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0052] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0053] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0054] This application proposes a processing method for hemispherical shells, which can be used by technicians for various hemispherical shells. The processed shells have small deformation, high pass rate, and high processing efficiency. It is a relatively universal and easy-to-promote processing method.

[0055] The present application will be further described in detail below with reference to the embodiments and accompanying drawings:

[0056] As an embodiment of the hemispherical shell processing method of this application, it is capable of processing various hemispherical shells that require openings. For ease of description and understanding, the circular opening side of the raw material blank 1 is referred to as the "front". The processing method includes the following steps:

[0057] Step 1, adjust the length of the clamping section 2 of the raw material blank 1 ( Figure 2 The middle section (X) accounts for 14-18% of the total length of the raw material blank 1, and the diameter ( Figure 2 The Y-shaped section accounts for 55-60% of the total diameter of the raw material blank.

[0058] It should be noted that the raw material used in processing the hemispherical shell is the raw material blank 1. For example... Figure 1 As shown, it generally includes a processing body 3 and a clamping section 2 coaxially connected to the rear end face of the processing body 3. The overall dimensions of the raw material blank 1 are determined according to the specific application scenario, and are not limited in this application.

[0059] It should be noted that, as Figure 7 The image shown is a comparison diagram of the existing raw material blank 1 and the improved raw material blank 1 of this application, wherein the dashed line represents the outer contour of the existing raw material blank 1. From Figure 7 As can be seen, this application optimizes the outer contour of the raw material blank 1 by shortening the axial length of the clamping section 2 and increasing the radial dimension of the machining body 3 near the clamping section 2. This effectively increases the number of process mounting positions and reduces the amount of raw material used. The re-optimized raw material blank 1 changes the original clamping position (clamping section 2) from the length direction to the small end diameter direction of the hemispherical part, enabling more stable and reliable clamping and positioning for subsequent processing, improving the overall production efficiency and achieving higher processing quality. In addition, by changing the clamping position, the amount of raw material used is reduced by approximately 13% compared to before.

[0060] In practical applications, to facilitate subsequent processing, such as Figure 2 As shown, the arc between the side wall of clamping section 2 and the rear end face can be... Figure 1 (Point A in the middle) is processed into an edge ( Figure 2 (At point B in the diagram), correspondingly, the outer wall of clamping section 2 is machined into a straight sidewall. Clamping section 2 is reusable, which can meet the processing requirements of multiple process steps for hemispherical shells, simplify the workload between each process step, and make the operation more convenient.

[0061] Step 2: Clamp the clamping section 2 and perform rough machining on the outer surface of the processing body 3;

[0062] It should be noted that by increasing the process clamping position in the diameter direction and performing rough machining on the outer arc surface, the total length of the raw material blank 1 can be shortened, and the rigidity of the blank can be improved during the machining process. This application does not limit the specific machining parameters when rough machining the outer surface of the machining body 3. However, to improve the production efficiency of rough machining, a larger depth of cut can be selected.

[0063] Step 3: Make a hole in the clamping section 2 to obtain the axial hole 6 of the clamping section.

[0064] It should be noted that the specific dimensions of the axial hole 6 in the clamping section are determined according to the requirements of the hemispherical shell, and this application does not limit them. The specific method for drilling can be used, or, to improve drilling accuracy, a method of drilling first and then reaming can be used. Drilling generally involves rotating the drill bit or the workpiece to create a hole on the side wall of the hemispherical shell. Reaming is performed using a reamer to further process the drilled hole, thereby increasing the hole diameter and improving the hole's machining quality. Reaming can be used as a pre-processing step before finishing the hole, or as a final processing step for holes with less stringent requirements.

[0065] Step 4: Perform rough machining of the inner arc of the inner surface of the machining body 3, and then perform semi-finishing and finishing machining on the inner surface of the machining body 3 and the inner surface of the axial hole 6 of the clamping section.

[0066] It should be noted that the equipment, tools, and specific process parameters used for rough machining of the inner arc can be determined according to machining needs and the material of the hemispherical shell, and this application does not impose any limitations. To improve production efficiency, the following machining parameters can be used to achieve a higher machining effect: a depth of cut Ap of 0.5–1 mm, a cutting speed Vc of 300–400 r / min, and a feed rate F of 0.1–0.15 mm / r. Other machining parameters can also be used in other embodiments of this application, but the above-mentioned parameters represent a more effective parameter setting.

[0067] After rough machining, semi-finishing and finishing machining are performed on the inner surface of the machining body 3 and the inner surface of the axial hole 6 of the clamping section. Firstly, the number of machining operations can be determined according to the required machining accuracy, and this application does not impose any limitations. Multiple machining operations, combined with the reliable machining results of the aforementioned clamping section 2, can effectively reduce machining deformation and improve the machining accuracy of the inner surface of the machining body 3. The specific parameters for finishing the inner surface of the machining body 3 and the inner surface of the axial hole 6 of the clamping section can be determined according to the material of the hemispherical shell and the required machining accuracy, and this application does not impose any limitations. To improve the machining effect, the following machining parameters can be used:

[0068] For machining the inner surface of the main body 3, the depth of cut Ap is 0.1-0.2 mm, the cutting speed Vc is 500-650 r / min, and the feed rate F is 0.06-0.08 mm / r.

[0069] With these processing parameters, multiple finishing processes can improve rigidity, eliminate vibration marks on the inner surface of the machined body 3, and achieve better surface quality. Other processing parameters may be used in other embodiments of this application, but the above-mentioned parameters represent a more effective setting.

[0070] Step 5, as follows Figure 3 The front end face of the processing body 3 is precision machined, and the front end of the outer wall of the processing body 3 is machined to form a cylindrical surface 5 at the front end of the outer wall of the processing body 3.

[0071] It should be noted that after finishing the front end face of the main body 3, this finished end face can be used as a reference only. Furthermore, when machining the front end of the outer wall of the main body 3, since the machining allowance for the outer arc surface is small, the following parameters can be used to ensure that there are no vibration marks on the cylindrical surface 5, thereby improving machining accuracy:

[0072] The depth of cut Ap is 0.1-0.2 mm, the cutting speed Vc is 500-650 r / min, and the feed rate F is 0.06-0.1 mm / r.

[0073] The front end of the outer wall of the machining body 3 is roughed, semi-finished and finished sequentially using optimized cutting parameters to produce a tooling clamping surface for subsequent machining. A reasonable and small depth of cut is used to reduce the deformation of the hemispherical part caused by cutting stress.

[0074] Step 6, as follows Figure 4 As shown, the cylindrical surface 5 is clamped, the clamping section 2 is removed, and the processing body 3 is formed into a hemispherical processing body 7.

[0075] Step 7: After installing the support and positioning fixture 4 inside the hemispherical machining body 7, perform precision machining on the outer surface of the hemispherical machining body 7.

[0076] It should be noted that when performing finishing on the outer surface of the hemispherical machining body 7, a support and positioning fixture 4 is installed inside the hemispherical machining body 7. The main purpose is to support the hemispherical machining body 7, as it has a hollow structure. Finishing its surface can easily cause deformation. Therefore, this application uses the support and positioning fixture 4 to reduce deformation. Furthermore, to further improve machining accuracy, appropriate machining parameters can be set in conjunction with the installation of the support and positioning fixture 4 to achieve even higher precision machining results.

[0077] In practical applications, the structure of the supporting and positioning fixture 4 only needs to be able to provide axial and radial support and positioning for the hemispherical machining body 7. This application proposes an optimized structure, as follows:

[0078] like Figure 5 and Figure 6 As shown, the support positioning fixture includes a stepped mandrel 401, a pressure cap 408, and screws 409, all fixedly installed. The stepped mandrel 401 comprises a first shaft segment 402, a second shaft segment 403, a third shaft segment 404, a fourth shaft segment 405, a fifth shaft segment 406, and a sixth shaft segment 407 connected sequentially from front to back. The first shaft segment 402 is used for clamping during processing. The outer diameter of the second shaft segment 403 is larger than that of the first shaft segment 402. A limiting step 410 is formed on the rear side wall of the second shaft segment 403, penetrating the rear end face of the second shaft segment 403 and abutting against the front end face of the hemispherical processing body 7. The outer diameter of the third shaft segment 404 is larger than that of the fifth shaft segment 406. The fourth shaft segment 405 is frustum-shaped, with its larger end connected to the third shaft segment 404, preventing the stepped mandrel 401 from contacting the inner wall of the hemispherical processing body 7 and causing damage to it. The outer wall of the fifth shaft segment 406 abuts against the inner wall of the axial hole 6 of the clamping segment. The sixth shaft segment 407 is connected to the rear end of the fifth shaft segment 406. The sixth shaft segment 407 is located outside the rear end of the hemispherical machining body 7. The front end face of the pressure cover 408 abuts against the rear end face of the sixth shaft segment 407. The pressure cover 408 and the stepped mandrel 401 are detachably connected by screws 409.

[0079] In practical use, the limiting step 410 of the stepped mandrel 401 abuts against the front end face of the machining body 3, which serves as a reference surface, providing support and positioning. The outer wall of the fifth shaft segment 406 abuts against the inner wall of the axial hole 6 of the clamping segment, supporting the axial hole 6 of the clamping segment. Thus, the limiting step 410 and the fifth shaft segment 406 together support the hemispherical machining body 7. To achieve higher machining accuracy, the machining parameters for finishing can be optimized as follows:

[0080] The depth of cut Ap is 0.1-0.2 mm, the cutting speed Vc is 550-650 r / min, and the feed rate F is 0.06-0.07 mm / r.

[0081] With the above processing parameters and support positioning fixture 4, processing deformation can be further reduced, the wall thickness of the hemispherical processing body 7 can be made more uniform, and the surface quality can also be improved, resulting in a hemispherical shell with better processing effect.

[0082] This application employs a support and positioning fixture 4, combined with precision machining, to ensure the final wall thickness and outer arc surface quality of the hemispherical shell. Alternatively, after precision machining, the axial hole 6 in the clamping section can be used for repeated positioning, in conjunction with a pressure cap 408. This ensures the pressure surface of the pressure cap 408 fits against the outer arc surface of the hemispherical machining body 7, increasing the clamping area through the curved pressing surface, and then tightening with screws 409 to complete the precision machining of the outer arc surface, ensuring the wall thickness and dimensional tolerance requirements of the design drawings are met. The support and positioning fixture 4 proposed in this application, based on the over-positioning method in the clamping and positioning principle, makes the positioning accuracy of the hemispherical shell more accurate, significantly improving the machining pass rate. Compared to existing machining methods where most of the interior of the hemispherical shell is suspended, deformation easily occurs during machining, resulting in uneven wall thickness and a higher likelihood of defective products.

[0083] It should be noted that the machining parameters in each of the above steps, individually, require coordination between the depth of cut, cutting speed, and feed rate to achieve the desired machining result. For all steps, the result obtained from the coordination of depth of cut, cutting speed, and feed rate in each step will affect the machining basis and parameters of subsequent steps. Therefore, the machining parameters for each step must not only be considered within the context of that step itself but also in conjunction with those of other steps to obtain the final machining result.

[0084] As an example of this application, the processing method described above is used to process spherical gas cylinders. Since the gas cylinders need to withstand corresponding gas pressures, the processing quality requirements are higher. Compared with existing conventional processing methods, the processing method of this application has at least the following advantages:

[0085] 1. When finishing the outer surface of a hemispherical gas cylinder, the use of support positioning fixture 4 can greatly improve the repeatability of positioning, reduce the vibration of the outer arc surface caused by poor rigidity of the parts during finishing, make it easier to ensure the wall thickness, facilitate the effective detection of the wall thickness during finishing, and improve production efficiency.

[0086] 2. When roughing the outer surface of the main body 3, try to leave a reasonable allowance for subsequent finishing, so that the final finishing can be completed with fewer cutting steps, and a uniform and consistent surface quality can be obtained.

[0087] 3. When roughing the arc shape and roughing and finishing the inner curved surface, selecting a clamping position closer to the cutting position can effectively improve the machining rigidity of the hemispherical shell. In addition, by combining optimized cutting parameters, the deformation of the part during machining can be significantly reduced, thereby resulting in better surface quality of the inner cavity curved surface, smaller repeatability error, and improved machining accuracy.

[0088] 4. When designing the structure of the clamping section 2 of the raw material blank 1, the original clamping position was changed from the length direction to the diameter direction of the small end of the hemispherical shell, so that the subsequent processing can obtain a more stable and reliable clamping position, improving the production efficiency and processing quality of the entire process. At the same time, by changing the clamping position, the amount of raw material used is also reduced by about 10% compared with the previous method.

[0089] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for processing hemispherical shells, characterized in that, Define the raw material blank (1) with a circular opening as the front; The method includes: The length of the clamping section (2) of the raw material blank (1) is 14-18% of the total length of the raw material blank (1), and the diameter is 55-60% of the total diameter of the raw material blank (1); the raw material blank (1) includes a processing body (3) and a clamping section (2) coaxially connected to the rear end face of the processing body (3); Clamp the clamping section (2) and perform rough machining on the outer surface of the processing body (3); A hole is made in the clamping section (2) to obtain the axial hole (6) of the clamping section; The inner surface of the machining body (3) is roughed by inner arc machining, and then the inner surface of the machining body (3) and the inner surface of the axial hole (6) of the clamping section are semi-finished and finished. The front end face of the processing body (3) is precision machined, and the front end of the outer wall of the processing body (3) is machined to form a cylindrical surface (5) at the front end of the outer wall of the processing body (3); The cylindrical surface (5) is clamped, and the clamping section (2) is removed, so that the processing body (3) forms a hemispherical processing body (7); After installing the support and positioning fixture (4) inside the hemispherical processing body (7), the outer surface of the hemispherical processing body (7) is finely processed to obtain the processed hemispherical shell.

2. The method for processing a hemispherical shell according to claim 1, characterized in that, The support positioning fixture (4) includes a stepped mandrel (401) that is fixedly installed; The front side wall of the stepped mandrel (401) abuts against the front end face of the hemispherical machining body (7), and the rear outer wall abuts against the inner wall of the axial hole (6) of the clamping section. The front end of the stepped mandrel (401) is used for clamping during machining.

3. The method for processing a hemispherical shell according to claim 2, characterized in that, The stepped mandrel (401) includes a first shaft segment (402), a second shaft segment (403), a third shaft segment (404), a fourth shaft segment (405), and a fifth shaft segment (406) connected sequentially from front to back; The first shaft segment (402) is used for clamping during machining; The outer diameter of the second shaft segment (403) is larger than that of the first shaft segment (402). A limiting step (410) is provided on the rear side wall of the second shaft segment (403). The limiting step (410) penetrates the rear end face of the second shaft segment (403) and abuts against the front end face of the hemispherical processing body (7). The outer diameter of the third shaft segment (404) is larger than the outer diameter of the fifth shaft segment (406); The fourth shaft segment (405) is frustum-shaped, and its large end is connected to the third shaft segment (404); The outer wall of the fifth shaft segment (406) abuts against the inner wall of the axial hole (6) of the clamping segment.

4. The method for processing a hemispherical shell according to claim 3, characterized in that, The supporting positioning fixture (4) also includes a pressure cap (408); the stepped mandrel (401) also includes a sixth shaft segment (407); The sixth shaft segment (407) is connected to the rear end of the fifth shaft segment (406), and the sixth shaft segment (407) is located outside the rear end of the hemispherical processing body (7); The front end face of the pressure cap (408) abuts against the rear end face of the sixth shaft segment (407), and the pressure cap (408) is detachably connected to the stepped mandrel (401).

5. The method for processing a hemispherical shell according to claim 4, characterized in that, The support positioning fixture (4) also includes screws (409); The screw (409) connects the gland (408) and the stepped mandrel (401) axially.

6. A method for processing a hemispherical shell according to any one of claims 1 to 5, characterized in that, Before rough machining the outer surface of the machining body (3), the process also includes: The arc between the side wall of the clamping section (2) and the rear end face is machined into an edge.

7. The method for processing a hemispherical shell according to claim 1, characterized in that, The rough machining of the inner arc of the inner surface of the machining body (3) includes the following machining parameters: The depth of cut Ap is 0.5–1 mm, the cutting speed Vc is 300–400 r / min, and the feed rate F is 0.1–0.15 mm / r.

8. The method for processing a hemispherical shell according to claim 1, characterized in that: The finishing of the front end face of the processing body (3) includes the following processing parameters: The depth of cut Ap is 0.1-0.2 mm, the cutting speed Vc is 500-650 r / min, and the feed rate F is 0.06-0.1 mm / r.

9. The method for processing a hemispherical shell according to claim 1, characterized in that, The finishing of the outer surface of the hemispherical machining body (7) includes the following machining parameters: The depth of cut Ap is 0.1-0.2 mm, the cutting speed Vc is 550-650 r / min, and the feed rate F is 0.06-0.07 mm / r.

10. A hemispherical shell, characterized in that: It is obtained by processing using any one of the methods described in claims 1 to 9.

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