Forming method of high-precision composite material pressure vessel

Abstract

The invention discloses a forming method of a high-precision composite material pressure container. The method comprises the following steps that a prefabricated part close to the final contour of a product is provided, the prefabricated part is provided with a front-end flange and a rear-end flange, and an inner core mold of the prefabricated part is removed; self-designing and manufacturing a turning clamp and a milling clamp suitable for the composite material pressure container; the turning clamp and the prefabricated part are clamped to a numerical control lathe, the public reference axis of the prefabricated part is aligned, the machining allowance is confirmed, and turning is conducted; removing the turning clamp from the prefabricated part; and the milling clamp and the prefabricated part are clamped to a gantry machining center rotary table, the public reference axis of the prefabricated part is aligned, the reference of the coordinate system is confirmed, milling is conducted, and the composite material pressure container product is obtained. The forming method that demolding is conducted firstly and then machining is conducted is adopted, absolute stability of the product during machining is guaranteed through the self-designed clamp, and the size precision and form and location tolerance of the product are improved by the order of magnitude.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a molding method for a high-precision composite material pressure vessel. Background Technology

[0002] In the field of machining, there are many thin-walled pressure vessels with complex structures that require high dimensional accuracy and strict geometric tolerances. These parts typically combine features of rotation (such as outer diameters, steps, and inner holes) with features of non-rotation (holes, grooves, and side planes). To achieve higher internal pressure resistance and lighter product weight, pressure vessels are shifting from traditional metals to composite materials.

[0003] When machining such composite material pressure vessels, the machining of the rotating parts is usually carried out first, followed by the removal of the internal core mold for internal pressure acceptance testing. After the test is passed, the external features are finally machined by milling, drilling, etc.

[0004] However, the processing method of the above-mentioned composite material pressure vessel has the following technical problems. First, demolding deformation: After removing the original internal core mold (plaster core mold or sand core mold) and conducting the internal pressure acceptance test, the shape and position characteristics of the machined rotating part are likely to change, and it is impossible to guarantee that the datum after the second clamping and alignment is consistent with that after the first machining. Second, clamping deformation: In the above processing scheme, in order to ensure the coaxiality of the external rotation feature and the internal metal structure, a boring machine support is required during the secondary clamping and alignment process. Not only does the boring machine support need to be repeatedly adjusted during the alignment process, resulting in a long alignment time, but after the processing is completed, the product is prone to deformation when the boring machine support is released, resulting in non-compliance of form and position tolerances and thus dimensional deviations. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a high-precision composite material pressure vessel molding method. This method not only achieves consistent datum during secondary clamping but also eliminates the need to adjust the boring machine support during secondary clamping and alignment, thereby greatly improving the machining accuracy, stability, and production efficiency of such products.

[0006] To achieve the above objectives, this invention provides a molding method for high-precision composite material pressure vessels, characterized by the following steps: S1) Provides prefabricated components that closely approximate the final profile of the composite pressure vessel product, and the prefabricated... The component is equipped with front and rear flanges, and the internal core mold of the prefabricated component is removed; S2) Design and manufacture machining fixtures and milling fixtures suitable for the composite material pressure vessel; The turning fixture includes a reference shaft, and a first front-end positioning and clamping module and a first rear-end positioning and clamping module that are matched with the reference shaft; the milling fixture includes a second front-end positioning and clamping module and a second rear-end positioning and clamping module. S3) Install the first rear positioning and clamping module of the machining fixture on the rear flange of the prefabricated part, insert the reference shaft into the rear flange of the prefabricated part and out through the front flange of the prefabricated part, and then insert the first front positioning and clamping module into the reference shaft and connect it to the front flange of the prefabricated part. Mount the machining fixture along with the prefabricated part onto the CNC lathe, align the common reference axis of the prefabricated part, and confirm the machining allowance; Based on the allowance distribution, the rotating features of the preform are machined using a lathe tool; S4) Remove the machining fixture from the precast component and select the qualified precast component to proceed to the next step; S5) Connect the second front-end positioning and clamping module of the milling fixture to the front flange of the prefabricated part, and connect the second rear-end positioning and clamping module to the rear flange of the prefabricated part. The milling fixture is clamped together with the preform onto the turntable of the gantry machining center. The common reference axis of the preform is aligned, the coordinate system reference is confirmed, and the non-rotating features of the preform are milled using a special drill bit and milling cutter to obtain the composite material pressure vessel product.

[0007] Furthermore, in S1), after removing the internal core mold of the preform, an internal pressure test and non-destructive testing need to be completed, and the time interval between the internal pressure test and the non-destructive testing is not less than 48 hours.

[0008] Furthermore, in S1), the front and rear flanges of the prefabricated component are provided with threaded holes that connect to the first front positioning clamping module, the first rear positioning clamping module, the second front positioning clamping module, and the second rear positioning clamping module.

[0009] Furthermore, in S2), the length of the reference shaft is greater than the length of the composite material pressure vessel, the two ends of the reference shaft are provided with positioning steps for assembling the composite material pressure vessel, and the rear end of the reference shaft is provided with a connecting flange for axial positioning and tightening of the rear end of the prefabricated component.

[0010] Furthermore, in S2), a reinforcing ring is provided inside the reference shaft at a position to improve rigidity.

[0011] Furthermore, in S2), the first front-end positioning and clamping module is used to position and clamp the front end of the preform, including a first front-end connecting sleeve and a front-end pull plate that are matched with the diameter of the reference shaft step. The first front-end connecting sleeve is connected to the threaded hole of the front flange of the preform, and the front-end pull plate is connected to the first front-end connecting sleeve.

[0012] Furthermore, in S2), the first rear-end positioning and clamping module is used to position and clamp the rear end of the preform, including a first rear-end connecting sleeve that matches the diameter of the reference shaft step and a connecting flange reserved on the reference shaft. The first rear-end connecting sleeve is connected to the threaded hole of the rear flange of the preform, and the connecting flange is connected to the first rear-end connecting sleeve.

[0013] Furthermore, in S2), the second front-end positioning and clamping module is used to position and clamp the front end of the preform, including a second front-end connecting sleeve and a front-end reinforcing plate that mate with the diameter of the reference shaft step. The second front-end connecting sleeve is connected to the threaded hole of the front flange of the preform, and the front-end reinforcing plate is fixedly connected to the second front-end connecting sleeve. The second front-end positioning and clamping module also includes a front-end reinforcing ring that abuts against the inner side of the front-end frame of the precast component. The front-end reinforcing ring is connected to the front-end reinforcing plate and the second front-end connecting sleeve through a front-end rib plate.

[0014] Furthermore, in S2), the second rear-end positioning and clamping module is used to position and clamp the rear end of the preform, including a second rear-end connecting sleeve and a rear-end reinforcing plate that mate with the diameter of the reference shaft step. The second rear-end connecting sleeve is connected to the threaded hole of the rear flange of the preform, and the rear-end reinforcing plate is fixedly connected to the second rear-end connecting sleeve. The second rear-end positioning and clamping module also includes a rear-end reinforcing ring that abuts against the inner side of the rear-end frame of the prefabricated part. The rear-end reinforcing ring is connected to the rear-end reinforcing plate and the second rear-end connecting sleeve through a rear-end rib.

[0015] Further, in S3), before the machining fixture is assembled with the preform, the positioning surfaces of the first front-end positioning clamping module and the first rear-end positioning clamping module are cleaned, and the contact surface between the preform and the machining fixture is cleaned; in S5), before the milling fixture is assembled with the preform, the positioning surfaces of the second front-end positioning clamping module and the second rear-end positioning clamping module are cleaned, and the contact surface between the preform and the milling fixture is cleaned.

[0016] The advantages of this invention are: 1. This invention eliminates the cumulative error caused by product stress deformation by conducting demolding and internal pressure acceptance tests on the product in advance. Through the deep integration of self-designed fixtures and CNC machining, the rotary feature machining is completed on the lathe, and the end frame connecting hole machining is completed on the high-precision CNC gantry machining center. Although two clamping is required, "the two clamping references are consistent" can be achieved, eliminating the alignment error caused by multiple clamping, and improving the dimensional accuracy and geometric tolerances (coaxiality, perpendicularity) of the product by orders of magnitude. 2. Both types of fixtures in this invention employ a two-pin principle for precise product positioning. The product clamping state is adjusted by regulating the tightening torque of the bolts. The machining fixture, through the dimensional matching of the reference shaft and connecting sleeve, and the axial clamping of the pre-reserved flange, ensures effective positioning of the product in both the axial and circumferential directions. The milling fixture, with its front and rear positioning clamping modules threadedly connected to the product and additional support added to the inner hole of the skirt, enhances clamping rigidity. Both the machining and milling fixtures ensure absolute stability of the product during machining, effectively reducing cutting vibration and resulting in superior surface finish. 3. This invention achieves rapid clamping and error prevention. The fixture is designed with a modular design, which greatly improves its versatility and makes it suitable for mass production. The high-precision composite material pressure vessel molding method of this invention adopts a molding method of demolding before processing. It not only ensures the absolute stability of the product during processing through self-designed fixtures, but also improves the dimensional accuracy and geometric tolerance of the product by orders of magnitude through "secondary clamping with consistent reference", thereby increasing the first-pass yield and significantly reducing quality costs. It is particularly suitable for the mass production of products with high precision requirements. Attached Figure Description

[0017] Figure 1 This is a flowchart of the molding method for the high-precision composite material pressure vessel of the present invention; Figure 2 This is a cross-sectional view of the reference shaft of the machining fixture of the present invention; Figure 3 This is a cross-sectional view of the first front-end positioning and clamping module in the machining fixture of the present invention; Figure 4 This is a top view of the first front-end positioning and clamping module in the machining fixture of the present invention; Figure 5 This is a cross-sectional view of the first rear-end positioning and clamping module in the machining fixture of the present invention; Figure 6 This is a top view of the first rear-end positioning and clamping module in the machining fixture of the present invention; Figure 7 This is a cross-sectional view of the machining fixture of the present invention; Figure 8 This is a cross-sectional view of the combined assembly of the machining fixture and the prefabricated part of the present invention; Figure 9 This is a cross-sectional view of the second front-end positioning and clamping module in the milling fixture of the present invention; Figure 10 This is a top view of the second front-end positioning and clamping module in the milling fixture of the present invention; Figure 11 This is a cross-sectional view of the second rear-end positioning and clamping module in the milling fixture of the present invention; Figure 12 This is a top view of the second rear-end positioning and clamping module in the milling fixture of the present invention; Figure 13 This is a cross-sectional view of the combined assembly of the milling fixture and the prefabricated part of the present invention; In the diagram: Turning fixture 1, Milling fixture 2; The machining fixture 1 includes: a reference shaft 1-1, a first front-end positioning and clamping module 1-2, and a first rear-end positioning and clamping module 1-3; Reference shaft 1-1 includes: reinforcing ring 1-11; The first front-end positioning and clamping module 1-2 includes: a first front-end connecting sleeve 1-21 and a front-end pull plate 1-22; The first rear-end positioning and clamping module 1-3 includes: a first rear-end connecting sleeve 1-31 and a connecting flange 1-32; The milling fixture 2 includes: a second front-end positioning and clamping module 2-1 and a second rear-end positioning and clamping module 2-2; The second front-end positioning and clamping module 2-1 includes: a second front-end connecting sleeve 2-11, a front-end reinforcing plate 2-12, a front-end reinforcing ring 2-13, and a front-end rib plate 2-14; The second rear-end positioning and clamping module 2-2 includes: a second rear-end connecting sleeve 2-21, a rear-end reinforcing plate 2-22, a rear-end reinforcing ring 2-23, and a rear-end rib plate 2-24. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on the invention.

[0020] like Figure 1 As shown, the present invention discloses a method for molding a high-precision composite material pressure vessel, comprising the following steps: S1) Provides prefabricated components that closely approximate the final profile of the composite pressure vessel product, and the prefabricated... The component is equipped with front and rear flanges, and the internal core mold of the prefabricated component is removed.

[0021] Preferably, after removing the internal core mold of the preform, an internal pressure test and non-destructive testing need to be completed, and the time interval between the internal pressure test and the non-destructive testing is not less than 48 hours.

[0022] Specifically, the front and rear flanges of the prefabricated component are provided with threaded holes that connect to the first front positioning and clamping module 1-2, the first rear positioning and clamping module 1-3, the second front positioning and clamping module 2-1, and the second rear positioning and clamping module 2-2.

[0023] In this embodiment, the precast component that has completed non-destructive testing and internal pressure acceptance testing is placed on a dedicated saddle. The appearance of the precast component at both the front and rear ends is inspected, especially the metal parts of the front and rear flanges, to check for defects such as dents and scratches.

[0024] S2) Design and manufacture machining fixture 1 and milling fixture 2 suitable for the composite material pressure vessel, such as... Figures 2-13 As shown.

[0025] The turning fixture 1 includes a reference shaft 1-1, and a first front-end positioning and clamping module 1-2 and a first rear-end positioning and clamping module 1-3 that are matched with the reference shaft 1; the milling fixture 2 includes a second front-end positioning and clamping module 2-1 and a second rear-end positioning and clamping module 2-2.

[0026] The reference shaft 1-1 is longer than the composite material pressure vessel, and both ends are provided with positioning steps for assembling the composite material pressure vessel. The reference shaft 1-1 is also provided with connecting flanges 1-32 for axial positioning and tightening of the rear end of the prefabricated component.

[0027] The reference shaft 1-1 serves as the mounting base for the entire turning fixture. It is preferably a hollow shaft, with reinforcing rings 1-11 installed inside at locations requiring increased rigidity. Sufficient clearance is provided at both ends of the reference shaft 1-1 to ensure unobstructed toolpaths and prevent interference between the turning fixture 1 and the tool. See details... Figure 2 .

[0028] Preferably, a reinforcing ring is provided inside the reference shaft 1-1 at the chuck clamping position.

[0029] The first front-end positioning and clamping module 1-2 is used to position and clamp the front end of the precast component. It includes a first front-end connecting sleeve 1-21 that matches the step diameter of the reference shaft 1-1 and a front-end pull plate 1-22. The first front-end connecting sleeve 1-21 is connected to the threaded hole of the front flange of the precast component, and the front-end pull plate 1-22 is connected to the first front-end connecting sleeve 1-21.

[0030] The first rear-end positioning and clamping module 1-3 is used to position and clamp the rear end of the preform, including a first rear-end connecting sleeve 1-31 that matches the step diameter of the reference shaft 1-1 and a connecting flange 1-32 reserved on the reference shaft 1-1. The first rear-end connecting sleeve 1-31 is connected to the threaded hole of the rear flange of the preform, and the connecting flange 1-32 is connected to the first rear-end connecting sleeve 1-31.

[0031] After the first front-end positioning and clamping module 1-2 and the first rear-end positioning and clamping module 1-3 are assembled, the product's degree of freedom is restricted to achieve the goal of positioning and clamping.

[0032] In this embodiment, the machining fixture has a reference shaft 1-1 made of 35CrMo and a connecting sleeve made of 45# steel.

[0033] Specifically, in S2), the second front-end positioning and clamping module 2-1 is used to position and clamp the front end of the preform, including a second front-end connecting sleeve 2-11 that matches the step diameter of the reference shaft 1-1 and a front-end reinforcing plate 2-12. The second front-end connecting sleeve 2-11 is connected to the threaded hole of the front flange of the preform, and the front-end reinforcing plate 2-12 is fixedly connected to the second front-end connecting sleeve 2-11. The second front-end positioning and clamping module 2-1 also includes a front-end reinforcing ring 2-13 that abuts against the inner side of the front-end frame of the precast component. The front-end reinforcing ring 2-13 is connected to the front-end reinforcing plate 2-12 and the second front-end connecting sleeve 2-11 through a front-end rib plate 2-14.

[0034] Specifically, in S2), the second rear-end positioning and clamping module 2-2 is used to position and clamp the rear end of the preform, including a second rear-end connecting sleeve 2-21 that matches the step diameter of the reference shaft 1-1 and a rear-end reinforcing plate 2-22. The second rear-end connecting sleeve 2-21 is connected to the threaded hole of the rear flange of the preform, and the rear-end reinforcing plate 2-22 is fixedly connected to the second rear-end connecting sleeve 2-21. The second rear-end positioning and clamping module 2-2 also includes a rear-end reinforcing ring 2-23 that abuts against the inner side of the rear-end frame of the precast component. The rear-end reinforcing ring 2-23 is connected to the rear-end reinforcing plate 2-22 and the second rear-end connecting sleeve 2-21 through a rear-end rib plate 2-24.

[0035] S3) Install the first rear positioning and clamping module 1-3 of the machining fixture 1 on the rear flange of the preform, insert the reference shaft 1-1 into the rear flange of the preform and out through the front flange of the preform, and then insert the first front positioning and clamping module 1-2 into the reference shaft 1-1 and connect it to the front flange of the preform. Mount the machining fixture 1 along with the prefabricated part onto the CNC lathe, align the common reference axis of the prefabricated part, and confirm the machining allowance; Based on the allowance distribution, the rotating features of the preform are machined using a lathe tool.

[0036] Preferably, before the machining fixture 1 is assembled with the preform, the positioning surfaces of the first front-end positioning clamping module 1-2 and the first rear-end positioning clamping module 1-3 are cleaned, and the contact surfaces between the preform and the machining fixture 1 are cleaned.

[0037] In this embodiment, the assembly and machining steps of the machining fixture 1 are as follows: First, place the machining fixture 1 along with the counterweight rod on the saddle, remove the first front connecting sleeve 1-21 and the front pull plate 1-22, and check whether the surface of the fixture is clean and free of any foreign matter.

[0038] The second step is to align the rear flange of the prefabricated component with the pre-reserved connecting flange 1-32 in the machining fixture 1, and to make the center of the prefabricated component and the center of the machining fixture 1 horizontal and at the same height.

[0039] The third step is to insert the reference shaft 1-1 through the rear flange of the precast component, and lock the end face of the rear flange to the first rear connecting sleeve 1-31 with 18 M14×30 bolts. Then, use 8 M10×40 bolts to adjust the connecting flange 1-32 to ensure that the connection between the rear flange of the precast component and the tooling is reliable and that the end face of the tooling fits the end face of the flange.

[0040] Fourth step: Insert the first front connecting sleeve 1-21 into the reference shaft 1-1 of the machining fixture, and tighten it to the front flange using 10 M10×30 bolts and washers. Then, adjust the front pull plate 1-22 using 8 M10×60 bolts to ensure a reliable connection between the front flange and the tooling, and that the end face of the tooling fits snugly against the end face of the flange. Figure 7 As shown.

[0041] Fifth, after the machining fixture 1 is clamped, install the preform along with the machining fixture 1 onto the lathe, and align the preform according to the process document requirements. After the alignment meets the requirements, machine the rotational features of the front and rear end frames of the preform. During machining, ensure the relevant dimensions and geometric tolerances of the front and rear end frames are met.

[0042] Step 6: After machining, hoist the prefabricated part along with machining fixture 1 onto the saddle. Place the overhanging shafts at both ends of machining fixture 1 on supports of equal height. Use a wrench to remove the bolts connecting the front flange to the tooling one by one. Then, with the help of two people using the front pull plate 1-22, remove the first front connecting sleeve 1-21. Connect the counterweight to the rear flange end, use a wrench to unthread the rear flange and the first rear connecting sleeve 1-31, and pull the shaft out of the rear flange.

[0043] S4) Remove machining fixture 1 from the precast component and select the qualified precast component to proceed to the next step. Specifically, inspect and accept the rotational feature dimensions and geometric tolerances of the precast component. If the acceptance is qualified, proceed to the next step.

[0044] S5) Connect the second front-end positioning and clamping module 2-1 of the milling fixture 2 to the front flange of the preform, and connect the second rear-end positioning and clamping module 2-2 to the rear flange of the preform. The milling fixture 2, together with the preform, is clamped onto the turntable of the gantry machining center. The common reference axis of the preform is aligned, the coordinate system reference is confirmed, and the non-rotating features of the preform are milled using a special drill bit and milling cutter to obtain the composite material pressure vessel product.

[0045] During milling, it is necessary to ensure the relevant dimensions and geometric tolerances of the stepped holes on the outer circles of the front and rear end frames and the square grooves on the outer sides of the column sections.

[0046] Preferably, before the milling fixture 2 is assembled with the preform, the positioning surfaces of the second front-end positioning clamping module 2-1 and the second rear-end positioning clamping module 2-2 are cleaned, and the contact surfaces between the preform and the milling fixture 2 are cleaned.

[0047] In this example, the second front connecting sleeve 2-11 and the second rear connecting sleeve 2-21 are made of Q235, and the front reinforcing ring 2-13 and the rear reinforcing ring 2-23 are made of 6061 aluminum alloy.

[0048] In this embodiment, the assembly and machining steps of the milling fixture 2 are as follows: The first step is to place the prefabricated parts that have been machined onto a special saddle. Inspect the appearance of the product at both the front and rear ends, especially the metal parts of the front and rear flanges, and check for defects such as dents and scratches.

[0049] The second step is to check that the surface of the milling fixture 2 is clean and free of any foreign matter. After confirmation, fix the second front-end positioning and clamping module 2-1 of the milling fixture 2 to the front flange of the prefabricated part using M10 bolts, and fix the second rear-end positioning and clamping module 2-2 to the rear flange of the prefabricated part using M14 bolts. Figure 13 As shown.

[0050] The third step is to align the prefabricated parts according to the requirements of the process documents, and then establish the machining coordinate system.

[0051] The fourth step involves using a special drill bit to machine 20 stepped holes of Φ16×Φ8.6 on the outer circumference of the front skirt and 18 stepped holes of Φ11.5×Φ6.6 on the outer circumference of the rear skirt.

[0052] The fifth step involves using milling cutters, drills, and taps to machine the square groove and threaded holes in the thickened area in the middle of the preform.

[0053] Step 6: After the milling is completed, hoist the prefabricated part together with the milling fixture 2 onto the saddle. Use a wrench to remove the bolts connecting the front flange of the prefabricated part to the second front positioning clamping module 2-1 and the bolts connecting the rear flange of the prefabricated part to the second rear positioning clamping module 2-2 one by one. Remove the second front positioning clamping module 2-1 and the second rear positioning clamping module 2-2.

[0054] The seventh step is to inspect and accept the dimensions and geometric tolerances formed by the milling process. After acceptance, the subsequent processes are carried out. Specifically, a coordinate measuring machine is used to inspect and confirm all the dimensions and geometric tolerances of the machined product.

[0055] This invention designs two different fixtures based on processing requirements and the actual conditions of the processing equipment used on site. Both fixtures utilize surface contact positioning and threaded connections to ensure reliable positioning and clamping. The modular design of the two fixtures ensures high versatility, suitability for mass production, and a unique installation method, preventing errors.

[0056] Furthermore, despite the secondary clamping, the alignment datum remains consistent, avoiding alignment errors caused by repeated clamping. During the product forming process, especially when machining stepped holes, specialized cutting tools are used to ensure machining accuracy and improve machining efficiency.

[0057] The high-precision composite material pressure vessel molding method of this invention adopts a molding method of demolding before processing. It not only ensures the absolute stability of the product during processing through self-designed fixtures, but also improves the dimensional accuracy and geometric tolerance of the product by orders of magnitude through "secondary clamping with consistent reference", thereby increasing the first-pass yield and significantly reducing quality costs. It is particularly suitable for the mass production of products with high precision requirements.

[0058] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for molding a high-precision composite material pressure vessel, characterized in that, Includes the following steps: S1) Provides prefabricated components that closely approximate the final profile of the composite pressure vessel product, and the prefabricated... The component is equipped with front and rear flanges, and the internal core mold of the prefabricated component is removed; S2) Design and manufacture machining fixtures (1) and milling fixtures (2) suitable for the composite material pressure vessel. The turning fixture (1) includes a reference shaft (1-1), a first front-end positioning and clamping module (1-2) and a first rear-end positioning and clamping module (1-3) that are matched with the reference shaft (1); the milling fixture (2) includes a second front-end positioning and clamping module (2-1) and a second rear-end positioning and clamping module (2-2). S3) Install the first rear end positioning clamping module (1-3) of the machining fixture (1) on the rear end flange of the preform, insert the reference shaft (1-1) into the rear end flange of the preform and out through the front end flange of the preform, and then insert the first front end positioning clamping module (1-2) into the reference shaft (1-1) and connect it to the front end flange of the preform. Mount the machining fixture (1) together with the prefabricated part onto the CNC lathe, align the common reference axis of the prefabricated part, and confirm the machining allowance; Based on the allowance distribution, the rotating features of the preform are machined using a lathe tool; S4) Remove the machining fixture (1) from the precast component and select the qualified precast component to proceed to the next step; S5) Connect the second front-end positioning and clamping module (2-1) of the milling fixture (2) to the front flange of the preform, and connect the second rear-end positioning and clamping module (2-2) to the rear flange of the preform; The milling fixture (2) is clamped together with the preform onto the turntable of the gantry machining center. The common reference axis of the preform is aligned, the coordinate system reference is confirmed, and the non-rotating features of the preform are milled using a special drill bit and milling cutter to obtain the composite material pressure vessel product.

2. The molding method for a high-precision composite material pressure vessel according to claim 1, characterized in that: In S1), after removing the internal core mold of the precast component, an internal pressure test and non-destructive testing need to be completed, and the time interval between the internal pressure test and the non-destructive testing shall not be less than 48 hours.

3. The molding method for the high-precision composite material pressure vessel according to claim 2, Its features are: In S1), the front and rear flanges of the prefabricated component are provided with threaded holes that connect to the first front positioning and clamping module (1-2), the first rear positioning and clamping module (1-3), the second front positioning and clamping module (2-1), and the second rear positioning and clamping module (2-2).

4. The molding method for the high-precision composite material pressure vessel according to claim 3, Its features are: In S2), the length of the reference shaft (1-1) is greater than the length of the composite material pressure vessel. The reference shaft (1-1) is provided with a positioning step for assembling the composite material pressure vessel, and the reference shaft (1-1) is provided with a connecting flange (1-32) for axial positioning and tightening of the rear end of the prefabricated part.

5. The molding method for the high-precision composite material pressure vessel according to claim 4, Its features are: In S2), the reference shaft (1-1) is a hollow shaft, and a reinforcing ring (1-11) is provided inside the shaft at a position to improve rigidity.

6. The molding method for a high-precision composite material pressure vessel according to claim 5, Its features are: In S2), the first front-end positioning and clamping module (1-2) is used to position and clamp the front end of the preform, including a first front-end connecting sleeve (1-21) and a front-end pull plate (1-22) that are matched with the step diameter of the reference shaft (1-1). The first front-end connecting sleeve (1-21) is connected to the threaded hole of the front flange of the preform, and the front-end pull plate (1-22) is connected to the first front-end connecting sleeve (1-21).

7. The molding method for a high-precision composite material pressure vessel according to claim 6, Its features are: In S2), the first rear-end positioning and clamping module (1-3) is used to position and clamp the rear end of the preform, including a first rear-end connecting sleeve (1-31) that matches the step diameter of the reference shaft (1-1) and a connecting flange (1-32) reserved on the reference shaft (1-1). The first rear-end connecting sleeve (1-31) is connected to the threaded hole of the rear flange of the preform, and the connecting flange (1-32) is connected to the first rear-end connecting sleeve (1-31).

8. The molding method for the high-precision composite material pressure vessel according to claim 3, Its features are: In S2), the second front-end positioning and clamping module (2-1) is used to position and clamp the front end of the preform, including a second front-end connecting sleeve (2-11) that matches the step diameter of the reference shaft (1-1) and a front-end reinforcing plate (2-12). The second front-end connecting sleeve (2-11) is connected to the threaded hole of the front flange of the preform, and the front-end reinforcing plate (2-12) is fixedly connected to the second front-end connecting sleeve (2-11). The second front-end positioning and clamping module (2-1) also includes a front-end reinforcing ring (2-13) that abuts against the inner side of the front-end frame of the precast component. The front-end reinforcing ring (2-13) is connected to the front-end reinforcing plate (2-12) and the second front-end connecting sleeve (2-11) through a front-end rib plate (2-14).

9. The molding method for a high-precision composite material pressure vessel according to claim 8, Its features are: In S2), the second rear-end positioning and clamping module (2-2) is used to position and clamp the rear end of the preform, including a second rear-end connecting sleeve (2-21) that matches the step diameter of the reference shaft (1-1) and a rear-end reinforcing plate (2-22). The second rear-end connecting sleeve (2-21) is connected to the threaded hole of the rear flange of the preform, and the rear-end reinforcing plate (2-22) is fixedly connected to the second rear-end connecting sleeve (2-21). The second rear-end positioning and clamping module (2-2) also includes a rear-end reinforcing ring (2-23) that abuts against the inner side of the rear-end frame of the precast component. The rear-end reinforcing ring (2-23) is connected to the rear-end reinforcing plate (2-22) and the second rear-end connecting sleeve (2-21) through a rear-end rib plate (2-24).

10. The molding method for a high-precision composite material pressure vessel according to claim 1, Its features are: In S3), before the machining fixture (1) is assembled with the preform, the positioning surfaces of the first front-end positioning clamping module (1-2) and the first rear-end positioning clamping module (1-3) are cleaned, and the contact surface between the preform and the machining fixture (1) is cleaned; in S5), before the milling fixture (2) is assembled with the preform, the positioning surfaces of the second front-end positioning clamping module (2-1) and the second rear-end positioning clamping module (2-2) are cleaned, and the contact surface between the preform and the milling fixture (2) is cleaned.

Images