Processing device and manufacturing method for a hydraulic turbine rotor

Abstract

The application relates to the field of mechanical processing manufacturing, in particular to a processing device and manufacturing method of a water turbine rotor. The processing device of the water turbine rotor comprises a rack, a rotating assembly, a cutting assembly and a lifting assembly, and a control unit. The rotating assembly is arranged on the rack and is used for carrying a hot melting base material and driving the hot melting base material to rotate. The cutting assembly comprises an electric heating framework in a ring-shaped profiling structure. The lifting assembly is used for driving the cutting assembly to linearly translate. The control unit is used for controlling rotating and lifting speeds to keep a preset linkage ratio to cut out a spiral torsion angle contour. The application further comprises other components of the device and steps of a water turbine rotor manufacturing method. The application can efficiently and accurately process the water turbine rotor with the spiral torsion angle contour, can guarantee processing quality and precision, the device is convenient to move and operate, and the device can effectively remove processing gasification smoke dust.

Description

Technical Field

[0001] This application relates to the field of mechanical processing and manufacturing, and in particular to a processing device and manufacturing method for a water turbine rotor. Background Technology

[0002] In the field of fire fighting, fire-fighting foam liquid is a concentrated extinguishing agent specifically designed to extinguish flammable liquid fires. During operation, it needs to be mixed with water in a precise ratio and sprayed through fire-fighting equipment to form a foam covering layer that isolates oxygen for fire suppression. Because water pressure and flow are prone to fluctuations during fire-fighting water supply, if the foam supply cannot be adaptively adjusted, the mixing ratio will deviate from standard parameters. Therefore, the industry commonly uses a water turbine as the power source for supplying foam. The water flow drives the turbine, which in turn drives the foam pump to deliver foam. A larger water flow results in a faster turbine speed, thus achieving a dynamic physical match between the foam supply and the fire-fighting water supply. The core energy conversion component inside the water turbine is a pair of rotors meshing within a cavity.

[0003] To meet fluid dynamics requirements, the rotor needs to be designed as a complex spatial curved surface with a specific petal-shaped cross-section and a large helical twist angle along the central axis. In existing technologies, for ease of processing and to reduce manufacturing costs, turbine rotors are mostly made of non-metallic plastic materials such as polyurethane. However, practical applications have revealed that non-metallic materials have a high coefficient of thermal expansion and are highly sensitive to rapid changes in external ambient temperature and water temperature. In summer or high-temperature fire conditions, the non-metallic rotor expands due to heat, easily causing interference fit between the two rotors, leading to jamming and equipment shutdown. In cold winter conditions, the rotor contracts significantly due to cooling, resulting in excessive clearance between rotors and between the rotor and the casing, causing severe internal water leakage. This drastically reduces the efficiency of the water-driven rotor, ultimately leading to insufficient foam supply and an imbalance in the fire-fighting fluid mixing ratio.

[0004] To address the environmental adaptability drawbacks caused by the inherent physical properties of materials, replacing the rotor material with a metal material with a lower coefficient of thermal expansion and more stable structural performance has become an inevitable choice for the industry. However, mass production of complex-shaped metal rotors faces enormous manufacturing challenges. On the one hand, if conventional machining methods are used, directly turning and milling the raw metal bar on a multi-axis machining center, the massive amount of metal removed results in severe tool wear and extremely long machining time per piece, leading to high manufacturing costs. On the other hand, when using traditional mold cavity casting to obtain the metal rotor blank to reduce the massive metal cutting time, the long axial length and complex spatial spiral twist angle of the turbine rotor make the matching cathode mold extremely difficult to process, and it is impossible to achieve a solid demolding as a whole. In actual production, it is necessary to cut the cavity mold into multiple sections and assemble them during casting. This segmented assembly mold inevitably produces assembly misalignment and splicing gaps at the joints, resulting in serious distortion of the dimensional accuracy of the final metal rotor blank. Therefore, the industry urgently needs a new processing device and manufacturing method to solve the technical dilemma of excessive machining allowance in the manufacturing process of high-precision complex helical twist angle metal rotors and poor casting accuracy of traditional splicing molds. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this application provides a processing device and manufacturing method for a water turbine rotor, which can efficiently and accurately manufacture a water turbine metal rotor blank with a helical twist profile, ensuring forming quality and dimensional accuracy. The device is easy to move and operate, and can effectively remove processing gasification dust.

[0006] This application is achieved through the following technical solution: A turbine rotor processing device is used to process turbine rotors with a petal-shaped cross-section. The device includes a frame, on which are provided: a rotating assembly for supporting a hot-melt substrate and driving the hot-melt substrate to rotate around its central axis; a cutting assembly including an annular, contoured electrothermal skeleton, the plane of which is perpendicular to the central axis of the hot-melt substrate, the inner contour of which is adapted to the outer cross-sectional shape of the turbine rotor with pre-reserved machining allowance; a lifting assembly connected to the cutting assembly for driving the cutting assembly to perform linear translational movement parallel to the central axis of the hot-melt substrate; and a control unit electrically connected to both the rotating assembly and the lifting assembly. The control unit controls the rotational speed of the rotating assembly and the linear translational speed of the lifting assembly to maintain a preset linkage ratio, so that the electrothermal skeleton synthesizes a relative helical cutting trajectory on the hot-melt substrate, cutting out a helical twist angle contour corresponding to the turbine rotor.

[0007] By adopting the above technical solution, this invention utilizes an annular, contour-following electrothermal skeleton to directly adapt to the petal-shaped outer cross-section of the turbine rotor. Through a control unit, the rotational motion of the rotating component and the linear translational motion of the lifting component are precisely proportionally linked, allowing the electrothermal skeleton to descend uniformly along its axial direction while the hot-melt substrate rotates at a constant speed. This directly synthesizes a helical twist profile with complex spatial curve characteristics within a single relative cutting stroke. This non-contact thermal cutting method forms a high-precision lost foam master mold in one step, fundamentally eliminating the need for traditional, poorly precise, segmented molding dies. Subsequent metal casting using this high-precision master mold replaces direct heavy machining with metal round bars, resulting in a final metal casting requiring only minimal surface finishing. Furthermore, the use of electrothermal cutting avoids the environmental pollution caused by the large amount of dust and debris generated from directly crushing and cutting hot-melt materials, significantly improving the rotor's manufacturing efficiency and dimensional consistency, and effectively reducing tolerances in subsequent metal manufacturing.

[0008] Furthermore, the lifting assembly includes guide columns vertically arranged on both sides of the frame, guide rails provided on the guide columns, and sliders slidably connected on the guide rails. The two sides of the cutting assembly are respectively fixedly installed on the sliders on both sides. The frame is provided with a translation mechanism that drives the sliders to slide along the guide rails. The translation mechanism is electrically connected to the control unit.

[0009] By adopting the above technical solution, the lifting assembly uses guide columns and guide rail sliders distributed on both sides of the frame, providing strong guiding support for the cutting assembly with equal force on both sides. This allows the electric heating frame spanning the frame to maintain a highly horizontal posture and stable stroke displacement during lifting and translation, effectively preventing skewing and jamming caused by uneven force on one side of the drive, and ensuring the smoothness and accuracy of the spiral cutting trajectory in the vertical direction.

[0010] Furthermore, an insulating connector is fixed on the slider, and an outwardly extending connecting section is provided at the end of the electric heating frame. The connecting section is connected to the insulating connector so that the electric heating frame is suspended and spans between the sliders on both sides. The frame is also provided with a cable drag chain guide groove, in which a cable drag chain that is dynamically connected to the slider is housed. A cable for supplying power to the electric heating frame is threaded through the cable drag chain.

[0011] By adopting the above technical solution, the heating element is fixed to the slider using insulating connectors, ensuring electrical safety during heating and achieving stable suspension of the heating element. Because the heating element uses a closed solid ring structure, it possesses extremely high structural rigidity. Even when heated, it can maintain the designed inner petal-shaped contour due to its structural strength, avoiding the problem of traditional flexible heating wires loosening and deforming under heat, thus ensuring the dimensional accuracy of the cut surface.

[0012] Furthermore, the frame has a frame structure, including multiple vertically arranged columns, and a top plate, a middle partition plate, and a bottom plate horizontally arranged between the multiple columns; a processing area is formed between the top plate and the middle partition plate, and the rotating assembly, the lifting assembly, and the cutting assembly are all distributed in the processing area; an equipment storage area is formed between the middle partition plate and the bottom plate.

[0013] By adopting the above technical solution, the overall frame adopts a layered spatial framework layout, rationally delineating independent processing areas and equipment storage areas. This not only provides a robust and shock-resistant machine structure system for each cutting linkage mechanism to reduce processing vibration, but also allows the drive motor and core electrical components to be centrally and isolated outside the processing area. This reduces the high-temperature radiation generated by the equipment during operation and the contamination and corrosion of sensitive parts by substrate vaporization debris, helping to extend the equipment's lifespan and reduce maintenance complexity.

[0014] Furthermore, the rotating assembly includes a first rotating shaft and a first turntable; the first rotating shaft is rotatably mounted on the middle partition plate; the first rotating shaft is fixed to the output end of the rotating mechanism; the first turntable is coaxially fixedly connected to the top end of the first rotating shaft, and the upper end surface of the first turntable is used to support the bottom end surface of the hot melt substrate; the outer diameter of the first turntable is smaller than the minimum inner diameter of the inner ring contour formed by the heating frame; the rotating mechanism is electrically connected to the control unit.

[0015] By adopting the above technical solution, the first turntable provides a stable and reliable support, gripping, and rotational drive input for the bottom end face of the hot melt substrate. The feature design of the first turntable having an outer diameter smaller than the minimum inner diameter of the electric heating frame ensures, from a structural perspective, that when the electric heating frame completes the cutting of the entire substrate from top to bottom and reaches the limit of its stroke, it can smoothly pass over the outer area of ​​the first turntable without any physical rigidity or interference. The structure of falling to the bottom ensures the continuity of the entire working mold's axial full-length cutting without blind spots.

[0016] Furthermore, the top plate is provided with a limiting component for downward translation to abut the top of the hot-melt substrate and form a vertical limiting position; the limiting component includes a steering transmission box, a handwheel, an adjusting screw, and a limiting plate; the steering transmission box is fixed to the top plate, and the handwheel is rotatably connected to the steering transmission box; the adjusting screw passes vertically through the steering transmission box and the top plate, and through the reversing transmission of the steering transmission box, performs linear lifting and lowering motion according to the rotation of the handwheel; the limiting plate is horizontally fixed to the bottom end of the adjusting screw.

[0017] By adopting the above technical solution, a limiting assembly composed of purely mechanical parts is configured on the top plate to reinforce the top of the hot-melt substrate by downward contact, forming a top-pressure clamping system that works in conjunction with the bottom support mechanism. The screw lifting mechanism, controlled by a handwheel and reversing, not only allows for stepless adaptation to hot-melt substrates of various heights and specifications, but more importantly, it eliminates the risk of eccentric swaying and tilting / bending that can easily occur with high aspect ratio foam columns when subjected to rotational force and weakened localized heating, firmly locking the central axis reference throughout the entire cutting process.

[0018] Furthermore, a second rotating shaft is rotatably connected to the bottom side of the limiting plate, and a second rotating disk coaxially arranged with the first rotating disk is fixed at the bottom end of the second rotating shaft; the outer diameter of the second rotating disk is smaller than the minimum inner diameter of the inner ring contour formed by the heating frame.

[0019] By adopting the above technical solution, the second turntable, which is rotatably attached to the bottom of the limiting plate, can ensure that the top of the hot-melt substrate is vertically constrained while still maintaining undamped coaxial synchronous rotation with the overall substrate without sliding friction. Furthermore, the design of the outer diameter of the second turntable avoids the outline area of ​​the heating frame, ensuring that the entire limiting mechanism does not affect the starting point of the top circumferential cutting. This allows the cutting component to smoothly cut into the substrate from the very beginning of the processing.

[0020] Furthermore, the processing area is equipped with a directional air supply component; the directional air supply component is arranged toward the cutting area of ​​the electric heating frame, and is used to continuously blow airflow onto the cutting part to cool and shape the hot melt cut and drive the processing gasification dust away from the processing area.

[0021] By adopting the above technical solution, the directional air supply component can accurately radiate cold air to the cutting surface area of ​​the electric heating frame throughout the entire operation. This firstly causes the high-temperature liquid edge at the hot melt cut to be instantly cooled, hardened, and contracted, preventing the secondary sticking and seizing phenomenon of the molten material at the cut due to slow cooling caused by residual heat, thus preserving the sharpness of the finished product. Secondly, it can also strongly encapsulate and quickly expel the dense vaporized toxic fumes emitted from the high-heat melting, maintaining transparent visual observation conditions in the processing and storage channels.

[0022] Furthermore, the bottom side of the base plate is provided with a walking assembly, which includes a plurality of casters with locking elements; the casters are used to provide support for the translation of the frame on the horizontal plane and are locked by the locking elements to form a parking brake on the frame.

[0023] By adopting the above technical solution, the caster device with locking components mounted on the bottom side of the equipment frame not only greatly enhances the flexibility of pushing and pulling the heavy box-type processing equipment for transportation and the mobility of quick placement, but also ensures the stability of the foundation of the equipment's long-term stationary position by using a braking and locking structure.

[0024] A method for manufacturing a water turbine rotor, using a water turbine rotor processing device, includes the following steps: S1, lost foam cutting and forming: a hot-melt substrate is mounted on the rotating assembly; using the electrically heated heating frame, in conjunction with the linkage operation of the control unit, the hot-melt substrate rotates while the heating frame translates vertically, removing waste material from the periphery of the hot-melt substrate and synthesizing a spiral cutting trajectory to generate a lost foam master mold with machining allowance and spiral twist angle characteristics on the outer contour; S2, preparing the cavity mold. Shell: A refractory coating is applied to the outer surface of the lost foam mold and cured to form a cavity shell that fits the spiral twist profile on the outside of the lost foam mold; S3, Molten metal pouring: Molten metal is poured into the cavity shell, and the lost foam mold is vaporized and emptied by the high temperature of the molten metal. The molten metal fills the space left after the original mold is vaporized; After the molten metal cools and solidifies and the outer shell is removed, a metal rotor blank with a spiral twist profile and machining allowance is obtained; S4, Allowance cutting and finishing: The machining allowance on the surface of the metal rotor blank is mechanically cut to obtain the finished turbine rotor.

[0025] By adopting the above technical solution, the linkage contour electrothermal cutting process is deeply embedded into the main process of lost foam casting manufacturing of turbine rotors. In the primary forming stage, the electrothermal skeleton combined with rotary cutting generates a spiral geometric surface contour to complete non-contact rapid mold making, effectively replacing the conventional three-dimensional large-area CNC milling material removal process. After the mold shell is translated and transitioned, a casting blank with high-precision dimensions closely approximating the features of the final part model is precisely obtained by displacement using high-temperature molten metal. This complete process eliminates the tedious task of massive spatial shaping and moves it to the stage of rapid and lightweight hot-melt substrate manufacturing. This not only greatly reduces the processing and manufacturing time and the cost of expensive tool wear, and significantly controls the waste of metal material, but also significantly reduces the technical barriers and operational difficulties of performing difficult mechanical cutting corrections on complex curved surfaces in the final finishing stage.

[0026] In summary, this application includes at least one of the following beneficial technical effects: This application utilizes an electrothermal skeleton with a petal-shaped inner ring contour, combined with precise linkage control of rotation and lifting, to achieve a one-time rapid cutting of complex spiral twisted contours from hot melt substrate. The high-precision lost foam original mold obtained by this process perfectly avoids the defects of traditional cathode molds used for casting metal rotors, such as the inability to demold as a whole and poor splicing accuracy. This application uses a double-sided symmetrical guide lifting mechanism, combined with an anti-interference turntable clamping and positioning structure at both ends, to ensure that the cutting motion of the electric heating frame is smooth and without dead angles throughout the entire process under heating, thereby improving the continuous accuracy of the forming of the spatial curved surface. This application establishes a novel forming and machining route for hydraulic turbine metal rotors, successfully solving the problem of excessive machining volume when directly cutting metal rotors from bar stock. By shifting the complex shaping and cutting work to the easily machinable hot-melt substrate layer, the raw material consumption rate of metal rotors and the workload of end-of-line mechanical finishing are significantly reduced, and the problems of traditional non-metallic rotors easily jamming when heated and leaking when cooled are completely solved. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural schematic diagram of a processing device for a water turbine rotor as described in Embodiment 1; Figure 2 This is a partial enlarged view of the lifting assembly described in Embodiment 1; Figure 3 This is a partially enlarged view of the cutting component described in Embodiment 1; Figure 4 This is a top view of the heating frame and the first turntable described in Embodiment 1; Figure 5 This is a partially enlarged view of the limiting component described in Embodiment 1; Figure 6 This is a schematic diagram of the turbine rotor described in the embodiment.

[0028] In the diagram: 1. Frame; 11. Column; 12. Top plate; 13. Middle partition; 14. Base plate; 15. Processing area; 16. Equipment storage area; 2. Rotating assembly; 21. First rotating shaft; 22. First turntable; 221. Outer diameter of the first turntable; 3. Cutting assembly; 31. Heating frame; 311. Connecting section; 312. Minimum inner diameter of the inner circle formed by the heating frame; 32. Insulating connector; 33. Cable drag chain guide groove; 34. Cable drag chain; 4. Lifting assembly; 41. Guide column; 42. Guide rail; 43. Slider; 5. Limiting assembly; 51. Steering transmission box; 52. Handwheel; 53. Adjusting screw; 54. Limiting plate; 541. Second rotating shaft; 542. Second turntable; 55. Guide rod; 6. Directional air supply assembly; 7. Traveling assembly; 8. Turbine rotor. Detailed Implementation

[0029] The technical solutions of various 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. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Example 1

[0030] Reference Figure 1 This application discloses a processing device for a turbine rotor, used to process a turbine rotor 8 with a petal-shaped cross-section. The device includes a frame 1, on which are mounted: a rotating assembly 2 for supporting a hot-melt substrate and driving the hot-melt substrate to rotate with its central axis as the axis; a cutting assembly 3 including an annular, contoured electric heating frame 31, the plane of which is perpendicular to the central axis of the hot-melt substrate, and the inner ring contour shape of the electric heating frame 31 matching the outer cross-sectional shape of the turbine rotor 8 with a pre-reserved machining allowance; a lifting assembly 4 connected to the cutting assembly 3, used to drive the cutting assembly 3 to perform linear translational movement along a direction parallel to the central axis of the hot-melt substrate; and a control unit electrically connected to both the rotating assembly 2 and the lifting assembly 4. The control unit controls the rotational speed of the rotating assembly 2 and the linear translational speed of the lifting assembly 4 to maintain a preset linkage ratio, so that the electric heating frame 31 synthesizes a relative spiral cutting trajectory on the hot-melt substrate, cutting out the corresponding spiral twist angle contour of the turbine rotor 8.

[0031] For details, please refer to Figure 1 The frame 1 has a layered frame structure, with the main body welded from steel profiles. Internally, it contains multiple vertically arranged columns 11 and parallel-arranged top plate 12, middle partition plate 13, and bottom plate 14. The top plate 12 and middle partition plate 13 form a processing area 15, where the rotating assembly 2, lifting assembly 4, and cutting assembly 3 are centrally located. The middle partition plate 13 and bottom plate 14 form an equipment storage area 16, used to install stepper motors and electrical control cabinets, providing physical isolation and protection for the core control components. The hot-melt substrate can be made of columnar rods processed from foamed materials with good hot-melt properties, such as polystyrene foam or polyurethane foam.

[0032] refer to Figure 1 A directional air supply component 6 is installed on one side of the processing area 15 of the machine casing. It primarily uses a high-pressure centrifugal fan with a ventilation grille, directing the airflow towards the hot-melt cutting area to cool and shape the melted cut and disperse the working fumes. Four self-locking swivel casters are installed at the lower corners of the base plate 14. These casters have built-in brake pedals, facilitating easy movement and stable parking of the entire equipment on the workshop floor. The control unit uses a programmable logic controller (PLC) that precisely matches the ratio of the circular rotation frequency to the linear descent speed through internal program algorithms.

[0033] refer to Figure 2 and Figure 3 Within the processing area 15, the lifting assembly 4 includes guide columns 41 vertically mounted on both sides of the frame 1. The guide columns 41 are equipped with linear guide rails 42 and sliding sliders 43 that cooperate with them. The translation mechanism includes a lifting drive motor and a lead screw and nut mechanism mounted in the equipment storage area 16. The translation mechanism is electrically connected to the control unit, synchronously driving the sliders 43 on both sides to move up and down. An insulating connector 32 is fixedly installed on the inner side of the slider 43. This insulating connector 32 is, for example, a high-temperature resistant ceramic insulator or a metal connecting block wrapped with a high-temperature resistant insulating layer to prevent leakage. The electric heating frame 31 in this application is a closed solid ring structure integrally formed from a rigid electric heating material, such as a nickel-chromium alloy plate or wide strip material, with its interior hollowed out to form the petal-shaped inner ring outline. The connecting sections 311 on both sides of the electric heating frame 31 are fixed to the insulating connector 32 by bolts or other fastening methods. Because the heating frame 31 adopts a closed solid structure, it possesses extremely high structural rigidity. When heated to the working temperature, it can resist thermal deformation by relying on its own structural strength, stably maintaining the petal-shaped contour of the inner ring without distortion, thereby completing the contour cutting operation with high precision. The frame 1 has cable drag chains 33 on both sides. The cable drag chains 34, which move synchronously with the slider 43, are installed inside the cable drag chains 33. The cable drag chains 34 are mainly used to collect and guide the cables supplying power to the heating frame 31, preventing the cables from getting tangled or damaged during operation. The partition plate 13 has a first rotating shaft 21 mounted on its tabletop. The rotating mechanism includes a rotary drive motor, such as a stepper motor or servo motor, installed in the equipment storage area 16. The rotating mechanism is electrically connected to the control unit, and its output end is fixedly connected to the first rotating shaft 21 to provide rotational power. A first turntable 22 with anti-slip texture is fixed to the top of the first rotating shaft 21. The first turntable 22 mainly supports the bottom end face of the hot-melt substrate.

[0034] refer to Figure 4 In the figure, the dashed circle represents the minimum inner diameter 312 of the inner ring outline formed by the heating frame 31; the solid circle represents the outer diameter 221 of the first turntable 22.

[0035] refer to Figures 3 to 5A limiting assembly 5 is installed on the lower side of the top plate 12. The limiting assembly 5 includes a steering transmission box 51 fixed on the top plate 12 and a handwheel 52. Rotating the handwheel 52 drives the vertically arranged adjusting screw 53 to rise and fall through the bevel gear in the steering transmission box 51. The lower end of the adjusting screw 53 has a limiting plate 54. Guide rods 55 are also provided on both sides of the adjusting screw 53. The guide rods 55 are slidably connected to the top plate 12, and the bottom of the guide rods 55 is fixedly connected to the limiting plate 54. A second rotating shaft 541 that can rotate freely is installed at the lower part of the limiting plate 54. A second turntable 542 is concentrically fixed to the second rotating shaft 541. The first turntable 22 and the second turntable 542 are arranged on the same central axis, and the outer diameter of both is smaller than the minimum dimension 312 of the inner ring contour of the electric heating frame 31, to prevent the electric heating frame 31 from rigidly colliding when it descends to the bottom or rises to the top.

[0036] The implementation principle of this embodiment is as follows: Based on the actual required length of the high aspect ratio hot-melt substrate and the design torsion angle of the turbine rotor 8, the linkage operation parameters of the control unit are calculated and set in advance. The handwheel 52 is cranked to raise the top limiting component 5, placing the hot-melt substrate vertically at the center of the first turntable 22. The handwheel 52 is then cranked in the opposite direction to lower the second turntable 542, pressing the top surface of the substrate for coaxial clamping. The power supply is turned on to heat the heating frame 31 to its working red-hot temperature. The processing program is then started, and the control unit commands the rotating component 2 to drive the entire substrate to rotate at a uniform speed via the first rotating shaft 21. Simultaneously, the lifting motor is instructed to pull the heating frame 31 down at a fixed speed along the guide rail 42. Under the combined spatial motion of the rotating substrate and the descending heating wire, the high-temperature annular heating frame 31 with a petal-shaped cross-section is continuously and undampedly burned off from the substrate surface, separating excess waste material and forming the original mold of the required spiral torsion three-dimensional shape in one step. During this process, the directional air supply component 6 is used to cool and harden the material and remove the flue gas. Once the cutting stroke reaches the base position, the heating power is cut off and the top adjusting screw 53 is released to remove the completed solid mold. Example 2

[0037] Reference Figure 6 This application discloses a method for manufacturing a turbine rotor, using a turbine rotor processing device as described in Embodiment 1. The manufacturing method includes the following steps: S1. Lost foam cutting and forming: The hot melt substrate is mounted on the rotating component 2. The electric heating frame 31 is heated by electricity and the control unit is linked to make the hot melt substrate rotate while the electric heating frame 31 moves in the vertical direction. The waste material is removed from the periphery of the hot melt substrate and a spiral cutting trajectory is synthesized to generate a lost foam master mold with machining allowance and spiral twist angle characteristics on the outer contour. S2. Preparation of cavity mold shell: Apply refractory coating to the outer surface of the lost foam original mold and perform curing treatment to form a cavity mold shell that fits the spiral twist angle profile on the outside of the lost foam original mold. S3. Molten metal pouring: Molten metal is poured into the cavity mold shell. The lost foam original mold is vaporized and emptied by the high temperature of the molten metal. The molten metal fills the original mold space left after the vaporization of the lost foam original mold. After the molten metal cools and solidifies and the outer mold shell is removed, a metal rotor blank with a helical twist angle profile and machining allowance is obtained. S4. Residual material cutting and finishing: Perform mechanical cutting operation on the surface of the metal rotor blank to obtain the finished water turbine rotor.

[0038] Specifically, refer to Figure 5 In the lost foam cutting and forming stage, the selected hot-melt substrate is a cylindrical piece of expandable polymer sheet, which possesses good thermal cutting and tear-breaking capabilities as well as self-supporting rigidity under external forces. The power module of the control device energizes the heating frame 31 to heat up to approximately 500 degrees Celsius within the high-temperature melting range. The annular shape of the heating frame 31 is pre-fixed by bending with a mold according to the finished product cross-sectional parameters. In this initial processing step, the physical dimensions of the model are designed to be larger than the thickness values ​​in the final design drawings, leaving a processing tolerance range.

[0039] Reference Figure 5 In the cavity mold shell preparation stage, a refractory coating paste layer made of quartz powder and silicate adhesive is applied to the outside of the original mold in multiple layers by manual brushing. The coating completely and evenly penetrates and fits every corner and gap of the original mold surface contour. After being left to set, it is transferred to a special drying room for high-temperature hot air constant temperature drying to form a hard ceramic shell. At this time, the foam mold body with its characteristic shape is still wrapped inside.

[0040] Reference Figure 5 During the molten metal pouring stage, the lower half of the externally dried model is embedded and fixed in a dry sand box with bottom vacuum vents. To prevent carbon enrichment defects in stainless steel or cast steel parts, styrene-methyl methacrylate copolymer is preferred as the hot-melt substrate. During pouring, a negative pressure vacuum is continuously applied to the bottom of the dry sand box to accelerate the discharge of vaporization products. Subsequently, molten stainless steel or cast steel alloy that has reached the required rheological properties is continuously poured into the pre-reserved inlet. Upon contact with the high-temperature molten metal, the foam body instantly and violently decomposes and burns, generating gas that is then extracted and discharged. The space consumed by the vaporization is completely occupied and replaced by the continuously replenished molten alloy. With natural cooling, it gradually undergoes phase transformation and crystallization to form the final shape.

[0041] Reference Figure 5In the finishing stage of the allowance cutting, the sand and slag remaining on the surface of the cast metal rotor blank are cleaned. Then, it is hoisted onto the five-axis CNC machining platform fixture for precise positioning and alignment of the center reference origin. Carbide tools are used to carry out precise turning and milling along the curved surface along the set CNC tool path to remove most of the pre-set machining allowance layer of the casing during the casting process, solve the defects of rough cast surface and improve the form and position tolerance accuracy coefficient, thereby completing the final manufacturing of the part.

[0042] The implementation principle of this embodiment is as follows: Utilizing the material replacement characteristics of lost foam casting technology, the heavy machining problem of turning large, hard metal blocks, which requires a huge amount of time, is transformed into starting with the processing of flexible and fragile polymer foam. Initially, relying on the aforementioned non-contact continuously heated shaped filaments and simple multi-axis rotary collaborative mechanism, solid simulation models are batch-cut with extremely low energy consumption. Subsequently, the complex spatial geometric surface is directly transferred to a hard coating to serve as the inner mold shell. Finally, the liquid metal fluid is guided to directly obtain a near-net-shape three-dimensional spatial rotor metal blank, greatly eliminating unnecessary losses of metal raw materials and relieving a significant workload on post-processing precision machines.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of this application.

Claims

1. A machining apparatus for a water turbine rotor, used for machining a water turbine rotor (8) with a petal-shaped cross-section, comprising a frame (1), characterized in that, The frame (1) is equipped with: Rotating component (2) is used to carry the hot melt substrate and drive the hot melt substrate to rotate with the central axis of the hot melt substrate as the axis; The cutting assembly (3) includes an electric heating frame (31) with a ring-shaped contour structure. The plane of the electric heating frame (31) is perpendicular to the central axis of the hot melt substrate. The inner ring contour shape of the electric heating frame (31) is adapted to the outer cross-sectional shape of the turbine rotor (8) with a reserved machining allowance. The lifting component (4) is connected to the cutting component (3) and is used to drive the cutting component (3) to make a linear translational movement along the direction parallel to the central axis of the hot melt substrate; The control unit is electrically connected to the rotating component (2) and the lifting component (4) respectively. The control unit is used to control the rotation speed of the rotating component (2) and the linear translation speed of the lifting component (4) to maintain a preset linkage ratio so that the electric heating frame (31) synthesizes a relative spiral cutting trajectory on the hot melt substrate and cuts out the spiral twist angle profile corresponding to the turbine rotor (8).

2. The machining apparatus for a water turbine rotor according to claim 1, characterized in that, The lifting assembly (4) includes guide columns (41) vertically arranged on both sides of the frame (1), a guide rail (42) is provided on the guide column (41), and a slider (43) is slidably connected on the guide rail (42). The two sides of the cutting assembly (3) are respectively fixedly installed on the sliders (43) on both sides. The frame (1) is provided with a translation mechanism that drives the slider (43) to slide along the guide rail (42). The translation mechanism is electrically connected to the control unit.

3. The machining apparatus for a water turbine rotor according to claim 2, characterized in that, An insulating connector (32) is fixed on the slider (43), and an outwardly extending connecting section (311) is provided at the end of the electric heating frame (31). The connecting section (311) is connected to the insulating connector (32) so that the electric heating frame (31) is suspended and spans between the sliders (43) on both sides. The frame (1) is also provided with a drag chain guide groove (33). The drag chain guide groove (33) contains a cable drag chain (34) that is dynamically connected to the slider (43). A cable for supplying power to the electric heating frame (31) is threaded through the cable drag chain (34).

4. The machining apparatus for a water turbine rotor according to claim 1, characterized in that, The frame (1) has a frame structure, including multiple vertically arranged columns (11), and a top plate (12), a middle partition (13) and a bottom plate (14) horizontally arranged between the multiple columns (11); a processing area (15) is formed between the top plate (12) and the middle partition (13), and the rotating assembly (2), the lifting assembly (4) and the cutting assembly (3) are all distributed in the processing area (15); an equipment storage area (16) is formed between the middle partition (13) and the bottom plate (14).

5. The machining apparatus for a water turbine rotor according to claim 4, characterized in that, The rotating assembly (2) includes a first rotating shaft (21) and a first turntable (22); the first rotating shaft (21) is rotatably mounted on the middle partition (13); the first rotating shaft (21) is fixed at the output end of the rotating mechanism; the first turntable (22) is coaxially fixedly connected to the top end of the first rotating shaft (21), and the upper end surface of the first turntable (22) is used to support the bottom end surface of the hot melt substrate; the outer diameter (221) of the first turntable (22) is smaller than the minimum inner diameter (312) of the inner ring contour formed by the electric heating frame (31); the rotating mechanism is electrically connected to the control unit.

6. The machining apparatus for a water turbine rotor according to claim 5, characterized in that, The top plate (12) is provided with a limiting component (5) for moving downward to abut the top of the hot melt substrate and forming a vertical limiting position; the limiting component (5) includes a steering transmission box (51), a handwheel (52), an adjusting screw (53) and a limiting plate (54); the steering transmission box (51) is fixed on the top plate (12), and the handwheel (52) is rotatably connected to the steering transmission box (51); the adjusting screw (53) passes vertically through the steering transmission box (51) and the top plate (12), and moves linearly up and down according to the rotation of the handwheel (52) through the reversing transmission of the steering transmission box (51); the limiting plate (54) is horizontally fixed to the bottom end of the adjusting screw (53).

7. The machining apparatus for a water turbine rotor according to claim 6, characterized in that, The bottom side of the limiting plate (54) is rotatably connected to a second rotating shaft (541), and the bottom end of the second rotating shaft (541) is fixed with a second rotating disk (542) arranged coaxially with the first rotating disk (22); the outer diameter of the second rotating disk (542) is smaller than the minimum inner diameter (312) of the inner ring contour formed by the electric heating frame (31).

8. The machining apparatus for a water turbine rotor according to claim 4, characterized in that, The processing area (15) is provided with a directional air supply component (6); the directional air supply component (6) is arranged toward the cutting area of ​​the electric heating frame (31) and is used to continuously blow airflow to the cutting part to cool and shape the hot melt cut and drive the processing gasification dust away from the processing area (15).

9. The machining apparatus for a water turbine rotor according to claim 4, characterized in that, The bottom side of the base plate (14) is provided with a walking assembly (7), which includes a plurality of casters with locking elements; the casters are used to provide support for the translation of the frame (1) on the horizontal plane and are locked by the locking elements to form a parking brake on the frame (1).

10. A method for manufacturing a water turbine rotor, characterized in that, Using a machining apparatus for a turbine rotor as described in any one of claims 1 to 9, the manufacturing method comprises the following steps: S1. Lost foam cutting and forming: The hot melt substrate is mounted on the rotating component (2). The electric heating frame (31) is heated by electricity and the control unit is linked to make the hot melt substrate rotate while the electric heating frame (31) moves in the vertical direction. The waste material is cut off from the periphery of the hot melt substrate and a spiral cutting trajectory is synthesized to generate a lost foam original mold with machining allowance and spiral twist angle characteristics on the outer contour. S2. Preparation of cavity mold shell: Apply refractory coating to the outer surface of the lost foam original mold and perform curing treatment to form a cavity mold shell that fits the spiral twist angle profile on the outside of the lost foam original mold. S3. Molten metal pouring: Molten metal is poured into the cavity mold shell. The lost foam original mold is vaporized and emptied by the high temperature of the molten metal. The molten metal fills the original mold space left after the vaporization of the lost foam original mold. After the molten metal cools and solidifies and the outer mold shell is removed, a metal rotor blank with a helical twist profile and machining allowance is obtained. S4. Residual material cutting and finishing: Perform mechanical cutting operation on the machining allowance on the surface of the metal rotor blank to obtain the finished water turbine rotor (8).

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