A sand casting method and apparatus for large ring-shaped castings

Abstract

The application discloses a sand mold casting method for large ring-shaped castings, which comprises the following steps: step a: according to the required shape and size of the ring-shaped castings, the ring-shaped product is divided into multiple modules, and drawing processing drawings of the multiple modules; step b: according to the processing drawings of the multiple modules in step a, five-axis continuous engraving is adopted to carry out engraving processing, and multiple segmented models are obtained; step c: according to the shape of the ring-shaped castings, the multiple segmented models are spliced to form a product model. The application provides a sand mold casting method and device for large ring-shaped castings, and overcomes the problem that large ring-shaped castings are cast by the sand mold casting method without molds and sand boxes in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of casting technology, and particularly relates to a sand casting method and apparatus for large ring castings. Background Technology

[0002] Castings are metal shaped objects obtained by various casting methods. They are objects with a certain shape, size and properties obtained by pouring, injecting, sucking or other casting methods into a pre-prepared mold after smelting liquid metal, cooling and then grinding.

[0003] Casting is the most widely used process for forming liquid metal. It involves pouring liquid metal into a mold cavity, allowing it to cool and solidify, and then obtaining a blank or part of a certain shape.

[0004] In actual production, it has been found that casting larger products is more difficult due to the lack of molds and melting furnaces with correspondingly larger melting capacities. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned problems in the prior art and provide a sand casting method and apparatus for large ring castings, which overcomes the difficulty of sand casting large ring castings without molds or sand boxes in the prior art.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0007] In a first aspect, the present invention provides a sand casting method for large annular castings, the method comprising the following steps:

[0008] Step a: Based on the required shape and dimensions of the ring casting, divide the ring product into multiple modules and draw machining drawings for each module;

[0009] Step b: Based on the processing drawings of multiple modules in step a, use a five-axis continuous carving method to perform carving processing and obtain multiple segmented models;

[0010] Step c: According to the shape of the ring casting product, multiple segmented models are spliced ​​together to form the casting product model; risers are provided on the end face of the casting product model;

[0011] Step d: Take the annular sand box, fill the bottom of the annular sand box with sand, move the casting product model into the annular sand box, continue to fill the annular sand box with sand until it is full, vibrate and compact the annular sand box to complete the shaping of the casting product model in the annular sand box.

[0012] Step e: After the molding is completed, use an electric hot knife to remove the casting product model inside the annular sand box, and the area where the original casting product model was located inside the annular sand box forms a cavity;

[0013] Step f: Apply paint to the annular sand box cavity portion of the removed model;

[0014] Step g: Pour the molten metal in the melting furnace along the riser to prepare the required ring casting.

[0015] Furthermore, in step b, the model material selected during the carving process is polystyrene foam.

[0016] Further, in step c, the specific steps of the splicing and forming process are as follows: according to the shape of the ring casting product, multiple segmented models are spliced ​​together, and hot melt glue guns are used to bond the connection between two adjacent segmented models. After all the segmented models are bonded, a casting product model is prepared.

[0017] Furthermore, in step f, the coating is an alcohol-based talc coating.

[0018] In a second aspect, the present invention provides an apparatus for a sand casting method for large annular castings, comprising an annular sand box, the annular sand box comprising a circular base and a first annular component disposed at the center of the top surface of the circular base, the first annular component being fitted with a second annular component.

[0019] The circular base one has a circular base two at its bottom. The top surface of the circular base two is evenly distributed with adjustment grooves along the circumference. An adjustment scale plate is slidably installed in the adjustment groove. A casting bracket is fixedly installed at the other end of the adjustment scale plate.

[0020] The second annular component includes a first curved portion and a second curved portion;

[0021] The two ends of the first curved portion are bent outward to form a first curved portion, and the two ends of the second curved portion are bent outward to form a second curved portion;

[0022] A first connector is provided between the adjacent first bend and the second bend, and the adjacent first bend and the second bend are connected and fixed by the first connector;

[0023] A trapezoidal base is fixedly installed at the lower end of each of the two first connectors;

[0024] The circular base is fixedly installed between the two trapezoidal bases;

[0025] A first casting zone is formed between the first curved portion and the second curved portion. An annular adjusting member is provided in the first casting zone. The annular adjusting member is tightly disposed on the inner surface of the first curved portion and the second curved portion.

[0026] The first annular component includes a pair of third arc-shaped plates, the two ends of which are bent inward to form third bends, and a second connector is provided between two adjacent third bends on the two third arc-shaped plates;

[0027] A fourth arc-shaped plate is slidably mounted on both ends of the outer circumferential surface of the third arc-shaped plate.

[0028] Furthermore, the casting support includes a support base and a support platform fixedly installed on the top surface of the support base. A U-shaped support is installed on the top of the support platform, and a casting liquid tank is provided in the open end of the U-shaped support.

[0029] The casting liquid tank is equipped with ear plates;

[0030] The casting liquid tank is tightly fitted with a placement shell, which is rotatably installed inside the open end of the U-shaped support. The ear plate is fixed to the top of the placement shell by bolt connection.

[0031] A baffle is installed at the bottom of the housing.

[0032] A cylinder seat plate is provided on the upper outer side of the support platform, and a lifting cylinder is rotatably mounted on the cylinder seat plate. The output end of the lifting cylinder is rotatably connected to the baffle.

[0033] An arc-shaped filter screen is fixedly installed inside the casting liquid tank.

[0034] Furthermore, the annular adjusting member includes a first arc-shaped plate and a second arc-shaped plate slidably mounted on the inner surface of the first arc-shaped plate;

[0035] Both ends of the outer circumferential surface of the first arc plate are equipped with U-shaped pull plates, and the closed end of the U-shaped pull plate has a fastening threaded hole, and a fastening bolt is threaded into the fastening threaded hole.

[0036] The outer surfaces of the first and second curved portions are both provided with grooves that mate with the two ends of the U-shaped pull plate.

[0037] Furthermore, the first connecting member includes a vertical partition and fixing bolts fixedly installed on the front and rear sides of the vertical partition, and the external thread of the fixing bolts has two first nuts connected to it;

[0038] Both the first bent portion and the second bent portion have a first through hole on their front side, and the fixing bolt can be placed in the first through hole.

[0039] Furthermore, the third and fourth arc-shaped plates are both placed closely on top of the circular base.

[0040] Furthermore, the second connecting member includes a vertical plate and a threaded rod fixedly installed on the front and rear sides of the vertical plate, wherein the threaded rod has two second nuts connected to its external thread.

[0041] The third bend is provided with an elongated hole, and the threaded rod is located inside the elongated hole, and the threaded rod can slide inside the elongated hole;

[0042] The second connector is fixedly installed on the top of the circular base.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] 1. This invention provides a sand casting method for large ring castings, overcoming the problem of sand casting of large ring castings without molds or sand boxes in the prior art.

[0045] 2. The present invention provides an apparatus for sand casting of large ring castings, which can adjust the ring sand box according to the actual size requirements of the ring casting.

[0046] 3. This invention provides an apparatus for sand casting of large ring castings, which adopts a method of casting multiple casting liquid tanks simultaneously, which not only solves the problem of asynchronous casting of molten metal for large castings, but also eliminates the safety hazards of manual casting. Attached Figure Description

[0047] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0048] Figure 1 This is a side view of the structure of Embodiment 1 provided by the present invention;

[0049] Figure 2 This is a schematic diagram of the annular sand box in Embodiment 1 provided by the present invention;

[0050] Figure 3 This is a schematic diagram of the casting support structure in Embodiment 1 provided by the present invention;

[0051] Figure 4 This is a schematic diagram of the arc-shaped filter screen in Embodiment 1 provided by the present invention;

[0052] Figure 5 This is a schematic diagram of the installation of the second annular component in Embodiment 1 provided by the present invention;

[0053] Figure 6 This is a schematic diagram of the structure of the second annular component in Embodiment 1 provided by the present invention;

[0054] Figure 7 This is a partial structural schematic diagram of the second annular component in Embodiment 1 provided by the present invention;

[0055] Figure 8 This is a schematic diagram of the structure of the annular adjusting member in Embodiment 1 provided by the present invention;

[0056] Figure 9 This is a schematic diagram of the U-shaped pull plate in Embodiment 1 provided by the present invention;

[0057] Figure 10 This is a schematic diagram of the structure of the first connector in Embodiment 1 provided by the present invention;

[0058] Figure 11 This is a schematic diagram of the structure of the first annular component in Embodiment 1 provided by the present invention;

[0059] Figure 12 This is a schematic diagram of the structure of the third arc-shaped plate in Embodiment 1 provided by the present invention;

[0060] Figure 13 This is a flowchart of the sand casting method for large ring-shaped castings provided by the present invention.

[0061] The attached figures are labeled as follows: 1. Circular base one; 2. First annular component; 3. Second annular component; 10. Circular base two; 20. Adjustment scale plate; 30. Casting bracket; 301. Support base; 302. Support platform; 303. U-shaped support component; 304. Casting liquid tank; 305. Housing shell; 306. Baffle; 307. Cylinder seat plate; 308. Lifting cylinder; 309. Arc-shaped filter screen; 31. First curved section; 32. Second curved section; 33. First bend section; 34. Second bend section. 4. Bend; 4. First connecting piece; 41. Trapezoidal base; 35. First casting area; 6. Annular adjusting piece; 61. First arc plate; 62. Second arc plate; 63. U-shaped pull plate; 64. Fastening threaded hole; 65. Fastening bolt; 42. Vertical partition; 43. Fixing bolt; 44. First nut; 21. Third arc plate; 22. Third bend; 23. Second connecting piece; 24. Fourth arc plate; 231. Vertical plate; 232. Threaded rod; 233. Second nut; 221. Long hole. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0064] Example 1

[0065] like Figures 1 to 2 As shown, this embodiment provides an apparatus for sand casting of a large annular casting, including an annular sand box. The annular sand box includes a circular base 1 and a first annular component 2 fixedly installed at the center of the top surface of the circular base 1. A second annular component 3 is fitted on the outside of the first annular component 2.

[0066] The bottom of the circular base 1 is provided with a circular base 2 10. The top surface of the circular base 2 10 is evenly distributed with adjustment grooves along the circumference. An adjustment scale plate 20 is slidably installed in the adjustment groove. A casting bracket 30 is fixedly installed at the other end of the adjustment scale plate 20.

[0067] Because the ring casting is large in size, the melting capacity of the existing melting furnace is limited. Therefore, it is necessary to use the molten metal from multiple melting furnaces to pour at the same time. The existing pouring method is generally done manually. The cylinder containing the molten metal is heavy. Usually, two or three people work together to lift one cylinder and then pour the casting. This is labor-intensive, has the risk of molten metal splashing, and the pouring time cannot be guaranteed to be completely uniform, which will affect the quality of the casting.

[0068] By setting multiple casting supports 30 on the outer periphery of the circular base 1, multiple casting processes can be carried out simultaneously, reducing the labor intensity of workers and improving work efficiency. Moreover, the individual casting supports 30 can be adjusted according to the actual size of the annular casting and the required amount of molten metal to suit different casting needs.

[0069] The adjusting scale plate 20 is used to adjust the length of the adjusting scale plate 20 sliding into the adjusting groove according to the specifications of the second annular part 3, so that the position of the casting support 30 is suitable for the release of molten metal.

[0070] like Figures 3 to 4As shown, the casting support 30 includes a support base 301 and a support platform 302 fixedly installed on the top surface of the support base 301. A U-shaped support member 303 is installed on the top of the support platform 302, and a casting liquid tank 304 is provided in the open end of the U-shaped support member 303.

[0071] The casting liquid tank 304 is equipped with ear plates;

[0072] The casting liquid tank 304 is tightly fitted with a housing 305. The housing 305 is rotatably installed in the open end of the U-shaped support 303. The ear plate is fixed to the top of the housing 305 by bolt connection.

[0073] A baffle 306 is installed at the bottom of the housing 305;

[0074] A cylinder seat plate 307 is provided on the upper part of the support platform 302. A lifting cylinder 308 is rotatably mounted on the cylinder seat plate 307. The output end of the lifting cylinder 308 is rotatably connected to the baffle 306.

[0075] An arc-shaped filter screen 309 is fixedly installed inside the casting liquid tank 304;

[0076] Among them, the arc-shaped filter screen 309 is installed in a semi-circle inside the casting liquid tank 304. During the casting of molten metal, it is used to filter the molten metal inside the casting liquid tank 304. After being filtered by the arc-shaped filter screen 309, the molten metal falls into the annular sand box.

[0077] The working principle of the casting support 30 is as follows: by starting the lifting cylinder 308, the baffle 306 is pushed, which causes the housing 305 to rotate in the opening end of the U-shaped support 303. The casting liquid tank 304 located in the housing 305 is tilted, and the molten metal in the casting liquid tank 304 flows out and falls into the annular sand box through the riser position.

[0078] Among them, multiple lifting cylinders 308 are controlled by a controller, so that multiple lifting cylinders 308 can rotate the casting liquid tank 304 at the same time, guiding the molten metal in the casting liquid tank 304 to flow out.

[0079] like Figures 5 to 9 As shown, the second annular component 3 includes a first curved portion 31 and a second curved portion 32;

[0080] The two ends of the first curved portion 31 are bent outward to form the first curved portion 33, and the two ends of the second curved portion 32 are bent outward to form the second curved portion 34.

[0081] A first connector 4 is provided between the adjacent first bend 33 and the second bend 34, and the adjacent first bend 33 and the second bend 34 are connected and fixed by the first connector 4;

[0082] Trapezoidal bases 41 are fixedly installed at the lower ends of both first connectors 4;

[0083] A circular base 1 is fixedly installed between two trapezoidal bases 41;

[0084] The first annular component 2 can be installed on the top of the circular base 1 by welding or sealing connection;

[0085] A first casting zone 35 is formed between the first curved portion 31 and the second curved portion 32. An annular adjusting member 6 is provided in the first casting zone 35. The annular adjusting member 6 is tightly disposed on the inner surface of the first curved portion 31 and the second curved portion 32.

[0086] The annular adjusting member 6 includes a first arc-shaped plate 61 and a second arc-shaped plate 62 that is slidably mounted on the inner surface of the first arc-shaped plate 61;

[0087] Both ends of the outer circumferential surface of the first arc plate 61 are equipped with U-shaped pull plates 63. The closed end of the U-shaped pull plate 63 has a fastening threaded hole 64, and a fastening bolt 65 is connected to the internal thread of the fastening threaded hole 64.

[0088] The outer surfaces of the first curved portion 31 and the second curved portion 32 are both provided with grooves that mate with the two ends of the U-shaped pull plate 63.

[0089] The two ends of the U-shaped pull plate 63 pass through the sliding groove and are fixedly connected to the first arc-shaped plate 61;

[0090] In actual adjustment, the size of the first casting area 35 is changed by changing the distance between the two adjacent first bends 33 and second bends 34. The first arc plate 61 and the second arc plate 62 inside are deformable metal plates, which can be adjusted adaptively by pulling the U-shaped pull plate 63. After the adjustment is completed, the position of the U-shaped pull plate 63 is limited by the fastening bolt 65.

[0091] After the first arc plate 61 and the second arc plate 62 are adjusted, they can be fixed to the first curved part 31 and the second curved part 32 by bolt connection. The first arc plate 61 and the second arc plate 62 can also be fixed by bolt connection.

[0092] Alternatively, the overlapping portions of the first arc plate 61 and the second arc plate 62 can be welded together and then welded to the top of the circular base 1. Or, a sealing connection can be used to seal the first arc plate 61 and the second arc plate 62 to the top of the circular base 1.

[0093] like Figure 10As shown, the first connector 4 includes a vertical partition 42 and fixing bolts 43 fixedly installed on the front and rear sides of the vertical partition 42. The external thread of the fixing bolts 43 has two first nuts 44.

[0094] Both the first bend 33 and the second bend 34 have a first through hole on their front side, and the fixing bolt 43 can be placed in the first through hole;

[0095] The first annular component 2 adopts a clamp-type structure, and the distance between the first curved part 31 and the second curved part 32 can be adjusted by the first connecting part 4, thereby adjusting the area of ​​the region formed between the first curved part 31 and the second curved part 32.

[0096] By setting the first connector 4, the first bent portion 33 is fixed between the two first nuts 44, thereby fixing the position of the first bent portion 31. This setting is used to adjust the area of ​​the region formed between the first bent portion 31 and the second bent portion 32, and then fix the first bent portion 31 and the second bent portion 32, which facilitates subsequent operations.

[0097] like Figures 11 to 12 As shown, the first annular component 2 includes a pair of third arc-shaped plates 21, the two ends of the third arc-shaped plates 21 are bent inward to form third bends 22, and a second connector 23 is provided between two adjacent third bends 22 on the two third arc-shaped plates 21.

[0098] The fourth arc plate 24 is slidably installed at both ends of the outer circumferential surface of the third arc plate 21;

[0099] The third arc plate 21 and the fourth arc plate 24 are both placed closely on the top of the circular base 1;

[0100] The third arc plate 21 and the fourth arc plate 24 can be installed on the top of the circular base 1 by welding or sealing connection.

[0101] The second connector 23 includes a vertical plate 231 and a threaded rod 232 fixedly installed on the front and rear sides of the vertical plate 231. The threaded rod 232 has two second nuts 233 connected to its external thread.

[0102] The vertical plate 231 is fixed to the top of the circular base 1 by welding or bolt connection;

[0103] The third bend 22 has an elongated hole 221, and the threaded rod 232 is located inside the elongated hole 221. The threaded rod 232 can slide inside the elongated hole 221.

[0104] The second connector 23 is fixedly installed on the top of the circular base 1;

[0105] The third connector 23 is used to fix the positions of the two third arc plates 21. Its adjustment steps and working principle are the same as those of the first connector 4.

[0106] The height of the third arc-shaped plate 21 is greater than the height of the first arc-shaped plate 61.

[0107] This embodiment provides an apparatus for sand casting of large ring castings, which can be flexibly adjusted according to different needs and scenarios to meet different manufacturing requirements.

[0108] This adjustable annular sand box can produce the required sand mold more quickly and accurately, improving production efficiency. Moreover, since the annular sand box can be used for annular parts of different sizes, it saves materials and costs.

[0109] This embodiment provides an apparatus for sand casting of large ring castings, which has high flexibility and adaptability, can improve the casting efficiency of ring castings, save costs and materials, and is easy to expand and safe to use.

[0110] Example 2

[0111] like Figure 13 As shown, a sand casting method for a large ring-shaped casting includes the following steps:

[0112] Step a: Based on the required shape and size of the ring casting, divide the ring product into multiple modules and draw the machining drawings for each module.

[0113] In this step, the large ring casting is divided into multiple modules for processing, which can effectively simplify the processing and facilitate the manufacturing of individual modules;

[0114] At the same time, based on the shape and size requirements of the ring casting provided by the customer, segmented drawing is performed, which can accurately control the size and shape of individual modules and improve the accuracy of ring casting products of different sizes.

[0115] In addition, for large ring castings, not only is the model processing difficult, but if processing damage or other abnormalities occur during the model processing, the entire model needs to be reprocessed, which not only wastes raw materials and increases costs, but also prolongs the production and processing time. Dividing large ring castings into multiple modules for segmented processing means that if processing damage or other abnormalities occur, only the corresponding individual modules need to be re-carved or replaced, reducing material waste and lowering production costs.

[0116] Step b: Based on the processing drawings of multiple modules in step a, use a five-axis continuous carving method to perform carving processing and obtain multiple segmented models;

[0117] In step b, the model material used in the carving process is polystyrene foam;

[0118] Step c: According to the shape of the ring casting product, assemble multiple segmented models to form a casting product model; risers are provided on the end face of the casting product model;

[0119] In step c, the specific steps of the splicing and forming process are as follows: according to the shape of the ring casting product, multiple segment models are spliced ​​together, and hot melt glue guns are used to glue the connection between two adjacent segment models. After all the segment models are glued together, a casting product model is prepared.

[0120] Among them, a riser is provided on the end face of the casting product model, which is to raise the end face of the casting product model by a certain height to serve as a riser;

[0121] Step d: Take the annular sand box, fill the bottom of the annular sand box with sand, move the casting product model into the annular sand box, continue to fill the annular sand box with sand until it is full, vibrate and compact the annular sand box to complete the shaping of the casting product model in the annular sand box.

[0122] Step e: After the molding is completed, use an electric hot knife to remove the casting product model inside the annular sand box, and the area where the original casting product model was located inside the annular sand box forms a cavity;

[0123] In step e, the heating power of the electric heating knife can be either 300W or 350W. When using a 300W electric heating knife, the preheating time is 3 minutes. When using a 350W electric heating knife, the preheating time is 2.5 minutes.

[0124] Setting a preheating time is to avoid excessive preheating time and overheating of the electric hot knife;

[0125] In the existing technology, the methods for removing white mold in the sand box mainly include mechanical removal, sandblasting, chemical etching and laser cutting. Some of these methods require special mechanical equipment and are costly.

[0126] Step f: Apply paint to the annular sand box cavity portion of the removed model;

[0127] The purpose of applying the coating is to ensure that the molten metal does not react with the resin sand during the casting process. For the resin sand in deep holes and grooves, the coating will be applied by dip-brushing.

[0128] Step g: Pour the molten metal in the melting furnace along the riser to prepare the required ring casting;

[0129] During this process, filter screens are installed at all pouring points of the molten metal. The filter screens are placed on the top of the annular sand box. After being filtered by the filter screens, the molten metal is poured through the riser. The filter screens are installed to filter the molten metal, prevent slag accumulation, and ensure product quality.

[0130] Since the maximum melting capacity of a single melting furnace is limited in the existing technology, multiple melting furnaces can be used simultaneously to melt the metal raw materials during the casting of large-sized ring castings. The molten metal prepared by multiple melting furnaces can be poured simultaneously from the riser position to produce qualified products in one go, saving cycle time and cost.

[0131] The sand casting method for large ring castings provided in this embodiment offers a new approach to the casting method in the subsequent prototype trial production stage.

[0132] This embodiment uses a white mold forming alloy casting method for sand casting of large ring castings;

[0133] In this embodiment, for larger ring-shaped castings, a segmented carving and splicing method is used to prepare the casting product model, which provides a reference for carving large casting product models of other shapes.

[0134] In this embodiment, an electric hot knife is used to remove the casting product model, i.e., the white model, in the annular sand box to avoid directly pouring molten metal, which would cause pinholes in the prepared annular casting and thus compromise product quality.

[0135] In this embodiment, a coating is applied inside the mold cavity to ensure that the molten metal does not react with the resin sand during the casting process.

[0136] Example 3

[0137] This embodiment provides a sand casting method for large ring-shaped castings based on actual conditions. It employs the apparatus of the sand casting method for large ring-shaped castings in Embodiment 1 and the sand casting method for large ring-shaped castings in Embodiment 2. The sand casting method for large ring-shaped castings based on actual conditions includes the following steps:

[0138] Step a: Based on the required shape and size of the ring casting, divide the ring product into multiple modules and draw the machining drawings for each module.

[0139] Step b: Based on the processing drawings of multiple modules in step a, use a five-axis continuous carving method to perform carving processing and obtain multiple segmented models;

[0140] In step b, the model material used in the carving process is polystyrene foam;

[0141] Step c: According to the shape of the ring casting product, use a hot melt glue gun to glue the connection between two adjacent segment models, thereby assembling multiple segment models into a shape, and obtaining the casting product model after assembly; risers are provided on the end face of the casting product model;

[0142] Among them, a riser is provided on the end face of the casting product model, which is to raise the end face of the casting product model by a certain height to serve as a riser;

[0143] Step d: Take the annular sand box and adjust its size according to the dimensions of the casting product model;

[0144] In step d, the specific adjustment process is as follows:

[0145] Step 3.1: Determine the inner and outer diameters of the annular sand box based on the dimensions of the casting product model;

[0146] Step 3.2: Adjust the first arc plate 61 and the second arc plate 62 according to the outer diameter value of the annular sand box in Step 3.1, so that the first arc plate 61 and the second arc plate 62 are bent to form the required outer diameter value of the annular sand box. After the adjustment is completed, the first arc plate 61 and the second arc plate 62 are connected and fixed by bolts or welding.

[0147] Step 3.3: After initially fixing the first arc plate 61 and the second arc plate 62, adjust the distance between the first curved part 31 and the second curved part 32 so that the first arc plate 61 and the second arc plate 62 fit tightly between the first curved part 31 and the second curved part 32. The first arc plate 61 and the second arc plate 62 can be fixed to the first curved part 31 and the second curved part 32 by bolt connection. After adjustment, use the first nut 44 to limit the position of the first curved part 31 and the second curved part 32.

[0148] Step 3.4: Fix the first bent part 31 and the second bent part 32 to the circular base 1 by means of sealing connection, bolt connection or welding;

[0149] Step 3.5: Adjust the first annular part 2 according to the inner diameter value of the annular sand box in Step 3.1, so that the two third arc plates 21 are bent to form the required inner diameter value of the annular sand box. After the adjustment is completed, use the second nut 233 to limit it.

[0150] Step 3.6: Fix the fourth arc-shaped plate 24 to the outside of the two third arc-shaped plates 21 using bolts or welding;

[0151] Step 3.7: Fix the two third arc plates 21 and the two fourth arc plates 24 to the top of the circular base 1 by means of sealing connection, bolt connection or welding to complete the adjustment of the annular sand box;

[0152] Step e: Move the casting product model into the annular sand box, vibrate and compact the annular sand box to complete the shaping of the casting product model in the annular sand box;

[0153] Step f: After the molding is completed, use an electric hot knife to remove the casting product model in the annular sand box, and the area where the original casting product model was located in the annular sand box forms a cavity;

[0154] In step f, the heating power of the electric heating knife can be either 300W or 350W. When using a 300W electric heating knife, the preheating time is 3 minutes. When using a 350W electric heating knife, the preheating time is 2.5 minutes.

[0155] Step g: Apply a coating to the inside of the cavity, wherein the coating is an alcohol-based coating for casting sand, specifically, an alcohol-based talc coating is selected;

[0156] Step h: Multiple filter screens are set on the top of the annular sand box along the circumference. The molten metal in the melting furnace is filtered through the filter screens and then poured into the riser to prepare the required annular casting.

[0157] The sand casting method for large ring castings provided in this embodiment offers a new approach to the casting method in the subsequent prototype trial production stage.

[0158] In this embodiment, for larger ring-shaped castings, a segmented carving and splicing method is used to prepare the casting product model. The adjustable ring sand box design is suitable for casting ring-shaped castings of different specifications and provides a reference for carving large casting product models of other shapes.

[0159] This invention provides a sand casting method and apparatus for large ring castings, which can be used for casting large ring castings without molds or sand boxes.

[0160] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0161] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A sand casting apparatus for large annular castings, comprising an annular sand box, characterized in that, The annular sand box includes a circular base (1) and a first annular component (2) disposed at the center of the top surface of the circular base (1). A second annular component (3) is fitted on the outside of the first annular component (2). The bottom of the circular base one (1) is provided with a circular base two (10). The top surface of the circular base two (10) is evenly distributed with adjustment grooves along the circumferential direction. An adjustment scale plate (20) is slidably installed in the adjustment groove. A casting bracket (30) is fixedly installed at the other end of the adjustment scale plate (20). The second annular member (3) includes a first curved portion (31) and a second curved portion (32); The two ends of the first bending portion (31) are bent outward to form a first bending portion (33), and the two ends of the second bending portion (32) are bent outward to form a second bending portion (34). A first connector (4) is provided between the adjacent first bend (33) and the second bend (34), and the adjacent first bend (33) and the second bend (34) are connected and fixed by the first connector (4); Trapezoidal bases (41) are fixedly installed at the lower ends of both first connectors (4). The circular base (1) is fixedly installed between the two trapezoidal bases (41); A first casting area (35) is formed between the first curved portion (31) and the second curved portion (32). An annular adjusting member (6) is provided in the first casting area (35). The annular adjusting member (6) is tightly disposed on the inner surface of the first curved portion (31) and the second curved portion (32). The first annular component (2) includes a pair of third arc-shaped plates (21), the two ends of the third arc-shaped plates (21) are bent inward to form third bends (22), and a second connector (23) is provided between two adjacent third bends (22) on the two third arc-shaped plates (21). The third arc plate (21) has a fourth arc plate (24) slidably installed at both ends of its outer circumferential surface. The annular adjusting member (6) includes a first arc plate (61) and a second arc plate (62) slidably mounted on the inner surface of the first arc plate (61). Both ends of the outer circumferential surface of the first arc plate (61) are equipped with U-shaped pull plates (63), and the closed end of the U-shaped pull plate (63) is provided with a fastening thread hole (64), and a fastening bolt (65) is connected to the internal thread of the fastening thread hole (64). The outer surfaces of the first curved portion (31) and the second curved portion (32) are both provided with grooves that cooperate with the two ends of the U-shaped pull plate (63); The second connector (23) includes a vertical plate (231) and a threaded rod (232) fixedly installed on the front and rear sides of the vertical plate (231). The threaded rod (232) has two second nuts (233) connected to its external thread. The third bend (22) is provided with an elongated hole (221), and the threaded rod (232) is located in the elongated hole (221). The threaded rod (232) can slide in the elongated hole (221). The second connector (23) is fixedly installed on the top of the circular base (1); The third arc plate (21) and the fourth arc plate (24) are both placed closely on the top of the circular base (1).

2. The sand casting apparatus for a large annular casting according to claim 1, characterized in that: The casting support (30) includes a support base (301) and a support platform (302) fixedly installed on the top surface of the support base (301). A U-shaped support (303) is installed on the top of the support platform (302), and a casting liquid tank (304) is provided in the open end of the U-shaped support (303). The casting liquid tank (304) is provided with ear plates; The casting liquid tank (304) is tightly fitted with a housing (305), which is rotatably installed in the opening end of the U-shaped support (303). The ear plate is fixed to the top of the housing (305) by bolt connection. A baffle (306) is installed at the bottom of the housing (305); A cylinder seat plate (307) is provided on the upper outer side of the support platform (302), and a lifting cylinder (308) is rotatably mounted on the cylinder seat plate (307). The output end of the lifting cylinder (308) is rotatably connected to the baffle (306). An arc-shaped filter screen (309) is fixedly installed inside the casting liquid tank (304).

3. The sand casting apparatus for a large annular casting according to claim 1, characterized in that: The first connector (4) includes a vertical partition (42) and fixing bolts (43) fixedly installed on the front and rear sides of the vertical partition (42). The external thread of the fixing bolts (43) has two first nuts (44). Both the first bent portion (33) and the second bent portion (34) have a first through hole on their front side, and the fixing bolt (43) can be placed in the first through hole.

4. A sand casting method for a large ring-shaped casting, characterized in that, Casting is performed using the sand casting apparatus for large annular castings as described in any one of claims 1-3, the method comprising the following steps: Step a: Based on the required shape and size of the ring casting, divide the ring product into multiple modules and draw the machining drawings for each module. Step b: Based on the processing drawings of multiple modules in step a, use a five-axis continuous carving method to perform carving processing and obtain multiple segmented models; Step c: According to the shape of the ring casting product, multiple segmented models are spliced ​​together to form a casting product model; risers are provided on the end face of the casting product model; Step d: Take the annular sand box, fill the bottom of the annular sand box with sand, move the casting product model into the annular sand box, continue to fill the annular sand box with sand until it is full, vibrate and compact the annular sand box to complete the shaping of the casting product model in the annular sand box. Step e: After the molding is completed, use an electric hot knife to remove the casting product model inside the annular sand box, and the area where the original casting product model was located inside the annular sand box forms a cavity; Step f: Apply paint to the annular sand box cavity portion of the removed model; Step g: Pour the molten metal in the melting furnace along the riser to prepare the required ring casting.

5. The sand casting method for a large ring-shaped casting according to claim 4, characterized in that: In step b, the model material used in the carving process is polystyrene foam.

6. The sand casting method for a large ring-shaped casting according to claim 4, characterized in that: In step c, the specific steps of the splicing and forming process are as follows: according to the shape of the ring casting product, multiple segmented models are spliced ​​together, and hot melt glue guns are used to bond the connection between two adjacent segmented models. After all the segmented models are bonded, a casting product model is prepared.

7. The sand casting method for a large ring-shaped casting according to claim 4, characterized in that: In step f, the coating is an alcohol-based talc coating.

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