Method for preparing castings containing multi-dimensional lumens

Abstract

This invention provides a method for preparing a casting containing a multi-dimensional cavity. The method includes assembling a core with multiple segmented wax models, such that the core is placed within the multi-dimensional cavity formed by the wax models. At least a portion of the core's tube body is suspended within the multi-dimensional cavity, and the distance between the suspended portion of the tube body and the corresponding wall of the multi-dimensional cavity is proportional to the wall thickness of the wax model corresponding to the suspended portion of the tube body. This invention utilizes the multi-dimensional fit between the core's multiple tube bodies distributed at multiple angles and the wax models, ensuring precise fit between the wax models and the core, and leveraging the core's dimensional accuracy to guarantee the dimensional accuracy of the casting's internal cavity.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and more specifically to a method for preparing castings containing multi-dimensional cavities. Background Technology

[0002] Titanium alloy precision castings are widely used in the aerospace, weaponry, and shipbuilding industries. Due to the stringent environmental requirements, high quality is essential for their production. Investment casting, also known as lost-wax casting, is typically employed. This method involves creating a pattern from a fusible material, coating the pattern with several layers of refractory material to form a shell, melting the pattern, removing it from the shell, and then firing it at high temperature to obtain the final casting. Molten metal is then poured into the shell to produce the final casting. The process generally includes wax pressing, shell preparation, dewaxing, molten metal pouring, and post-processing. Therefore, the quality of the titanium alloy shell significantly impacts the final casting quality.

[0003] For precision titanium alloy castings, due to the requirement for unified structure and function, the internal structure is complex, often containing blind cavities. This necessitates the use of ceramic cores to form these complex internal cavities. After casting, the cores are removed to reveal the internal cavity structure. Therefore, during the wax pressing process, a core is placed in the wax pressing mold before wax is poured in, forming a wax model with the core. For castings with complex internal cavities, a method of preparing segmented wax models in different areas and then assembling them into a single, integrated wax model is typically used. Since the integrated wax model is composed of multiple parts, misalignment can easily occur during assembly when fitting the segmented wax models and multi-angled cavity cores due to dimensional accuracy issues. This can prevent precise assembly of the segmented wax models with the cores, thus affecting the dimensional accuracy of the casting. Furthermore, core removal can result in incomplete removal or damage to the inner wall of the casting. Since castings are made by forming a mold shell and are finally formed after the core is removed, the above processes all affect the overall forming, dimensional accuracy and internal cavity quality of the castings, which seriously affects the reliability of the castings in use. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the main objective of the present invention is to provide a method for preparing a casting containing a multi-dimensional cavity. In this method, the core is partially suspended by a design that enables precise assembly of the core and the wax model. The multiple tubes of the core, distributed at multiple angles, form a multi-dimensional fit with the segmented wax model, which not only ensures the precise fit between the segmented wax model and the core, but also ensures the dimensional accuracy of the inner cavity of the casting by utilizing the dimensional accuracy of the core.

[0005] To achieve the above object, the present invention provides a method for preparing a casting containing multi-dimensional lumens, which includes the following steps: preparing a core according to the lumen structure of the casting, the core including a plurality of tubes distributed at multiple angles; designing a plurality of segmented wax molds according to the lumen structure of the casting, and combining and assembling the core with the plurality of segmented wax molds, so that the core is placed in the multi-dimensional lumen formed by surrounding of the plurality of segmented wax molds to obtain a casting wax film; wherein, at least a partial area of at least some of the tubes of the core is suspended in the multi-dimensional lumen, and the distance between the suspended part of the tube and the lumen wall at the corresponding position of the multi-dimensional lumen is in a proportional relationship with the wall thickness of the casting wax mold corresponding to the suspended part of the tube: d = kx; where k is a proportionality coefficient, d is the distance between the suspended part of the tube and the lumen wall at the corresponding position of the multi-dimensional lumen, and x is the wall thickness of the wax mold; preparing a mold shell on the surface of the casting wax film, and then roasting and dewaxing to obtain a casting mold shell; using the casting mold shell for molten liquid pouring, and removing the core after pouring to obtain the casting containing multi-dimensional lumens.

[0006] In some embodiments of the present invention, when 1mm ≤ x ≤ 8mm, 0.4 ≤ k ≤ 0.5; when 8mm < x ≤ 20mm, 0.1 ≤ k ≤ 0.15.

[0007] In some embodiments of the present invention, the inner diameter at the port of at least some of the tubes of the core is the same as the inner diameter at the port of the multi-dimensional lumen at the corresponding position for precise fitting.

[0008] In some embodiments of the present invention, the length of the tube with the same inner diameter at the port is ≥ 8mm.

[0009] In some embodiments of the present invention, designing a plurality of segmented wax molds according to the lumen structure of the casting includes: dividing the plurality of tubes of the core into X tubes, Y tubes, and Z tubes according to the extending direction of the tubes; taking the plane formed by the center lines of the X tubes and the Y tubes as the first dividing surface, and taking the plane formed by the center lines of the X tubes and some of the Z tubes connected to the X tubes as the second dividing surface, and dividing at the corresponding positions of the casting wax mold to obtain the plurality of segmented wax molds, and respectively serving as the bottom wax mold, the rear wax mold, and the front wax mold.

[0010] In some embodiments of the present invention, the X tubes, Y tubes, and Z tubes represent the three-dimensional directions of the X-axis, Y-axis, and Z-axis of the coordinate axes where the tubes are located, and there is at least one X tube, one Y tube, and one Z tube respectively.

[0011] In some embodiments of the present invention, a first channel groove is provided on the bottom wax model, a second channel groove is provided on the rear wax model, and a third channel groove is provided on the front wax model; the first channel groove, the second channel groove, and the third channel groove together form the multi-dimensional cavity.

[0012] In some embodiments of the present invention, the assembly of the core and the plurality of segmented wax molds includes: placing the X-tube, Y-tube and part of the Z-tube of the core in the first channel groove of the bottom wax mold for positioning in the X, Y and Z directions; assembling the front wax mold and the rear wax mold onto the bottom wax mold respectively, with the front wax mold and the rear wax mold aligned, such that part of the second channel groove and part of the third channel groove surround to form a cavity for sleeved part of the Z-tube, and such that the first channel groove and part of the third channel groove and part of the second channel groove surround to form a cavity for sleeved X-tube, Y-tube and part of the Z-tube.

[0013] In some embodiments of the present invention, the Z tube body further includes a Z1 tube body connected to the Y tube body, and the rear wax mold is further provided with a through-tube cavity for fitting the Z1 tube body.

[0014] In some embodiments of the present invention, a portion of the Z1 tube body has the same inner diameter as the corresponding sleeve cavity for precise fit, while the remaining portion of the Z1 tube body is suspended in the sleeve cavity.

[0015] In some embodiments of the present invention, the preparation of the shell on the surface of the casting wax film includes: applying a surface layer slurry to the surface of the casting wax mold, and then removing the excess surface layer slurry; then applying surface layer sandblasting, and after drying, forming a surface layer shell; applying a back layer slurry to the surface of the surface layer shell, and removing the excess back layer slurry; then applying back layer sandblasting, and after drying, forming a first back layer shell; repeating the steps of applying back layer slurry and applying back layer sandblasting in the preparation of the back layer shell multiple times to form a multi-layer back layer shell.

[0016] In some embodiments of the present invention, the dewaxing process includes: heating to the dewaxing temperature and then holding it at that temperature, allowing the wax liquid to flow out from the dewaxing port, and then cooling the mold shell to room temperature with the furnace.

[0017] In some embodiments of the present invention, the dewaxing temperature is 100℃~250℃, and the holding time is 3h~8h.

[0018] In some embodiments of the present invention, the wax flows out from the wax outlet in the middle or side of the bottom region of the mold shell.

[0019] In some embodiments of the present invention, the roasting is carried out in a segmented continuous roasting process, which includes: sequentially raising the temperature to a first, second, and third roasting temperature, holding the temperature at the first, second, and third roasting temperatures respectively, and then cooling and removing the product from the furnace.

[0020] In some embodiments of the present invention, the first calcination temperature is 500℃~600℃, and the holding time is ≥3h, preferably 3h~6h.

[0021] In some embodiments of the present invention, the second calcination temperature is 600℃~800℃, and the holding time is ≥3h, preferably 3h~8h.

[0022] In some embodiments of the present invention, the third calcination temperature is 900℃~1200℃, and the holding time is ≥3h, preferably 4h~12h.

[0023] In some embodiments of the present invention, the cooling and unloading process involves cooling the furnace to room temperature before unloading, or cooling the furnace to below 450°C before unloading.

[0024] In some embodiments of the invention, at least a portion of the core tube passes through the inner cavity of the mold shell and protrudes outside the casting mold shell.

[0025] In some embodiments of the present invention, before the shell is fired, the tube body through which the core passes through the inner cavity of the shell and protrudes outside the casting shell is covered with the same material as the shell, and the covered area is connected to part of the shell.

[0026] In some embodiments of the present invention, the covering area serves as the fixing area between the mold shell and the casting equipment.

[0027] In some embodiments of the present invention, the casting shell is preheated before casting, and the preheating temperature is 300°C to 500°C.

[0028] Advantages of this invention:

[0029] In this invention, the multi-dimensional fit between the multi-angled tubes of the core and the segmented wax mold ensures precise fit between the segmented wax mold and the core, and the dimensional accuracy of the core can be used to ensure the dimensional accuracy of the inner cavity of the casting later.

[0030] The method of fabricating a core in which at least a portion of the tube body is suspended in a multi-angle irregular cavity can avoid the problem that the core cannot be assembled with a multi-dimensional cavity in a certain dimension due to the multiple tube bodies distributed at multiple angles.

[0031] This invention enhances the stability of the mold shell and internal core through the fixing effect of the coating zone. During the casting process, when molten metal enters the mold shell, the coating zone and casting equipment are fixed, while the core portion protrudes from the outer side of the mold shell and is directly connected to the coating zone. This enhances the stability of the core under the impact of molten metal, preventing displacement that could affect the internal dimensions of the casting. Simultaneously, during centrifugal casting, it prevents the mold shell from shifting position on the centrifugal disc due to centrifugal force, thus preventing turbulent flow of the molten metal or incomplete filling. Attached Figure Description

[0032] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. In the drawings:

[0033] Figure 1 This is a schematic diagram of the core structure in an embodiment provided by the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of the bottom wax mold in the embodiments provided by the present invention;

[0035] Figure 3 This is a schematic diagram of the structure after the bottom wax mold and the core are assembled in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the structure of the front wax model in an embodiment provided by the present invention;

[0037] Figure 5 This is a schematic diagram of the structure of the core, bottom wax model and front wax model after assembly in the embodiment provided by the present invention;

[0038] Figure 6 Schematic diagram of the post-wax mold structure in the embodiments provided by the present invention Figure 1 ;

[0039] Figure 7 Schematic diagram of the post-wax mold structure in the embodiments provided by the present invention Figure 2 ;

[0040] Figure 8 This is a schematic diagram of the wax model structure of the casting provided in the embodiments of the present invention.

[0041] In the picture:

[0042] 1. Core; 11. X tube body; 12. Y tube body; 13. Z1 tube body; 14. Z2 tube body; 15. Z3 tube body; 16. Z4 tube body;

[0043] 2. Bottom wax mold; 21. First pipe groove; 22. First positioning protrusion; 23. Second positioning protrusion;

[0044] 3. Rear wax mold; 31. Second pipe groove; 32. Through-sleeve cavity;

[0045] 4. Front wax model; 41. Third pipe groove;

[0046] 5. Splice the top surface. Detailed Implementation

[0047] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0048] Because the overall wax model is composed of multiple parts, misalignment can easily occur during assembly when assembling segmented wax models and multi-angle tubular cores due to dimensional accuracy issues in their manufacturing. This can prevent precise assembly of the segmented wax models with the cores, thus affecting the dimensional accuracy of the casting. For wax models with internal cores, the cores are susceptible to displacement and breakage due to wax impact during the wax pressing process. Furthermore, since the shell requires high-temperature firing, this process affects the cores. For shells with internal cores, after dewaxing, the core is only connected to the shell at a fixed end, with the rest being a suspended structure. During high-temperature firing, thermal expansion and contraction can easily cause cracking or displacement, requiring controlled firing process to stabilize the quality of the shell and core. Additionally, core removal can result in incomplete removal or damage to the inner wall of the casting. Since castings are made by forming a mold shell and are finally formed after the core is removed, the above processes all affect the overall forming, dimensional accuracy and internal cavity quality of the castings, which seriously affects the reliability of the castings in use.

[0049] Reference Figures 1-8 As shown, the method for preparing a casting containing a multi-dimensional cavity in this embodiment of the invention is carried out according to the following steps.

[0050] (1) Preparation of core 1.

[0051] In an embodiment of the present invention, core 1 is prepared according to the casting cavity structure.

[0052] In an embodiment of the present invention, the core 1 includes multiple tubes distributed at multiple angles. The multiple tubes are distributed in different orientations in the X, Y, and Z three dimensions, which can be understood as the core 1 having a multi-angled pipe-like structure.

[0053] Figure 1 The diagram shows a specific structural schematic of a core 1.

[0054] According to the extension direction of the tube body, the multiple tube bodies that make up the core 1 are divided into X tube body 11, Y tube body 12 and Z tube body, wherein: Z tube body includes Z1 tube body 13, Z2 tube body 14, Z3 tube body 15 and Z4 tube body 16.

[0055] In an embodiment of the present invention, Z1 tube 13 is connected to Y tube 12, Z2 tube 14 is connected to X tube 11, and Z1 tube 13 and Z2 tube 14 are arranged in opposite directions.

[0056] In an embodiment of the present invention, tube Z3 15 is connected at the junction of tube X 11 and tube Y 12, and tube Z4 16 is connected at the junction of tube X 11 and tube Y 12.

[0057] In some embodiments of the present invention, the X tube 11 includes the X1 tube and the X2 tube; the Y tube 12 includes the Y1 tube and the Y2 tube.

[0058] (2) Design multiple segmented wax molds according to the structure of the casting cavity.

[0059] The wax model of the casting containing multi-dimensional cavities in this invention is obtained by assembling multiple segmented wax models and core 1.

[0060] In an embodiment of the present invention, each segmented wax mold has a channel groove formed thereon, and multiple segmented wax molds together form a multi-dimensional cavity. The core 1 is placed in the multi-dimensional cavity, thereby obtaining a casting wax film containing a multi-dimensional cavity.

[0061] In some embodiments of the present invention, designing multiple segmented wax molds according to the cavity structure of the casting includes the following steps:

[0062] According to the extension direction of the tube body, the multiple tube bodies of core 1 are divided into X tube body, Y tube body and Z tube body;

[0063] Using the plane formed by the centerlines of tubes X and Y as the first dividing plane, the bottom wax model 2 is obtained by dividing the wax model at the corresponding position of the casting wax model; and

[0064] Using the plane formed by the centerline of the X tube and the part of the Z tube connected to the X tube as the second dividing plane, the remaining wax pattern is divided at the corresponding position of the casting wax pattern to obtain the rear wax pattern 3 and the front wax pattern 4.

[0065] Therefore, the splicing of the front wax model 4, the rear wax model 3 and the bottom wax model 2 inevitably involves the positioning of the wax models in the three-dimensional directions of X, Y and Z, which helps to ensure that the wax models containing multi-angle cores are accurately positioned in all three dimensions during the splicing process.

[0066] Among them, a first pipe groove 21 is formed on the bottom wax mold 2, a second pipe groove 31 is formed on the rear wax mold 3, and a third pipe groove 41 is formed on the front wax mold 4. The core 1 is assembled with the bottom wax mold 2, the rear wax mold 3 and the front wax mold 4, and the core 1 is placed in the multi-dimensional pipe cavity formed by the enclosure of the first pipe groove 21, the second pipe groove 31 and the third pipe groove 41.

[0067] (3) Assemble and fit the core 1 with multiple segmented wax molds to prepare a casting wax film.

[0068] In an embodiment of the present invention, at least part of the tube body of the core 1 is suspended in the multi-dimensional pipe cavity, and the distance between the suspended part of the tube body and the cavity wall of the multi-dimensional pipe cavity at the corresponding position is proportional to the wall thickness of the casting wax mold corresponding to the suspended part of the tube body: d = kx; where k is the proportionality coefficient, d is the distance between the suspended part of the tube body and the cavity wall of the multi-dimensional pipe cavity at the corresponding position, and x is the wall thickness of the wax mold.

[0069] In an embodiment of the present invention, when 1 mm ≤ x ≤ 8 mm, 0.4 ≤ k ≤ 0.5.

[0070] In an embodiment of the present invention, when 8 mm < x ≤ 20 mm, 0.1 ≤ k ≤ 0.15.

[0071] In an embodiment of the present invention, the distance d designed according to the proportional relationship can meet the assembly requirements of the core 1 and also meet the requirements of wax mold shrinkage and deformation.

[0072] In an embodiment of the present invention, at least part of the tube body of the core 1 is suspended in the multi-dimensional pipe cavity, and the remaining part of at least part of the tube body has the same inner diameter as the inner diameter of the multi-dimensional pipe cavity at the corresponding position for precise fitting.

[0073] In the present invention, the method of suspending at least part of the tube body of the core 1 in the multi-dimensional pipe cavity can avoid the problem that the core 1 cannot be assembled with the multi-dimensional pipe cavity in a certain dimension due to having multiple tube bodies with multi-angle distributions.

[0074] In the present invention, due to the multi-dimensional fitting relationship formed by the multi-angle distributed tube bodies of the core 1 and the segmented wax molds, it can not only ensure the precise fitting of the segmented wax molds and the core 1, but also ensure the dimensional accuracy of the inner cavity of the later casting by using the dimensional accuracy of the core 1.

[0075] In some embodiments of the present invention, the inner diameter of the port of at least part of the tube body of the core 1 is the same as the inner diameter of the port of the multi-dimensional pipe cavity for precise fitting, and the remaining part of at least part of the tube body is suspended in the multi-dimensional pipe cavity.

[0076] In some embodiments of the present invention, the tube body length of the part with the same inner diameter at the port of the tube body ≥ 8 mm to ensure high-precision fitting.

[0077] The present invention employs a method in which the port of the multi-dimensional cavity is precisely matched with the port of at least a portion of the tube body of the core 1, while the remaining portion of the tube body is suspended in the multi-dimensional cavity. This method avoids the problem that the core 1, due to having multiple tube bodies distributed at multiple angles, cannot be assembled with the multi-dimensional cavity in a certain dimension.

[0078] In an embodiment of the present invention, when the wall thickness of the casting wax model corresponding to the suspended part of the tube body is ≤10mm, the distance between the suspended part of the tube body and the cavity wall of the multi-dimensional tube at the corresponding position is ≤1mm. This can also be understood as the distance between the suspended part of the tube body and the groove walls of the first pipe groove 21, the second pipe groove 31, and the third pipe groove 41 at the corresponding position is ≤1mm.

[0079] In an embodiment of the present invention, when the wall thickness of the casting wax model corresponding to the suspended part of the tube body is >10mm, the distance between the suspended part of the tube body and the cavity wall of the multi-dimensional tube at the corresponding position is ≤2mm. This can also be understood as the distance between the suspended part of the tube body and the groove walls of the first pipe groove 21, the second pipe groove 31, and the third pipe groove 41 at the corresponding position is ≤2mm.

[0080] In some embodiments of the present invention, when the wall thickness of the casting wax model corresponding to the suspended part of the tube body is ≤3mm, the distance between the suspended part of the tube body and the cavity wall of the multi-dimensional tube at the corresponding position is ≤0.5mm. It can also be understood that the distance between the suspended part of the tube body and the groove walls of the first pipe groove 21, the second pipe groove 31, and the third pipe groove 41 at the corresponding position is ≤0.5mm.

[0081] In the embodiments of the present invention, the spacing design between the suspended part of the tube and the cavity wall of the multi-dimensional tube at the corresponding position can adapt to the assembly requirements of the core 1, as well as the requirements of wax mold shrinkage and deformation.

[0082] As one embodiment of the present invention, the assembly of the core 1 and multiple segmented wax molds includes the following steps:

[0083] (3-1) Assemble the core 1 onto the bottom wax mold 2 to obtain the combined structure of the core 1 and the bottom wax mold 2.

[0084] Figure 3 A schematic diagram of the structure of a base wax mold 2 is shown. Figure 4 A schematic diagram of the assembly structure of the core 1 being assembled onto the bottom wax mold 2 is shown.

[0085] In an embodiment of the present invention, the core 1 is placed in the first channel groove 21 corresponding to the bottom wax mold 2, and part of the tube is placed in the first channel groove 21, and positioning in the X, Y and Z directions is achieved to prevent the core 1 from sliding in the first channel groove 21.

[0086] In some embodiments of the present invention, the X tube 11, Y tube 12 and part of the Z tube of the core 1 are placed in the first channel groove 21 of the bottom wax mold 2 to be positioned in the X, Y and Z directions.

[0087] In some embodiments of the present invention, the X tube 11, Y tube 12, and Z2 tube 14 of the core 1 are placed correspondingly in the first channel groove 21 of the bottom wax mold 2. The X tube 11 and Y tube 12 respectively mate with a portion of the first channel groove 21 (which can be called the first core groove) to be positioned in the X and Y directions; the Z2 tube 14 mates with a portion of the first channel groove 21 (which can be called the first positioning groove) to be positioned in the Z direction. At this time, the core 1 is positioned in the X, Y, and Z directions by the X tube 11, Y tube 12, and Z2 tube 14, preventing the core 1 from sliding in the first channel groove 21.

[0088] It is worth mentioning that the inner diameters at the ports of the X tube 11 and Y tube 12 of the core 1 are the same as the inner diameters at the ports of the first pipe groove 21 at the corresponding positions, which is a precision fit.

[0089] The inner diameter of the remaining parts of the X tube 11 and Y tube 12 of the core 1 is smaller than the inner diameter of the first pipe groove 21 at the corresponding position. After the core 1 is assembled into the first pipe groove 21, the X tube 11 and Y tube 12 are fixed only through the port of the first pipe groove 21, and the remaining parts of the X tube 11 and Y tube 12 are suspended in the first pipe groove 21.

[0090] In some embodiments of the present invention, the inner diameter of the Z2 tube 14 is the same as the inner diameter of the first pipe groove 21 at the corresponding position for a precise fit, ensuring accurate positioning in the Z direction.

[0091] In some embodiments of the present invention, when the wall thickness of the casting wax model corresponding to the suspended portion of the X-tube 11 and Y-tube 12 is ≤10mm, the distance between the suspended portion of the X-tube 11 and Y-tube 12 and the cavity wall of the multi-dimensional cavity at the corresponding position is ≤1mm. It can also be understood that the distance between the suspended portion of the X-tube 11 and Y-tube 12 and the groove wall of the first pipe groove 21 at the corresponding position is ≤1mm.

[0092] In some embodiments of the present invention, when the wall thickness of the casting wax model corresponding to the suspended portion of the X-tube 11 and Y-tube 12 is >10mm, the distance between the suspended portion of the X-tube 11 and Y-tube 12 and the cavity wall of the multi-dimensional cavity at the corresponding position is ≤2mm. This can also be understood as the distance between the suspended portion of the X-tube 11 and Y-tube 12 and the groove wall of the first pipe groove 21 at the corresponding position is ≤2mm.

[0093] In some embodiments of the present invention, when the wall thickness of the casting wax model corresponding to the suspended portion of the X-tube 11 and Y-tube 12 is ≤3mm, the distance between the suspended portion of the X-tube 11 and Y-tube 12 and the cavity wall of the multi-dimensional cavity at the corresponding position is ≤0.5mm. This can also be understood as the distance between the suspended portion of the X-tube 11 and Y-tube 12 and the groove wall of the first pipe groove 21 at the corresponding position is ≤0.5mm.

[0094] (3-2) Assemble the front wax mold 4 onto the bottom wax mold 2 to obtain the combined structure of the core 1, the bottom wax mold 2 and the front wax mold 4.

[0095] Figure 5 A schematic diagram of a front wax mold 4 is shown. The structure of the core 1, bottom wax mold 2, and front wax mold 4 after assembly is as follows. Figure 6 As shown.

[0096] In an embodiment of the present invention, the third pipe groove 41 of the front wax mold 4 is provided in a corresponding part of the pipe body, and the front wax mold 4 is assembled onto the bottom wax mold 2.

[0097] In some embodiments of the present invention, a portion of the third pipe groove 41 corresponds to a portion of the first pipe groove 21 and surrounds it for connecting the X pipe body 11 and the Y pipe body 12.

[0098] In some embodiments of the present invention, a portion of the third pipe groove 41 is provided corresponding to the Z3 pipe body 15 and the Z4 pipe body 16.

[0099] After the front wax mold 4 is assembled with the X tube 11, Y tube 12 and Z2 tube 14 of the core 1, it is assembled onto the bottom wax mold 2. Therefore, the front wax mold 4 and the bottom wax mold 2 are positioned in the X and Y directions, and the front wax mold 4 cannot move in the X and Y directions, thus ensuring accurate assembly in the X and Y directions.

[0100] It is worth mentioning that the inner diameter of the port of the third pipe groove 41 of the front wax mold 4 is the same as the inner diameter of the port of the corresponding fitting pipe body, which is a precision fit.

[0101] The inner diameter of the remaining part of the third pipe groove 41 is larger than the inner diameter of the corresponding pipe body. After the current wax model 4 is assembled onto the bottom wax model 2, the X pipe body 11, Y pipe body 12 and part of the Z pipe body, such as Z3 pipe body 15 and Z4 pipe body 16, are fixed only through the port of the third pipe groove 41. The remaining parts of the X pipe body 11, Y pipe body 12 and part of the Z pipe body are suspended in the third pipe groove 41.

[0102] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 is ≤10mm, the distance between the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 and the groove wall of the third pipe groove 41 at the corresponding position is ≤1mm.

[0103] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 is >10mm, the distance between the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 and the groove wall of the third pipe groove 41 at the corresponding position is ≤2mm.

[0104] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 is ≤3mm, the distance between the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 and the groove wall of the third pipe groove 41 at the corresponding position is ≤0.5mm.

[0105] In an embodiment of the present invention, a second positioning protrusion 23 is also provided on the bottom wax mold 2. The second positioning protrusion 23 is used for positioning and assembly with the front wax mold 4, so that the front wax mold 4 and the bottom wax mold 2 form a positioning assembly.

[0106] (3-3) Assemble the rear wax mold 3 onto the bottom wax mold 2 to obtain the combined structure of core 1, bottom wax mold 2, front wax mold 4 and rear wax mold 3.

[0107] Figure 7 A schematic diagram of the structure of a post-wax mold 3 is shown. Figure 1 , Figure 8 A schematic diagram of the structure of a post-wax mold 3 is shown. Figure 2 The overall wax model structure after assembling the core 1, bottom wax model 2, front wax model 4, and rear wax model 3 is as follows: Figure 8 As shown.

[0108] In an embodiment of the present invention, the second pipe groove 31 of the rear wax mold 3 is placed corresponding to a portion of the tube body of the core 1, and the rear wax mold 3 is assembled onto the bottom wax mold 2. The front wax mold 4 and the rear wax mold 3 are aligned, such that a portion of the second pipe groove 31 of the rear wax mold 3 and a portion of the third pipe groove 41 of the front wax mold 4 enclose a cavity for a sleeved portion of the Z tube body, such as the cavity of the Z3 tube body 15 and the Z4 tube body 16. At the same time, the first pipe groove 21 of the bottom wax mold 2, a portion of the third pipe groove 41 and a portion of the second pipe groove 31 enclose a cavity for a sleeved X tube body 11, Y tube body 12 and a portion of the Z tube body, such as the Z2 tube body 14.

[0109] After the rear wax mold 3 is assembled with the X tube 11, Y tube 12 and Z4 tube 16 of the core 1, it is mounted on the bottom wax mold 2 and the front wax mold 4. Therefore, the rear wax mold, the front wax mold 4 and the bottom wax mold 2 are positioned in the X and Y directions, and the rear wax mold 3 cannot move in the X and Y directions, thus ensuring accurate assembly in the X and Y directions.

[0110] It is worth mentioning that the inner diameter of the port of the second pipe groove 31 of the rear wax mold 3 is the same as the inner diameter of the port of the corresponding fitting pipe body, which is a precision fit.

[0111] The inner diameter of the remaining part of the second pipe groove 31 is larger than the inner diameter of the corresponding pipe body. After the rear wax model 3 is assembled onto the bottom wax model 2, the X pipe body 11, Y pipe body 12 and part of the Z pipe body, such as Z3 pipe body 15 and Z4 pipe body 16, are fixed only through the port of the second pipe groove 31. The remaining parts of the X pipe body 11, Y pipe body 12 and part of the Z pipe body are suspended in the second pipe groove 31.

[0112] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 is ≤10mm, the distance between the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 and the groove wall of the second pipe groove 31 at the corresponding position is ≤1mm.

[0113] In some embodiments of the present invention, when the wall thickness of the casting wax model corresponding to the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 is >10mm, the distance between the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 and the groove wall of the second pipe groove 31 at the corresponding position is ≤2mm.

[0114] In some embodiments of the present invention, when the wall thickness of the casting wax mold corresponding to the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 is ≤3mm, the distance between the suspended portion of the X-tube 11, Y-tube 12, Z3-tube 15, and Z4-tube 16 and the groove wall of the second pipe groove 31 at the corresponding position is ≤0.5mm.

[0115] In some embodiments of the present invention, the inner diameter of the Z2 tube 14 is the same as the inner diameter of the second pipe groove 31 at the corresponding position for a precise fit.

[0116] It can be understood that the inner diameter of tube 14 of Z2 is the same as the inner diameter of the multi-dimensional lumen at the corresponding position for precise fit.

[0117] In an embodiment of the present invention, the rear wax mold 3 is further provided with at least one through-tube cavity 32, which is sleeved on the corresponding Z-tube body. Through the through-tube cavity 32, the front wax mold 4 and the rear wax mold 3 are fixed as a whole, restricting the movement of the front wax mold 4 and the rear wax mold 3 in the Z direction, and forming the positioning of the front wax mold 4 and the rear wax mold 3 in the Z direction.

[0118] As one embodiment of the present invention, the rear wax mold 3 is provided with a through-tube cavity 32 for sleeved onto the Z1 tube body 13.

[0119] It is worth mentioning that a portion of the Z1 tube body 13 has the same inner diameter as the corresponding sleeve cavity 32 for precise fit, while the remaining portion of the Z1 tube body 13 is suspended in the sleeve cavity 32.

[0120] In an embodiment of the present invention, at least a portion of the tube of the core 1 passes through the multi-dimensional cavity and is exposed outside the casting wax model, that is, there is a portion of the tube of the core 1 that is exposed outside the casting wax model.

[0121] (3-4) Melt at least part of the joint between the bottom wax model 2, the rear wax model 3, and the front wax model 4 and fuse them together.

[0122] In an embodiment of the present invention, after the overall assembly is completed, a cover is set outside the position where the core 1 and the segmented wax molds are spliced ​​and the casting wax mold is exposed. The cover is made of an elastic material that can tightly fix at least two segmented wax molds and the core 1.

[0123] Then, at point 5 on the top surface of the splicing, the wax model in the local area of ​​the splicing seam is melted, and the splicing seam is fused together, splicing the segmented wax models into a whole.

[0124] Finally, remove the envelope.

[0125] In embodiments of the present invention, a soldering iron can be selected as the tool for melting the seam.

[0126] (4) The mold shell is prepared on the surface of the wax film of the casting, and then dewaxing and baking are performed to obtain the casting mold shell with core 1.

[0127] (4-1) Shell preparation includes:

[0128] Apply a surface layer slurry to the surface of the wax model of the casting, and then remove the excess surface layer slurry; then apply surface layer sand, and after drying, form a surface layer shell;

[0129] The surface of the shell is coated with the back layer slurry, and the excess back layer slurry is removed; then the back layer is sand-sprayed, and after drying, the first back layer shell is formed.

[0130] The back layer slurry coating and back layer sanding steps in the preparation of the back layer shell are repeated multiple times to form a multi-layer back layer shell.

[0131] In an embodiment of the present invention, at least a portion of the core 1 passes through the inner cavity of the mold shell and protrudes outside the casting mold shell.

[0132] It is worth mentioning that during the application of the top and back layers of slurry, the tubes that pass through the multi-dimensional cavity and protrude outside the casting wax mold are protected, ensuring that this part of the tubes of the core 1 is always exposed outside the casting shell.

[0133] It should be noted that the surface of the wax model can be cleaned before applying the topcoat slurry to prepare the mold shell, in order to remove surface stains.

[0134] (4-2) Dewaxing the mold shell: removing the wax mold inside the mold shell. In an embodiment of the present invention, the temperature is raised to the dewaxing temperature and then kept at that temperature. After the wax liquid flows out from the dewaxing port, the mold shell is cooled to room temperature with the furnace.

[0135] In embodiments of the present invention, the dewaxing temperature is 100℃ to 250℃, for example, it can be one of 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 165℃, 170℃, 178℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃ or any value satisfying the above range. The holding time is 3h to 8h, for example, it can be one of 3h, 4h, 5h, 6h, 7h, 8h or any value satisfying the above range.

[0136] In an embodiment of the present invention, the wax flows out from the wax outlet in the middle or side of the bottom region of the mold shell.

[0137] In an embodiment of the present invention, before firing after dewaxing the mold shell, the tube body that the core protrudes from the outside of the casting mold shell through the inner cavity of the mold shell is covered with the same material as the mold shell, and the covered area is connected to part of the mold shell.

[0138] After dewaxing the mold shell and before firing, the tube body of the core that passes through the inner cavity of the mold shell and protrudes outside the mold shell of the casting is covered. This can avoid the situation where the dewaxing temperature is too low, and the covered area can only be partially dried and cannot be ceramicized when heated at this temperature. The heating and cooling process of dewaxing involves the thermal expansion and contraction of the covered area, which makes it impossible for the covered area to be completely connected with the mold shell and the tube body of the core that protrudes outside the mold shell.

[0139] (4-3) Segmented shell firing removes residual wax mold inside the shell and ceramicizes the shell through high-temperature firing.

[0140] In an embodiment of the present invention, the temperature is sequentially raised to the first, second, and third calcination temperatures, and held at the first, second, and third calcination temperatures respectively, and then cooled and removed from the furnace.

[0141] In an embodiment of the present invention, the residual wax mold inside the shell can be removed by the first firing, and the shell is ceramized by the third firing.

[0142] In embodiments of the present invention, the first calcination temperature is 500℃~600℃, and the holding time is ≥3h, for example, 3h~6h. Exemplarily, the first calcination temperature can be one of 500℃, 510℃, 515℃, 518℃, 520℃, 540℃, 550℃, 560℃, 580℃, 590℃, 600℃, or any value satisfying the above range. The holding time can be one of 3h, 3.2h, 3.5h, 4h, 5h, 6h, or any value satisfying the above range.

[0143] In embodiments of the present invention, the second calcination temperature is 600℃~800℃, and the holding time is ≥3h, for example, 3h~8h. Exemplarily, the second calcination temperature can be one of 600℃, 620℃, 640℃, 650℃, 660℃, 680℃, 700℃, 720℃, 740℃, 750℃, 760℃, 780℃, and 800℃, or any value satisfying the above range. The holding time can be one of 3h, 4h, 5h, 6h, 7h, and 8h, or any value satisfying the above range.

[0144] In embodiments of the present invention, the third calcination temperature is 900℃~1200℃, and the holding time is ≥3h, for example, 4h~12h. Exemplarily, the third calcination temperature can be one of 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, and 1200℃, or any value satisfying the above range. The holding time can be one of 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, and 12h, or any value satisfying the above range.

[0145] In embodiments of the present invention, the furnace is cooled to room temperature while in the furnace, or cooled to below 450°C while in the furnace before being removed from the furnace.

[0146] (4-4) After the shell is fired, the quality of the casting shell is inspected.

[0147] In an embodiment of the present invention, an endoscope is used to inspect the inner cavity of the shell and the surface of the core 1 to prevent cracking on the surface of the core 1.

[0148] (4-5) Use an air gun to clean the inside of the casting shell.

[0149] (5) Casting.

[0150] (5-1) Preheat the casting shell.

[0151] In an embodiment of the present invention, the casting shell is preheated before the molten metal is poured. To ensure the stability of the core 1, the preheating temperature is in the range of 300°C to 500°C.

[0152] For example, the preheating temperature is one of 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, and 500℃, or any value that satisfies the above range.

[0153] (5-2) Casting.

[0154] In an embodiment of the present invention, the shell covering area can serve as the fixing area between the shell and the casting equipment.

[0155] The stabilizing effect of the coating zone enhances the stability of the mold shell and internal core. During the casting process, when molten metal is poured into the mold shell, the coating zone and the casting equipment are fixed, while the core portion protrudes from the outside of the mold shell and is directly connected to the coating zone. This enhances the stability of the core under the impact of molten metal, preventing displacement that could affect the internal dimensions of the casting. Furthermore, for centrifugal casting, it prevents the mold shell from shifting position on the centrifugal disc due to centrifugal force during centrifugal casting, thus preventing turbulent flow of the molten metal or incomplete filling.

[0156] In embodiments of the present invention, the casting is performed by gravity or centrifugal force.

[0157] (5-3) Remove the core 1 inside the casting to obtain a casting with an inner cavity.

[0158] In an embodiment of the present invention, after the casting is poured, the internal core 1 of the casting is removed.

[0159] In embodiments of the present invention, the core 1 inside the casting is removed by vibration or corrosion.

[0160] In an embodiment of the present invention, the residual core 1 inside the casting is removed by grinding.

[0161] It should be noted that the term "comprising" and any variations thereof in the specification and claims of this invention are intended to cover non-exclusive inclusion, for example, including a series of components that are not necessarily limited to those explicitly listed, but may include other components that are not explicitly listed or that are inherent to the component.

[0162] In this invention, the terms "upper," "lower," "bottom," "top," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0163] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0164] Furthermore, the descriptions of "first," "second," etc., involved in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0165] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0166] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a casting containing a multi-dimensional cavity, characterized in that, Includes the following steps: A core is prepared according to the cavity structure of the casting, the core comprising multiple interconnected tubes distributed at multiple angles; Design multiple segmented wax patterns according to the cavity structure of the casting, and assemble the core with the multiple segmented wax patterns so that the core is placed in the multi-dimensional cavity formed by the enclosure of the multiple segmented wax patterns to obtain a casting wax pattern; wherein, at least a partial area of at least part of the tube body of the core is suspended in the multi-dimensional cavity, and the distance between the suspended part of the tube body and the cavity wall of the multi-dimensional cavity at the corresponding position is proportional to the wall thickness of the casting wax pattern corresponding to the suspended part of the tube body: d = kx ; In the formula, k is the proportionality coefficient, d is the distance between the suspended part of the tube body and the cavity wall of the multi-dimensional cavity at the corresponding position, x is the wall thickness of the wax pattern; when 1 mm ≤ x ≤ 8 mm, 0.4 ≤ k ≤ 0.5; when 8 mm < x ≤ 20 mm, 0.1 ≤ k ≤ 0.15; A shell is prepared on the surface of the wax pattern of the casting, followed by dewaxing and baking to obtain the casting shell; The molten metal is poured into the mold shell, and the core is removed after pouring to obtain the casting containing multi-dimensional cavities.

2. The method for preparing a casting containing a multi-dimensional cavity as described in claim 1, characterized in that, The inner diameter at the port of at least a portion of the core is the same as the inner diameter at the port of the multi-dimensional cavity at the corresponding position for a precise fit.

3. The method for preparing a casting containing a multi-dimensional cavity as described in claim 2, characterized in that, The length of the portion of the tube with the same inner diameter at the port of the tube is ≥8 mm.

4. The method for preparing a casting containing a multi-dimensional cavity as described in claim 1, characterized in that, Based on the structure of the casting cavity, multiple segmented wax models are designed, including: The multiple tubes of the core are divided into X tubes, Y tubes, and Z tubes according to the extension direction of the tubes; The multiple segmented wax models are obtained by dividing the wax model at corresponding positions using the plane formed by the center lines of the X tube and the Y tube as the first dividing plane, and the plane formed by the center lines of the X tube and the part of the Z tube connected to the X tube as the second dividing plane, and these segments serve as the bottom wax model, the rear wax model, and the front wax model, respectively.

5. The method for preparing a casting containing a multi-dimensional cavity as described in claim 4, characterized in that, The bottom wax model is provided with a first pipe groove, the rear wax model is provided with a second pipe groove, and the front wax model is provided with a third pipe groove; the first pipe groove, the second pipe groove, and the third pipe groove together form the multi-dimensional cavity.

6. The method for preparing a casting containing a multi-dimensional cavity as described in claim 5, characterized in that, The assembly of the core and the plurality of segmented wax molds includes: The X tube, Y tube and part of the Z tube of the core are placed in the first pipe groove of the bottom wax mold to be positioned in the X, Y and Z directions; The front wax model and the rear wax model are respectively assembled onto the bottom wax model, and the front wax model and the rear wax model are aligned so that a portion of the second pipe groove and a portion of the third pipe groove surround to form a cavity that sleeves a portion of the Z pipe body, and the first pipe groove and a portion of the third pipe groove and a portion of the second pipe groove surround to form a cavity that sleeves the X pipe body, the Y pipe body and a portion of the Z pipe body.

7. The method for preparing a casting containing a multi-dimensional cavity as described in claim 6, characterized in that, The Z tube body also includes a Z1 tube body connected to the Y tube body, and the rear wax mold is further provided with a through-tube cavity for fitting the Z1 tube body.

8. The method for preparing a casting containing a multi-dimensional cavity as described in claim 7, characterized in that, A portion of the Z1 tube body has the same inner diameter as the corresponding sleeve cavity for precise fit, while the remaining portion of the Z1 tube body is suspended in the sleeve cavity.

9. The method for preparing a casting containing a multi-dimensional cavity as described in claim 1, characterized in that, The preparation of the mold shell on the surface of the wax pattern of the casting includes: Apply a surface layer slurry to the surface of the wax model of the casting, and then remove the excess surface layer slurry; then apply surface layer sand, and after drying, form a surface layer shell; The surface of the shell is coated with the back layer slurry, and the excess back layer slurry is removed; then the back layer is sand-sprayed, and after drying, the first back layer shell is formed. The back layer slurry coating and back layer sanding steps in the preparation of the back layer shell are repeated multiple times to form a multi-layer back layer shell.

10. The method for preparing a casting containing a multi-dimensional cavity as described in claim 1, characterized in that, The dewaxing process includes: heating to the dewaxing temperature and then holding it at that temperature, allowing the wax liquid to flow out from the dewaxing port, and then cooling the mold shell to room temperature with the furnace.

11. The method for preparing a casting containing a multi-dimensional cavity as described in claim 1, characterized in that, The roasting process employs a segmented continuous roasting method, which includes sequentially raising the temperature to the first, second, and third roasting temperatures, holding the temperature at the first, second, and third roasting temperatures respectively, and then cooling and removing the product from the furnace.

12. The method for preparing a casting containing a multi-dimensional cavity as described in claim 11, characterized in that, The first calcination temperature is 500℃~600℃, and the holding time is ≥3 h.

13. The method for preparing a casting containing a multi-dimensional cavity as described in claim 11, characterized in that, The second calcination temperature is 600℃~800℃, and the holding time is ≥3 h.

14. The method for preparing a casting containing a multi-dimensional cavity as described in claim 11, characterized in that, The third roasting temperature is 900℃~1200℃, and the holding time is ≥3 h.

15. The method for preparing a casting containing a multi-dimensional cavity as described in claim 11, characterized in that, The cooling process involves either cooling the furnace to room temperature before unloading, or cooling the furnace to below 450°C before unloading.

16. The method for preparing a casting containing a multi-dimensional cavity as described in claim 10, characterized in that, The dewaxing temperature is 100℃~250℃, and the holding time is 3 h~8 h.

17. The method for preparing a casting containing a multi-dimensional cavity as described in claim 10, characterized in that, The wax flows out from the wax outlet in the middle or side of the bottom area of ​​the mold shell.

18. The method for preparing a casting containing a multi-dimensional cavity as described in claim 1, characterized in that, At least a portion of the core tube passes through the inner cavity of the mold shell and protrudes outside the mold shell of the casting.

19. The method for preparing a casting containing a multi-dimensional cavity as described in claim 18, characterized in that, Before the shell is fired, the tube body that is exposed outside the casting shell after the core passes through the inner cavity of the shell is covered with the same material as the shell, and the covered area is connected to part of the shell.

20. The method for preparing a casting containing a multi-dimensional cavity as described in claim 19, characterized in that, The covering area serves as the fixing area between the mold shell and the casting equipment.

21. The method for preparing a casting containing a multi-dimensional cavity as described in claim 1, characterized in that, Before casting, the casting shell is preheated at a temperature of 300℃ to 500℃.

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