A wax model of a titanium alloy casting, its mold, and its preparation method.

Abstract

This invention belongs to the field of titanium alloy investment casting technology, specifically relating to a titanium alloy casting wax model, its wax model mold, and a preparation method. The preparation method includes the following steps: designing connected inserts and main components based on a three-dimensional digital model of the titanium alloy casting; printing and fabricating insert wax models based on the three-dimensional digital model of the inserts; fabricating a wax model mold based on the three-dimensional digital model of the titanium alloy casting, and placing the insert wax model in the wax model mold, wherein the cavity enclosed by the insert wax model and the wax model mold has the same shape as the main component; injecting wax into the cavity to pour the main component wax model; and opening the mold to obtain a titanium alloy casting wax model with the insert wax model and the main component wax model coupled together. This method not only makes it possible to integrally form titanium alloy casting wax models with complex, narrow spaces and inverted mold structures, but also reduces mold complexity, improves mold manufacturing accuracy, improves wax model surface quality, and reduces wax model repair and assembly difficulty.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy investment casting technology, specifically relating to a titanium alloy casting wax model and its mold, and preparation method. Background Technology

[0002] With the increasing complexity and dimensional accuracy requirements of titanium alloy investment castings, closed and semi-closed structures are becoming more common. Simply relying on metal molds to completely form the wax model is no longer sufficient. Current solutions include embedding water-soluble wax, disassembling and bonding the wax model, and embedding ceramic cores. Water-soluble wax requires a separate mold, has low dimensional accuracy, and necessitates repeated mold repairs to achieve the required dimensions, resulting in long mold manufacturing and repair cycles. Furthermore, the surface of the water-soluble wax core inevitably has parting lines, requiring manual repair. Removing the water-soluble wax requires citric acid dissolution, generating wastewater and extending the production cycle. The cost of pressing and melting the water-soluble wax is also high. Partial disassembly and reassembly of the wax model not only results in poor dimensional accuracy but also uncontrollable deformation due to heat bonding. It can also be limited by space constraints in some products where assembly is impossible. Titanium alloys typically use yttrium oxide ceramic cores, requiring specialized ceramic core molds. Ceramic cores have lower precision, are prone to misalignment during assembly and wax injection, and hollow ceramic cores are easily crushed during wax filling, while solid ceramic cores are difficult to clean during shell removal. Summary of the Invention

[0003] The purpose of this invention is to provide a method and apparatus for preparing wax models of titanium alloy castings, so as to solve the problems of high manufacturing difficulty and low precision caused by the complex structure of existing titanium alloy casting wax models.

[0004] The first aspect of this invention provides a method for preparing a wax model of a titanium alloy casting, the method comprising the following steps:

[0005] Based on the shape characteristics of the three-dimensional digital model of the titanium alloy casting, the insert design and main component design are carried out.

[0006] A wax model of the insert is created by printing a three-dimensional digital model of the insert's shape.

[0007] A wax model mold is made based on the three-dimensional digital model of the titanium alloy casting, and the insert wax model is placed in the wax model mold. The cavity enclosed by the insert wax model and the wax model mold has the same shape as the main component.

[0008] Inject wax into the cavity to pour the wax model of the main component;

[0009] The mold is opened to obtain a titanium alloy casting wax model that couples the insert wax model with the main component wax model.

[0010] According to the method for preparing a titanium alloy casting wax model of the present invention, the complex and difficult-to-process parts of the three-dimensional digital model of the titanium alloy casting are obtained by printing to obtain the insert wax model. Then, the insert wax model is placed into the wax model mold and the mold is closed to make the main component wax model, so that the titanium alloy casting wax model with the insert wax model and the main component wax model is finally obtained. The above method processes the inverted mold structure or narrow space part of the wax model by printing. This not only simplifies the wax model processing of complex and difficult-to-process parts of the casting shape, but also eliminates the need for mold making, thus saving mold making costs and production cycle. At the same time, because the complex structure is processed by printing, the wax model mold does not need to be designed with corresponding structural parts, thus simplifying the structure of the wax model mold. This makes it possible to form the whole wax model of titanium alloy castings with complex, narrow space and inverted mold structure. The structure of the wax model mold also improves the precision of mold making and the surface quality of the wax model. In addition, since the main component wax model is directly formed on the insert wax model, it not only reduces the amount of wax model repair and the difficulty of wax assembly, but also makes the final titanium alloy casting wax model have advantages such as good surface quality, fewer burrs, fewer step differences, smooth transition at the joint, and simple and convenient mold removal.

[0011] In addition, the preparation method according to the present invention may also have the following additional technical features:

[0012] In some embodiments of the present invention, the insert design includes the selection of the insert position and the design of the docking structure with the main component.

[0013] In some embodiments of the present invention, the insert position selection design in the insert design includes:

[0014] The insert is designed based on the inverted drawing die structure and / or narrow structure in the three-dimensional digital model of the titanium alloy casting, and the main component is designed based on the remaining structure. The assembly structure of the insert and the main component is the same as the structure of the titanium alloy casting.

[0015] In some embodiments of the present invention, the design of the docking structure between the insert and the main component includes: designing the docking structure between the insert and the main component, wherein the docking structure can be a sawtooth docking structure, a dovetail docking structure, a planar docking structure, or a fully enclosed docking structure.

[0016] In some embodiments of the present invention, designing the docking structure between the insert and the main component includes: designing the wall thickness of the docking structure portion of the insert, wherein the wall thickness of the docking structure portion of the insert is not less than 2 mm, and the wall thickness of the remaining portion is not less than 0.5 mm.

[0017] In some embodiments of the present invention, when the docking structure is a fully enclosed structure, the wall thickness of the docking structure portion in the main component is not less than 5 mm.

[0018] In some embodiments of the present invention, when printing and manufacturing the insert wax model, the pre-reserved drainage hole on the insert wax model is located in the non-connecting structural part.

[0019] In another aspect, the present invention provides a wax model of a titanium alloy casting, which is prepared by the above-described method for preparing a wax model of a titanium alloy casting.

[0020] In another aspect, the present invention provides a wax mold for a titanium alloy casting wax model, the wax mold comprising:

[0021] An upper mold with an upper cavity;

[0022] A lower mold with a lower cavity;

[0023] A core mold is provided in the lower mold cavity. The core mold has an outer surface that matches the inner surface of the cavity structure of the main component and a cavity to accommodate the non-butt joint structure of the insert wax model.

[0024] A first movable block and a second movable block are provided in the lower mold cavity, and the first movable block and the second movable block are adapted to clamp and fix the insert wax mold and the core mold;

[0025] The upper mold is adapted to the lower mold, the first movable block, and the second movable block, and together with the lower mold, the first movable block, the second movable block, the insert wax model, and the core mold, forms a cavity with the same shape as the main component.

[0026] In some embodiments of the present invention, the core mold includes a core and an outer mold fitted outside the core. The outer surface of the outer mold is adapted to the inner surface of the cavity structure of the main component and is radially split into multiple assembleable segmented molds. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a titanium alloy casting wax model according to a specific embodiment of the present invention;

[0029] Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure of the wax model mold and the insert wax model when they are closed;

[0030] Figure 3 for Figure 2 A schematic diagram of the structure of the wax mold during mold opening.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1-Main component wax model, 2-Installation wax model, 3-Upper mold, 4-Lower mold, 5-Cavity, 6-Wax injection port, 7-First movable block, 8-Second movable block, 9-Core mold, 91-Segmented mold, 92-Mold core. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0036] The preparation method and apparatus provided by this invention are mainly used for preparing annular titanium alloy casting wax models.

[0037] The present invention discloses a method for preparing a wax model of a titanium alloy casting, comprising the following steps:

[0038] Based on the shape characteristics of the three-dimensional digital model of the titanium alloy casting, the insert design and main component design are carried out.

[0039] 2. Create a wax model of the insert by printing a three-dimensional digital model based on the shape of the insert;

[0040] A wax model mold is made based on the three-dimensional digital model of the titanium alloy casting, and the insert wax model 2 is placed in the wax model mold. The cavity 5 enclosed by the insert wax model 2 and the wax model mold has the same shape as the main component.

[0041] Inject wax into cavity 5 to pour the wax model 1 of the main component;

[0042] The mold is opened to obtain a titanium alloy casting wax model that couples the insert wax model 2 with the main component wax model 1.

[0043] According to the method for preparing a titanium alloy casting wax model of the present invention, the complex and difficult-to-process parts of the three-dimensional digital model of the titanium alloy casting are obtained by printing to obtain the insert wax model. Then, the insert wax model is placed into the wax model mold and the mold is closed to make the main component wax model, so that the titanium alloy casting wax model with the insert wax model and the main component wax model is finally obtained. The above method processes the inverted mold structure or narrow space part of the wax model by printing. This not only simplifies the wax model processing of complex and difficult-to-process parts of the casting shape, but also eliminates the need for mold making, thus saving mold making costs and production cycle. At the same time, because the complex structure is processed by printing, the wax model mold does not need to be designed with corresponding structural parts, thus simplifying the structure of the wax model mold. This makes it possible to form the whole wax model of titanium alloy castings with complex, narrow space and inverted mold structure. The structure of the wax model mold also improves the precision of mold making and the surface quality of the wax model. In addition, since the main component wax model is directly formed on the insert wax model, it not only reduces the amount of wax model repair and the difficulty of wax assembly, but also makes the final titanium alloy casting wax model have advantages such as good surface quality, fewer burrs, fewer step differences, smooth transition at the joint, and simple and convenient mold removal.

[0044] In some embodiments of the present invention, the insert design includes the selection of the insert position and the design of the docking structure with the main component.

[0045] In some embodiments of the present invention, the insert position selection design in the insert design includes: designing the insert based on the inverted drawing die structure and / or narrow structure in the three-dimensional digital model of the titanium alloy casting, and designing the main component based on the remaining structure. The splicing structure of the insert and the main component is the same as the structure of the titanium alloy casting. When designing the insert, it is necessary to ensure the joint strength between the insert and the main component so that the insert and the main component cannot detach or break apart. At the same time, it is necessary to ensure that the overall wax model does not crack and the shell surface layer does not crack during subsequent processes such as coating.

[0046] In some embodiments of the present invention, the design of the docking structure between the insert and the main component includes: designing the docking structure between the insert and the main component. The docking structure can be a sawtooth docking structure, a dovetail docking structure, a planar docking structure, or a fully enclosed docking structure, which can be selected according to structural needs. The fully enclosed form means that the main component completely encloses the insert, and the insert is fixed in both the radial and axial directions.

[0047] In some embodiments of the present invention, the design of the mating structure between the insert and the main component includes: designing the wall thickness of the mating structure portion of the insert, wherein the wall thickness of the mating structure portion of the insert is not less than 2 mm, and the wall thickness of the remaining portion is not less than 0.5 mm. Setting the minimum thickness of the mating structure portion of the insert can effectively prevent excessive wax injection pressure from causing the insert surface to crack; the thickness of the non-matting structure portion depends on the size of the insert.

[0048] In some embodiments of the present invention, when the docking structure is a fully enclosed structure, the wall thickness of the docking structure portion in the main component is not less than 5 mm. Setting the minimum wall thickness of the docking structure portion of the main component is to ensure the strength of the wax mold 1 of the main component and to avoid damage to the docking structure.

[0049] In some embodiments of the present invention, the fabrication of the insert wax model 2 based on the three-dimensional digital model of the insert includes: using photosensitive resin as the raw material and employing RP technology to print the insert wax model 2. The strength of the photosensitive resin itself is higher than that of the molding wax, so the overall strength of the coupled wax model is not lower than that of the pure wax model.

[0050] In some embodiments of the present invention, the drainage hole reserved on the insert wax model 2 is located in a non-butting structural part. When printing the photosensitive resin insert wax model 2, the reserved drainage hole is avoided from being placed on the surface that is mated with the main component wax model 1, so as to prevent the wax liquid from breaking through the drainage hole plug and entering the cavity of the photosensitive resin insert, thereby causing the photosensitive resin insert to crack.

[0051] This invention also provides a wax model of a titanium alloy casting, which is prepared using the above-described method for preparing a wax model of a titanium alloy casting. Since the wax model of the titanium alloy casting adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0052] The present invention also provides a wax mold for a titanium alloy casting wax model. The wax mold includes an upper mold 3, a lower mold 4, a core mold 9, a first movable block 7, and a second movable block 8. The upper mold 3 has an upper mold cavity, the lower mold 4 has a lower mold cavity, and the core mold 9 is disposed in the lower mold cavity and has an outer surface that matches the inner surface of the cavity structure of the main component and a cavity for accommodating the non-butt joint structure of the insert wax model 2. The first movable block 7 and the second movable block 8 are disposed in the lower mold cavity and clamp and fix the insert wax model 2 and the core mold 9. The upper mold is adapted to the lower mold 4, the first movable block 7, and the second movable block 8, and together with the lower mold 4, the first movable block 7, the second movable block 8, the insert wax model 2, and the core mold 9, they form a cavity 5 with the same shape as the main component.

[0053] In some embodiments of the present invention, the core mold 9 includes a core mold 92 and an outer mold fitted around the core mold 92. The outer surface of the outer mold is adapted to the inner surface of the cavity structure of the main component and is radially divided into multiple assemblyable segmented molds 91. Specifically, the use of the core mold 92 in conjunction with the outer mold formed by assembling the segmented molds 91 facilitates subsequent demolding. Specifically, during demolding, the core mold 92 is first removed, and then the segmented molds 91 are radially moved to detach from the wax model 1 of the main component before being removed. Subsequently, the other segmented molds 91 are removed in sequence, thereby achieving the separation of the core mold 9 from the wax model 1 of the main component.

[0054] This application is based on Figure 1 The above preparation method and apparatus are illustrated using the annular titanium alloy casting shown as an example.

[0055] Specifically, such as Figure 1 As shown, the titanium alloy casting has a minimum inner diameter of 23.5 mm and a second minimum inner diameter of 35.9 mm, and is in the shape of a stepped shaft with a length of 75.4 mm. If this structure is formed using a metal block, there is insufficient space to extract the block, making it impossible to form or difficult to form. Therefore, the preparation method described in this application is used for processing.

[0056] First, the titanium alloy casting is designed as an insert and a main component, as shown in the figure. The insert is located in the middle, and the main component is on the outside. The insert connects to the main component through its end face and cylindrical surface, forming a fully enclosed connection structure, thus achieving the integration of the insert and the wax model. At the connection point, the main component has an axial thickness of 5.2mm and a radial thickness of 5.9mm at the insert's end face. The insert is a hollow structure; the cylindrical thickness at the connection point is 2-3mm, effectively preventing excessive wax injection pressure from causing surface cracking of the photosensitive resin insert. The thickness of other parts is 0.5-0.8mm, reducing the amount of photosensitive resin used. The drainage hole reserved for the printed photosensitive resin insert is avoided on the surface that connects with the model wax, preventing wax from breaking through the drainage hole plug and entering the cavity of the photosensitive resin insert, which could lead to cracking. Furthermore, the fully enclosed cylindrical connection structure eliminates the need for cold wax during casting of the thicker areas of the main component, reducing cold wax preparation time.

[0057] Secondly, the photosensitive resin insert wax model 2 is printed using RP technology.

[0058] Secondly, a wax model mold is made based on the titanium alloy casting. Specifically, the cross-sectional structure of the wax model mold of the aforementioned titanium alloy casting when it is assembled with the insert is as follows: Figure 2During installation, first, insert the second movable block 8 on the right side into the lower mold cavity. Then, fit the core mold 9 onto the printed photosensitive resin insert wax mold 2 and place it in the corresponding position in the lower mold cavity. The right end face of the photosensitive resin insert wax mold 2 and the core mold 9 should contact the left end face of the second movable block 8. Next, insert the first movable block 7 into the lower mold cavity and make the right end face of the first movable block 7 contact the inner cavity end face of the photosensitive resin insert wax mold 2. Then, close the upper mold 3 to complete the molding process.

[0059] Next, set the wax model mold temperature to 20-23℃, the wax injection pressure of the wax press to 2MPa, the wax nozzle temperature to 65℃-68℃, the wax injection time to 99s, and use CL-162 wax material. The wax enters the mold cavity 5 through the wax injection port 6. After reaching the holding pressure time, open the upper mold 3. At this point, the structure is as follows: Figure 3 As shown. The first movable block 7, the second movable block 8, and the core mold 9 are sequentially ejected to obtain the titanium alloy casting wax model formed by coupling the insert wax model 2 and the main component wax model 1. The photosensitive resin printing accuracy is ±0.2mm, the main component wax model 1 has a dimensional accuracy of ±0.2mm, the mating surface transitions well during coupling, and the dimensional accuracy is ±0.2mm, meeting the overall wax model dimensional accuracy requirements.

[0060] Since the wax mold of the titanium alloy casting wax model is used to realize all the technical solutions of all the embodiments of the above preparation method, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a wax model of a titanium alloy casting, characterized in that, The titanium alloy casting is a stepped shaft shape, and includes the following steps: Based on the shape characteristics of the three-dimensional digital model of the titanium alloy casting, the insert design and main component design are carried out. A wax model of the insert is created by printing a three-dimensional digital model of the insert's shape. A wax model mold is made based on the three-dimensional digital model of the titanium alloy casting, and the insert wax model is placed in the wax model mold. The cavity enclosed by the insert wax model and the wax model mold has the same shape as the main component. Inject wax into the cavity to pour the wax model of the main component; Open the mold to obtain a titanium alloy casting wax model that couples the insert wax model with the main component wax model; The insert design includes insert position selection, and specifically includes designing the insert based on the inverted drawing die structure and / or narrow structure in the three-dimensional digital model of the titanium alloy casting, designing the main component based on the remaining structure, and the splicing structure of the insert and the main component is the same as the structure of the titanium alloy casting; The insert is located in the middle, the main component is located on the outside, and the insert is connected to the main component through the end face and the cylindrical surface to form a fully enclosed connection structure. The wall thickness of the connection structure part of the insert is not less than 2mm, and the wall thickness of the remaining part is not less than 0.5mm. The wall thickness of the connection structure part of the main component is not less than 5mm. Wax molds include: An upper mold with an upper cavity; A lower mold with a lower cavity; The core mold is located in the lower mold cavity. The core mold has an outer surface that matches the inner surface of the cavity structure of the main component and a cavity that accommodates the non-butt joint structure of the insert wax model. A first movable block and a second movable block are provided in the lower mold cavity, and the first movable block and the second movable block are adapted to clamp and fix the insert wax mold and the core mold; The upper mold is adapted to the lower mold, the first movable block, and the second movable block, and together with the lower mold, the first movable block, the second movable block, the insert wax model, and the core mold, they form a cavity with the same shape as the main component; The core mold includes a core and an outer mold fitted on the outside of the core. The outer surface of the outer mold is adapted to the inner surface of the cavity structure of the main component and is radially split into multiple assembleable segmented molds.

2. The method for preparing a wax model of a titanium alloy casting according to claim 1, characterized in that, When printing and making the wax model of the insert, the pre-reserved drainage hole on the wax model of the insert is located in the non-connecting structural part.

3. A wax model for a titanium alloy casting, characterized in that, It is prepared using the preparation method described in any one of claims 1-2.

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