Gate wax mold, wax mold shell assembly, and thin product lost wax casting method

Abstract

The application discloses a runner wax mold, a wax mold shell assembly and a thin product lost wax casting method. The runner wax mold is internally provided with a cavity, and the runner wax mold is provided with a pore communicating the cavity with an external environment, and the pore is sealed by bonding wax with a lower melting point than the runner wax mold. In the thin product lost wax casting method, firstly, a product wax mold and the runner wax mold are prepared; then, the runner wax mold is connected with at least one group of product wax molds to form a wax tree; then, ceramic slurry is coated on the surface of the wax tree and solidified into a ceramic mold shell; then, the wax mold shell assembly is placed in a dewaxing kettle, a high-temperature environment capable of causing the bonding wax and the product wax mold to melt in sequence is arranged in the kettle, a high-pressure environment capable of causing the molten wax to flow into the cavity along the pore is arranged, and the process is continued until the wax tree is completely melted and discharged from the ceramic mold shell; finally, the thin product is cast in the ceramic mold shell. The thin product lost wax casting method can avoid the damage of the ceramic mold shell caused by the expansion of the product wax mold.

Description

Technical Field

[0001] This invention relates to the field of lost-wax casting, and more specifically, to a sprue wax model, a wax model shell assembly, and a lost-wax casting method for thin products. Background Technology

[0002] In the field of lost-wax casting, there are many types of wax materials for wax patterns, and most of them contain fillers (such as high molecular polymers like vinyl plastic powder) to improve the accuracy, structural strength, and stability of the wax pattern. However, these high molecular polymers are prone to thermal expansion, so during the dewaxing process of the ceramic shell, the wax pattern is prone to thermal expansion and extrusion into the ceramic shell.

[0003] Especially for slender and thin turbine blades, the melting and expansion of the wax mold can easily cause the ceramic shell to crack. However, the working environment of aero-engine and gas turbine blades is extreme, and the requirements for product precision and quality are extremely high. The traditional lost-wax casting method mentioned above results in a high scrap rate of ceramic shells for aero-engine and gas turbine blades, making it difficult to meet production requirements. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a lost-wax casting method for a gating wax model, a wax model shell assembly, and thin-film products.

[0005] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a runner wax mold, wherein the runner wax mold has a cavity inside and a pore on the runner wax mold that connects the cavity with the external environment, and the pore is sealed by an adhesive wax with a melting point lower than that of the runner wax mold.

[0006] The wax mold of the present invention has a cavity sealed by adhesive wax. During the process of dewaxing by heating, the pores are exposed due to the melting of the adhesive wax, allowing the wax liquid of the wax mold to flow into the cavity along the pores. This can prevent the wax mold from expanding and causing compression damage to the ceramic shell.

[0007] Furthermore, the runner wax model includes a base, a cover plate, and adhesive wax; The base has a recessed cavity inside; A cover plate is placed over the cavity to form a hollow space; The joint between the cover plate and the base forms a pore; Adhesive wax is used to fill the joints; The separate design of the base and cover plate makes it easier to produce and assemble the sprue wax mold.

[0008] Furthermore, a V-shaped chamfer is formed on the outer surface of the joint, and adhesive wax is filled in the V-shaped chamfer to increase the contact area and connection strength between the adhesive wax and the base and cover plate.

[0009] Furthermore, several reinforcing members that abut against the cover plate are integrally formed in the cavity inside the base to increase the structural strength of the sprue wax mold and the cavity.

[0010] Furthermore, the cover plate has a first end face and a second end face, and the cover plate is provided with through holes corresponding to a number of reinforcing members; The end of the reinforcing member is also provided with a stepped surface. The end face of the reinforcing member passes through the through hole and is flush with the first end face of the cover plate. The stepped surface abuts against the second end face of the cover plate. The inner wall of the through hole and the outer wall of the reinforcing member are sealed with adhesive wax. The above design increases the structural strength of the sprue wax mold and cavity while facilitating assembly; in addition, it increases the number and area of ​​pores, allowing the wax liquid to quickly enter the cavity.

[0011] Furthermore, the sprue wax mold and cavity are disc-shaped, and the reinforcing members include a first reinforcing member disposed in the center of the cavity and several second reinforcing members surrounding the first reinforcing member.

[0012] In a second aspect, the present invention provides a wax model shell assembly, including a ceramic shell, a product wax model, and the aforementioned gating wax model; The product wax model and the sprue wax model are connected, and a ceramic shell covers the outer surface of the product wax model and the sprue wax model.

[0013] Thirdly, the present invention provides a lost-wax casting method for thin products, comprising the following steps: Make product wax models and the aforementioned sprue wax models; Connect the runner wax model to at least one set of product wax models to form a wax tree; The ceramic slurry is coated onto the surface of the wax tree and then cured into a ceramic shell. The wax model shell assembly is placed in a dewaxing kettle, and a high-temperature environment is set inside the kettle to allow the adhesive wax and the product wax model to melt sequentially, and a high-pressure environment is set to allow the melted wax liquid to flow into the cavity along the pores until the wax tree is completely melted and discharged from the ceramic shell. Thin products are cast inside a ceramic mold.

[0014] In the thin-film lost-wax casting method of the present invention, since the bonding wax has a lower melting point, it can melt before the gating wax model and the product wax model of the same material, so that the joints of the connecting cavities are fully exposed before the wax tree melts.

[0015] At the same time, because the product wax mold is thin, it is easier to be heated and melted in the dewaxing kettle than the runner wax mold. Therefore, during the melting process of the product wax mold, the cavity inside the runner wax mold can maintain its shape and contain the melted wax, thus preventing the ceramic shell from breaking due to the expansion of the product wax mold.

[0016] Furthermore, in the dewaxing kettle, the wax tree is inverted so that the sprue wax mold is located below the product wax mold. This allows the wax liquid to flow into the cavity more quickly using the gravitational potential energy of the wax liquid, and also facilitates the rapid and complete removal of the wax liquid along the sprue of the ceramic shell.

[0017] Furthermore, the high-temperature environment is between 170°C and 180°C, and the high-pressure environment is not less than 5 bar. Attached Figure Description

[0018] Figure 1 This is a flowchart of the lost-wax casting method for thin products in an embodiment of the present invention; Figure 2 This is an exploded view of the sprue wax model in an embodiment of the present invention; Figure 3 This is a schematic diagram of the internal structure of the sprue wax mold in an embodiment of the present invention; Figure 4 for Figure 3 A magnified view of a portion of the image; The attached diagram lists the components represented by each number as follows: 10. Cover plate; 100. Through hole; 11. Base; 12. Cavity; 13. V-shaped chamfer; 14. Reinforcing member; 140. Second reinforcing member; 141. First reinforcing member; 142. Step surface; 15. Adhesive wax. Detailed Implementation

[0019] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0020] Reference Figures 2 to 4 This invention provides a runner wax model, which has a cavity 12 inside and pores on it. The pores connect the cavity 12 to the external environment outside the runner wax model. The pores of the runner wax model are sealed by adhesive wax 15 to isolate the cavity 12 from the external environment outside the runner wax model. The melting point of the adhesive wax 15 is lower than that of the runner wax model itself.

[0021] The shape of the sprue wax model can be designed according to actual needs and is not limited here.

[0022] The sprue wax model and its cavity 12 can be integrally formed, or the sprue wax model can be integrally formed first, and then the cavity 12 can be machined in the sprue wax model. No limitation is made here.

[0023] For example, refer to Figure 2In this embodiment, the runner wax model is generally disc-shaped; the runner wax model includes a base 11, a cover plate 10 and adhesive wax 15, wherein the base 11 has a cavity formed inside, the cover plate 10 covers the cavity to form the aforementioned cavity 12, the joint between the cover plate 10 and the base 11 constitutes the aforementioned pore, and the adhesive wax 15 fills the joint; since the base 11 and the cover plate 10 adopt a split design, the production and assembly of the runner wax model are convenient.

[0024] Reference Figure 3 and Figure 4 In this embodiment, a V-shaped chamfer 13 is provided on the outer surface of the joint between the cover plate 10 and the base 11, and the adhesive wax 15 is filled in the V-shaped chamfer 13, which can increase the contact area and connection strength between the adhesive wax 15 and the base 11 and the cover plate 10, and ensure the sealing of the cavity 12.

[0025] In some embodiments, when the internal volume of the cavity 12 is large, in order to ensure the structural strength of the sprue wax mold and the cavity 12, a number of reinforcing members 14 are integrally formed in the cavity 12 of the base 11, and the number of reinforcing members 14 abut against the cover plate 10.

[0026] Accordingly, in some embodiments, the cover plate 10 may also have an integrally formed reinforcing rib structure.

[0027] Reference Figure 2 If the cover plate 10 is defined to have a first end face and a second end face, then the cover plate 10 is provided with through holes 100 corresponding to a plurality of reinforcing members 14. The shape and contour of the through holes 100 are adapted to the outer contour of the corresponding reinforcing member 14, so that the reinforcing member 14 can be supported and sealed with the through holes 100.

[0028] To enhance the support and sealing effect between the reinforcing member 14 and the through hole 100, a stepped surface 142 may be provided at the end of the reinforcing member 14, which is lower than the end face of the reinforcing member 14. The end face of the reinforcing member 14 passes through the through hole 100 and is flush with the first end face of the cover plate 10, while the stepped surface 142 abuts against the second end face of the cover plate 10. In this case, the inner wall of the through hole 100 and the outer wall of the reinforcing member 14 are sealed by adhesive wax 15.

[0029] By setting a stepped surface 142 on the reinforcing member 14, the overall structural strength of the cavity 12 and the sprue wax mold can be increased, while also facilitating positioning and assembly. In addition, it can increase the number and area of ​​holes between the cover plate 10 and the base 11, so that the wax liquid can quickly enter the cavity 12.

[0030] For example, refer to Figure 2 The reinforcing member 14 includes a first reinforcing member 141 disposed in the middle of the cavity 12 and a plurality of second reinforcing members 140 surrounding the first reinforcing member 141.

[0031] In addition, the present invention also provides a wax model shell assembly, including a ceramic shell, a product wax model and a sprue wax model in any of the foregoing embodiments, wherein the product wax model and the sprue wax model are connected, and the ceramic shell covers the outer surfaces of the product wax model and the sprue wax model.

[0032] In addition, refer to Figure 1 The present invention also provides a lost-wax casting method for thin products, comprising the following steps: S1. Make product wax models and sprue wax models. Among them, the product wax models are wax models for thin products such as turbine blades. S2. Making a wax tree: Connecting the sprue wax model to at least one set of product wax models to form a wax tree; S3. Making the ceramic shell: Coating the surface of the wax tree with ceramic slurry and waiting for the ceramic slurry to solidify into a ceramic shell; the ceramic shell and the wax tree together form the wax model shell assembly. S4. Place the wax model shell assembly in the dewaxing kettle, and set a high-temperature environment in the kettle that allows the adhesive wax 15 and the product wax model to melt sequentially, and set a high-pressure environment that allows the melted wax liquid to flow into the cavity 12 along the pores, until the wax tree is completely melted and discharged from the ceramic shell. S5. Cast thin-walled products: Thin-walled products are cast inside ceramic molds.

[0033] Steps S2, S3, and S5 are common technical methods in the industry and will not be described in detail here.

[0034] In step S4, since the melting point of the adhesive wax 15 is lower than that of the product wax mold and the runner wax mold, after a high temperature and high pressure environment is created in the dewaxing kettle, the adhesive wax 15 melts before the runner wax mold and the product wax mold, exposing the connecting cavity 12. At the same time, since the product wax mold is thin, it is easier to be heated and melted in the dewaxing kettle than the runner wax mold. Therefore, during the melting process of the product wax mold, the cavity 12 in the runner wax mold can maintain its shape and contain the melted wax liquid after the product wax mold melts, avoiding the expansion of the product wax mold and causing damage to the ceramic shell.

[0035] For example, in step S4 above, the high-temperature environment created inside the dewaxing vessel is between 170°C and 180°C, and the high-pressure environment is not less than 5 bar.

[0036] In step S4, the wax model shell assembly can be tilted or completely inverted so that the sprue wax model is located below or directly below the product wax model. This allows the wax liquid to flow into the cavity 12 more quickly using the gravitational potential energy of the wax liquid, and also facilitates the rapid and complete removal of the wax liquid along the sprue of the ceramic shell.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0042] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A wax mold for a sprue, characterized in that, The sprue wax mold has an internal cavity, and the sprue wax mold has pores that connect the cavity to the external environment. The pores are sealed by a bonding wax with a melting point lower than that of the sprue wax mold.

2. The sprue wax model according to claim 1, characterized in that, The runner wax mold includes a base, a cover plate, and the adhesive wax; The base has a cavity inside; The cover plate covers the cavity to form the cavity; The joint between the cover plate and the base forms the pore; The adhesive wax is filled into the joint.

3. The sprue wax model according to claim 2, characterized in that, The outer surface of the joint is provided with a V-shaped chamfer, and the adhesive wax is filled in the V-shaped chamfer.

4. The sprue wax model according to claim 2, characterized in that, Several reinforcing members that abut against the cover plate are integrally formed in the cavity inside the base.

5. The sprue wax model according to claim 4, characterized in that, The cover plate has a first end face and a second end face opposite to each other, and the cover plate is provided with through holes corresponding to the plurality of reinforcing members; The end of the reinforcing member is also provided with a stepped surface. The end face of the reinforcing member passes through the through hole and is flush with the first end face of the cover plate. The stepped surface abuts against the second end face of the cover plate. The inner wall of the through hole and the outer wall of the reinforcing member are sealed by the adhesive wax.

6. The sprue wax model according to claim 5, characterized in that, The sprue wax mold and the cavity are disc-shaped, and the reinforcing member includes a first reinforcing member disposed in the middle of the cavity and a plurality of second reinforcing members surrounding the first reinforcing member.

7. A wax model shell assembly, characterized in that, Includes a ceramic shell, a product wax model, and a sprue wax model as described in any one of claims 1 to 6; The product wax mold and the sprue wax mold are connected, and the ceramic shell covers the outer surfaces of the product wax mold and the sprue wax mold.

8. A lost-wax casting method for thin products, characterized in that, Includes the following steps: To make product wax models and sprue wax models as described in any one of claims 1 to 6; The runner wax model is connected to at least one set of product wax models to form a wax tree; The wax tree is coated with ceramic slurry and cured into a ceramic shell. The wax tree and the ceramic shell together form a wax model shell assembly. The wax model shell assembly is placed in a dewaxing kettle, and a high-temperature environment is set in the dewaxing kettle to allow the adhesive wax and the product wax model to melt sequentially, and a high-pressure environment is set to allow the melted wax to flow into the cavity along the pores until the wax tree is completely melted and discharged from the ceramic shell. Thin products are cast inside the ceramic mold shell.

9. The lost-wax casting method for thin products according to claim 8, characterized in that, In the dewaxing kettle, the wax tree is inverted so that the gating wax mold is located below the product wax mold.

10. The lost-wax casting method for thin products according to claim 8, characterized in that, The high-temperature environment is between 170°C and 180°C; The high-pressure environment is not less than 5 bar.

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