Preparation method of thin-wall cavity type investment casting mold

Abstract

The invention belongs to the technical field of mold production, and discloses a preparation method of a thin-wall cavity type investment casting mold. The method comprises the following steps that firstly, a standard melting mold is prepared, and the melting mold is provided with an inner cavity, a first open hole and a second open hole; 2, forming a first coating layer on the outer surface of the fired mold; forming a second coating layer on the inner surface of the fired mold; thirdly, the inner cavity is filled with a supporting material, and the first open hole and the second open hole are blocked; 4, melting the fired mold, and discharging the melted fired mold from the space between the first coating layer and the second coating layer; and fifthly, the first open hole and the second open hole are blocked, the supporting material is separated from the inner cavity, and the thin-wall cavity type investment mold is formed.

Description

Technical Field

[0001] The invention belongs to the technical field of mold production, and in particular relates to a method for preparing a thin-walled cavity investment casting mold. Background Art

[0002] With the advancement of science and technology, the use of investment wax is becoming more and more widespread. In the process of producing investment wax, thin-walled cavity investment wax molds are usually required, so thin-walled cavity investment wax molds need to be processed in order to mass-produce thin-walled cavity investment wax castings. However, in the related art, the method for processing and producing thin-walled cavity investment wax molds is relatively complicated, and it is not convenient to process and produce thin-walled cavity investment wax molds. At the same time, in the original investment casting process, the coating layer in the inner cavity of the thin-walled cavity casting has no stable support, and only relies on the connection between the coating layers to fix the position. The coating layer in the inner cavity is prone to offset, resulting in uneven wall thickness in the cavity of the casting, and severe cases will cause local meat loss in the cavity of the casting. Summary of the invention

[0003] Purpose of the invention: In order to solve the above problems, the present application provides a method for preparing a thin-walled cavity type investment casting mold, which at least solves the problem that the method for processing and producing thin-walled cavity type investment molds is relatively complicated and inconvenient to process and produce thin-walled cavity type investment molds. Summary of the invention:

[0005] A method for preparing a thin-walled cavity investment casting mold, the steps are as follows:

[0006] Step 1: prepare a standard investment mold, wherein the investment mold has an inner cavity, a first opening, and a second opening; to determine the exact size and structure of the thin-walled cavity mold,

[0007] Step 2: forming a first coating layer on the outer surface of the molten mold; forming a second coating layer on the inner surface of the molten mold;

[0008] Step 3: Fill the inner cavity with supporting material and seal the first opening and the second opening to support and reinforce the second coating layer on the inner surface of the investment mold to prevent the second coating layer on the inner surface of the investment mold from deviating due to lack of stable support, thereby causing partial meat loss in the casting;

[0009] Step 4, melting the investment pattern, and discharging the melted investment pattern from between the first and second coating layers to form a thin-walled investment pattern mold;

[0010] Step 5: Unblocking the first opening and the second opening, separating the support material from the inner cavity, and forming a thin-walled cavity-type investment mold.

[0011] Further, the first coating layer and the second coating layer include a first type of sand particles.

[0012] Furthermore, the first coating layer and the second coating layer include three sub-layers, each of which includes the first type of sand particles and adhesive, and the molding process is as follows:

[0013] A first sublayer is formed, and after a first preset time period, a second sublayer is formed on the first sublayer. After a second preset time period, a third sublayer is formed on the second sublayer, and the second preset time period is different from the first preset time period.

[0014] Furthermore, the first preset duration is shorter than the second preset duration.

[0015] Furthermore, the viscosity of the adhesive is in the range of 20s to 26s.

[0016] Further, in step three, the process is as follows: one of the first opening and the second opening is blocked, and the supporting material is injected into the inner cavity through the other of the first opening and the second opening until the supporting material fills the inner cavity, and then the other of the first opening and the second opening is blocked.

[0017] Further, the supporting material includes a second type of sand particles and a bonding glue;

[0018] The mass ratio of the second type of sand particles to the bonding glue is 1:1.

[0019] Further, after the first opening and the second opening are blocked, the device is left to stand for a third preset time period, and the third preset time period is not less than 120 hours.

[0020] Furthermore, the first type of sand particles is: zircon sand of 80-150 meshes or quartz sand of 40-70 meshes.

[0021] Furthermore, the second type of sand particles is: 16-30 mesh Shangdian sand or 20-40 mesh quartz sand.

[0022] The beneficial effects of this application are:

[0023] The mold designed and manufactured according to the present invention has the following beneficial effects: it can ensure the complete forming of the investment casting during the production process, prevent the occurrence of meat defects in the inner cavity of the casting caused by the deviation of the coating layer, improve the qualified rate of the casting, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of a method for producing a thin-walled cavity type investment mold provided by an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of investment molds at different preparation stages provided in Example 1;

[0026] Figure 3Schematic diagram of investment mold at different preparation stages provided for Example 2. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0028] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0029] In a first aspect, an embodiment of the present invention provides a method for producing a thin-walled cavity type investment mold, the method for producing a thin-walled cavity type investment mold comprising:

[0030] Providing a standard investment mold to determine the exact size and structure of a thin-walled cavity mold, wherein the investment mold has an inner cavity, a first opening, and a second opening;

[0031] Forming a first coating layer on the outer surface of the molten mold, and forming a second coating layer on the inner surface of the molten mold, wherein the first coating layer and the second coating layer both avoid the first opening and the second opening;

[0032] Prop material is arranged in the inner cavity, and the first opening and the second opening are blocked to support and reinforce the second coating layer on the inner surface of the investment mold, so as to prevent the second coating layer on the inner surface of the investment mold from deviating due to lack of firm support, thereby causing partial meat loss in the casting;

[0033] Melting the investment pattern, and separating the melted investment pattern from the first coating layer and the second coating layer to form a thin-wall investment pattern mold;

[0034] The first opening and the second opening are unblocked, and the support material is separated from the inner cavity to form a thin-walled cavity-type investment mold.

[0035] Optionally, forming a first coating layer on the outer surface of the molten mold and forming a second coating layer on the inner surface of the molten mold comprises:

[0036] A coating layer is formed on both the outer surface and the inner surface of the molten mold, the coating layer comprising a first type of sand particles, the coating layer on the outer surface of the molten mold forms the first coating layer, and the coating layer on the inner surface of the molten mold forms the second coating layer.

[0037] Optionally, forming a coating layer on both the outer surface of the molten mold and the inner surface of the molten mold comprises:

[0038] A first sub-layer is formed on both the outer surface of the investment mold and the inner surface of the investment mold, wherein the first sub-layer includes first type sand particles and adhesive;

[0039] After a first preset time, forming a second sublayer on the first sublayer, the second sublayer comprising the first type of sand particles and the adhesive;

[0040] After a second preset time, a third sublayer is formed on the second sublayer, the third sublayer includes the first type of sand particles and the adhesive, the first sublayer, the second sublayer and the third sublayer form the coating layer, and the second preset time is different from the first preset time.

[0041] Optionally, the first preset duration is shorter than the second preset duration.

[0042] Optionally, the viscosity of the adhesive is in the range of 20s to 26s.

[0043] Optionally, the step of providing a support material in the inner cavity and sealing the first opening and the second opening comprises:

[0044] One of the first opening and the second opening is blocked, and the supporting material is injected into the inner cavity through the other of the first opening and the second opening until the inner cavity is filled with the supporting material, and then the other of the first opening and the second opening is blocked.

[0045] Optionally, blocking one of the first opening and the second opening includes:

[0046] preparing a supporting material, wherein the supporting material comprises a second type of sand particles and a bonding glue;

[0047] One of the first opening and the second opening is blocked by the supporting material.

[0048] Optionally, the mass ratio of the second type of sand particles to the adhesive is 1:1.

[0049] Optionally, after the support material is arranged in the inner cavity and the first opening and the second opening are blocked, the method for producing the thin-walled cavity type investment mold further includes:

[0050] The time for leaving the investment mold to stand still reaches a third preset time, and the third preset time is greater than or equal to 120 hours.

[0051] In a second aspect, an embodiment of the present invention provides a production device for a thin-walled cavity type investment mold, the production device for a thin-walled cavity type investment mold comprising:

[0052] Providing a module for providing a standard investment mold, wherein the investment mold has an inner cavity, a first opening and a second opening;

[0053] A forming module, used for forming a first coating layer on the outer surface of the molten mold and forming a second coating layer on the inner surface of the molten mold, wherein the first coating layer and the second coating layer both avoid the first opening and the second opening;

[0054] A setting module, used for setting a supporting material in the inner cavity and sealing the first opening and the second opening;

[0055] A melting module, used for melting the molten mold and separating the melted molten mold from the first coating layer and the second coating layer;

[0056] The release module is used to release the blockage of the first opening and the second opening, and separate the support material from the inner cavity to form a thin-walled cavity-type investment mold.

[0057] In an embodiment of the present invention, a standard melt mold is provided, and the melt mold has an inner cavity, a first opening, and a second opening; a first coating layer is formed on the outer surface of the melt mold, and a second coating layer is formed on the inner surface of the melt mold, and both the first coating layer and the second coating layer avoid the first opening and the second opening; a support material is set in the inner cavity, and the first opening and the second opening are blocked; the melt mold is melted, and the melt mold is separated from the first coating layer and the second coating layer after melting; the blocking of the first opening and the second opening is released, and the support material is separated from the inner cavity to form a thin-walled cavity type melt mold. That is, in an embodiment of the present invention, a coating layer can be directly formed on the standard melt mold, and the first opening and the second opening are blocked, and the stability of the coating layer is maintained by the support material, and then the melt mold in the coating layer is melted, so as to form a thin-walled cavity type melt mold, and the thin-walled cavity type melt mold has the same shape as the standard melt mold, so that the method for forming a thin-walled cavity type melt mold is relatively simple, and it is convenient to form a thin-walled cavity type melt mold.

[0058] Embodiment 1

[0059] Due to a certain type of small thin-walled cavity casting, the outer dimensions of the casting are φ50mm×90mm, the wall thickness is about 4mm, and the wall thickness at the cavity is only 2mm. Figure 2 According to the conventional investment casting production process, quartz sand with a mesh size of 40 to 70 is used to make the coating layer. However, the coating layer formed by the quartz sand has a low strength, and the coating layer connection parts in the inner cavity are prone to fracture and displacement, resulting in local lack of meat in the casting cavity.

[0060] According to the implementation of the present invention, firstly, a tool is used to make an investment mold, and then quartz sand of 40-70 meshes and an adhesive with a viscosity of 20s-26s are used to form the first and second coating layers on the outer surface and inner surface of the investment mold, and the investment mold is left to stand for a preset time of greater than or equal to 4 hours; then, a support material prepared by quartz sand of 20-40 meshes and an adhesive with a viscosity of 20s-26s in a mass ratio of 1:1 is filled in the inner cavity, and the first opening and the second opening are blocked, and the investment mold is left to stand for a preset time of greater than or equal to 120 hours; then, the investment mold is placed in a high-temperature and high-pressure steam dewaxing kettle, and the investment mold is melted and discharged from between the first and second coating layers under an environment of 160°C and 0.4Mpa; the blocking of the first opening and the second opening is released, and the support material is separated from the inner cavity to form a thin-walled cavity-type investment mold.

[0061] Embodiment 2

[0062] Due to a certain type of large thin-walled cavity casting, the casting size is 200mm×150mm×150mm, the wall thickness is about 6mm, and the thinnest wall thickness in the cavity is only 3mm. Figure 3 As shown in the figure, according to the conventional investment casting production process, 80-150 mesh zircon sand is used to make the coating layer. Due to the large size of the casting, the coating layer in the inner cavity is not stable and is prone to offset, resulting in uneven wall thickness in the casting cavity.

[0063] According to the implementation of the present invention, firstly, a tool is used to make an investment mold, and then zircon sand with a mesh size of 80 to 150 and an adhesive with a viscosity of 20s to 26s are used to form the first and second coating layers on the outer and inner surfaces of the investment mold. In order to enhance the strength of the coating layer, the first coating layer and the second coating layer include three sublayers, each of which includes a first type of sand and an adhesive. A first sublayer is formed, and the investment mold is allowed to stand for a preset time of greater than or equal to 4 hours; a second sublayer is formed on the first sublayer, and the investment mold is allowed to stand for a preset time of greater than or equal to 5 hours; and a second sublayer is formed on the second sublayer. The third sub-layer is formed; then, the inner cavity is filled with a support material prepared by upper sand of 16-30 meshes and a bonding glue with a viscosity of 20s-26s in a mass ratio of 1:1, and the first opening and the second opening are sealed, and the investment mold is left to stand for a preset time of greater than or equal to 120 hours; then the investment mold is placed in a high-temperature and high-pressure steam dewaxing kettle, and the investment mold is melted and discharged from between the first and second coating layers under an environment of 160°C and 0.4Mpa; the first opening and the second opening are unblocked, and the support material is separated from the inner cavity to form a thin-walled cavity investment mold.

[0064] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the method and device in the embodiment of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0065] Through the description of the above implementation modes, those skilled in the art can clearly understand that the above implementation modes can be implemented by means of software plus a necessary general hardware platform, and of course by means of hardware, but in many cases the former is a better implementation mode. The above describes the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above specific implementation modes, which are merely illustrative and not restrictive. Under the enlightenment of the present invention, those skilled in the art can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for preparing a thin-walled cavity investment casting mold, characterized in that: Here are the steps: Step 1, preparing a standard investment mold, wherein the investment mold has an inner cavity, a first opening and a second opening; Step 2: forming a first coating layer on the outer surface of the molten mold; forming a second coating layer on the inner surface of the molten mold; Step 3: Fill the inner cavity with supporting material and seal the first opening and the second opening; Step 4, melting the molten mold, and discharging the melted molten mold from between the first and second coating layers; Step 5: Unblocking the first opening and the second opening, separating the support material from the inner cavity, and forming a thin-walled cavity-type investment mold.

2. The method according to claim 1, characterized in that: The first paint layer and the second paint layer include a first type of grit.

3. The method according to claim 1, characterized in that: The first coating layer and the second coating layer include three sub-layers, each of which includes the first type of sand particles and adhesive, and the molding process is as follows: A first sublayer is formed, and after a first preset time period, a second sublayer is formed on the first sublayer. After a second preset time period, a third sublayer is formed on the second sublayer, and the second preset time period is different from the first preset time period.

4. The method according to claim 3, characterized in that: The first preset time length is shorter than the second preset time length.

5. The method according to claim 4, characterized in that: The viscosity of the adhesive is in the range of 20s to 26s.

6. The method according to claim 5, characterized in that: In step three, the process is as follows: one of the first opening and the second opening is blocked, and the support material is injected into the inner cavity through the other of the first opening and the second opening until the support material fills the inner cavity, and then the other of the first opening and the second opening is blocked.

7. The method according to claim 6, characterized in that: The supporting material includes a second type of sand and a bonding glue; The mass ratio of the second type of sand particles to the bonding glue is 1:

1.

8. The method according to claim 7, characterized in that: After the first opening and the second opening are blocked, the device is left to stand for a third preset time period, and the third preset time period is not less than 120 hours.

9. The method according to claim 7, characterized in that: The first type of sand is: 80-150 mesh zircon sand or 40-70 mesh quartz sand.

10. The method according to claim 7, characterized in that: The second type of sand is: 16-30 mesh Shangdian sand or 20-40 mesh quartz sand.

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