A kind of thin-walled structure high-temperature alloy casting 3D printing wax mould's dewaxing method

Abstract

The present application relates to the technical field of investment precision casting of high-temperature alloy, in particular to a kind of thin-walled structure high-temperature alloy casting 3D printing wax mould's dewaxing method.Printed wax mould support wax mould part is placed in anhydrous ethanol and soaked, then immersed in polypropylene glycol solution, and the solution is heated and stirred to remove the support wax mould part.Wax piece main body is fished out and placed in clean water with the same temperature as the soaking solution, completely immersed, and taken out after cooling to room temperature with water, to prevent being directly taken out from the soaking solution.Wax mould produces shrinkage stress due to local shrinkage difference of wax mould, and cracks or fractures occur at thin-walled position of wax mould, improving the qualified rate of 3D printing wax mould.The present application has the characteristics of structural stability and high qualified rate for thin-walled structure 3D printing wax mould, greatly reduces the production cost of casting, and improves the production efficiency and qualified rate of high-temperature alloy casting.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of investment casting of high-temperature alloy, in particular to a kind of thin-walled structure high-temperature alloy casting 3D printing wax mould's dewaxing method. BACKGROUND

[0002] With the rapid development of 3D printing technology, the three-dimensional model of product can be directly imported into printing equipment, and the casting prototype wax mould can be directly obtained, which is used to replace traditional wax mould. It is the only choice for small-batch production and short manufacturing cycle of castings, which eliminates mold design, manufacturing cycle and related costs in the production process, thereby saving the manufacturing cost of castings and shortening the manufacturing cycle. And the wax mould deformation problem, size change problem and fracture problem at weak position of thin-walled structure casting in the post-processing of 3D printing dewaxing also affect the qualified rate of wax mould printing. SUMMARY

[0003] The purpose of the present application is to provide a kind of thin-walled structure high-temperature alloy casting 3D printing wax mould's dewaxing method, mainly suitable for the dewaxing of 3D printing wax mould of thin-walled structure and complex shape structure.

[0004] The technical scheme of the present application is:

[0005] A kind of thin-walled structure high-temperature alloy casting 3D printing wax mould's dewaxing method, comprising the following steps:

[0006] Step one, first, the 3D printed wax mould includes wax part main body and support wax mould part, the support wax mould part is stacked on the printing platform, and the wax part main body is printed on the support wax mould part;The printed wax mould support wax mould part is placed in anhydrous ethanol for soaking, to prevent the wax parts from floating and colliding with each other or the wax mould from colliding with the dewaxing container and causing wax mould deformation;

[0007] Step two, immerse in polypropylene glycol solution for immersion washing, and heat and stir the solution to remove the support wax mould part;

[0008] After removing the support wax mould part, the wax part main body is taken out and placed in clean water at the same temperature as the immersion washing solution, completely immersed, and taken out after the water cools to room temperature, the wax part main body is used as a production module to prevent direct removal from the immersion washing solution, which causes shrinkage stress of the wax mould due to local shrinkage difference of the wax mould, and cracks or root fractures at the thin-walled position of the wax mould.

[0009] The dewaxing method of the thin-walled structure high-temperature alloy casting 3D printing wax mould, in step one, 3D wax mould printer is used for 3D printing, and the wax material density of the wax part main body and the support wax mould part is 0.85g / cm 3 ~ 0.91g / cm 3 .

[0010] The thin-walled structure high-temperature alloy casting 3D printing wax mold dewaxing method, in step one, the printed wax mold support wax mold part is placed in anhydrous ethanol for 1min to 3min.

[0011] The thin-walled structure high-temperature alloy casting 3D printing wax mold dewaxing method, in step two, the polypropylene glycol solution is a solution prepared by mixing anhydrous ethanol and polypropylene glycol at a volume ratio of 4:1, the heating temperature is 32 DEG C to 40 DEG C, and the stirring speed is 800rpm to 1200rpm.

[0012] The thin-walled structure high-temperature alloy casting 3D printing wax mold dewaxing method, in step three, after removing the support wax mold part, the wax part body is taken out and placed in clean water at 32 DEG C to 40 DEG C, completely immersed, and taken out after cooling to room temperature with water, and used for wax mold combination after natural air drying on the surface.

[0013] The thin-walled structure high-temperature alloy casting 3D printing wax mold dewaxing method, the thin-walled structure high-temperature alloy casting adopts single crystal high-temperature alloy thin-walled castings with a wall thickness of 0.5mm to 1mm.

[0014] The design idea of the present application is:

[0015] After removing the support wax mold part of the 3D printing thin-walled structure wax mold, the wax part body is directly taken out from the immersion solution, and due to the difference in temperature between the immersion solution and the indoor temperature, local shrinkage difference leads to shrinkage stress of the wax mold, and cracks or thin-walled root fractures occur at the thin-walled position of the wax mold.

[0016] The present application has the following advantages and beneficial effects:

[0017] 1. The present application is easy to operate and has a short production cycle.

[0018] 2. By placing the printed wax mold support wax in anhydrous ethanol for immersion, the present application can reduce the mutual collision or collision between the wax mold and the dewaxing container caused by the wax mold floating up during the dewaxing process, so as to ensure the size of the wax part.

[0019] 3. By placing the wax part body in clean water at the same temperature as the immersion solution, the present application avoids directly taking out the wax part body from the immersion solution after dewaxing, and due to the local shrinkage difference of the wax mold, shrinkage stress of the wax mold is generated, and cracks or thin-walled root fractures occur at the thin-walled position of the wax mold, thereby improving the qualified rate of the 3D printing wax mold of the thin-walled structure casting.

[0020] 4. The wax mold for 3D printing thin-walled castings has the characteristics of structural stability and high pass rate, which greatly reduces the production cost of castings and improves the production efficiency and pass rate of castings. Attached Figure Description

[0021] Figure 1 This is a flowchart of the 3D printing wax model dewaxing process of the present invention. Detailed Implementation

[0022] like Figure 1 As shown, the dewaxing method for 3D printing wax models of thin-walled high-temperature alloy castings of the present invention is as follows:

[0023] (1) After printing the wax model, heat the printing platform to remove the wax model. Place the printed wax model support wax in anhydrous ethanol for 1 min to 3 min to prevent air holes in the gaps of the support wax. Then place it in the dewaxing solution. Due to its light weight and low density, the wax parts float up and collide with each other or the wax model collides with the dewaxing container, resulting in wax model deformation and size changes.

[0024] (2) The printed wax model includes the main body of the wax part and the supporting wax model part. The supporting wax model part is piled on the printing platform. The printing platform is placed on the constant temperature heating platform and the temperature is set to 70-90℃. After heating the printing platform for 1-5 minutes, when the supporting wax model part begins to melt, carefully remove the wax model from the printing platform.

[0025] (3) Immerse it again in a polypropylene glycol solution prepared by mixing anhydrous ethanol and polypropylene glycol in a 4:1 ratio (by volume), and heat and stir the solution at a temperature of 32℃~40℃ and a stirring speed of 800rpm~1200rpm for 10min~30min to remove the supporting wax mold part.

[0026] The principle behind retaining the main body of the wax piece and removing the supporting wax mold through the above operation is as follows: Due to the difference in materials between the main body of the wax piece and the supporting wax mold, the supporting wax mold dissolves in a mixed solution of anhydrous ethanol and polypropylene glycol at a certain temperature, while the main body of the wax piece does not dissolve in the mixed solution.

[0027] (4) After removing the support wax, take out the wax body and place it in clean water at 32℃~40℃ for complete immersion. After cooling to room temperature, take it out and let the surface dry naturally before using the wax model assembly. This is to prevent the wax model from being taken out directly from the immersion solution. Due to the large temperature difference, the local shrinkage difference of the wax model will cause shrinkage stress, which will cause cracks in the thin wall position or breakage at the root of the thin wall.

[0028] The present invention will now be further described in detail through examples.

[0029] Example 1

[0030] An equiaxed crystal blade is printed in this embodiment, the blade length is 95 mm, the blade body is relatively thin as a whole, the exhaust edge thickness is about 0.5 mm, the structure is solid with a crown, and the alloy grade is K417G.

[0031] The wax mold of the thin-walled structure high-temperature alloy casting 3D printing is processed by the following method:

[0032] (1) Three-dimensional casting model design stage

[0033] The blade model is uniformly enlarged by 2.2% in the X and Y directions and by 1.6% in the Z direction according to the process requirements, that is, the blade model is printable.

[0034] (2) Wax mold printing stage

[0035] The printable blade model is imported into the 3D wax mold printer for printing. The printed wax mold includes a wax part main body and a support wax mold part. The material of the wax part main body is a special wax material, and the density is 0.85 g / cm 3 ~ 0.91 g / cm 3 ; the material of the support wax mold part is a special wax material, and the density is 0.85 g / cm 3 ~ 0.91 g / cm 3 The main materials of the wax part main body and the support wax mold part are paraffin, and a small amount of aliphatic hydrocarbon compounds is added to the wax part main body to prevent the wax part main body from dissolving in the immersion solution. The lowest position of the blade is 3 mm away from the printing platform, and the support wax mold part is filled to avoid direct contact between the blade and the printing platform, which may damage the blade during the post-processing process. The blade is laid on the printing platform, and the hollow position is also filled with the support wax mold part to protect the wax part from deformation during the printing process. The support wax mold part is porous inside.

[0036] (3) Post-processing stage of wax mold dewaxing

[0037] Put the printing platform on the constant temperature heating platform, set the temperature to 80℃, heat the printing platform for 2-3 minutes, and then carefully take the wax mold off the printing platform when the support wax mold part starts to melt. The operator holds the blade tenon excess position, immerses the support wax mold part of the wax mold in anhydrous ethanol for 1 minute to exhaust the air holes in the support wax mold part. In order to prevent air holes from existing between the gaps of the support wax mold part, which may cause deformation of the wax mold when placed in the dewaxing solution due to the light weight and small density of the wax mold.

[0038] The leaching solution is configured, and the solution is prepared by mixing anhydrous ethanol and polypropylene glycol 4:1 (by volume ratio). The printed wax mold is placed in a container sleeved with a mesh screen and the prepared solution is poured into the container. The solution is placed on a magnetic stirrer, heated to 35°C, and stirred at a speed of 1100 rpm. After 15-20 minutes, the support wax mold part is completely dissolved in the solution to obtain a blade wax mold. After the leaching of the support wax mold part is completed, the wax body is carefully taken out and immediately placed in 35°C clean water. The blade wax mold is cooled to room temperature (23°C) with the clean water, and then taken out to prevent direct removal from the leaching solution. Because of the large temperature difference between the solution and the room temperature, the local shrinkage difference of the wax mold causes shrinkage stress, and cracks or blade body breakage occur at the air exhaust edge of the blade body. After the blade wax mold is taken out, the surface is naturally dried, and the blade wax mold is used as a wax mold combination.

[0039] After the dewaxing post-processing by the method, the number of wax molds with micro-cracks at the air exhaust edge is significantly reduced, and the qualified rate reaches 95%.

[0040] After the wax mold combination, shell making, casting, and post-processing, a high-temperature alloy blade is made, which meets the requirements of the drawings through three-coordinate inspection.

[0041] Example 2

[0042] In this example, a single crystal structure part is printed, which is 40 mm long, 10 mm wide, and 281 mm high, with a 1 mm crystal bar around the circumference, and the alloy grade is DD5.

[0043] The dewaxing method of the 3D printed wax mold of the thin-walled structure high-temperature alloy casting is as follows:

[0044] (1) Three-dimensional casting model design stage

[0045] The casting model is uniformly enlarged by 2.4% in the X and Y directions and 1.8% in the Z direction according to the process requirements, which is the printable model.

[0046] (2) Wax mold printing stage

[0047] The printable casting model is imported into the 3D wax mold printer for printing. The printed wax mold includes a wax body and a support wax mold part. The material of the wax body is a special wax material, and its density is 0.85 g / cm 3 ~ 0.91 g / cm 3 ; the material of the support wax mold part is a special wax material, and its density is 0.85 g / cm 3 ~ 0.91 g / cm 3, wax body and support wax mold part of the main material are paraffin, a small amount of aliphatic hydrocarbons are added to the wax body, to prevent the wax body dissolved in the soak solution. The castings are printed on the printing platform, the bottom surface is spaced 3mm from the printing platform, and the support wax mold part is filled to avoid direct contact between the castings and the printing platform, which can cause damage to the castings during post-processing. The support wax mold part is porous inside.

[0048] (3) Wax mold dewaxing post-processing stage

[0049] Put the printing platform on the constant temperature heating platform, set the temperature to 80℃, heat the printing platform for 3-4 minutes, then carefully remove the wax mold from the printing platform when the support wax mold part starts to melt. Prepare the soak solution, which is a mixture of anhydrous ethanol and polypropylene glycol in a ratio of 4:1 by volume. Put the printed wax mold into a container with a mesh screen and pour the prepared solution into it. Heat the solution to 38℃ on a magnetic stirrer, and stir at a speed of 1200rpm. After 20-30 minutes, the support wax mold part will completely dissolve in the solution to obtain the casting wax mold. After the support wax mold part is soaked, carefully remove the casting wax mold and immediately place it in 38℃ water. The casting wax piece cools with the water to room temperature 23℃, which can prevent direct removal from the soak solution, as the large temperature difference between the solution and room temperature can cause cracks in the circumferential barrier or break along the root. After natural air drying, the wax mold is used as a combination.

[0050] After dewaxing post-processing by this method, the number of cracks in the circumferential barrier and root of the wax mold is significantly reduced, and the wax mold pass rate reaches 90%.

[0051] After the wax mold combination, shell making, casting and post-processing, single crystal superalloy castings are made, and the size is checked by a caliper and meets the requirements of the drawing.

Claims

1. A method of dewaxing a thin-walled structure superalloy castings 3D printed wax pattern, characterized in that, The method comprises the following steps: Step one, the first 3D printed wax mold includes a wax part body and a support wax mold part, the support wax mold part is stacked on the printing platform, and the wax part body is printed on the support wax mold part; the printed support wax mold part is placed in anhydrous ethanol for soaking, so as to prevent the wax parts from colliding with each other or the wax mold from colliding with the dewaxing container after floating up, and wax mold deformation is generated; Step two, immerse in a polypropylene glycol solution for immersion washing, and heat and stir the solution to remove the support wax mold part; Step three, after removing the support wax mold part, the wax part body is taken out and placed in clean water at the same temperature as the immersion washing solution for complete immersion, and is taken out after the water cools to room temperature, the wax part body is used as a mold group for manufacturing, so as to prevent the wax mold from being directly taken out from the immersion washing solution, and shrinkage stress is generated in the wax mold due to local shrinkage difference of the wax mold, cracks are generated at thin wall positions of the wax mold or the thin wall root is broken.

2. The method of claim 1, wherein the method further comprises, In step one, 3D printing is performed using a 3D wax mold printer, and the density of the wax material of the wax body and the support wax mold part is 0.85 g / cm 3 ~ 0.91 g / cm 3 .

3. The method of claim 1, wherein the method further comprises, In step one, the printed support wax mold part is placed in anhydrous ethanol for soaking for 1 min to 3 min.

4. The method of claim 1, wherein the method further comprises, In step two, the polypropylene glycol solution is a solution prepared by mixing anhydrous ethanol and polypropylene glycol at a volume ratio of 4:1, the heating temperature is 32°C to 40°C, and the stirring speed is 800 rpm to 1200 rpm.

5. The method of claim 1, wherein the method further comprises, In step three, after removing the support wax mold part, the wax part body is taken out and placed in clean water at 32°C to 40°C for complete immersion, and is taken out after the water cools to room temperature, and is used for wax mold combination after the surface is naturally dried.

6. The method of claim 1, wherein the method further comprises, The thin-wall structure high-temperature alloy castings adopt single crystal high-temperature alloy thin-wall castings with a wall thickness of 0.5 mm to 1 mm.

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