3D printing sand casting mold and manufacturing method

Abstract

The invention relates to a 3D printing sand casting mold and a manufacturing method, the 3D printing sand casting mold comprises a shell and a reinforcing plate, the reinforcing plate is arranged in the shell, the reinforcing plate is flush with the attachment surface of the shell and a printing platform, a plurality of stress holes are formed in the reinforcing plate, and a deformation hole is formed in the upper portion of the platform surface, facing the printing platform, of the shell; fillers are arranged in the deformation holes; the manufacturing method comprises the following steps: establishing a product contour three-dimensional model and determining a bottom surface; arranging a reinforcing plate; arranging a plurality of stress holes; forming a deformation hole; printing a sand casting mold; and the deformation hole is filled, and the surface of the sand casting mold is polished. The sand casting mold has the advantages that the three layers of shells are matched with the reinforcing plates, the stress holes are formed in the reinforcing plates, the mechanical strength of the sand casting mold is ensured while materials are reduced, the printing time is shortened, meanwhile, the deformation holes are formed in the shells, deformation of the deformation holes replaces deformation of edge angles of a platform surface, and the production efficiency is improved. And the condition that the sand-casting mold tilts due to different temperatures of upper and lower layers of materials during printing is avoided.

Description

Technical Field

[0001] The present invention relates to the field of sand casting, and in particular to a 3D printing sand casting mold and a manufacturing method thereof. Background Art

[0002] When casting sand molds, you need to use a sand mold to make a sand mold first. Traditional sand molds are usually wooden molds or metal molds, which are difficult to make, heavy, easy to deform and require regular maintenance. Compared with traditional wooden molds and metal molds, 3D printed sand molds have the advantages of fast production cycle and low cost. However, due to the long printing time during the printing process of 3D printed sand molds, especially large sand molds, there will be a significant temperature difference between the upper and lower materials. This temperature difference will cause the edge corners of the printed sand mold to be warped, affecting the flatness of the sand mold. After the sand mold is assembled, there will be gaps, which will make it impossible to produce accurate sand molds. Summary of the invention

[0003] The present invention mainly solves the above-mentioned problem and provides a 3D printing sand casting mold and a manufacturing method. A three-layer shell is used in combination with a reinforcing plate and stress holes are opened on the reinforcing plate. While reducing the material consumption, the mechanical strength of the sand casting mold is ensured and the printing time is shortened. At the same time, deformation holes are formed on the shell to replace the deformation of the edge angle of the platform surface with the deformation of the deformation holes, so as to avoid the sand casting mold from warping due to the different temperatures of the upper and lower layers of materials during printing.

[0004] The technical solution adopted by the present invention to solve its technical problem is a 3D printing sand casting mold, including a shell and a reinforcing plate, wherein the reinforcing plate is arranged in the shell, the reinforcing plate is flush with the attachment surface of the shell and the printing platform, a plurality of stress holes are arranged on the reinforcing plate, a deformation hole is arranged above the platform surface of the shell facing the printing platform, and a filler is arranged in the deformation hole.

[0005] As a preferred embodiment of the above scheme, the shell includes an outer layer, a reinforcement layer and an inner layer, and the reinforcement layer is arranged between the outer layer and the inner layer.

[0006] As a preferred embodiment of the above solution, the reinforcement layers are distributed in a grid shape.

[0007] As a preferred solution of the above solution, the reinforcing plate includes a transverse reinforcing plate and a longitudinal reinforcing plate, and the transverse reinforcing plate and the longitudinal reinforcing plate are distributed in a cross shape in the shell.

[0008] As a preferred embodiment of the above solution, the reinforcing plate forms a matching convex splicing portion and a concave splicing portion at the splicing position of the shell.

[0009] As a preferred embodiment of the above solution, the deformation hole corresponds to the edge angle of the platform surface.

[0010] The present invention also provides a 3D printing sand casting mold manufacturing method, which is used to manufacture the above-mentioned 3D printing sand casting mold, comprising the following steps: S1: Establish a three-dimensional model of the product contour according to the target product and determine the bottom surface attached to the printing platform; S2: a reinforcing plate is arranged in the three-dimensional model of the product outline, wherein the reinforcing plate is flush with the bottom surface and connected to the inner wall of the three-dimensional model of the product outer outline; S3: Arrange a plurality of stress holes on the reinforcing plate; S4: Find the platform surface facing the printing platform in the three-dimensional model of the product contour and set a deformation hole above the platform surface; S5: Printing the sand-casting mold; S6: filling the deformation holes on the sand-casting mold and polishing the surface of the sand-casting mold.

[0011] As a preferred embodiment of the above scheme, in step S2, if the three-dimensional model of the product contour is assembled from two separate structures, the reinforcing plates respectively form matching convex splicing parts and concave splicing parts at the assembly surfaces of the two separate structures.

[0012] As a preferred embodiment of the above scheme, the three-dimensional model of the product external contour includes an outer layer and an inner layer, and a reinforcement layer is arranged between the outer layer and the inner layer.

[0013] As a preferred solution of the above solution, in step S6, the deformation hole is filled with hot melt adhesive.

[0014] The advantages of the present invention are: a three-layer shell is used in combination with a reinforcing plate and stress holes are opened on the reinforcing plate, so as to reduce the material consumption while ensuring the mechanical strength of the sand casting mold and shorten the printing time. At the same time, deformation holes are formed on the shell to replace the deformation of the edge angle of the platform surface with the deformation of the deformation holes, so as to avoid the sand casting mold from warping due to the different temperatures of the upper and lower layers of materials during printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the sand casting mold in the embodiment.

[0016] Figure 2 for Figure 1 A partial enlarged view of area A.

[0017] Figure 3 This is a schematic diagram of another sand casting mold structure.

[0018] 1-shell 2-reinforcement plate 3-stress hole 4-attachment surface 5-deformation hole 6-sand casting mold. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be further described below through embodiments in conjunction with the accompanying drawings.

[0020] Embodiment: A 3D printing sand casting mold in this embodiment, as Figure 1 and Figure 2 shown, includes a housing 1 and a reinforcing plate 2. The reinforcing plate 2 is arranged in the housing 1 and is flush with the attachment surface 4 between the housing and the printing platform. The housing 1 includes an outer layer, a reinforcing layer, and an inner layer. The reinforcing layer is arranged between the outer layer and the inner layer and is distributed in a grid pattern. The reinforcing plate 2 includes a transverse reinforcing plate and a longitudinal reinforcing plate. The transverse reinforcing plate and the longitudinal reinforcing plate are cross-distributed in the housing. A number of stress holes 3 are evenly distributed on the reinforcing plate 2. The setting of the stress holes 3 can not only improve the mechanical strength of the reinforcing plate and thus effectively support the housing to ensure the mechanical strength of the mold, but also reduce the overall weight of the mold and lower the cost. For large molds, it can also prevent the housing from deforming due to the deformation of the reinforcing plate.

[0021] At the same time, a deformation hole 5 is provided above the platform surface of the housing 1 facing the printing platform. The deformation hole 5 corresponds to the edge angle of the platform surface. A filler is provided in the deformation hole 5, and the filler is hot melt adhesive. If the deformation hole is not provided, during the printing process, due to the large size of the mold and the long printing time for each layer, there will be an obvious temperature difference between the upper and lower layer materials. Under the influence of the thermal expansion and contraction of the materials, the edge angle of the platform surface will show a warping angle. And setting the deformation hole near the edge angle can allow the acting force of the thermal expansion and contraction of the materials to act on the deformation hole and replace the deformation of the edge angle with the deformation hole, thereby avoiding the warping angle of the platform surface. After the mold printing is completed, the deformation hole can be filled with hot melt adhesive to make up for the deformation hole and eliminate the influence of the deformation hole on the sand mold.

[0022] In addition, if the 3D printing sand casting mold is composed of two parts spliced together, the reinforcing plate 2 can be made to form a matching convex splicing part and concave splicing part at the splicing place of the housing 1. In this embodiment, the complete sand casting mold is composed of Figure 1 and Figure 3 two sand casting molds 6 in the figure spliced together, and the attachment surface 4 is the splicing surface. As Figure 1 shown, the splicing surface is only composed of the housing frame and the reinforcing plate, and the rest are all hollowed out. Such a setting reduces the planar area of the splicing surface. The smaller planar area makes the splicing surface not easy to deform. In addition, an outer convex splicing part and an inner concave splicing are respectively provided on the reinforcing plates at the splicing surfaces of the two sand casting molds 6. The outer convex splicing part and the inner concave splicing further reduce the planar area of the splicing surface and also solve the problem of inconvenient splicing caused by the reduction of the splicing area.

[0023] The sand casting mold in this embodiment is realized by 3D printing. A cavity is formed in the mold in the form of a shell cooperating with a reinforcing plate, making the mold hollow to avoid deformation caused by the thermal expansion and contraction of materials. Three layers of shells are used and stress holes are opened on the reinforcing plate to ensure the mechanical strength of the mold. Deformation holes are provided at the edge corners of the mold platform surface. During the printing process, the deformation of the deformation holes under the action of thermal expansion and contraction of the material replaces the deformation of the edge corners of the mold platform surface, ensuring that the mold platform surface does not have the problem of warping corners.

[0024] Correspondingly, this embodiment also provides a method for manufacturing a 3D printed sand casting mold for manufacturing the above-mentioned 3D printed sand casting mold, including the following steps: S1: Establish a three-dimensional model of the product contour according to the target product and determine the bottom surface attached to the printing platform. The three-dimensional model of the external contour of the product includes an outer layer and an inner layer, and a reinforcing layer is provided between the outer layer and the inner layer. The three-layer structure is set to ensure the mechanical strength of the side of the sand casting mold.

[0025] S2: Set a reinforcing plate in the three-dimensional model of the product contour. The reinforcing plate is flush with the bottom surface and connected to the inner wall of the three-dimensional model of the external contour of the product. If the three-dimensional model of the product contour is assembled and combined by two split structures, the reinforcing plate forms a matching outer convex splicing part and an inner concave splicing part at the assembly surface of the two split structures respectively. The reinforcing plate is used to further improve the mechanical strength of the sand casting mold and make the inside of the sand casting mold hollow, avoiding the deformation of the shape of the sand casting mold caused by the thermal expansion and contraction of materials.

[0026] S3: Set a number of stress holes on the reinforcing plate; improve the mechanical strength of the reinforcing plate through the stress holes, reduce the weight of the reinforcing plate, reduce the material consumption, and reduce the cost.

[0027] S4: Locate the platform surface of the three-dimensional model of the product contour facing the printing platform and set deformation holes above the platform surface; ensure the flatness of the platform surface by deforming the deformation holes instead of deforming the platform surface.

[0028] S5: Perform 3D printing of the sand casting mold.

[0029] S6: Fill the deformation holes on the sand casting mold with hot melt adhesive and polish the surface of the sand casting mold.

[0030] During the 3D printing process of the sand casting mold, the sand casting mold takes Figure 3The state shown is printed and formed layer by layer from bottom to top. For traditional large-scale sand casting molds, during the 3D printing process, due to the relatively long printing time for each layer, the lower layer of material has cooled while the upper layer of material has just been extruded from the print head and is still at a relatively high temperature. As printing progresses, the upper layer of material shrinks after cooling, ultimately resulting in deformation of the sand casting mold. However, in this embodiment, due to the provision of deformation holes, the force of thermal expansion and contraction of the material will act on the deformation holes, causing the deformation holes to deform while the edge angles of the platform surface can remain unchanged. After printing is completed, the deformation holes can be filled with hot melt adhesive and polished to eliminate the influence of the deformation holes on the sand casting mold.

[0031] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A 3D printed sand casting mold, characterized in that: It includes a housing and a reinforcing plate. The reinforcing plate is disposed in the housing. The reinforcing plate is flush with the attachment surface of the housing and the printing platform. A plurality of stress holes are provided on the reinforcing plate. A deformation hole is provided above the platform surface of the housing facing the printing platform, and a filler is provided in the deformation hole.

2. The 3D printed sand casting mold according to claim 1, characterized in that: The housing includes an outer layer, a reinforcing layer, and an inner layer. The reinforcing layer is disposed between the outer layer and the inner layer.

3. The 3D printed sand casting mold according to claim 1, characterized in that: The reinforcing layer is distributed in a grid pattern.

4. The 3D printed sand casting mold according to claim 1, characterized in that: The reinforcing plate includes a transverse reinforcing plate and a longitudinal reinforcing plate. The transverse reinforcing plate and the longitudinal reinforcing plate are cross-distributed in the housing.

5. The 3D printed sand casting mold according to claim 1, characterized in that: The reinforcing plate forms a matching convex splicing part and a concave splicing part at the splicing position of the housing.

6. The 3D printed sand casting mold according to claim 7, characterized in that: The deformation hole corresponds to the edge angle of the platform surface.

7. A method for manufacturing a 3D printing sand casting mold, which is used to manufacture the 3D printing sand casting mold according to any one of claims 1 to 6, and is characterized in that: It includes the following steps: S1: Establish a three-dimensional model of the product contour according to the target product and determine the bottom surface attached to the printing platform. S2: Set a reinforcing plate in the three-dimensional model of the product contour. The reinforcing plate is flush with the bottom surface and is connected to the inner wall of the three-dimensional model of the external contour of the product. S3: Set a plurality of stress holes on the reinforcing plate. S4: Find the platform surface of the three-dimensional model of the product contour facing the printing platform and set a deformation hole above the platform surface. S5: Perform sand casting mold printing. S6: Fill the deformation holes on the sand casting mold and polish the surface of the sand casting mold.

8. The method for manufacturing a 3D printed sand casting mold according to claim 1, characterized in that: In step S2, if the three-dimensional model of the product contour is assembled by two split structures, the reinforcing plate forms a matching convex splicing part and a concave splicing part at the assembly surface of the two split structures respectively.

9. The method for manufacturing a 3D printing sand casting mold according to claim 1, wherein: The three-dimensional model of the external contour of the product includes an outer layer and an inner layer, and a reinforcing layer is provided between the outer layer and the inner layer.

10. The method for manufacturing a 3D printed sand casting mold according to claim 1, wherein: In step S6, the deformation holes are filled with hot melt adhesive.

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