Breathable sand mold and preparation method thereof

Abstract

The embodiment of the invention provides an air-permeable sand mold and a preparation method, a plurality of groups of continuous through air-permeable grid structures are preset in the sand mold, and the air-permeable grid structures are radially distributed along the profile of a cavity of the sand mold and communicate with an exhaust port in the outer surface of the sand mold. According to the sand mold disclosed by the invention, the continuous through breathable grid structure is arranged in the sand mold, so that gas in the sand mold can be exhausted in time, the sand mold cracking risk caused by untimely exhaust of the sand mold is reduced, and the casting quality and efficiency of castings are improved.

Description

Technical Field

[0001] This application relates to the field of sand mold technology for aluminum alloy casting, and in particular to a permeable sand mold and its preparation method. Background Technology

[0002] Sand casting, due to its advantages such as low cost and flexible forming, has long been used as the core forming process for complex castings and is widely applied in the production of castings in fields such as engineering machinery, rail transportation and energy equipment.

[0003] As high-end equipment demands increasingly higher levels of density and mechanical properties in castings, the core requirement for sand molds is to effectively remove gas from within the mold during the pouring process, while ensuring its strength and dimensional accuracy. When casting large, deep-cavity parts, gas deep within the sand mold is difficult to expel quickly, and additional venting structures can easily compromise the overall strength of the mold, increasing the risk of cracking. Summary of the Invention

[0004] This application provides a method for manufacturing a lightweight alloy structural component with a complex structure.

[0005] In a first aspect, embodiments of this application provide a breathable sand mold, wherein multiple sets of continuous and interconnected breathable mesh structures are preset inside the sand mold, the breathable mesh structures are radially distributed along the contour of the sand mold cavity, and are connected to the exhaust ports on the outer surface of the sand mold.

[0006] In one feasible implementation, the pore diameter of the breathable mesh structure is 3mm to 5mm, and the pore wall surface is roughened.

[0007] And / or, the pore spacing ranges from 5mm to 15mm.

[0008] Secondly, embodiments of this application provide a method for preparing a permeable sand mold, comprising:

[0009] Based on the cavity structure of the casting, the process of molten metal filling is simulated through fluid dynamics simulation to identify key areas where gas tends to accumulate in the sand mold;

[0010] Design a sand mold model and set up a breathable mesh structure in key areas;

[0011] Sand molds are formed using 3D printing equipment, and a breathable mesh structure is simultaneously formed during the printing process.

[0012] In one feasible implementation, the printing power of the 3D printing equipment is in the range of 150W to 200W, and the scanning speed is in the range of 800mm / s to 1200mm / s.

[0013] In one feasible implementation, the 3D printing equipment is equipped with a dual-nozzle printing mechanism, which includes a main material nozzle and a functional material nozzle, both of which are slidably connected to a slide table via angle adjustment seats.

[0014] In one feasible implementation, the 3D printing equipment is provided with a height-adjustable support base, and the height-adjustable support base is provided with a buffer and shock absorption component. The buffer and shock absorption component includes several shock-absorbing springs and dampers, and the shock-absorbing springs and dampers are arranged in parallel to absorb the vibration and impact during the printing process.

[0015] In one feasible implementation, the 3D printing equipment further includes a waste recycling unit located below the printing platform. The waste recycling unit includes a negative pressure suction device and a screening mechanism. The negative pressure suction device is used to collect the sand core material scattered during the printing process, and the screening mechanism is used to separate the material from impurities.

[0016] This application provides a permeable sand mold and its preparation method. The sand mold contains multiple sets of continuously connected permeable mesh structures, which are radially distributed along the mold cavity contour and connected to venting ports on the outer surface of the sand mold. By setting a continuously connected permeable mesh structure inside the sand mold, gas inside the mold can be promptly expelled, reducing the risk of sand mold cracking due to untimely venting and improving the casting quality and efficiency. Attached Figure Description

[0017] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain this application and do not constitute an undue limitation of the invention.

[0018] In the attached diagram:

[0019] Figure 1 This is a schematic diagram of the overall structure of a permeable sand mold provided in one embodiment of this application;

[0020] Figure 2 yes Figure 1 A cross-sectional view of the permeable sand mold in the middle;

[0021] Figure 3 This is a schematic diagram of the structure of a 3D printing device provided in one embodiment of this application;

[0022] 100 - Breathable mesh structure; 200 - Main material nozzle; 300 - Functional material nozzle; 400 - Adjustable support base; 500 - Buffer and shock absorption components; 600 - Angle adjustment base; 700 - Slide table. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0024] In the description of the embodiments of this application, 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 indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," 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; 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 expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] In this application, unless otherwise expressly 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.

[0027] Sand casting, due to its advantages such as low cost and flexible forming, has long been used as the core forming process for complex castings and is widely applied in the production of castings in fields such as engineering machinery, rail transportation and energy equipment.

[0028] As high-end equipment demands increasingly higher levels of density and mechanical properties in castings, the core requirement for sand molds is to effectively remove gas from within the mold during the pouring process, while ensuring its strength and dimensional accuracy. When casting large, deep-cavity parts, gas deep within the sand mold is difficult to expel quickly, and additional venting structures can easily compromise the overall strength of the mold, increasing the risk of cracking.

[0029] To address the aforementioned issues, this application provides a permeable sand mold and its preparation method. The solution provided in this application will be described in detail below with reference to the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of the overall structure of a permeable sand mold provided in one embodiment of this application; Figure 2 yes Figure 1 A cross-sectional view of the permeable sand mold.

[0031] Reference Figure 1 and Figure 2 As shown, in a first aspect, embodiments of this application provide a permeable sand mold. Multiple sets of continuously connected permeable mesh structures 100 are pre-set inside the sand mold. The permeable mesh structures 100 are radially distributed along the contour of the sand mold cavity and are connected to the venting ports on the outer surface of the sand mold. It is understood that by setting continuously connected permeable mesh structures 100 inside the sand mold, gas inside the sand mold can be promptly expelled, reducing the risk of sand mold cracking due to untimely venting and improving the casting quality and efficiency of the castings.

[0032] For example, the pore diameter of the breathable mesh structure 100 is 3mm to 5mm, and the pore wall surface is roughened; the pore spacing ranges from 5mm to 15mm.

[0033] Secondly, embodiments of this application provide a method for preparing a permeable sand mold, comprising:

[0034] Based on the cavity structure of the casting, the process of molten metal filling is simulated through fluid dynamics simulation to identify key areas where gas tends to accumulate in the sand mold;

[0035] Design a sand mold model and set up a breathable mesh structure of 100 in key areas;

[0036] Sand molds are formed using 3D printing equipment, and a breathable mesh structure 100 is formed simultaneously during the printing process.

[0037] For example, the printing power of the 3D printing equipment ranges from 150W to 200W, and the scanning speed ranges from 800mm / s to 1200mm / s.

[0038] Figure 3 This is a schematic diagram of the setup of a 3D printing device provided in one embodiment of this application.

[0039] like Figure 3 As shown, for example, the 3D printing equipment is equipped with a dual-nozzle printing mechanism, which includes a main material nozzle 200 and a functional material nozzle 300, which are slidably connected to the slide table 700 via an angle adjustment seat 600.

[0040] The 3D printing equipment is equipped with a height-adjustable support base 400, on which a buffer and shock-absorbing component 500 is provided. The buffer and shock-absorbing component 500 includes several shock-absorbing springs and dampers, which are arranged in parallel to absorb vibration and impact during the printing process.

[0041] The 3D printing equipment also includes a waste recycling unit, which is located below the printing platform and includes a negative pressure suction device and a screening mechanism. The negative pressure suction device is used to collect the sand core material that is scattered during the printing process, and the screening mechanism is used to separate the material from impurities.

[0042] In addition, this 3D printing equipment is equipped with a data interaction module, supporting real-time updates of the design model and dynamic synchronization of printing parameters. When the porosity-enhanced mesh structure model is modified, the parameter adaptation unit can trigger adjustment prompts for printing process parameters, and then the feedback execution unit drives the printing system to make adaptive adjustments. The printing process parameter library includes printing speed ranges, nozzle temperatures, layer thickness parameters, and curing temperature curves corresponding to different material types and mesh structures. The parameter adaptation unit can integrate process parameters according to the structural characteristics of the final design model and supports manual adjustment. The gradient heating channel of the drying and curing unit of the 3D printing equipment is divided into a preheating section, a curing section, and a cooling section. The temperature of the preheating section is 80-120℃, the temperature of the curing section is 180-220℃, and the temperature gradient of the cooling section is 5-10℃ / min. The insulation chamber is equipped with a temperature uniformity monitoring sensor to ensure that the curing degree of each part of the sand core is consistent.

[0043] Example 1

[0044] Sand molds for preparing automobile engine block castings

[0045] Design Phase: Input the 3D model of the engine block, casting temperature 850℃, sand core compressive strength ≥30MPa, and weight reduction of 30%. The mesh optimization unit diameter gradually changes from φ8mm at the intake end to φ12mm at the exhaust end, and the inner wall is coated with a ceramic-based wear-resistant coating; the structural verification unit is optimized by finite element simulation and outputs the final design model; the parameter adaptation unit matches the printing parameters corresponding to the resin sand material: printing speed 50mm / s, nozzle temperature 60℃, layer thickness 0.1mm, and curing temperature profile of preheating 100℃ / 30min, curing 200℃ / 60min, and cooling 8℃ / min.

[0046] Printing process: In the dual-nozzle printing mechanism, the main material nozzle 200 sprays resin sand matrix material, while the functional material nozzle 300 sprays carbon fiber reinforcing agent at the key joint between the sand core and the cylinder. The closed-loop control module detects in real time that there is a lack of material on the inner wall of the guide channel and automatically adjusts the spraying amount of the functional material nozzle 300 to replenish the material. The buffer and shock absorption component 500 of the printing platform effectively absorbs vibration, and the rotation adjustment module works with the nozzles to complete the printing of the annular channel.

[0047] Drying and curing: After the sand core is processed in sections by the drying and curing unit, the test results show that the weight of the sand core is reduced by 32% compared with the traditional structure, the compressive strength is increased by 35MPa, the dimensional accuracy is ±0.25mm, the surface roughness is Ra1.2μm, and the airflow and exhaust efficiency is increased by 45%, which meets the casting requirements of engine cylinder block castings.

[0048] Example 2

[0049] Sand mold for preparing gearbox housing castings

[0050] Design phase: Input the 3D model of the gearbox housing, pouring temperature 780℃, sand core deformation resistance ≥25MPa, mesh optimization unit generates structural model with cross-shaped reinforcing ribs and built-in airflow and exhaust channels; parameter adaptation unit matches the printing parameters corresponding to water glass sand material: printing speed 40mm / s, nozzle temperature 55℃, layer thickness 0.15mm.

[0051] Printing and curing: Dual printheads work together to print, with the functional material printhead spraying high-temperature sealant at 300mm; a closed-loop control module dynamically adjusts printing parameters to ensure the molding accuracy of complex cavity structures; after drying and curing, the sand core defect rate is only 3%, which is 42% lower than traditional technology, the production cycle is shortened by 55%, and the raw material recovery rate is 92%.

[0052] It is readily understood that, based on the several embodiments provided in this application, those skilled in the art can combine, split, or reorganize the embodiments of this application to obtain other embodiments, none of which exceed the protection scope of this application.

[0053] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A permeable sand mold, characterized in that, Multiple sets of continuous and interconnected permeable mesh structures are pre-set inside the sand mold. The permeable mesh structures are radially distributed along the contour of the sand mold cavity and are connected to the exhaust ports on the outer surface of the sand mold.

2. The permeable sand mold according to claim 1, characterized in that, The pore diameter of the breathable mesh structure is 3mm~5mm, and the pore wall surface is roughened. And / or, the pore spacing ranges from 5mm to 15mm.

3. A method for preparing a permeable sand mold, characterized in that, include: Based on the cavity structure of the casting, the process of molten metal filling is simulated through fluid dynamics simulation to identify key areas where gas tends to accumulate in the sand mold; Design a sand mold model and set up a breathable mesh structure in key areas; Sand molds are formed using 3D printing equipment, and a breathable mesh structure is simultaneously formed during the printing process.

4. The method for preparing a permeable sand mold according to claim 3, characterized in that, The printing power of the 3D printing equipment ranges from 150W to 200W, and the scanning speed ranges from 800mm / s to 1200mm / s.

5. The method for preparing a permeable sand mold according to claim 3, characterized in that, The 3D printing equipment is equipped with a dual-nozzle printing mechanism, which includes a main material nozzle and a functional material nozzle, both of which are slidably connected to the slide table via angle adjustment seats.

6. The method for preparing a permeable sand mold according to claim 3, characterized in that, The 3D printing equipment is equipped with a height-adjustable support base, on which a buffer and shock-absorbing component is installed. The buffer and shock-absorbing component includes several shock-absorbing springs and dampers, which are connected in parallel to absorb vibration and impact during the printing process.

7. The method for preparing a permeable sand mold according to claim 3, characterized in that, The 3D printing equipment also includes a waste recycling unit located below the printing platform. The waste recycling unit includes a negative pressure suction device and a screening mechanism. The negative pressure suction device is used to collect the sand core material scattered during the printing process, and the screening mechanism is used to separate the material from impurities.

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