CN114289685A - A kind of multi-material composite sand molding method and device - Google Patents

Abstract

The invention belongs to the field of additive manufacturing, and discloses a method and a device for forming a multi-material composite sand mold. The device comprises a molding sand pretreatment system, a vacuum sand feeding system, a multi-material sand paving system, a printing system, an infrared heating system and a lifting platform device. The method carries out additive manufacturing through a 3D printing (3 DP) technology, realizes preparation of the multi-material composite sand mold by combining the advantages of strong flexible manufacturing capability, high forming quality and high efficiency of the 3D printing (3 DP) technology, and has great innovation, application, popularization and use values.

Description

A kind of multi-material composite sand molding method and device

technical field

The invention belongs to the field of additive manufacturing, and in particular relates to a multi-material composite sand mold forming method and device.

Background technique

The additive manufacturing technology based on sand 3D printing has the characteristics of strong flexible manufacturing capability, high dimensional accuracy, energy saving and material reduction. However, the forming material is limited and single. A single molding material cannot have excellent casting properties such as strength, air permeability, and gas generation. At the same time, the local thermal conductivity, interface heat transfer coefficient, thermal expansion and other parameters of the casting mold are low, resulting in complex castings. The structure properties, poor mechanical properties, and dimensional accuracy It is difficult to meet the high-performance casting requirements of high-end complex castings. It is urgent to innovate, develop new equipment, explore new processes, develop new composite materials, and complete the preparation of multi-material and multi-functional composite sand molds.

3D printing (3DP) technology is to make parts by bonding resin sand into a whole. When 3D printing (3DP) technology is formed, a 3D model of the casting mold is first established, and the computer performs layered slice processing on the 3D geometric model of the printed sand mold; Then, the printing pattern of each layer is generated according to the two-dimensional contour data of each layer of sand mold, and the cross-sectional information is obtained; the sand particles pre-mixed with the curing agent are stored in the sand-laying tank for sand-laying, and the printing nozzle sprays the resin binder according to the cross-sectional information. , the resin binder and the curing agent have a glue-linking reaction, solidified layer by layer, and formed by accumulation; after the sand mold is prepared, the sand mold is cleaned out and the surface floating sand can be removed. The sand mold formed based on 3D printing (3DP) technology has the following disadvantages: (1) the material is limited and single; (2) the sand laying system can only lay a single material of sand particles.

SUMMARY OF THE INVENTION

In order to solve the above problems, combined with the advantages of 3D printing (3DP) technology, which has the advantages of strong flexible manufacturing capability and high strength of forming sand mold, a multi-material composite sand mold forming method and device are proposed.

In order to achieve the above purpose, a multi-material composite sand mold forming method proposed by the present invention is carried out according to the following steps:

Step 1: According to the 3D model, select the molding sand formula;

Step 2: The computer performs layered slice processing on the three-dimensional geometric model to obtain two-dimensional slice information of each layer;

Step 3: Process the slicing information of the required 3D printing and 3DP technology, and transform the slicing data according to the slicing characteristics to obtain the final slicing information; 0≤n≤10, improve the forming efficiency; for sand molds with special structure, single-layer additive and single-layer subtractive production is performed to improve sand mold accuracy;

Step 4: When the sand mold is prepared, additive manufacturing is firstly carried out; the proportioned raw sand particles are pumped into the sand mixer through the vacuum sand feeding system, so that the curing agent will enter the sand mixer through the peristaltic pump; the raw sand particles are It is stored in the original sand particle storage tank, and the curing agent is stored in the curing agent storage tank;

Step 5: uniformly stir the raw sand particles and the curing agent in the sand mixer to obtain molding sand particles pre-mixed with the curing agent;

Step 6: The molding sand particles pre-mixed with the curing agent are evenly loaded into the sand laying tank of the multi-material composite sand laying system through the shakeout port, and the sand loading process is completed;

Step 7: The multi-material composite sand laying system moves from the left to the right, and the molding sand particles pre-mixed with the curing agent in the sand laying tank are placed on the lifting platform device through the vibration shakeout device to carry out the sand laying process;

Step 8: The multi-material composite sand laying system moves from the right side to the left side, and spreads the molding sand particles pre-mixed with the curing agent on the lifting platform device through the powder spreading roller;

Step 9: The printing system moves from the right to the left, and the array nozzle performs the current layer of resin injection;

Step 10: The printing platform device is lowered by one layer thickness;

Step 11: Repeat steps 3 to 10, layer by layer, until the preparation of the composite sand mold is completed;

Step 14: Clean up the waste sand and take out the sand mold.

In the present invention, it is further preferred that after the laying and printing of each layer of molding sand is completed, scanning heating will be performed to speed up the curing speed of the current layer of sand molding.

It is further preferred in the present invention that the multi-material composite sand spreading system adopts the combination of a vibration shakeout device and a powder spreading roller.

It is further preferred in the present invention that the used molding sand can be one or more of quartz sand, ceramsite sand, chromite sand, zircon sand, magnesia sand and olivine sand.

It is further preferred in the present invention that the used molding sand is foundry refractory molding sand, and the commonly used particle size is 70/140 mesh.

It is further preferred in the present invention that the used binder is one of furan resin binder, phenolic resin binder and inorganic binder.

The present invention further preferably: during the preparation of the sand mold, the processing chamber is continuously filled with nitrogen to ensure the safety of the sintering process.

A multi-material composite sand mold forming device, the device includes a raw sand particle storage box, a curing agent storage box; a vacuum sand loading system, a multi-material composite sand mold sand laying system, a printing system, an infrared heating system, and a lifting platform device; The discharge pipes of the particle storage tank and the curing agent storage tank are both connected with the vacuum sanding system; the bottom of the vacuum sanding system is provided with a shakeout port; wherein the multi-material composite sand moulding system is located below the shakeout port; The material compound sand moulding sand laying system is located on one side of the lifting platform device and the bottom side is provided with powder coating; the upper part of the lifting platform device is provided with a printing system; the printing system is installed on the left side of the infrared heating system; wherein the infrared heating system The temperature of the mid-infrared heating tube is 275°C-374°C.

The invention discloses that firstly, the required composite molding sand material is selected according to the molding sand model; the computer performs layered slicing processing on the three-dimensional geometric model to obtain the two-dimensional slice information of each layer; Pump it into the sand mixer, make the curing agent 2 enter the sand mixer through the peristaltic pump, and evenly stir the original sand particles and the curing agent in the sand mixer to obtain the molding sand particles pre-mixed with the curing agent; The molding sand particles of the curing agent are evenly loaded into the sand-laying tank of the multi-material composite sand-laying system through the shakeout port; further, the multi-material composite sand-laying system moves from the left to the right, and the sand-laying groove is premixed and cured. The molding sand particles of the agent are shaken out by the vibration shakeout device; the multi-material composite sand laying system moves from the right side to the left side, and the molding sand particles pre-mixed with the curing agent are spread out by the powder spreading roller; the computer-controlled printing system starts from The right side moves to the left, the array nozzle sprays the resin of the current layer, the infrared heating system heats and cures the current layer, returns to the starting position after the stroke, and the infrared heating system heats and cures the current layer and the second layer; at this time, a multi-material is completed. The composite sand mold is prepared; the lifting platform is lowered by one layer thickness; the steps are repeated to add materials layer by layer until the preparation of the composite sand mold is completed; finally, the waste sand is cleaned and the composite sand mold is taken out.

Adopt above-mentioned technical scheme, beneficial effect of the present invention:

(1) Fill in the limited and single vacancy of sand 3D printing materials;

(2) The multi-material composite mold is formed by sand 3D printing technology to realize multi-functional and gradient sand mold preparation, realize efficient and high-precision mold preparation, and complete the comprehensive control of the microstructure and mechanical properties of the casting.

Description of drawings

Figure 1 is a schematic diagram of a multi-material composite sand mold forming device;

1- Raw sand particle storage box; 2- Curing agent storage box; 3- Vacuum sand loading system; 4- Shattering port; 5- Multi-material composite sand spreading system; ; 8-printing system; 9-infrared heating system.

Figure 2 is a flow chart of a multi-material composite sand molding method.

Detailed ways

The present invention will be further clarified below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the words "inner" and "outer" ” refer to directions towards or away from the geometric center of a particular part, respectively.

As shown in Figure 1, the device includes a raw sand particle storage tank 1, a curing agent storage tank 2; a vacuum sand application system 3, a multi-material composite sand molding system 5, a printing system 8, an infrared heating system 9, and a lifting platform device 7; wherein The discharge pipes of the raw sand particle storage tank 1 and the curing agent storage tank 2 are both connected to the vacuum sand application system 3; the bottom of the vacuum sand application system 3 is provided with a sand drop port 4; wherein the multi-material composite sand mold sand laying system 5 is located in the drop sand. Below the sand port 4; the multi-material composite sand moulding sand laying system 5 is located on one side of the lifting platform device 7 and the bottom side is provided with a powder coating 6; the top of the lifting platform device 7 is provided with a printing system 8; The system 8 is installed to the left of the infrared heating system 9 .

As shown in Figures 1 and 2, a method for forming a multi-material composite sand mold of the present embodiment includes the following steps:

Step 1: According to the 3D model, select the molding sand formula;

Step 2: The computer performs layered slice processing on the three-dimensional geometric model to obtain two-dimensional slice information of each layer;

Step 3: Process the slicing information of the required 3D printing and 3DP technology, and transform the slicing data according to the slicing characteristics to obtain the final slicing information; 0≤n≤10, improve the forming efficiency; for sand molds with special structure, single-layer additive and single-layer subtractive production is performed to improve sand mold accuracy;

Step 4: When the sand mold is prepared, firstly carry out additive manufacturing; pump the proportioned raw sand particles into the sand mixer through the vacuum sand feeding system 3, so that the curing agent will enter the sand mixer through the peristaltic pump; The particles are stored in the original sand particle storage tank 1, and the curing agent is stored in the curing agent storage tank 2;

Step 5: uniformly stir the raw sand particles and the curing agent in the sand mixer to obtain molding sand particles pre-mixed with the curing agent;

Step 6: The molding sand particles pre-mixed with the curing agent are evenly loaded into the sand laying tank of the multi-material composite molding sand laying system 5 through the shakeout port 4, and the sand loading process is completed;

Step 7: The multi-material composite sand laying system 5 moves from the left to the right, and the molding sand particles pre-mixed with the curing agent in the sand laying tank are subjected to the sand laying process on the lifting platform device 7 through the vibration shakeout device;

Step 8: The multi-material composite sand spreading system 5 moves from the right side to the left side, and spreads the molding sand particles pre-mixed with the curing agent on the lifting platform device 7 through the powder spreading roller 6;

Step 9: The printing system 8 moves from the right to the left, and the array nozzles spray the current layer of resin; the infrared heating system 9 performs heating, and the temperature of the infrared heating tube in the infrared heating system 9 is 275°C-374°C; the external heating system performs The current layer is heated and cured, and after the journey is completed, it returns to the starting position, and the infrared heating system performs heating and curing of the current layer and the second layer.

Step 10: The printing platform device 7 is lowered by one layer thickness; after laying and printing of each layer of molding sand, scanning heating will be performed to speed up the curing speed of the current layer of sand.

Step 11: Repeat steps 3 to 10, layer by layer, until the preparation of the composite sand mold is completed;

Step 14: Clean up the waste sand and take out the sand mold.

The used molding sand can be one or more of quartz sand, ceramsite sand, chromite sand, zircon sand, magnesia sand, and olivine sand; the used molding sand is foundry refractory molding sand.

The binder used is one of furan resin binder, phenolic resin binder and inorganic binder.

In the process of sand mold preparation, the processing chamber is continuously filled with nitrogen to ensure the safety of the sintering process.

In this embodiment, the computer performs layered slicing processing on the three-dimensional geometric model to obtain the two-dimensional slice information of each layer; then, the raw sand particles in a certain proportion are pumped into the sand mixer through the vacuum sand loading system 3, and the peristaltic pump makes the The curing agent storage box 2 enters the sand mixer, and the raw sand particles and curing agent in the sand mixer are uniformly stirred to obtain molding sand particles pre-mixed with curing agent; 4. Evenly put it into the sand laying tank of the multi-material composite sand laying system 5; further, the multi-material composite sand laying system moves from the left to the right, and the molding sand particles pre-mixed with the curing agent in the sand laying groove are dropped by vibration. The sanding device performs the sanding process; the multi-material composite sand spreading system 5 moves from the right side to the left side, and spreads the molding sand particles pre-mixed with the curing agent through the powder spreading roller; the computer-controlled printing system 8 moves from the right side to the left side Move, the array nozzle sprays the resin of the current layer, the infrared heating system performs the heating and curing of the current layer, and returns to the starting position after the stroke ends, and the infrared heating system 9 performs the heating and curing of the current layer and the second layer; at this time, a multi-material composite sand mold preparation is completed; The lifting platform is lowered by one layer thickness; the steps are repeated to add materials layer by layer until the preparation of the composite sand mold is completed; finally, the waste sand is cleaned and the composite sand mold is taken out.

The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims (9)

1. a multi-material composite sand mould forming method, is characterized in that, the method comprises the steps: Step 1: According to the 3D model, select the molding sand formula; Step 2: The computer performs layered slice processing on the three-dimensional geometric model to obtain two-dimensional slice information of each layer; Step 3: Process the slicing information of the required 3D printing and 3DP technology, and transform the slicing data according to the slicing characteristics to obtain the final slicing information; 0≤n≤10, improve the forming efficiency; for sand molds with special structure, single-layer additive and single-layer subtractive production is performed to improve sand mold accuracy; Step 4: When the sand mold is prepared, additive manufacturing is firstly carried out; the proportioned raw sand particles are pumped into the sand mixer through the vacuum sand feeding system (3), so that the curing agent will enter the sand mixer through the peristaltic pump; wherein The raw sand particles are stored in the raw sand particle storage tank (1), and the curing agent is stored in the curing agent storage tank (2); Step 5: uniformly stir the raw sand particles and the curing agent in the sand mixer to obtain molding sand particles pre-mixed with the curing agent; Step 6: The molding sand particles pre-mixed with the curing agent are evenly loaded into the multi-material composite molding sand laying system (5) sand laying tank through the shakeout port (4), and the sand loading process is completed; Step 7: The multi-material composite sand laying system (5) moves from the left to the right, and the molding sand particles pre-mixed with the curing agent in the sand laying tank are placed on the lifting platform device (7) through the vibration shakeout device to carry out the sand laying process. ; Step 8: The multi-material composite sand spreading system (5) moves from the right side to the left side, and spreads the molding sand particles pre-mixed with the curing agent on the lifting platform device (7) through the powder spreading roller (6); Step 9: The printing system (8) moves from the right side to the left side, and the array nozzle performs the current layer of resin injection; Step 10: The printing platform device (7) is lowered by one layer thickness; Step 11: Repeat steps 3 to 10, layer by layer, until the preparation of the composite sand mold is completed; Step 14: Clean up the waste sand and take out the sand mold. 2 . The method for forming a multi-material composite sand mold according to claim 1 , wherein after laying and printing each layer of molding sand, scanning heating is performed to speed up the curing speed of the current layer of sand mold. 3 . 3 . The method for forming a multi-material composite sand mold according to claim 1 , wherein the multi-material composite sand spreading system ( 5 ) adopts a combination of a vibration shakeout device and a powder spreading roller ( 6 ). 4 . 4. a kind of multi-material composite sand mould forming method according to claim 1 is characterized in that, used moulding sand can be quartz sand, ceramsite sand, chromite sand, zircon sand, magnesia sand, olivine sand. one or more. 5 . The method for forming a multi-material composite sand mold according to claim 1 , wherein the molding sand used is foundry refractory molding sand. 6 . 6 . The method for forming a multi-material composite sand mold according to claim 1 , wherein the binder used is one of a furan resin binder, a phenolic resin binder, and an inorganic binder. 7 . 7 . The method for forming a multi-material composite sand mold according to claim 1 , wherein, during the preparation of the sand mold, the processing chamber is continuously filled with nitrogen to ensure the safety of the sintering process. 8 . 8. A multi-material composite sand mold forming device, characterized in that the device comprises a raw sand particle storage tank (1), a curing agent storage tank (2); a vacuum sand application system (3), and a multi-material composite sand mold sand laying system (5), printing system (8), infrared heating system (9), lifting platform device (7); among them, the discharge pipes of the original sand particle storage box (1) and the curing agent storage box (2) are connected to the vacuum sanding box. The system (3) is connected; the bottom of the vacuum sand feeding system (3) is provided with a shakeout port (4); wherein the multi-material composite sand moulding sand laying system (5) is located below the shakeout port (4); The sand molding system (5) is located beside one side of the lifting platform device (7) and is provided with powder coating (6) on the side of the bottom; a printing system (8) is arranged above the lifting platform device (7); the printing system (8) is installed on the left side of the infrared heating system (9). 9 . The multi-material composite sand mold forming device according to claim 8 , wherein the temperature of the infrared heating tube in the infrared heating system (9) is 275°C-374°C. 10 .

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