An injection molding apparatus for facilitating lost foam casting

Abstract

The utility model relates to the field of foundry equipment, concretely relates to a pouring forming device beneficial to lost foam casting, including sand mould case, pouring unit and exhaust slag collection subassembly, exhaust slag collection subassembly is equipped with the gas guide slag collection pipe with slag collection cavity and exhaust valve, the valve core ball of elastic top pressure is equipped with exhaust valve, and several groups of exhaust slag collection subassembly are divided in the periphery of pouring unit. The utility model utilizes the gas guide slag collection pipe to gather the gas and dross produced in the pouring of the lost foam model in the sand mould case, and gradually opens up to exhaust through the valve core ball of elastic top pressure in the exhaust valve under the action of airflow, makes the gas in the sand mould case discharge after the buffer of exhaust valve, and utilizes the slag collection cavity to collect the dross, and further is favorable to reducing the efficiency influence and safety risk brought by pouring resistance or back spray caused by the gas produced in the lost foam casting, is favorable to reducing the casting defect of the gas hole or slag inclusion produced in the pouring, thereby can improve the casting efficiency and casting quality.

Description

Technical Field

[0001] This utility model relates to the field of casting equipment, specifically to a casting and molding device that is beneficial for lost foam casting. Background Technology

[0002] Lost foam casting is a novel one-time casting process. The lost foam pattern is made of polymer material and is embedded in molding sand within a sand mold box before pouring. During pouring, molten high-temperature metal is injected into the sand mold box through the gating system. The high temperature of the molten metal causes the lost foam pattern to rapidly vaporize. The resulting cavity is filled with the molten metal and, after cooling and solidification, forms the casting. However, the high-temperature vaporization of the polymer-based lost foam pattern generates a large amount of gas and a small amount of unvaporized slag. Some of the gas escapes through the gaps in the gating system; some seeps into the molding sand; but some gas remains in the solidified casting, forming pores. The dried slag easily adheres to the surface or interior of the casting, forming inclusions. Porosity and inclusions affect casting quality. Furthermore, if gas escapes through the gaps in the gating system, the gas pressure can sometimes affect the flow rate of the injected molten metal, creating obstruction. Excessive gas accumulation can also cause molten metal to spray back out, leading to safety accidents. Therefore, it is necessary to improve the casting and molding apparatus for lost foam casting. If multiple channels for gas venting and slag collection can be installed on the sand mold box, the impact of residual gas and slag generated during lost foam casting on the quality of the casting, or the risks of flow obstruction and safety, can be reduced. In view of this, this case arises. Utility Model Content

[0003] To overcome the shortcomings of the existing technology, this utility model discloses a casting and molding device that is beneficial to lost foam casting, including a sand mold box, a casting unit, and an exhaust and slag collection assembly. The exhaust and slag collection assembly is provided with an exhaust pipe that runs vertically through the middle and has a bulging slag collection cavity in the middle, and an exhaust valve placed at the upper end of the exhaust pipe. The exhaust valve is provided with a valve core ball that is elastically pressed and can be lifted by air pressure to open the exhaust valve and exhaust air. Several sets of exhaust and slag collection assemblies are placed around the casting unit, and the lower end of the exhaust pipe abuts against the lost foam pattern. This invention improves the casting and molding device for lost foam casting. It utilizes a gas guide and slag collection pipe to collect the gas and slag generated by the high-temperature melting and vaporization of the lost foam pattern in the sand mold box during casting. The gas is then vented by the elastically pressed valve core ball in the vent valve gradually opening under the action of airflow. The gas in the sand mold box is buffered by the vent valve and then discharged. The slag is collected by the bulging slag collection chamber. This helps to reduce the efficiency impact and safety risks caused by the gas generated during lost foam casting, such as pouring obstruction or backflow. It also helps to reduce casting defects such as porosity or slag inclusions during pouring, thereby improving casting efficiency and casting quality.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A casting and forming apparatus beneficial for lost foam casting includes a sand mold box and a casting unit. The pouring cup of the casting unit is placed above the sand mold box, and its gating system is inserted into the sand mold box with its lower end abutting against the lost foam pattern inside the sand mold box. The apparatus is characterized by further including an venting and slag collection component. The venting and slag collection component has a vertically penetrating venting and slag collection pipe with a bulging central section, and an venting valve located at the upper end of the venting and slag collection pipe. The venting valve has a spherical valve core with elastic pressure, which can be lifted by air pressure to open the venting valve and release air. The venting and slag collection component is configured in several groups, with the venting and slag collection pipes of the several groups of venting and slag collection components placed around the gating system of the casting unit and above the lost foam pattern inside the sand mold box. The lower end of the venting and slag collection pipe abuts against the lost foam pattern, and the upper end of the venting and slag collection pipe is located outside the sand mold box. The venting and slag collection component can release the gas generated by the high-temperature melting and vaporization of the lost foam pattern and collect the slag.

[0006] The gas-guiding and slag-collecting pipe is a circular tubular body with a bulging slag-collecting cavity in the middle. The top of the slag-collecting cavity is inclined. Preferably, the gas-guiding and slag-collecting pipe is made of heat-resistant ceramic.

[0007] The exhaust valve includes a conical base, which is a block-shaped body with a conical horn hole and a cylindrical hole at the center of its upper and lower surfaces, respectively. The horn hole and the cylindrical hole are connected. The outer diameter of the upper end of the gas guide and slag collection pipe matches the inner diameter of the cylindrical hole of the conical base. The upper end of the gas guide and slag collection pipe can be inserted into the cylindrical hole of the conical base.

[0008] The exhaust valve also includes a valve core ball and a spring. The valve core ball is spherical, and the spring is a compression spring. The spring is placed above the valve core ball and applies elastic pre-compression to the valve core ball. The lower end of the spring is connected to the valve core ball. The valve core ball is placed in the flared hole of the conical base and can elastically seal the flared hole under the action of the spring pre-compression force.

[0009] The exhaust valve also includes a top plate and support rods. The top plate is placed above the spring and the upper end of the spring is connected to the top plate. The support rods are in several pieces and are placed between the top plate and the conical base, with their upper and lower ends connected to the top plate and the conical base, respectively.

[0010] The exhaust valve is located on the top of the sand mold box, and the conical base of the exhaust valve is detachably connected to the top of the sand mold box.

[0011] The sand mold box includes a box body and a box cover that is detachably fixed to the upper opening of the box body.

[0012] The pouring unit includes a pouring cup, a runner, a flow meter, and a temperature sensor.

[0013] As described above, the advantages of the casting and molding device for lost foam casting provided by this utility model are as follows: Several sets of venting and slag-collecting components are set in the sand mold box. Each component has a venting and slag-collecting pipe with a slag-collecting chamber and an venting valve located at the upper end of the venting and slag-collecting pipe. The venting and slag-collecting pipe collects the gas and slag generated during the high-temperature melting and vaporization of the lost foam pattern in the sand mold box during casting. The venting valve, with its elastically pressed valve core ball, gradually opens under the action of airflow to vent the gas. The gas in the sand mold box is then buffered and discharged, and the slag is collected using the bulging slag-collecting chamber. This helps reduce the efficiency impact and safety risks caused by gas generated during lost foam casting leading to pouring obstruction or backflow. It also helps reduce casting defects such as porosity or slag inclusions during pouring, thereby improving casting efficiency and casting quality. This utility model has a reasonable design, simple structure, low cost, and is easy to promote. Attached Figure Description

[0014] Figure 1 This is a general schematic diagram of a casting and molding device that is beneficial for lost foam casting according to the present invention;

[0015] Figure 2 This is an enlarged schematic diagram of the exhaust and slag collection assembly;

[0016] Figure 3 This is an enlarged schematic diagram of the gas guide and slag collection pipe;

[0017] Figure 4 This is an enlarged schematic diagram of the exhaust valve.

[0018] Figure label:

[0019] 1 Sand mold box; 2 Casting unit; 3 Exhaust and slag collection assembly; 31 Exhaust and slag collection pipe; 311 Slag collection chamber; 32 Exhaust valve; 321 Conical base; 322 Top plate; 323 Support rod; 324 Valve core ball; 325 Spring; 900 Vanishing model. Detailed Implementation

[0020] The present invention will be further described below through specific embodiments.

[0021] like Figures 1 to 3As shown, the present invention provides a casting and molding device for lost foam casting, comprising a sand mold box 1, a casting unit 2, and a venting and slag collection assembly 3. The sand mold box 1 includes a box body and a box cover detachably fixed to the upper opening of the box body. The casting unit 2 includes a pouring cup, a gating system, a flow meter, and a temperature sensor. The casting unit 2 is a known technology. The pouring cup of the casting unit 2 is positioned above the sand mold box 1, and its gating system is inserted into the sand mold box 1, with the lower opening of the gating system contacting the lost foam pattern 900 inside the sand mold box 1. The venting and slag collection assembly 3 is provided with a vertically penetrating venting and slag collection pipe 31 with a bulging central section and a venting valve 32 located at the upper end of the venting and slag collection pipe 31. The venting and slag collection pipe 31 is a circular tubular body with a bulging central slag collection cavity 311, the top of which is inclined. In this embodiment, the venting and slag collection pipe 31 is made of heat-resistant ceramic. The exhaust valve 32 is equipped with a spherical valve core with elastic pressure. The valve core can be lifted by air pressure to open the exhaust valve 32 and exhaust air. The exhaust slag collection assembly 3 is set in several groups. The air guide slag collection pipes 31 of the several groups of exhaust slag collection assemblies 3 are placed around the gating channel of the casting unit 2 and above the vanishing model 900 in the sand mold box 1. The lower port of the air guide slag collection pipe 31 is in contact with the vanishing model 900, and the upper port of the air guide slag collection pipe 31 is placed outside the sand mold box 1. The exhaust slag collection assembly 3 can discharge the gas generated by the high-temperature melting and vaporization of the vanishing model 900 by the molten metal and collect the floating slag.

[0022] like Figures 1 to 4 As shown, the exhaust valve 32 of this utility model includes a conical base 321, a top plate 322, a support rod 323, a valve core ball 324, and a spring 325. The conical base 321 is a block-shaped body with a conical horn hole and a cylindrical hole respectively at the center of its upper and lower surfaces. The horn hole and the cylindrical hole are connected. The outer diameter of the upper end of the gas guide and slag collection pipe 31 matches the inner diameter of the cylindrical hole of the conical base 321, and the upper end of the gas guide and slag collection pipe 31 can be inserted into the cylindrical hole of the conical base 321. The valve core ball 324 is spherical. The spring 325 is a compression spring. The spring 325 is placed above the valve core ball 324 and provides elastic pre-compression to the valve core ball 324. The lower end of the spring 325 is connected to the valve core ball 324. The valve core ball 324 is placed in the horn hole of the conical base 321 and can elastically seal the horn hole under the action of the pre-compression force of the spring 325. The top plate 322 is positioned above the spring 325, and the upper end of the spring 325 is connected to the top plate 322. Several support rods 323 are positioned between the top plate 322 and the conical base 321, with their upper and lower ends connected to the top plate 322 and the conical base 321 respectively. The exhaust valve 32 is positioned on the top of the sand mold box 1, and the conical base 321 of the exhaust valve 32 is detachably connected to the top of the sand mold box 1.

[0023] The operating method of this casting and molding device is as follows:

[0024] Place the vanishing mold 900, the gating system of the casting unit 2, and the venting and slag collection pipe 31 of the venting and slag collection assembly 3 into the sand mold box 1, fill it with molding sand, and then firmly cover the box. When placing the vanishing mold 900, select a flat surface as the upper surface and keep it horizontal. Then, attach the cylindrical hole of the conical base 321 of the venting valve 32 to the upper port of the venting and slag collection pipe 31. Lock the conical base 321 to the box cover of the sand mold box 1. Then, connect the pouring cup of the casting unit 2 to the upper end of the gating system. At this time, the venting and slag collection assembly 3 is fixed to the sand mold box 1 and the lower port of the venting and slag collection pipe 31 touches the upper surface of the vanishing mold 900, and the molten metal can be poured. When the high-temperature molten metal comes into contact with the disappearing mold 900, the high temperature of the molten metal causes the disappearing mold 900 to be rapidly heated and vaporized, producing a large amount of gas and a small amount of unvaporized slag. At this time, the gas enters the nearby gas guide and slag collection pipe 31 and continues to accumulate. When the gas pressure rises enough to overcome the elastic force of the spring 325, it will push the valve core ball 324 off the conical base 321 to release the gas. When the molten metal reaches the set pouring volume and fills the cavity, the disappearing mold 900 has vaporized and disappeared. The gas pressure in the gas guide and slag collection pipe 31 continuously decreases, and under the elastic force of the spring 325, the exhaust valve 32 gradually closes. The molten metal filling the cavity will push the slag produced by the vaporization of the disappearing mold 900 into the slag collection chamber 311 of the nearby gas guide and slag collection pipe 31 for collection, thereby avoiding slag residue on the surface or inside of the casting and forming casting defects caused by inclusions.

[0025] This invention improves the casting device for lost foam casting by incorporating several sets of venting and slag collection components 3 within the sand mold box 1. Each venting and slag collection component 3 includes a venting and slag collection pipe 31 with a slag collection chamber 311 and an venting valve 32 located at the upper end of the venting and slag collection pipe 31. The venting and slag collection pipe 31 collects the gas and slag generated during the high-temperature melting and vaporization of the lost foam pattern 900 within the sand mold box 1 during casting. The slag is then vented by the valve core ball 324 in the venting valve 32, which is elastically pressed open by the airflow. This allows the gas within the sand mold box 1 to be released after being buffered by the venting valve 32, and the slag is collected by the bulging slag collection chamber 311. This reduces the efficiency impact and safety risks caused by gas generated during lost foam casting leading to pouring obstruction or backflow, and helps reduce casting defects such as porosity or slag inclusions during pouring, thereby improving casting efficiency and casting quality.

[0026] The above is only one specific embodiment of the present utility model, but the design concept of the present utility model is not limited thereto. Any non-substantial modifications made to the present utility model using this concept shall be deemed as an infringement of the protection scope of the present utility model.

Claims

1. A casting apparatus for lost foam casting, comprising a sand mold box (1) and a casting unit (2), wherein the pouring cup of the casting unit (2) is positioned above the sand mold box (1), and its gating system is inserted into the sand mold box (1) with the lower end of the gating system abutting against the lost foam pattern (900) inside the sand mold box (1), characterized in that: It also includes an exhaust and slag collection assembly (3), which is provided with an exhaust and slag collection pipe (31) that runs vertically through the middle and is bulging in the middle, and an exhaust valve (32) placed at the upper port of the exhaust and slag collection pipe (31). The exhaust valve (32) is provided with a ball valve core that is elastically pressed. The exhaust and slag collection assembly (3) is provided in several groups. The exhaust and slag collection pipes (31) of the several groups of exhaust and slag collection assemblies (3) are placed around the gating channel of the casting unit (2) and above the vanishing model (900) in the sand mold box (1). The lower port of the exhaust and slag collection pipe (31) abuts against the vanishing model (900).

2. The casting and molding apparatus for lost foam casting according to claim 1, characterized in that: The gas guide and slag collection pipe (31) is a circular tubular body with a bulging slag collection cavity (311) in the middle.

3. The casting and molding apparatus for lost foam casting according to claim 2, characterized in that: The exhaust valve (32) includes a conical base (321), which is a block with a conical horn hole and a cylindrical hole respectively provided at the center of its upper and lower surfaces. The horn hole and the cylindrical hole are connected. The outer diameter of the upper end of the gas guide and slag collection pipe (31) matches the inner diameter of the cylindrical hole of the conical base (321). The upper end of the gas guide and slag collection pipe (31) can be inserted into the cylindrical hole of the conical base (321).

4. The casting and molding apparatus for lost foam casting according to claim 3, characterized in that: The exhaust valve (32) further includes a valve core ball (324) and a spring (325). The valve core ball (324) is spherical, and the spring (325) is a compression spring. The spring (325) is placed above the valve core ball (324) and provides elastic pre-compression to the valve core ball (324). The lower end of the spring (325) is connected to the valve core ball (324). The valve core ball (324) is placed in the flared hole of the conical base (321) and can elastically seal the flared hole.

5. The casting and molding apparatus for lost foam casting according to claim 4, characterized in that: The exhaust valve (32) further includes a top plate (322) and a support rod (323). The top plate (322) is positioned above the spring (325) and the upper end of the spring (325) is connected to the top plate (322). The support rod (323) consists of several pieces, which are positioned between the top plate (322) and the conical base (321) with their upper and lower ends connected to the top plate (322) and the conical base (321) respectively.

6. A casting and molding apparatus for lost foam casting according to claim 5, characterized in that: The exhaust valve (32) is placed on the top of the sand mold box (1), and the conical base (321) of the exhaust valve (32) is connected to the top of the sand mold box (1).

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