Low-pressure casting machine with back-pressure bubble discharging function

Abstract

The invention relates to the field of metal casting, in particular to a low-pressure casting machine with a back pressure bubble discharging function, which comprises a metal liquid container, a casting unit arranged on the metal liquid container, an air compression unit arranged on the casting unit and a mechanical arm arranged on the casting unit, the air compression unit comprises an air compressor arranged near the metal liquid container, an air delivery pipe arranged on the air compressor and communicated with the metal liquid container, and a pressure control assembly arranged on the air compressor and communicated with the casting unit, and the air compressor drives the piston to move in the movable cavity; reverse pressure is applied in the molten metal filling process, gas in molten metal is effectively discharged, bubbles in a casting are reduced, the mechanical property and surface quality of the casting are remarkably improved by reducing the bubbles, the rejection rate of the casting is reduced, meanwhile, a negative pressure area between a casting groove and a workpiece is eliminated through cooperation of an air compressor and a ventilation valve, and the casting efficiency is improved. Demolding is convenient, and casting efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of metal casting, in particular to a low-pressure casting machine with a back-pressure bubble removal function. Background Art

[0002] A low-pressure casting machine is a machine that fills low-pressure gas into liquid metal to drive the liquid metal into a mold to complete casting. It is often used in the precision manufacturing of metal materials such as aluminum alloys and magnesium alloys.

[0003] During the low-pressure casting process, bubbles may be generated inside the casting due to the entrapment of air by the molten metal during the filling process or poor mold venting. The bubbles will reduce the mechanical properties and surface quality of the casting and may even cause the casting to be scrapped. Summary of the invention

[0004] In view of the problem in the above or prior art that bubbles may be generated inside the casting due to air being drawn into the molten metal during the filling process or poor exhaust of the mold during the casting process, the present invention is proposed.

[0005] Therefore, an object of the present invention is to provide a low-pressure casting machine with a back-pressure bubble removal function.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising a metal liquid container, a casting unit arranged on the metal liquid container, an air compression unit arranged on the casting unit, and a robotic arm arranged on the casting unit; the air compression unit comprises an air compressor arranged near the metal liquid container, an air supply pipe arranged on the air compressor and connected to the metal liquid container, and a pressure control component arranged on the air compressor and connected to the casting unit; when the casting unit is in a casting state, the interior of the casting unit is separated from the outside air by the air compression unit, and the pressure between the casting unit and the air compression unit is reduced by the air compression unit to form a negative pressure zone, so that the bubbles are accelerated to float up and leave the metal solution.

[0007] As a preferred solution of the low-pressure casting machine with counter-pressure bubble removal function of the present invention, the metal liquid container includes an insulating shell, a crucible arranged in the insulating shell, and a liquid injection port arranged on the crucible; the gas pipe is connected to the insulating shell, the interior of the insulating shell is connected to the interior of the crucible, and the port height of the crucible is higher than the gas pipe.

[0008] As a preferred solution of the low-pressure casting machine with the back-pressure bubble removal function of the present invention, a sealing plug is provided at the port of the liquid injection port.

[0009] As a preferred solution of the low-pressure casting machine with counter-pressure bubble removal function of the present invention, the casting unit includes a lower mold assembly arranged on the heat-insulating outer shell, and an upper mold assembly arranged on the lower mold assembly, and a casting groove is arranged between the lower mold assembly and the upper mold assembly.

[0010] As a preferred solution of the low-pressure casting machine with counter-pressure bubble removal function of the present invention, the lower mold assembly includes a lower mold arranged on the insulation shell, a connecting hole arranged on the lower mold, and a rising pipe arranged on the connecting hole; the rising pipe penetrates the insulation shell to the inside of the crucible.

[0011] As a preferred solution of the low-pressure casting machine with counter-pressure bubble removal function of the present invention, the upper mold assembly includes an upper mold arranged on the lower mold, an exhaust hole arranged on the upper mold, and a positioning block arranged on the upper mold.

[0012] As a preferred solution of the low-pressure casting machine with the back-pressure bubble removal function of the present invention, there are multiple groups of positioning blocks, and the upper mold is provided with positioning grooves matching the positioning blocks.

[0013] As a preferred solution of the low-pressure casting machine with the back-pressure bubble removal function of the present invention, the casting groove is connected with the connecting hole and the exhaust hole.

[0014] As a preferred solution of the low-pressure casting machine with back-pressure bubble removal function of the present invention, the pressure control component includes an exhaust pipe arranged on the air compressor, a pressure control member arranged on the exhaust pipe, and a ventilation valve arranged on the exhaust pipe.

[0015] As a preferred solution of the low-pressure casting machine with counter-pressure bubble removal function of the present invention, the pressure control part includes a piston cylinder arranged on the exhaust hole and connected to the exhaust pipe, the piston cylinder is arranged to be narrow at the top and wide at the bottom, the narrower part at the bottom is arranged as a connecting cavity, the wider part at the top is arranged as an active cavity, and a piston is arranged in the active cavity.

[0016] The beneficial effects of the low-pressure casting machine with back-pressure bubble removal function of the present invention are as follows: the present invention drives the piston to move in the active cavity through an air compressor, applies reverse pressure during the metal liquid filling process, forms a negative pressure zone, effectively discharges the gas in the metal liquid, and significantly reduces the bubbles in the casting. By reducing the bubbles, the mechanical properties and surface quality of the casting are significantly improved, and the scrap rate of the casting is reduced. At the same time, through the cooperation of the air compressor and the ventilation valve, the negative pressure zone between the casting groove and the workpiece is eliminated, which facilitates demolding and improves casting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the overall structure of a low-pressure casting machine with a back-pressure bubble removal function.

[0019] Figure 2 It is a schematic diagram of the structure of the metal liquid container of the low-pressure casting machine with the function of counter-pressure bubble removal.

[0020] Figure 3 It is a schematic diagram of the cross-sectional structure of a low-pressure casting machine with a counter-pressure bubble removal function.

[0021] Figure 4 It is a schematic diagram of the cross-sectional structure of the upper mold of a low-pressure casting machine with a counter-pressure bubble removal function.

[0022] Figure 5 It is a schematic diagram of the cross-sectional structure of the piston cylinder of a low-pressure casting machine with a counter-pressure bubble removal function.

[0023] In the figure: 1. Metal liquid container; 11. Insulation shell; 12. Crucible; 13. Liquid filling port; 2. Casting unit; 21. Lower mold assembly; 211. Lower mold; 212. Connecting hole; 213. Lifting pipe; 214. Positioning groove; 22. Upper mold assembly; 221. Upper mold; 222. Exhaust hole; 223. Positioning block; 3. Air compression unit; 31. Air compressor; 32. Air supply pipe; 33. Pressure control assembly; 331. Exhaust pipe; 332. Pressure control member; 3321. Piston cylinder; 3322. Connecting chamber; 3323. Active chamber; 3324. Piston; 333. Ventilation valve; 4. Robotic arm; 5. Casting tank; 6. Workpiece. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0025] Example 1, reference Figure 1-Figure 2, which is the first embodiment of the present invention, and provides a low-pressure casting machine with a back-pressure bubble removal function, comprising a metal liquid container 1 for containing the metal liquid to be cast and keeping the metal liquid warm, a casting unit 2 arranged on the metal liquid container 1 for casting the metal liquid, an air compression unit 3 arranged on the casting unit 2 for introducing low-pressure gas into the metal liquid container 1, so that the metal liquid in the metal liquid container 1 is filled into the casting unit 2, and at the same time cooperates with the casting unit 2 to form a negative pressure zone, promote exhaust, and reduce bubbles in the metal liquid, and a mechanical arm 4 arranged on the casting unit 2 for driving the casting unit 2 to move, and cooperates with the air compression unit 3 to facilitate demolding of the workpiece after casting; The air compression unit 3 includes an air compressor 31 disposed near the metal liquid container 1, used to output or inhale gas, an air delivery pipe 32 disposed on the air compressor 31 and connected to the metal liquid container 1, used to cooperate with the air compressor 31 to output low-pressure gas to the metal liquid container 1, and a pressure control component 33 disposed on the air compressor 31 and connected to the casting unit 2, used to cooperate with the air compressor 31 to reduce the air pressure between the metal liquid entering the casting unit 2 and the casting unit 2, so as to form a negative pressure area and accelerate the separation of air from the metal liquid; When the casting unit 2 is in the casting state, the interior of the casting unit 2 is separated from the outside air by the air compression unit 3. The air compression unit 3 reduces the pressure between the casting unit 2 and the air compression unit 3 to form a negative pressure zone, so that the bubbles are accelerated to float up and separate from the metal solution. Through such a setting, moisture in the air is prevented from combining with the metal liquid, and poor exhaust gas causes the bubbles to stay in the metal liquid, thereby improving the surface quality and mechanical properties of the casting.

[0026] In summary, first, add the metal liquid to be cast into the metal liquid container 1, close the casting unit 2 through the robotic arm, start the air compressor 31, and introduce low-pressure gas into the metal liquid container 1 through the air pipe 32. At this time, the pressure inside the metal liquid container 1 increases, and the metal liquid is squeezed into the casting unit 2. At this time, the metal liquid is slowly filled into the casting unit 2. At this time, the pressure control component 33 generates suction through the air compressor 31, so that the air pressure between the metal liquid entering the casting unit 2 and the casting unit 2 is reduced. At this time, due to the pressure difference, the bubbles in the metal liquid accelerate to move upward and separate from the metal liquid, thereby ensuring the quality of the workpiece 6.

[0027] Example 2, reference Figure 1-Figure 3, which is the second embodiment of the present invention, and is different from the previous embodiment in that: the metal liquid is low-pressure casted. Compared with the embodiment 1, further, the metal liquid container 1 comprises a heat-insulating shell 11 for supporting and heat-insulating, a crucible 12 arranged in the heat-insulating shell 11 for containing the metal liquid, and a liquid injection port 13 arranged on the crucible 12 for injecting the metal liquid into the crucible 12; The gas pipe 32 is connected to the heat-insulating shell 11, and the interior of the heat-insulating shell 11 is connected to the interior of the crucible 12. The port height of the crucible 12 is higher than the gas pipe 32. Through such an arrangement, the gas pipe 32 is prevented from contacting the metal liquid in the crucible 12, and at the same time, the gas is prevented from being directly filled into the crucible 12 and mixing with the metal liquid, resulting in an increase in bubbles in the metal liquid.

[0028] A sealing plug is provided at the port of the liquid injection port 13 for sealing the inner space of the heat-insulating shell 11 to prevent pressure leakage during low-pressure casting.

[0029] Among them, the casting unit 2 includes a lower mold assembly 21 arranged on the insulation shell 11, and an upper mold assembly 22 arranged on the lower mold assembly 21. A casting trough 5 is arranged between the lower mold assembly 21 and the upper mold assembly 22. The lower mold assembly 21 cooperates with the upper mold assembly 22 to cast the metal liquid, and the casting trough 5 is used for casting the metal liquid.

[0030] The lower mold assembly 21 includes a lower mold 211 disposed on the heat-insulating shell 11 for supporting, a connecting hole 212 disposed on the lower mold 211 for communicating with the inside of the heat-insulating shell 11, and a liquid riser 213 disposed on the connecting hole 212 for delivering liquid metal into the casting tank 5 for casting; The riser pipe 213 passes through the insulation shell 11 to the inside of the crucible 12, and is used to maintain the sealed environment inside the insulation shell 11. At the same time, it cooperates with the low-pressure gas in the insulation shell 11 to press the metal liquid into the riser pipe 213 and enter the casting tank 5 through the riser pipe 213 for casting.

[0031] Among them, the upper mold assembly 22 includes an upper mold 221 arranged on the lower mold 211, which is used to cooperate with the lower mold 211 to cast through the casting groove 5, an exhaust hole 222 arranged on the upper mold 221, which is used for exhausting the metal liquid and the inside of the casting groove 5, and a positioning block 223 arranged on the upper mold 221 for positioning.

[0032] There are multiple groups of positioning blocks 223, and the upper mold 221 is provided with positioning grooves 214 that match the positioning blocks 223. The positioning grooves 214 cooperate with the positioning blocks 223 to make the lower mold 211 and the upper mold 221 fully fit together to ensure the casting accuracy and tightness.

[0033] The casting trough 5 is connected to the connecting hole 212 and the exhaust hole 222 . With such an arrangement, the bubbles in the casting trough 5 and the metal liquid are discharged through the upper mold assembly 22 .

[0034] The rest of the structure is the same as that of Example 1.

[0035] In summary, metal liquid is added to the crucible 12 through the liquid injection port 13. At this time, the upper mold 221 is driven by the mechanical arm 4 to fit tightly with the lower mold 211. At this time, the air compressor 31 is started to output low-pressure gas to the heat-insulating shell 11 through the gas pipe 32. As the pressure in the heat-insulating shell 11 continues to increase, the pressure drives the metal liquid to flow into the liquid riser 213, and the metal liquid enters the casting tank 5 through the liquid riser 213. At this time, the rising metal liquid fills the casting tank 5 and continuously squeezes the air between the lower mold 211 and the upper mold 221. At this time, the pressure control component 33 generates suction through the air compressor 31, reduces the air pressure above the metal liquid, forms a negative pressure area, drives the bubbles in the metal liquid to float upward faster, and separates from the metal liquid, thereby ensuring the quality of the workpiece 6 Example 3, reference Figure 1-Figure 4 , which is the second embodiment of the present invention, and is different from the previous embodiment in that: poor exhaust of the metal liquid is prevented. Compared with embodiment 2, further, the pressure control component 33 includes an exhaust pipe 331 arranged on the air compressor 31, which is used to cooperate with the air compressor 31 to generate suction, a pressure control member 332 arranged on the exhaust pipe 331, which is used to cooperate with the suction generated by the exhaust pipe 331 to form a negative pressure area above the exhaust hole 222, accelerate the detachment of bubbles in the metal liquid, and a vent valve 333 arranged on the exhaust pipe 331, which is used to control the connection between the exhaust pipe 331 and the outside world.

[0036] Among them, the pressure control component 332 includes a piston cylinder 3321 arranged on the exhaust hole 222 and connected to the exhaust pipe 331. The piston cylinder 3321 is set to a shape that is narrow at the top and wide at the bottom. The narrower part at the bottom is set as a connecting cavity 3322, and the wider part at the top is set as an active cavity 3323, and a piston 3324 is set in the active cavity 3323. The connecting cavity 3322 is used for bubbles to enter the piston cylinder 3321 after escaping from the metal liquid, and the active cavity 3323 is used to cooperate with the piston 3324 to achieve that the piston 3324 moves a shorter distance to generate a greater pressure, thereby reducing the height of the equipment and improving the stability of the equipment.

[0037] The rest of the structure is the same as that of Example 2.

[0038] In summary, when the metal liquid enters the casting tank 5 through the liquid riser 213, the air compressor 31 is started at this time, and suction is generated through the exhaust pipe 331, driving the piston 3324 to move upward in the active chamber 3323. At this time, the space between the connecting chamber 3322 and the piston 3324 becomes larger, the total amount of air remains unchanged, and the pressure decreases, which generates suction on the metal liquid and bubbles in the casting tank 5, and is used for the bubbles to enter the low-pressure environment above the casting tank 5 from the high-pressure environment in the heat-insulating shell 11. The pressure decreases, and the bubbles expand, and the buoyancy becomes larger, which accelerates the bubbles to rise, separate from the metal liquid and enter the active chamber 3323, so that the surface quality and mechanical properties of the workpiece 6 are improved. At the same time, the low-pressure environment in the casting tank 5 cooperates with the high-pressure environment in the heat-insulating shell 11 to accelerate the process of the metal liquid filling the casting tank 5, thereby improving the casting efficiency. After the workpiece 6 is cast, the pressure inside the heat-insulating shell 11 is reduced by the air compressor 31. The unsolidified metal liquid in the riser 213 flows back into the crucible 12. The upper mold 221 is driven upward by the robotic arm 4. Since the exhaust hole 222 and the workpiece 6 are still in a negative pressure state, the workpiece 6 is firmly adsorbed on the upper mold 221. The upper mold 221 moves to drive the workpiece 6 to leave the device. The workpiece 6 is moved to the placement point by the upper mold 221. The vent valve 333 is opened to connect the exhaust pipe 331 to the outside world. The internal pressure of the exhaust pipe 331 is restored. The piston 3324 cannot maintain pressure balance up and down. The piston 3324 moves downward to increase the pressure inside the exhaust hole 222 to the same as the external pressure. At the same time, the weight of the workpiece 6 is used to complete rapid demoulding.

[0039] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A low-pressure casting machine with a back-pressure bubble removal function, characterized in that: It comprises a metal liquid container (1), a casting unit (2) arranged on the metal liquid container (1), an air compression unit (3) arranged on the casting unit (2), and a mechanical arm (4) arranged on the casting unit (2); The air compression unit (3) comprises an air compressor (31) arranged near the metal liquid container (1), an air delivery pipe (32) arranged on the air compressor (31) and connected to the metal liquid container (1), and a pressure control component (33) arranged on the air compressor (31) and connected to the casting unit (2); When the casting unit (2) is in a casting state, the interior of the casting unit (2) is isolated from the outside air by the air compression unit (3), and the pressure between the casting unit (2) and the air compression unit (3) is reduced by the air compression unit (3), thereby forming a negative pressure zone, so that the bubbles are accelerated to float up and separate from the metal solution.

2. The low-pressure casting machine with a back-pressure bubble removal function according to claim 1, characterized in that: The metal liquid container (1) comprises a heat-insulating outer shell (11), a crucible (12) arranged in the heat-insulating outer shell (11), and a liquid injection port (13) arranged on the crucible (12); The gas delivery pipe (32) is connected to the heat-insulating outer shell (11), and the interior of the heat-insulating outer shell (11) is connected to the interior of the crucible (12). The port height of the crucible (12) is higher than the gas delivery pipe (32).

3. The low-pressure casting machine with a back-pressure bubble removal function as claimed in claim 2, characterized in that: A sealing plug is provided at the end of the liquid injection port (13).

4. The low-pressure casting machine with a back-pressure bubble removal function as claimed in claim 3, characterized in that: The casting unit (2) comprises a lower mold assembly (21) arranged on the heat-insulating shell (11), and an upper mold assembly (22) arranged on the lower mold assembly (21), and a casting groove (5) is arranged between the lower mold assembly (21) and the upper mold assembly (22).

5. The low-pressure casting machine with counter-pressure bubble removal function as claimed in claim 4, characterized in that: The lower mold assembly (21) comprises a lower mold (211) arranged on the heat-insulating outer shell (11), a connecting hole (212) arranged on the lower mold (211), and a liquid riser (213) arranged on the connecting hole (212); The liquid riser (213) passes through the heat-insulating outer shell (11) to the interior of the crucible (12).

6. The low-pressure casting machine with a back-pressure bubble removal function as claimed in claim 5, characterized in that: The upper mold assembly (22) comprises an upper mold (221) arranged on the lower mold (211), an exhaust hole (222) arranged on the upper mold (221), and a positioning block (223) arranged on the upper mold (221).

7. The low-pressure casting machine with a back-pressure bubble removal function as claimed in claim 6, characterized in that: A plurality of positioning blocks (223) are provided, and positioning grooves (214) matching the positioning blocks (223) are provided on the upper mold (221).

8. The low-pressure casting machine with the back-pressure bubble removal function according to claim 7, characterized in that: The casting groove (5) is connected to the connection hole (212) and the exhaust hole (222).

9. The low-pressure casting machine with a back-pressure bubble removal function as claimed in claim 8, characterized in that: The pressure control assembly (33) comprises an exhaust pipe (331) arranged on the air compressor (31), a pressure control member (332) arranged on the exhaust pipe (331), and a ventilation valve (333) arranged on the exhaust pipe (331).

10. The low-pressure casting machine with a back-pressure bubble removal function as claimed in claim 9, characterized in that: The pressure control member (332) comprises a piston cylinder (3321) arranged on the exhaust hole (222) and connected to the exhaust pipe (331); the piston cylinder (3321) is arranged in a shape that is narrow at the top and wide at the bottom, the narrower portion at the bottom is arranged as a communicating cavity (3322), the wider portion at the top is arranged as an active cavity (3323), and a piston (3324) is arranged in the active cavity (3323).

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