阅读说明：本技术 一种用于液态金属3d打印的连续供液打印系统及方法 (Continuous liquid supply printing system and method for 3D printing of liquid metal ) 是由 张佼 姜海涛 万祥辉 东青 于 2020-05-07 设计创作，主要内容包括：本申请实施例提供一种用于液态金属3D打印的连续供液打印系统及方法,涉及3D打印技术领域。连续供液打印系统包括：惰性气体供应站、真空泵,以及上下设置的上腔室和下腔室,惰性气体供应站、真空泵分别依次和上腔室、下腔室连通；上腔室内顺次布置有倾倒坩埚、熔体净化池和熔体储存池,倾倒坩埚被配置成能够朝熔体净化池倾转且倾倒嘴位于熔体净化池上方,熔体净化池位于熔体储存池上,且二者之间通过陶瓷过滤板隔开；喷嘴安装于熔体储存池底部,且喷射方向朝向下腔室内；下腔室内设置有三维运动平台。该连续供液打印系统及方法,能够连续提供高纯净度的液态金属,并保证液态金属所处环境气氛,以实现大规格、高性能要求的3D打印产品的制造。(The embodiment of the application provides a continuous liquid supply printing system and method for 3D printing of liquid metal, and relates to the technical field of 3D printing. A continuous fluid supply printing system comprising: the device comprises an inert gas supply station, a vacuum pump, an upper chamber and a lower chamber which are arranged up and down, wherein the inert gas supply station and the vacuum pump are respectively communicated with the upper chamber and the lower chamber in sequence; the upper chamber is internally provided with a pouring crucible, a melt purification pool and a melt storage pool in sequence, the pouring crucible is configured to be capable of tilting towards the melt purification pool, a pouring nozzle is positioned above the melt purification pool, the melt purification pool is positioned on the melt storage pool, and the pouring crucible, the melt purification pool and the melt storage pool are separated by a ceramic filter plate; the nozzle is arranged at the bottom of the melt storage pool, and the spraying direction faces to the lower chamber; a three-dimensional motion platform is arranged in the lower cavity. The continuous liquid supply printing system and the method can continuously provide high-purity liquid metal and ensure the environment atmosphere of the liquid metal, so that the 3D printing product with large specification and high performance requirement can be manufactured.)

1. A continuous liquid supply printing system for 3D printing of liquid metal, comprising: the device comprises an inert gas supply station, a vacuum pump, an upper cavity and a lower cavity which are arranged up and down, wherein the inert gas supply station and the vacuum pump are respectively communicated with the upper cavity and the lower cavity in sequence; a pouring crucible with heating and degassing functions, a melt purification tank and a melt storage tank are sequentially arranged in the upper chamber, the pouring crucible is configured to be capable of being tilted towards the melt purification tank, a pouring nozzle is positioned above the melt purification tank, the melt purification tank is positioned on the melt storage tank, and the pouring crucible, the melt purification tank and the melt storage tank are separated through a ceramic filter plate; a nozzle is arranged at the bottom of the melt storage pool, and the spraying direction faces the lower chamber; and a three-dimensional motion platform is arranged in the lower cavity and is positioned below the nozzle.

2. A continuous feed liquid printing system for 3D printing of liquid metal as claimed in claim 1 wherein the periphery of the pouring crucible is provided with heating coils for heating;

the rotary blowing device also comprises a rotary blowing nozzle which can extend into the pouring crucible and can rotate and spray argon or chlorine.

3. A continuous liquid supply printing system for liquid metal 3D printing as defined in claim 2, wherein the outside of the tilting crucible is provided with a hydraulic cylinder for pushing the tilting of the tilting crucible, the upper chamber is provided with a hydraulic control system outside, a laser level meter is arranged in the melt storage tank, the hydraulic control system is respectively connected with the hydraulic cylinder and the laser level meter, the laser level meter monitors the liquid level in the melt storage tank at any time and feeds back a signal to the hydraulic control system, and the hydraulic control system controls the hydraulic cylinder to push the tilting crucible.

4. A continuous feed liquid printing system for 3D printing of liquid metal as claimed in claim 1 wherein a melt receiving tank is provided between the pouring crucible and the melt purification tank, the melt receiving tank being in communication with the melt purification tank, the melt receiving tank being of a fluted construction, the pouring spout being located directly above the melt receiving tank and at a distance of 10-20mm when the pouring crucible is tilted to 45 ° towards the melt purification tank.

5. A continuous liquid supply printing system for 3D printing of liquid metal as claimed in claim 4 wherein the melt cleaning tank is of a trough configuration, the bottom surface of the melt cleaning tank and the melt receiving tank communicating portion being flush with the bottom surface of the melt receiving tank and above the ceramic filter plate.

6. The continuous liquid supply printing system for 3D printing of liquid metal of claim 1, wherein the ceramic filter plates are double layer ceramic filter plates arranged one above the other, the upper layer ceramic filter plate being of a type 50ppi and the lower layer ceramic filter plate being of a type 30 ppi.

7. The continuous liquid supply printing system for 3D printing of liquid metal of claim 1, wherein the melt reservoir is fixedly connected to the nozzle in a slot configuration and is sealed by a refractory material;

and/or the nozzles are arranged in a matrix.

8. A continuous feed liquid printing system for 3D printing of liquid metal as claimed in claim 1 wherein the outer surfaces of the pouring crucible, the melt purification tank and the melt storage tank are each coated with an insulating layer;

and/or heating elements are arranged on the peripheries of the melt purifying pool, the melt storage pool and the nozzle.

9. A continuous liquid supply printing system method based on the continuous liquid supply printing system as claimed in claim 1, characterized in that it comprises the steps of:

vacuumizing the upper chamber through a vacuum pump or introducing inert gas into the upper chamber through an inert gas station;

putting a blocky metal raw material into a pouring crucible, heating the blocky metal raw material to be molten, and degassing to obtain a metal liquid;

tilting the pouring crucible towards the melt purification tank until the molten metal flows into the melt purification tank from the pouring nozzle, flows towards the melt storage tank under the action of gravity, and is subjected to deslagging and purification treatment through the ceramic filter plate until the molten metal flows into the melt storage tank;

and vacuumizing the upper cavity and/or introducing inert gas into the upper cavity through an inert gas station by a vacuum pump so as to adjust the pressure of the upper cavity and the lower cavity, so that the pressure of the upper cavity is greater than that of the lower cavity, the pressure difference between the upper cavity and the lower cavity is 10-35 kpa, and the nozzle adopts the metal melt in the melt storage tank to perform 3D printing on the three-dimensional motion platform.

10. The continuous liquid supply printing system method of claim 9, wherein the degassing method comprises: degassing treatment is carried out by using rotary blowing which can extend into the pouring crucible, wherein the rotary blowing rotates and sprays argon or chlorine for degassing.

Technical Field

The application relates to the technical field of 3D printing, in particular to a continuous liquid supply printing system and method for 3D printing of liquid metal.

Background

Materials related to the additive manufacturing technology cover metal materials, resin, paraffin, ceramics and the like, and have important application prospects in the fields of aerospace, ships, oceans, national defense transportation and the like. The metal additive manufacturing technology is a metal processing technology which slices a complex three-dimensional model of a part to be formed layer by layer into a 2D section, then piles materials layer by layer along the height direction, and finally forms the metal part. The metal additive manufacturing technology changes the traditional casting mode of large-volume solidification, prepares a final product through continuous melting and superposition of a infinitesimal region, and avoids a series of defects of the conventional casting method. Liquid metal 3D printing technique belongs to one kind of metal vibration material disk, and liquid printing technical principle does: and continuously spraying the metal melt from the nozzle outlet under vacuum pressure, solidifying on the substrate, and accumulating layer by layer to finally directly form the metal part. The technology adopts metal melt to directly form metal parts, and obtains the optimal structure performance of the metal parts through the adjustment of the running speed of a substrate and the adjustment of the height from the substrate to a nozzle opening during forming. The liquid metal 3D printing can be used for preparing materials with complete equiaxial crystal structures, the materials have good comprehensive performance, and the application of the metal materials in high-end fields of aviation, electronics and the like is further widened.

For the liquid metal 3D printing technology, continuous and stable liquid supply is important, and on one hand, stable liquid flow can ensure stable process parameters and optimal product performance; on the other hand, continuous liquid supply can achieve 3D printed products of larger size. The quality of 3D printed products is affected by the quality of the melt, and the melt is directly subjected to 3D printing without treatment, so that printing failure or serious product defects can be caused. In addition, the ambient atmosphere of the melt has a significant influence on the smooth 3D printing and the final 3D printed product.

The existing liquid supply method is generally to directly melt metal to form liquid metal, and then to print by using the liquid metal, and the liquid supply method has the following problems: firstly, continuous supply and automatic control of liquid metal cannot be realized, and the requirements of large-specification 3D printing products cannot be met; secondly, the purity of the prepared liquid metal is not high, so that the 3D printing process is blocked or the 3D printed product has the defects of air holes, slag inclusion, microcracks and the like.

Therefore, there is a need for a continuous liquid supply printing system and method that can continuously provide high purity liquid metal and ensure the atmosphere of the environment.

Disclosure of Invention

An object of the embodiment of the application is to provide a continuous liquid supply printing system and method for 3D printing of liquid metal, which can continuously provide high-purity liquid metal and ensure the ambient atmosphere of the liquid metal, so as to realize the manufacturing of 3D printed products with large specification and high performance requirements.

In a first aspect, an embodiment of the present application provides a continuous liquid supply printing system for 3D printing of liquid metal, including: the device comprises an inert gas supply station, a vacuum pump, an upper chamber and a lower chamber which are arranged up and down, wherein the inert gas supply station and the vacuum pump are respectively communicated with the upper chamber and the lower chamber in sequence; the upper chamber is internally provided with a pouring crucible with heating and degassing functions, a melt purification tank and a melt storage tank in sequence, the pouring crucible is configured to be capable of being tilted towards the melt purification tank, a pouring nozzle is positioned above the melt purification tank, the melt purification tank is positioned on the melt storage tank, and the pouring crucible, the melt purification tank and the melt storage tank are separated by a ceramic filter plate; the bottom of the melt storage pool is provided with a nozzle, and the spraying direction faces the lower chamber; and a three-dimensional motion platform is arranged in the lower cavity and is positioned below the nozzle.

In the technical scheme, the pouring crucible, the melt purification tank and the melt storage tank are positioned in the upper chamber, namely, the internal air pressure is the same. The pouring crucible can heat and melt metal raw materials and degas the metal raw materials to obtain liquid metal, the pouring crucible tilts towards the melt purification tank, the liquid metal in the pouring crucible can be poured into the melt purification tank, the pouring crucible is arranged to realize continuous supply of melt, the melt leakage phenomenon caused by other modes is avoided, and furnace bottom slag can be prevented from flowing into downstream; the melt purifying tank is positioned on the melt storage tank, and the liquid metal in the melt purifying tank can automatically flow to the melt storage tank and can be filtered and purified by the ceramic filter plate, so that the liquid metal with high purity can be continuously provided. In addition, the inert gas supply station and the vacuum pump are respectively communicated with the upper chamber and the lower chamber in sequence, and inert gas is introduced into the upper chamber through the inert gas supply station or the upper chamber is vacuumized through the vacuum pump, so that the quality of the liquid metal can not be affected by the atmosphere in the environment; through independent or matched work of the inert gas supply station and the vacuum pump, the pressure in the upper cavity and the lower cavity can be adjusted, particularly the pressure difference between the upper cavity and the lower cavity is adjusted, so that the nozzle can utilize liquid metal in the melt storage tank to jet and print towards the three-dimensional moving platform, and the 3D printing product with large specification and high performance requirement is manufactured.

In a possible realization, the periphery of the pouring crucible is provided with a heating coil for heating;

the rotary blowing device also comprises a rotary blowing nozzle which can extend into the pouring crucible and can rotate and spray argon or chlorine.

In the technical scheme, the heating coil arranged on the periphery of the pouring crucible works to heat the metal raw material in the pouring crucible and melt the metal raw material to obtain liquid metal; the rotary blowing and spraying device stretches into the pouring crucible to spray argon or chlorine into the liquid metal to achieve the purpose of degassing, and the rotary blowing and spraying device can spray gas while rotating, so that a gas vortex which moves quickly can be formed at the liquid depth of the liquid metal, the size of bubbles becomes small, the bubbles are uniformly distributed, and the refining purpose is achieved.

In a possible implementation mode, the outer portion of the toppling crucible is provided with a hydraulic cylinder used for pushing the toppling crucible to tilt, the upper cavity is externally provided with a hydraulic control system, a laser liquid level meter is arranged in the melt storage tank, the hydraulic control system is respectively connected with the hydraulic cylinder and the laser liquid level meter, the laser liquid level meter monitors the liquid level height in the melt storage tank at any time, a signal is fed back to the hydraulic control system, and the hydraulic control system controls the hydraulic cylinder to push the toppling crucible to tilt.

In the technical scheme, the laser liquid level meter measures the height of the liquid metal by utilizing the laser ranging technical principle, accurately measures the liquid level height in the liquid metal and transmits a signal to the hydraulic control system; the hydraulic control system is arranged to realize the automatic feedback of the liquid level height of the metal melt, automatically control the hydraulic cylinder to push the tilting crucible to tip, ensure the continuous supply of the liquid metal and keep the liquid level height in the melt storage tank unchanged.

In a possible implementation mode, a melt receiving pool is arranged between the pouring crucible and the melt purifying pool, the melt receiving pool is communicated with the melt purifying pool, the melt receiving pool is of a groove structure, and when the pouring crucible is tilted to be 45 degrees towards the melt purifying pool, the pouring nozzle is positioned right above the melt receiving pool and is 10-20mm away from the melt receiving pool.

In the technical scheme, the melt receiving pool is arranged between the pouring crucible and the melt purifying pool and is designed into a groove structure, so that splashing of liquid metal poured from the pouring crucible is reduced, buffering is realized, and liquid metal flow is stable; when the pouring crucible is controlled to be at 45 degrees, the height between the pouring nozzle and the melt receiving pool is 10-20mm, the purpose is to prevent serious splashing caused by too high liquid metal liquid level difference between the pouring crucible and the melt receiving pool, the purpose is to reduce disturbance of the liquid metal and reduce gas entrainment, and the purpose is to reduce heat loss.

In a possible implementation mode, the melt purifying tank is of a chute structure, and the bottom surface of the communicating part of the melt purifying tank and the melt receiving tank is flush with the bottom surface of the melt receiving tank and is positioned above the ceramic filter plate.

In the technical scheme, the melt purifying tank is designed into a chute structure, so that the liquid metal poured into the pouring crucible can be further buffered, and the liquid metal in the melt receiving tank automatically flows into the melt storage tank through the ceramic filter plate under the action of gravity.

In one possible implementation, the ceramic filter plate is a double-layer ceramic filter plate arranged up and down, the model of the upper layer ceramic filter plate is 50ppi, and the model of the lower layer ceramic filter plate is 30 ppi.

In above-mentioned technical scheme, set up double-deck ceramic filter and can effectively filter and get rid of impurity in the liquid metal to reduce impurity content, obtain pure liquid metal, in addition, can obtain stable, excellent filter effect through the ceramic filter cooperation filtration that adopts model 30ppi and 50 ppi.

In one possible implementation mode, the melt storage pool and the nozzle are fixedly connected by adopting a clamping groove structure, and are bonded and sealed by using a refractory material;

and/or the nozzles are arranged in a matrix.

In the technical scheme, the melt storage pool is fixedly connected with the nozzle, so that the nozzle can continuously perform 3D printing by utilizing the liquid metal of the melt storage pool, the clamping groove structure is adopted for connection and is sealed by the refractory material, the upper chamber and the lower chamber can be ensured to be isolated relatively, on one hand, the high-temperature liquid metal in the melt storage pool can be prevented from leaking from the place outside the nozzle, on the other hand, the pressure difference between the upper chamber and the lower chamber can be accurately adjusted, and 3D printing products under different process parameters can be manufactured.

The nozzles are designed to be arranged in a rectangular shape, 3D printing products of large-size liquid metal can be rapidly printed in corresponding areas, and printing pass, cold shut defects and the like are reduced.

In one possible implementation mode, the outer surfaces of the pouring crucible, the melt purification tank and the melt storage tank are all wrapped with insulating layers;

and/or heating elements are arranged on the peripheries of the melt purifying pool, the melt storage pool and the nozzle.

In the technical scheme, the heating coils and the heating elements are arranged on the peripheries of the pouring crucible, the melt purifying pool and the melt storage pool and are matched with the heat-insulating layer, so that the liquid metal can be ensured to keep a certain temperature in the melting, transferring and storing processes.

In a second aspect, an embodiment of the present application provides a continuous liquid supply printing system method based on the continuous liquid supply printing system provided in the first aspect, which includes the following steps:

vacuumizing the upper chamber through a vacuum pump or introducing inert gas into the upper chamber through an inert gas station;

putting a blocky metal raw material into a pouring crucible, heating the blocky metal raw material to be molten, and degassing to obtain a metal liquid;

tilting the pouring crucible towards the melt purification tank until the metal liquid flows into the melt purification tank from the pouring nozzle, flows into the melt storage tank under the action of gravity, and is subjected to slag removal and purification treatment through a ceramic filter plate until the metal liquid flows into the melt storage tank;

and vacuumizing the upper cavity through a vacuum pump and/or introducing inert gas into the upper cavity through an inert gas station to adjust the pressure of the upper cavity and the lower cavity, so that the pressure of the upper cavity is greater than that of the lower cavity, the pressure difference between the upper cavity and the lower cavity is 10-35 kpa, and the nozzle adopts the metal melt in the melt storage tank to perform 3D printing on the three-dimensional motion platform.

In the technical scheme, the upper chamber is firstly vacuumized by a vacuum pump or inert gas is introduced into the upper chamber through an inert gas station, and then a subsequent series of treatments are carried out on the liquid metal, so that the environmental atmosphere of the liquid metal in the upper chamber can be ensured; the massive metal raw materials are correspondingly processed by a pouring crucible, a melt purification tank and a melt storage tank, so that high-purity liquid metal is continuously provided. And then the vacuum pump is used for vacuumizing the upper chamber and/or inert gas is introduced into the upper chamber through the inert gas station so as to adjust the pressure difference between the upper chamber and the lower chamber within a specific range, so that the liquid metal in the upper chamber can be stably and continuously sprayed onto the three-dimensional motion platform in the lower chamber by the nozzle, 3D printing is realized, and the requirements of large-specification and high-performance 3D printing products can be particularly met. According to the method, the pressure difference between the upper chamber and the lower chamber is controlled to be 10-35 kpa, if the pressure difference between the upper chamber and the lower chamber is controlled to be too large, the 3D printed product has poor formability due to serious impact of liquid metal, and the problems of pores, shrinkage cavities, interface effects and the like exist in the structure; if the pressure difference between the two is too small, problems of insufficient liquid metal injection, insufficient liquid supply and nozzle blockage can occur.

In one possible implementation, the degassing method is as follows: degassing treatment is carried out by using rotary blowing which can extend into the pouring crucible, and the rotary blowing rotates and sprays argon or chlorine for degassing.

In the technical scheme, the rotary blowing device extends into the pouring crucible to spray argon or chlorine into the liquid metal to achieve the purpose of degassing, and the rotary blowing device sprays gas while rotating to achieve the purpose of refining.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of a continuous liquid supply printing system for 3D printing of liquid metal according to an embodiment of the present application.

Icon: 100-a continuous liquid supply printing system; 110-an upper chamber; 120-pouring the crucible; 121-a heating coil; 122-an insulating layer; 123-hydraulic cylinder; 124-rotating and blowing; 125-pour spout; 130-a melt receiving tank; 140-melt purification tank; 141-ceramic filter plate; 150-melt reservoir; 151-laser level gauge; 152-a thermocouple; 153-hydraulic control system; 160-a nozzle; 170-lower chamber; 171-a three-dimensional motion platform; 181-vacuum pump; 182-an inert gas supply; 183-support frame.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of embodiments of the present application, generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The following description will be made in detail about a continuous liquid supply printing system and a method for 3D printing of liquid metal in the present application example.

Referring to fig. 1, the present example provides a continuous liquid supply printing system 100 for 3D printing of liquid metal, comprising: an inert gas supply station 182, a vacuum pump 181, and an upper chamber 110 and a lower chamber 170 which are arranged up and down, wherein the inert gas supply station 182 and the vacuum pump 181 are respectively communicated with the upper chamber 110 and the lower chamber 170 in turn. A pouring crucible 120 with heating and degassing functions, a melt purification pool 140 and a melt storage pool 150 are sequentially arranged in the upper chamber 110, the pouring crucible 120 is configured to be capable of being tilted towards the melt purification pool 140, a pouring nozzle 125 is positioned above the melt purification pool 140, the melt purification pool 140 is positioned on the melt storage pool 150, and the two are separated by a ceramic filter plate 141; the nozzle 160 is arranged at the bottom of the melt storage pool 150, the injection direction of the nozzle faces to the lower cavity 170, the melt storage pool 150 and the nozzle 160 are fixedly connected by adopting a clamping groove structure, the bonding and sealing are realized by using refractory materials, and the nozzles 160 are arranged in a matrix; a three-dimensional motion platform 171 is disposed in the lower chamber 170, and the three-dimensional motion platform 171 is located below the nozzle 160.

In the present example, in order to realize the heating and degassing functions of the pouring crucible 120, the periphery of the pouring crucible 120 is provided with a heating coil 121 for heating; and a rotary blowing nozzle which can be inserted into the pouring crucible 120 and which can rotate and spray argon or chlorine gas. In order to make rotatory blowing spout can stretch into in empting crucible 120 at the during operation, can not disturb empting crucible 120 and vert during out-of-work, rotatory blowing spout is installed on the top cap of big cavity to stretch into in last cavity 110, rotatory blowing spout realizes going up and down through the motor, when needs during operation, in motor drive rotation blowing spouts the decline and stretches into the crucible 120 of empting of below, when not needing during operation, motor drive rotation blowing spouts and rises, keeps away from and emptys crucible 120.

In the example of this application, in order to realize that the liquid level in melt storage pool 150 keeps the unanimity, the outside of empting crucible 120 is provided with and is used for promoting the pneumatic cylinder 123 that emptys crucible 120 and vert, it is provided with hydraulic control system 153 to go up chamber 110 outside, hydraulic control system 153 includes signal processor, be provided with laser level gauge 151 in the melt storage pool 150, hydraulic control system 153 is connected with pneumatic cylinder 123 and laser level gauge 151 respectively, laser level gauge 151 monitors the liquid level in the melt storage pool 150 at any time, and give the signal processor of hydraulic control system 153 with the signal feedback, hydraulic control system 153 promotes according to signal processor's result control pneumatic cylinder 123 and emptys crucible 120: when the liquid level in the melt storage pool 150 is lower than the preset height, the hydraulic cylinder 123 pushes the tilting crucible 120 to tilt at a certain angle, so that the liquid metal in the tilting crucible flows into the melt purification pool 140 and then flows into the melt storage pool 150, and the liquid level in the melt storage pool 150 is ensured to be consistent. A thermocouple 152 for monitoring the temperature of the liquid metal is also provided in the melt reservoir 150.

In the present application example, a melt receiving pool 130 is arranged between the pouring crucible 120 and the melt purifying pool 140, the melt receiving pool 130 is communicated with the melt purifying pool 140, the melt receiving pool 130 is of a groove structure, and when the pouring crucible 120 is tilted towards the melt purifying pool 140 to a position of 45 degrees relative to the liquid surface, the pouring nozzle 125 is located right above the melt receiving pool 130 and is 10-20mm away from the melt receiving pool 130. The melt purifying tank 140 is of a chute structure, the bottom surface of the communicating part of the melt purifying tank 140 and the melt receiving tank 130 is flush with the bottom surface of the melt receiving tank 130, and is located above the ceramic filter plate 141, namely, the edge of the melt receiving tank 130 naturally transitions to the melt purifying tank 140, so as to reduce the sputtering of liquid metal.

In the present example, the outer surfaces of the pouring crucible 120, the melt receiving tank 130, the melt purifying tank 140 and the melt storage tank 150 are all wrapped with insulating layers 122; the melt purification tank 140, the melt storage tank 150 and the nozzle 160 are provided with heating elements on their peripheries, for example, heating pipes are provided on the top of the melt purification tank 140.

In this example, the ceramic filter plate 141 is a double-layer ceramic filter plate 141 disposed up and down, the model of the upper ceramic filter plate 141 is 50ppi, and the model of the lower ceramic filter plate 141 is 30 ppi. According to the non-ferrous metal industry standard of the people's republic of China, the pore density corresponding to 30ppi is 27-33, namely the number of pores in any length of 25.4mm is 27-33, and the pore density corresponding to 50ppi is 47-53, namely the number of pores in any length of 25.4mm is 47-53. The ceramic filter plate 141 is specifically an alumina foamed ceramic filter plate 141, which can effectively remove various inclusions with fineness up to micron level in the liquid metal, so that the liquid metal is changed into stable laminar flow, and the alumina foamed ceramic filter plate 141 has a unique mullite-corundum structure, has good mechanical strength and chemical stability, and has excellent aluminum water scouring resistance. In use, a ceramic fibre gasket is provided around the ceramic foam filter 141 to assist in sealing the filter within the melt cleaning bath 140 and to ensure that there is no liquid metal bypass.

The continuous liquid supply printing system 100 is simple in structure, short in process and high in efficiency, and by designing the short-process liquid metal processing system, continuous liquid supply, high in melt purity and automatic control of liquid metal 3D printing are achieved. The continuous liquid supply printing system 100 is divided into an upper chamber 110 and a lower chamber 170, wherein the upper chamber 110 is internally provided with a pouring crucible 120, a melt receiving pool 130, a melt purifying pool 140 and a melt storage pool 150 from left to right, and the upper chamber 110 is integrally arranged on a support frame 183 so as to be integrally connected with the lower chamber 170. Wherein the melt receiving pool 130 is located below the pouring spout 125 of the pouring crucible 120, and the pouring crucible 120 is mainly used for melting metal, such as 7150 aluminum alloy in the embodiment, and can melt the required aluminum melt according to the 3D printing requirement; a melt-cleaning tank 140 is provided on the right side of the melt-receiving tank 130 and functions to receive the melt flowing out of the pouring crucible 120; the melt storage pool 150 is positioned at the right side of the melt purification pool 140 and is separated by a double-layer ceramic filter plate 141, the melt purification pool 140 is used for removing impurities in the metal melt, including metal impurities, non-metal impurities and the like, the impurities mainly come from the falling of blocky raw materials and refractory materials on the inner surface of the melting furnace and a top cover, in addition, the crucible 120 is poured, rotated, blown and 124 and then slagging is carried out, the slag or the impurities enter the melt purification pool 140 along with the fluid, the purified melt flows into the melt storage pool 150, the melt storage pool 150 is set for keeping the stable liquid metal level, the stability of process parameters is ensured, the continuous supply of the liquid metal is realized, the liquid metal is used for 3D printing, and the stability of the liquid flow in the printing process is ensured; a nozzle 160 is located below the melt reservoir 150 and is connected to the lower chamber 170, and the entire system is provided with a 3D printing atmosphere by a vacuum pump 181 and an inert gas supply 182. 3D printing of various conditions is achieved by regulating the pressure difference of the upper chamber 110 and the lower chamber 170. The continuous liquid supply printing system 100 can effectively realize continuous and stable liquid supply in the liquid metal 3D printing process, provide high-purity liquid metal, prevent the nozzle 160 from being blocked and the like, and meet the requirements of large-specification and high-performance 3D printing products.

In addition, the present application example also provides a continuous liquid supply printing system 100 method based on the above continuous liquid supply printing system 100, which includes the following steps:

s1: the atmosphere is provided by evacuating the upper chamber 110 by means of a vacuum pump 181 or by introducing an inert gas into the upper chamber 110 through an inert gas station.

S2: loading blocky metal raw materials into the pouring crucible 120 according to a certain proportion, turning on a switch of the heating coil 121, heating the blocky metal raw materials to a corresponding temperature until the blocky metal raw materials are molten, degassing treatment is started after the blocky metal raw materials are completely molten and reach specified stability, stretching the rotary blowing into the pouring crucible 120, turning on the rotary blowing 124, rotating the rotary blowing and spraying argon or chlorine to degas for a period of time, for example, removing gas in 7150 aluminum alloy melt is realized by introducing argon to obtain molten metal.

In the examples of the present application, the metal generally includes at least one of steel, aluminum alloy, magnesium alloy, titanium alloy and high-entropy alloy, and the bulk metal raw materials are selected and combined according to the corresponding proportion according to the type and performance requirements of the 3D printed product.

S3: and starting a hydraulic control system 153, controlling a hydraulic cylinder 123 to enable the pouring crucible 120 to tilt towards the melt purification tank 140 until the molten metal flows into the melt receiving tank 130 from the pouring nozzle 125, then flows into the melt purification tank 140, flows into the melt storage tank 150 under the action of gravity, and performs deslagging and purification treatment through a ceramic filter plate until the molten metal flows into the melt storage tank 150 for standby.

S4: vacuumizing the upper chamber 110 through a vacuum pump 181 and/or introducing inert gas into the upper chamber 110 through an inert gas station to adjust the pressure of the upper chamber 110 and the pressure of the lower chamber 170, so that the pressure of the upper chamber 110 is greater than the pressure of the lower chamber 170, the pressure difference between the upper chamber 110 and the lower chamber 170 is 10kpa-35kpa, the pressure in the lower chamber 170 is controlled to be-90 kpa-10kpa, and the nozzle 160 sprays the metal melt in the melt storage pool 150 onto the three-dimensional moving platform 171 by using the pressure difference to perform 3D printing.

The key point of S4 is that the pressure difference between the upper chamber 110 and the lower chamber 170 is adjusted by the vacuum pump 181 and the inert gas station, and there are three ways to adjust the pressure difference: the first is that the upper chamber 110 is vacuumized, the lower chamber 170 is also vacuumized, and the vacuum degree of the lower chamber 170 is greater than that of the upper chamber 110; the second is to adjust the upper chamber 110 to be inert gas (generally, first vacuumize, then introduce inert gas, the pressure can be atmospheric pressure), and vacuumize the lower chamber 170; the third is that inert gas is introduced into the upper chamber 110, inert gas is also introduced into the lower chamber 170, and the pressure of the upper chamber 110 is greater than that of the lower chamber 170, specifically, different pressure supply modes are selected according to product performance requirements. Generally, it is preferable to control the lower chamber 170 to be a vacuum environment, so as to avoid gas from entering into the 3D printed product, and ensure that the product has higher compactness.

S5: as the 3D printing proceeds, the metal level in the melt storage pool 150 begins to drop, the laser level meter 151 feeds back a signal to the signal processor of the hydraulic control system 153, the automatic control hydraulic cylinder 123 pushes the tilting crucible 120 to be in a tilting state, generally, to be tilted to 45 °, the liquid metal automatically flows from the tilting crucible 120 into the melt receiving pool 130, passes through the melt purification pool 140, and finally flows into the melt storage pool 150, and the level of the melt storage is kept stable.

During 3D printing, the temperature of the liquid metal in the pouring crucible 120, the melt purification tank 140 and the melt storage tank 150 is monitored, for example, by a thermocouple 152, and when the temperature is lower than a set value, the corresponding heating device is activated to heat, and when the temperature is higher than the set value, the temperature of the liquid metal is lowered by blowing a low-temperature inert gas into the corresponding chamber, so that the liquid metal is maintained at a certain temperature during melting, transferring and storing.

The features and properties of the present application are described in further detail below with reference to examples.

Example 1

The present embodiment provides a continuous liquid supply printing system 100 based continuous liquid supply printing, comprising the steps of:

s1: vacuum pumping is carried out from the upper chamber 110 by a vacuum pump 181, aluminum alloy is prepared according to the component proportion of 7150 aluminum alloy, namely, 0.12 percent of Si, 0.15 percent of Fe, 1.9-2.5 percent of Cu, 0.1 percent of Mn, 2.0-2.7 percent of Mg, 0.04 percent of Cr, 5.9-6.9 percent of Zn, 0.08-0.15 percent of Zr, 0.15 percent of Ti and 0.15 percent of the total amount of other impurities, block or powder materials are filled into the pouring crucible 120, a switch of a heating coil 121 is turned on, and the metal is heated to 750 ℃ to melt the metal.

S2: and after the aluminum alloy is completely melted, degassing treatment is carried out, the rotary blowing 124 is opened, and argon is introduced for degassing for 30 min.

S3: the hydraulic control system 153 is started to tilt the pouring crucible 120, and the molten metal flows into the melt receiving tank 130 from the pouring nozzle 125 and is subjected to deslagging and purifying treatment sequentially through the double-layer ceramic filter plate 141 in the melt purifying tank 140.

S4: the metal melt flows into the melt storage pool 150 from the melt purification pool 140 for standby, 3D printing is started by adjusting the internal pressure difference between the upper chamber 110 and the lower chamber 170 through the vacuum pump 181, the pressure difference is controlled to be 20kpa, and the vacuum degree of the lower chamber is 40 kpa.

S5: along with the 3D printing, the metal liquid level in the melt storage pool 150 begins to descend, the laser liquid level meter 151 feeds back signals to the hydraulic control system 153, the hydraulic control system 153 is linked with the hydraulic cylinder 123 to control the tilting crucible 120 to be in a tilting state, liquid metal automatically flows into the melt receiving pool 130 from the tilting crucible 120 and finally flows into the melt storage pool 150, and the liquid level is kept stable for 20 cm.

Example 2

The present embodiment provides a continuous liquid supply printing based on the continuous liquid supply printing system 100, except that the step S4 of the liquid supply method is different from that of embodiment 1, and S1, S2 and S3 of the liquid supply system and the liquid supply method are the same as that of embodiment 1.

In this embodiment, the vacuum degree of the lower chamber 170 is 25kpa, the vacuum degree of the upper chamber 110 is argon, and the pressure difference is controlled to be 35 kpa.

Example 3

The present embodiment provides a continuous liquid supply printing based on the continuous liquid supply printing system 100, except that the step S4 of the liquid supply method is different from that of embodiment 1, and S1, S2 and S3 of the liquid supply system and the liquid supply method are the same as that of embodiment 1.

In this embodiment, argon is introduced into the lower chamber 170 at a pressure of 10kpa, argon is introduced into the upper chamber 110 at a pressure of 35kpa, and the pressure difference is controlled to be 10 kpa.

Comparative example 1

This comparative example provides a continuous liquid feed printing based continuous liquid feed printing system 100, which is substantially the same as example 3 except that: the differential pressure was controlled at 50 kpa.

The 3D printed samples of examples 1-3 and comparative example 1 were subjected to the detection analysis below, and the results are shown in table 1 below.

TABLE 1 results of different samples

	Porosity (per m)2Number of (2)	Sample Density (g/cm)3)
			Example 1	5	2.651
Example 2	1	2.682
			Example 3	8	2.645
Comparative example 1	56	2.543

From the results in table 1, it can be seen that examples 1-3 can print 3D printed products of excellent quality, but the product prepared in comparative example 1 has significantly more porosity and lower density.

In summary, the continuous liquid supply printing system and method for 3D printing of liquid metal in the embodiment of the present application can continuously provide high-purity liquid metal, and ensure the ambient atmosphere of the liquid metal, so as to realize the manufacturing of 3D printed products with large specification and high performance requirements.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.