A screw extrusion type metal droplet generation device and method

Abstract

The application discloses a spiral extrusion type metal droplet generating device and method, and aims to solve the technical problems of strong coupling of heat and mass transfer and poor forming precision of formed parts in the additive manufacturing process. The device comprises a droplet generating device, a substrate, a three-dimensional motion platform device and a control system. A mechanical spiral device is installed above the droplet generating device and can freely stretch and shrink up and down. By controlling the three-dimensional motion platform to move together with the substrate, the metal droplet is deposited and solidified on the substrate. The mechanical spiral device can drive the transition of the metal droplet fast or slow by rotating fast or slow. By controlling the amount of the metal droplet, the temperature of the droplet generating device and the rotating speed of the mechanical spiral device, the purpose of precise forming of the metal droplet is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of additive manufacturing, relates to the field of metal droplet forming control, and particularly relates to a spiral extrusion type metal droplet generating device and method. BACKGROUND

[0002] Additive manufacturing is based on the principle of "discrete-accumulation", and according to the shape of a part to be manufactured, a path is programmed in advance by a computer, and deposition is performed layer by layer from bottom to top. Compared with traditional part manufacturing methods, additive manufacturing reduces material waste, and does not require a casting mold or forging stamping forming, thereby reducing part manufacturing costs. In the manufacturing of small-batch structural parts, the manufacturing cycle is greatly shortened, and the efficiency is improved.

[0003] Micro-droplet additive manufacturing technology is one of additive manufacturing technologies, and has the advantages of low manufacturing cost, high production efficiency, high material applicability, good mechanical properties of manufactured parts, and low environmental dependence. However, traditional micro-droplet additive manufacturing mainly relies on gas pressure to make the droplet drop, but the controllability of droplet generation is poor, mainly because the gas pressure is not adjusted in time, which easily leads to low forming precision. Therefore, in order to solve the problem of low forming precision caused by the fact that the gas pressure is not adjusted in time in the additive manufacturing process, it is decided not to use gas pressure, but to use a spiral extrusion type metal droplet generating device and method. SUMMARY

[0004] The present application provides a spiral extrusion type metal droplet generating device and method to solve the problem of low control precision caused by the fact that the gas pressure is not adjusted in time in the existing additive manufacturing technology.

[0005] The present application also provides a complete thermal-mass decoupling device. Thermal-mass decoupling is used to precisely control metal droplet forming. Traditional additive manufacturing methods do not have the characteristic of separate transmission of heat and mass, so that the forming precision cannot be guaranteed after a large number of layers. The present application solves the problem of low wall size precision caused by thermal-mass coupling in the additive manufacturing process by changing two heat source parameters to form a complete thermal-mass decoupling device. The metal droplet in the additive manufacturing process can be independently explored to find the best parameter combination of a heat source on the forming in the additive manufacturing process, thereby successfully solving the problem of low wall size precision caused by thermal-mass coupling in the additive manufacturing process.

[0006] The technical scheme adopted by the present application is a spiral extrusion type metal droplet generating device, which comprises a metal droplet generating device 1, a substrate 2, a three-dimensional motion platform 3, a mechanical spiral device 4, and a control system 5.

[0007] The connection relationship of each component is that the three-dimensional movement platform 3 is fixed on the aluminum profile frame, the substrate 2 is fixed on the three-dimensional movement platform 3 through a clamp, the three-dimensional movement platform 3 can move with the substrate, the mechanical screw device 4 is fixed on the aluminum profile frame and fixed through bolt connection, the mechanical screw device 4 forms an integral whole with the three-dimensional movement platform 3 and the substrate 2, the metal droplet generating device 1, the three-dimensional movement platform 3 and the mechanical screw device 4 are connected with a desktop computer through a cable, and a control system of the metal droplet generating device 1, the three-dimensional movement platform 3 and the mechanical screw device 4 is arranged in the desktop computer. Two heat source parameters are combined into a complete thermal mass decoupling device by changing the two heat source parameters respectively, the two heat source parameters are a substrate heating temperature and a temperature at which the metal droplet generating device generates a metal droplet; the metal droplet mass in the metal droplet generating device 1, the current of the metal droplet generating device, the distance from the metal droplet generating device to the substrate, and the speed of the metal droplet transition driven by the rotation speed of the mechanical screw device are changed, the metal droplet mass, the temperature of the metal droplet generating device and the rotation speed of the mechanical screw device are controlled, and the additive manufacturing wall body with different shapes and masses is obtained.

[0008] Further, the mechanical screw device 4 is used to control the metal droplet forming. The positive rotation of the screw device generates pressure on the metal droplet in the metal droplet generating device 1. If the positive rotation is continuously performed, pressure is continuously generated, and the metal droplet generated by the metal droplet generating device 1 is in a strip shape. The reverse rotation of the mechanical screw device 4 causes the metal droplet in the metal droplet generating device 1 to be subjected to an upward force. The metal droplet outside the mechanical screw device 4 is subjected to the action of gravity, and the generated metal droplet is in a droplet shape, thereby achieving the purpose of controlling the shape of the metal droplet.

[0009] Further, the heating metal mode of the metal droplet generating device 1 is not limited to a high-frequency induction heating mode.

[0010] Further, the substrate 2 is placed on the three-dimensional movement platform 3, and the top is the metal droplet generating device 1.

[0011] A spiral extrusion type metal droplet generation method, characterized by comprising the following steps:

[0012] (a) First, the metal raw material is cleaned to remove the surface oxides and impurities, and the substrate is cleaned and dried by removing the substrate oil stains with acetone. After that, the cleaned metal raw material is placed in the metal droplet generating device, and the water tank and the heating equipment of the metal droplet generating device are turned on.

[0013] (b) The temperature of the metal droplet generating device is set. After the metal raw material is heated to be completely melted, the metal droplet is generated, and the metal droplet is dropped by the positive rotation or reverse rotation of the mechanical screw device, so as to maintain the stability of the metal droplet transition mode.

[0014] (c) after opening the three-dimensional motion platform, the substrate is moved by the three-dimensional motion platform, the metal droplet is solidified on the substrate to form a wall body. The droplet generating device is closed, and the three-dimensional motion mechanism is controlled to return to the initial position. The droplet generating device is opened, and the second additive manufacturing is carried out. By analogy, a shaped and accurate wall body is finally obtained.

[0015] (e) by changing the mass of the metal droplet in the metal droplet generating device, the current of the metal droplet generating device, the distance from the metal droplet generating device to the substrate; the mechanical screw device can drive the transition speed of the metal droplet by rotating fast or slow, control the amount of metal droplet, the temperature of the droplet generating device and the rotating speed of the mechanical screw device; finally, different shape and quality of additive manufacturing wall body is obtained.

[0016] An advantage of the present application is to solve the problem of not timely air pressure adjustment in traditional droplet additive manufacturing. The advantage is a mechanical screw device for controlling the shape of metal additive manufacturing. The working mode is that the positive rotation of the screw device generates pressure on the droplet in the droplet generating device. If the positive rotation is continuous, the pressure is also continuous. The droplet that comes out will be in a strip shape. The reverse rotation of the mechanical screw device will make the droplet in the droplet generating device receive an upward force, and the droplet outside the device will be affected by gravity. In this way, the generated droplet will be in a droplet shape. This achieves the purpose of controlling the shape of the droplet. The present application solves the problem of not easy to control the forming process and not enough precision in the additive manufacturing process. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the device.

[0018] Figure 2 It is a partial enlarged view of the mechanical screw device.

[0019] In the figure, 1 is a droplet generating device, 2 is a substrate, 3 is a three-dimensional motion platform, 4 is a mechanical screw device, and 5 is a control system. DETAILED DESCRIPTION

[0020] The device of the present application will be described in detail below in combination with the drawings and examples.

[0021] As shown in Figure 1 A spiral extrusion type metal droplet generating device and method, the device includes a metal droplet generating device 1, a substrate 2, a three-dimensional motion platform 3, a mechanical screw device 4 (MNT998518 stepless speed regulation electric grinder), and a control system 5. The heating metal method of the metal droplet generating device 1 is not limited to the high-frequency induction heating method. The substrate 2 is placed on the three-dimensional motion platform 3, and the droplet generating device 1 is above.

[0022] The connection relationship of each component is that the three-dimensional movement platform 3 is fixed on the aluminum profile frame, the substrate 2 is fixed on the three-dimensional movement platform 3 through a clamp, the three-dimensional movement platform 3 can move with the substrate, the mechanical screw device (MNT998518 stepless speed regulation electric grinder) 4 is fixed on the aluminum profile frame and is fixed through bolt connection, the mechanical screw device (MNT998518 stepless speed regulation electric grinder) 4 and the three-dimensional movement platform 3 and the substrate 2 form an integral whole, the metal droplet generating device 1, the three-dimensional movement platform 3 and the mechanical screw device 4 are connected with a desktop computer through a cable, and the desktop computer is provided with a control system of the metal droplet generating device 1, the three-dimensional movement platform 3 and the mechanical screw device 4.

[0023] Further, the mechanical screw device 4 is used to control the metal droplet forming, and the working mode is that the positive rotation of the screw device generates pressure on the droplet in the metal droplet generating device 1, if the positive rotation is continuously performed, pressure is continuously generated, and the metal droplet generated by the metal droplet generating device 1 is in a strip shape; the reverse rotation of the mechanical screw device 4 makes the metal droplet in the metal droplet generating device 1 subjected to an upward force, the metal droplet outside the mechanical screw device 4 is subjected to the action of gravity, and the generated metal droplet is in a droplet shape, so that the purpose of controlling the shape of the metal droplet is achieved.

[0024] The complete hot decoupling device includes a droplet generating device, a substrate and a control system. First, the metal raw material is cleaned to remove the oxides and impurities on the surface, and the substrate is cleaned with acetone to remove the oil stains, then the substrate is kept clean and dry, and the cleaned metal raw material is placed in the droplet generating device. The water tank and the heating device of the droplet generating device are opened. The temperature of the droplet generating device is set, and after the metal is heated to be completely melted, the metal droplet is generated, and the droplet is dropped by the positive rotation or reverse rotation of the mechanical screw device, and the transition mode of the droplet is maintained stable. Then the three-dimensional movement platform is opened to drive the substrate to move, the metal droplet is solidified on the substrate to form a wall. The droplet generating device is closed, and the three-dimensional movement mechanism is controlled to return to the initial position, the droplet generating device is opened, the second additive manufacturing is performed, and the subsequent steps are repeated, and finally the shaped wall with high precision is obtained.

[0025] The application can solve the problem that the metal droplet forming is not easy to control and the forming precision is poor in the additive manufacturing process, and the main technical route is that a complete hot decoupling additive manufacturing device is used to control the forming of the metal droplet on the substrate by the rotation of the mechanical screw device, the device includes a metal droplet generating device 1, a substrate 2, a three-dimensional movement platform 3, a mechanical screw device (2000r / min) 4 and a control system 5, the metal droplet generating device 1 is used to generate the metal droplet, the mechanical screw device 4 is used to drop the droplet by the positive rotation or reverse rotation, the metal droplet generated by the metal droplet generating device 1 is deposited on the substrate 3, collides with the substrate 3, and is solidified on the substrate 3.

[0026] The device for metal droplet forming based on thermal mass decoupling of the application is a complete thermal mass decoupling device, that is, the heating temperature of the substrate and the temperature at which the droplet generating device generates the droplets are completely independent, the droplet generating device controls the temperature and the amount of the metal droplets, the heat and mass are decoupled by changing the temperature field of the substrate, the heat is transferred to the substrate, one parameter is changed to control the metal droplet forming, and the optimal combination of the two parameters of the substrate temperature and the droplet temperature is selected to precisely control the shape.

[0027] The mechanical screw device 4 is used to control the droplet forming, and the working mode is that the positive rotation of the screw device generates pressure on the droplets in the droplet generating device 1, if the positive rotation is continuously performed, the pressure is continuously generated, and the droplets that come out are in a strip shape, and the reverse rotation of the mechanical screw device generates an upward force on the droplets in the droplet generating device 1, and the droplets outside the device are subjected to the action of gravity, so that the generated droplets are in a droplet shape. In this way, the shape of the droplets is controlled.

[0028] The complete thermal decoupling device includes a droplet generating device, a mechanical screw device, a substrate, and a control system. First, the metal raw material is cleaned to remove the surface oxides and impurities, and the substrate is cleaned with acetone to remove the oil stains, and then the substrate is kept clean and dry, and the cleaned metal raw material is placed in the droplet generating device. The water tank and the heating equipment of the droplet generating device are opened.

[0029] The temperature of the droplet generating device is set, and after the metal is heated to be completely melted, the metal droplets are generated, and the droplets are dropped by the positive rotation or the reverse rotation of the mechanical screw device.

[0030] Then the three-dimensional motion platform is opened to drive the substrate to move, so that the metal droplets are solidified and formed on the substrate along the laser heating area to form a wall. The droplet generating device is closed, and the three-dimensional motion mechanism is controlled to return to the initial position, the droplet generating device is opened, the second additive manufacturing is performed, and the process is repeated in sequence, and finally the shaped wall with precise shape is obtained.

[0031] By changing the amount of the metal droplets, the current of the droplet generating device, and the distance from the droplet generating device to the substrate, the additive manufacturing wall with different shapes and qualities is obtained.

[0032] Embodiment

[0033] The heating mode in the droplet generating device is high-frequency heating, i.e. electromagnetic induction heating device, the additive manufacturing device based on thermal mass decoupling and the additive manufacturing method controlled by the mechanical screw device (rotation speed is 2000r / min) designed by the application, comprising an electromagnetic induction coil, a heater, a crucible, a nozzle, a heat insulation ring, a mechanical screw device controlled forming, a control system, a thermocouple and a three-dimensional motion platform. The top of the crucible is designed with a mechanical screw device, the bottom of the crucible is designed with a nozzle in the middle, the outside of the crucible is provided with a heat insulation ring, is installed in the electromagnetic induction coil, the outside of the bottom of the crucible is provided with a thermocouple temperature measuring device, is used for detecting the temperature of the heated metal in real time, and feeds back the temperature to the control system.

[0034] Specific operation is, before the metal is put in, a chemical method is used to remove most of the oxide scale on the surface of the metal, then the metal is put into the inside of the crucible, the electromagnetic induction heating device and the mechanical screw device are connected, the droplet generating device is heated to the preheating temperature, then the droplet generating device generates metal droplets, then the mechanical screw device (rotation speed is 2000r / min) is opened to make the droplets drop, the three-dimensional motion platform drives the substrate to move, the metal droplets drop on the substrate, finally the metal droplets solidify on the substrate, the width of the wall body is consistent with the width of the laser heating area, finally the purpose of controlling the droplet forming is achieved.

Claims

1. A spiral extrusion metal droplet generation method, the device for realizing the method comprising a metal droplet generating device (1), a base plate (2), a three-dimensional motion platform (3), a mechanical spiral device (4) and a control system (5); The three-dimensional motion platform (3) is fixed on an aluminum profile frame, the base plate (2) is fixed on the three-dimensional motion platform (3) by a clamp, the three-dimensional motion platform (3) can move with the base plate, the mechanical spiral device (4) is fixed on the aluminum profile frame and fixed by bolt connection, the mechanical spiral device (4) forms an integral whole with the three-dimensional motion platform (3) and the base plate (2), the metal droplet generating device (1), the three-dimensional motion platform (3) and the mechanical spiral device (4) are connected with a desktop computer through a cable, and the control system (5) of the metal droplet generating device (1), the three-dimensional motion platform (3) and the mechanical spiral device (4) is arranged in the desktop computer; characterized in that By changing two heat source parameters to form a complete thermal mass decoupling device, the two heat source parameters are the base plate heating temperature and the temperature of the droplet generating device; By changing the metal droplet mass in the metal droplet generating device (1), the current of the metal droplet generating device, the distance from the metal droplet generating device to the base plate, and the speed of the mechanical spiral device, the amount of metal droplet, the temperature of the droplet generating device and the rotating speed of the mechanical spiral device are controlled, and the additive manufacturing wall with different shapes and masses is obtained; The mechanical spiral device (4) is used to control the metal droplet forming, the positive rotation of the spiral device will generate pressure on the droplet in the metal droplet generating device (1), if the positive rotation is continuous, the pressure is also continuous, and the metal droplet generated by the metal droplet generating device (1) is in strip shape; The reverse rotation of the mechanical spiral device (4) will make the metal droplet in the metal droplet generating device (1) receive an upward force, the external metal droplet of the mechanical spiral device (4) is affected by gravity, and the generated metal droplet is in droplet shape, achieving the purpose of controlling the shape of the metal droplet.

2. The screw extrusion metal droplet generation method according to claim 1, characterized by, The heating metal mode in the metal droplet generating device (1) is a high-frequency induction heating mode.

3. The screw extrusion metal droplet generation method according to claim 1, characterized by: The base plate heating temperature and the temperature of the droplet generating device are completely independent, the metal droplet generating device controls the metal droplet temperature and the metal droplet amount, the temperature field of the base plate is changed to transfer heat to the base plate, the heat mass decoupling is realized, one parameter can be changed alone to control the metal droplet forming, and the combination of the base plate temperature and the droplet temperature is selected to control the shape accurately.

4. The screw extrusion metal droplet generation method according to claim 1, characterized by, The base plate (2) is placed on the three-dimensional motion platform (3), and the metal droplet generating device (1) is above the base plate.

5. The method of claim 1-4, wherein The steps include: (a) First, clean the metal raw material to remove the surface oxides and impurities, and remove the base plate oil stains with acetone, then keep the base plate clean and dry, put the cleaned metal raw material into the metal droplet generating device, open the water tank and the heating equipment of the metal droplet generating device; (b) Set the temperature of the droplet generating device, and after the metal raw material is heated to be completely melted, the metal droplet is generated, and the metal droplet is dropped by the positive rotation or the reverse rotation of the mechanical screw device, so that the transition mode of the metal droplet is stable; (c) Then, the three-dimensional motion platform is opened to drive the substrate to move, the metal droplet is solidified on the substrate to form a wall; the droplet generating device is closed, the three-dimensional motion mechanism is controlled to return to the initial position, the metal droplet generating device is opened, the second additive manufacturing is performed, and the subsequent steps are sequentially performed, so that the shaped and accurate wall is finally obtained; (d) The metal droplet mass in the metal droplet generating device, the current of the metal droplet generating device, and the distance from the metal droplet generating device to the substrate are changed; the mechanical screw device can drive the metal droplet transition speed by the rotation speed, so as to control the metal droplet mass, the temperature of the droplet generating device, and the rotation speed of the mechanical screw device; and finally, the additive manufacturing wall with different shapes and qualities is obtained.

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