Screw extrusion type metal molten drop generation device and method

Abstract

The invention discloses a spiral extrusion type metal molten drop generating device and method which are used for solving the technical problems that in the additive manufacturing technology, heat and mass transfer is strongly coupled, forming of a formed part is difficult to predict in the additive manufacturing process, and the forming precision is poor. The device comprises a molten drop generating device, a base plate, a three-dimensional motion platform device and a control system. The mechanical spiral device is installed above the molten drop generating device and can freely stretch out and draw back up and down, deposition, solidification and forming of the molten metal drops on the base plate are achieved by controlling the three-dimensional motion platform to move together with the base plate, and the mechanical spiral device can drive the transition speed of the molten metal drops through the rotation speed. By controlling the amount of the metal molten drops, the temperature of the molten drop generating device and the rotating speed of the mechanical spiral device, the purpose of precise forming of the metal molten drops is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of additive manufacturing, relates to the field of metal droplet forming control, and in particular to a spiral extrusion type metal droplet generating device and method. Background Art

[0002] Additive manufacturing is based on the principle of "discrete-accumulation". According to the shape of the part you want to manufacture, the computer pre-programs the path and deposits it layer by layer from bottom to top. Compared with traditional part manufacturing methods, additive manufacturing reduces material waste and does not require casting molds or forging and stamping, which reduces the cost of part manufacturing. When manufacturing small batches of structural parts, it greatly shortens the manufacturing cycle and improves efficiency.

[0003] Droplet additive manufacturing technology is one of the additive manufacturing technologies. It has the advantages of low manufacturing cost, high production efficiency, high material applicability, good mechanical properties of manufactured parts, and low environmental dependence. However, in traditional droplet additive manufacturing, the molten droplets are mainly caused by gas pressure, but the controllability of droplet generation is poor, mainly due to untimely air pressure regulation, which can easily lead to low forming accuracy. Therefore, in order to solve the problem of low forming accuracy caused by untimely air pressure regulation in the additive manufacturing process, we decided not to use air pressure, but to use a spiral extrusion type metal droplet generation device and method. Summary of the invention

[0004] The present invention provides a spiral extrusion type metal molten droplet generating device and method, which are used to solve the problem of low control accuracy due to untimely air pressure regulation in the existing additive manufacturing technology.

[0005] The present invention also provides a complete thermal-mass decoupling device. Thermal-mass decoupling is for accurately controlling the forming of metal droplets. Traditional additive manufacturing methods do not have the characteristics of separate transmission of heat and mass, so the forming accuracy cannot be guaranteed after a high number of layers. The present invention solves the problem of metal droplets in the additive manufacturing process by changing the parameters of two heat sources respectively and combining them into a complete thermal-mass decoupling device. It can also independently explore the influence of a heat source on the forming process of the additive manufacturing process and then obtain the optimal parameter combination, successfully solving the problem of low wall size accuracy caused by thermal-mass coupling in the additive manufacturing process.

[0006] The technical solution adopted by the present invention is a spiral extrusion type metal droplet generating device, which includes 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 motion platform 3 is fixed on the aluminum profile frame, the substrate 2 is fixed on the three-dimensional motion platform 3 by a clamp, the three-dimensional motion platform 3 can move with the substrate, the mechanical screw device 4 is fixed on the aluminum profile frame and fixed by bolt connection, the mechanical screw device 4 forms a whole with the three-dimensional motion platform 3 and the substrate 2, the metal droplet generating device 1, the three-dimensional motion platform 3 and the mechanical screw device 4 are connected to the desktop computer through cables, and the desktop computer is provided with a control system for the metal droplet generating device 1, the three-dimensional motion platform 3 and the mechanical screw device 4. By respectively changing the two heat source parameters to form a complete thermal mass decoupling device, the two heat source parameters are respectively the substrate heating temperature and the temperature of the droplet generating device generating the droplet; by changing the mass of the metal droplet 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 mechanical screw device can drive the metal droplet transition speed by rotating the speed, the metal droplet amount, the temperature of the droplet generating device and the rotation speed of the mechanical screw device are controlled, and the additive manufacturing wall with different shapes and qualities is obtained.

[0008] Furthermore, the mechanical spiral device 4 is used to control the forming of metal droplets. The positive rotation of the spiral device will generate pressure on the droplets in the metal droplet generating device 1. If the positive rotation is continuous, pressure will be continuously generated, and the metal droplets generated by the droplet generating device 1 will be in the shape of strips; the reverse rotation of the mechanical spiral device 4 will cause the metal droplets in the droplet generating device 1 to be subjected to an upward force, and the metal droplets outside the mechanical spiral device 4 will be affected by gravity, and the generated metal droplets will be in the shape of drops, thereby achieving the purpose of controlling the shape of the metal droplets.

[0009] Furthermore, the method of heating metal by the metal droplet generating device 1 is not limited to high-frequency induction heating.

[0010] Furthermore, the substrate 2 is placed on a three-dimensional motion platform 3 , with the molten droplet generating device 1 located above it.

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

[0012] (a) First, clean the metal raw material to remove oxides and impurities on the surface, and use acetone to remove oil stains on the substrate. Then keep the substrate clean and dry. Put the cleaned metal raw material into the droplet generating device, and turn on the water tank and the heating equipment of the droplet generating device.

[0013] (b) Setting the temperature of the molten droplet generating device, and generating molten metal droplets after the metal raw material is heated to the point where it can be completely melted, and causing the molten metal droplets to drip through the forward or reverse rotation of the mechanical screw device, thereby maintaining a stable molten metal droplet transition mode.

[0014] (c) Then, the three-dimensional motion platform is turned on to drive the substrate to move, and the metal droplets solidify on the substrate to form a wall. The droplet generating device is turned off, and the three-dimensional motion mechanism is controlled to return to the initial position, and the droplet generating device is turned on to perform the second additive manufacturing, and so on, to finally obtain a precisely formed wall.

[0015] (e) By changing the mass of the metal droplets 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; the mechanical screw device can drive the transition speed of the metal droplets by rotating at a certain speed, thereby controlling the amount of metal droplets, the temperature of the droplet generating device, and the rotation speed of the mechanical screw device; and finally obtaining an additively manufactured wall with different shapes and qualities.

[0016] One advantage of the present invention is that it solves the problem of untimely air pressure regulation in traditional droplet additive manufacturing. The advantage is that the metal additive manufacturing method in which the mechanical spiral device controls the molding is in a way that the positive rotation of the spiral device will generate pressure on the molten droplets in the molten droplet generating device. If the positive rotation is continuous, the pressure will be continuously generated, and the molten droplets that come out will be in the shape of strips, while the reverse rotation of the mechanical spiral device will cause the molten droplets in the molten droplet generating device to be subjected to an upward force, and the molten droplets outside the device will be subjected to gravity, so that the generated molten droplets will be in the shape of drops. This achieves the purpose of controlling the shape of the molten droplets, and the present invention solves the problem that the forming process of the formed part is difficult to control and the precision is insufficient during the additive manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0020] The device of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0021] like Figure 1 As shown, a spiral extrusion type metal droplet generation device and method, the device includes a metal droplet generation device 1, a substrate 2, a three-dimensional motion platform 3, a mechanical spiral device 4 (Menite MNT998518 stepless speed regulating electric grinder), and a control system 5. The metal heating method of the metal droplet generation 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 generation device 1 is placed above it.

[0022] The connection relationship between the various components is that the three-dimensional motion platform 3 is fixed on the aluminum profile frame, the substrate 2 is fixed on the three-dimensional motion platform 3 by a clamp, the three-dimensional motion platform 3 can move with the substrate, the mechanical spiral device (Menite MNT998518 stepless speed regulation electric grinder) 4 is fixed on the aluminum profile frame and fixed by bolt connection, the mechanical spiral device (Menite MNT998518 stepless speed regulation electric grinder) 4 forms a whole with the three-dimensional motion platform 3 and the substrate 2, the metal droplet generating device 1, the three-dimensional motion platform 3 and the mechanical spiral device 4 are connected to a desktop computer through cables, and the desktop computer is provided with a control system for the metal droplet generating device 1, the three-dimensional motion platform 3 and the mechanical spiral device 4.

[0023] Furthermore, the mechanical spiral device 4 is used to control the forming of metal droplets. Its working mode is that the positive rotation of the spiral device will generate pressure on the droplets in the metal droplet generating device 1. If the positive rotation is continuous, pressure will be continuously generated, and the metal droplets generated by the droplet generating device 1 will be in the shape of strips; the reverse rotation of the mechanical spiral device 4 will cause the metal droplets in the droplet generating device 1 to be subjected to an upward force, and the metal droplets outside the mechanical spiral device 4 are affected by gravity, and the generated metal droplets will be in the shape of drops, thereby achieving the purpose of controlling the shape of the metal droplets.

[0024] The fully thermal decoupling device described in the present invention includes a molten droplet generating device, a substrate, and a control system. First, the metal raw material is cleaned to remove oxides and impurities on the surface, and acetone is used to remove oil stains on the substrate. Then, the substrate is kept clean and dry, and the cleaned metal raw material is placed in the molten droplet generating device. Turn on the water tank and the heating equipment of the molten droplet generating device. Set the temperature of the molten droplet generating device, and after the metal is heated to be completely melted, it generates metal droplets, and the molten droplets are dripped through the forward or reverse rotation of the mechanical spiral device, and the molten droplet transition mode is maintained stable. Then, the three-dimensional motion platform is turned on to drive the substrate to move, and the metal droplets are solidified on the substrate to form a wall. The molten droplet generating device is turned off, and the three-dimensional motion mechanism is controlled to return to the initial position, and the molten droplet generating device is turned on to perform the second additive manufacturing, and so on, to finally obtain a precisely formed wall.

[0025] The present invention can solve the problems of difficult control and poor forming accuracy of metal droplet forming in the additive manufacturing process. The main technical route is: a completely thermally decoupled additive manufacturing device, which controls the forming of metal droplets on a substrate by rotating a mechanical screw device. The device includes a metal droplet generating device 1, a substrate 2, a three-dimensional motion platform 3, a mechanical screw device (rotation speed is 2000r / min) 4, and a control system 5. The droplet generating device 1 is used to generate metal droplets. The mechanical screw device 4 lowers the droplets by forward or reverse rotation. The metal droplets generated by the droplet generating device 1 are deposited on the substrate 3, collide with the substrate 3, and are solidified on the substrate 3.

[0026] The device for metal droplet forming based on thermal-mass decoupling of the present invention is a complete thermal-mass decoupling device, that is, the substrate heating temperature and the temperature at which the droplet generating device generates the droplet are completely independent. The droplet generating device controls the metal droplet temperature and the metal droplet amount, and transfers heat to the substrate by changing the temperature field of the substrate, thereby achieving thermal-mass decoupling. It can control the metal droplet forming by changing one of the parameters alone, and can perform precise shape control by selecting the best combination of the two parameters, substrate temperature and droplet temperature.

[0027] The mechanical screw device 4 is used to control the formation of droplets. The positive rotation of the screw device will generate pressure on the droplets in the droplet generating device 1. If the positive rotation is continuous, the pressure will be continuously generated, and the droplets will be strip-shaped. The reverse rotation of the mechanical screw device will cause the droplets in the droplet generating device 1 to be subjected to an upward force, and the droplets outside the device will be subjected to gravity. In this way, the droplets generated will be drop-shaped. This achieves the purpose of controlling the shape of the droplets.

[0028] The complete thermal decoupling device of the present invention comprises a droplet generating device, a mechanical screw device, a substrate, and a control system. First, the metal raw material is cleaned to remove oxides and impurities on the surface, and acetone is used to remove oil stains on the substrate. 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 turned on.

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

[0030] Then, the three-dimensional motion platform is turned on to drive the substrate to move, so that the metal droplets solidify and form on the substrate along the laser heating area to form a wall. The droplet generation device is turned off, and the three-dimensional motion mechanism is controlled to return to the initial position, and the droplet generation device is turned on to perform the second additive manufacturing, and so on, to finally obtain a precisely formed wall.

[0031] By changing the amount of metal droplets, the current of the droplet generating device, and the distance from the droplet generating device to the substrate, additively manufactured walls with different shapes and qualities can be obtained.

[0032] Example

[0033] The heating method in the droplet generating device is heating by high-frequency heating, i.e., electromagnetic induction heating device. The additive manufacturing device designed by the present invention is based on thermal mass decoupling and the additive manufacturing method controlled by a mechanical screw device (rotation speed is 2000r / min), including an electromagnetic induction coil, a heater, a crucible, a nozzle, a heat insulation ring, a mechanical screw device controlled molding, a control system, a thermocouple, and a three-dimensional motion platform. A mechanical screw device is designed on the top of the crucible, a nozzle is designed in the middle of the bottom of the crucible, a heat insulation ring is installed on the outside of the crucible, and it is installed inside the electromagnetic induction coil. A thermocouple temperature measuring device is installed on the outside of the bottom of the crucible, which is used to detect the temperature of the heated metal in real time and feed the temperature back to the control system.

[0034] The specific operation is that before the metal is put in, most of the oxide scale on its surface is removed by chemical method, and then the metal is put into the crucible, and the electromagnetic induction heating device and the mechanical screw device are turned on. After the molten droplet generating device is heated to the preheating temperature, the molten droplet generating device generates metal droplets, and then the mechanical screw device is turned on (the speed is 2000r / min) to make the molten droplets fall, and the substrate is driven to move by the three-dimensional motion platform, and the molten metal droplets fall on the substrate. Finally, the metal droplets solidify on the substrate. The wall width is consistent with the width of the laser heating area, and finally the purpose of controlling the molten droplet formation is achieved.

Claims

1. A spiral extrusion type metal droplet generating device, characterized in that: The invention comprises a metal droplet generating device (1), a substrate (2), a three-dimensional motion platform (3), a mechanical screw device (4) and a control system (5). The connection relationship between the various components is that the three-dimensional motion platform (3) is fixed on the aluminum profile frame, the substrate (2) is fixed on the three-dimensional motion platform (3) by a clamp, the three-dimensional motion platform (3) can move with the substrate, the mechanical screw device (4) is fixed on the aluminum profile frame and fixed by bolt connection, the mechanical screw device (4) forms a whole with the three-dimensional motion platform (3) and the substrate (2), the metal droplet generating device (1), the three-dimensional motion platform (3) and the mechanical screw device (4) are connected to a desktop computer by cables, and the desktop computer is provided with a control system (5) for the metal droplet generating device (1), the three-dimensional motion platform (3) and the mechanical screw device (4). By changing two heat source parameters respectively to form a complete thermal-mass decoupling device, the two heat source parameters are respectively the substrate heating temperature and the temperature at which the molten droplet generating device generates the molten droplet; by changing the mass of the metal molten droplet in the metal molten droplet generating device (1), the current of the metal molten droplet generating device, the distance from the metal molten droplet generating device to the substrate, and the mechanical screw device can drive the metal molten droplet transition speed by rotating the mechanical screw device, the amount of metal molten droplet, the temperature of the molten droplet generating device and the rotation speed of the mechanical screw device are controlled, and an additive manufacturing wall with different shapes and qualities is obtained.

2. A spiral extrusion type metal droplet generating device according to claim 1, characterized in that: The mechanical screw device (4) is used to control the formation of metal droplets. The positive rotation of the screw device will generate pressure on the droplets in the metal droplet generating device (1). If the positive rotation is continuous, the pressure will be continuously generated, and the metal droplets generated by the metal droplet generating device (1) will be in the shape of strips. The reverse rotation of the mechanical screw device (4) will cause the metal droplets in the metal droplet generating device (1) to be subjected to an upward force. The metal droplets outside the mechanical screw device (4) are affected by gravity, and the generated metal droplets are in the shape of drops, thereby achieving the purpose of controlling the shape of the metal droplets.

3. A spiral extrusion type metal droplet generating device according to claim 1, characterized in that: The method of heating the metal in the metal droplet generating device (1) is a high-frequency induction heating method.

4. A spiral extrusion type metal droplet generating device and method according to claim 1, characterized in that: The two heat source parameters, the substrate heating temperature and the temperature at which the molten droplet generating device generates the molten droplet, are completely independent. The metal droplet generating device controls the metal droplet temperature and the metal droplet amount, and transfers heat to the substrate by changing the temperature field of the substrate to achieve heat and mass decoupling. It can also control the metal droplet formation by changing one of the parameters alone, and precisely control the shape by selecting a combination of the two parameters, the substrate temperature and the droplet temperature.

5. A spiral extrusion type metal droplet generating device according to claim 1, characterized in that: The substrate (2) is placed on a three-dimensional motion platform (3), with a metal droplet generating device (1) located above it.

6. A method for generating a metal droplet by spiral extrusion using the device according to any one of claims 1 to 5, characterized in that: The following steps are involved: (a) First, clean the metal raw material to remove oxides and impurities on the surface, and use acetone to remove oil stains on the substrate. Then, keep the substrate clean and dry. Put the cleaned metal raw material into the metal droplet generating device, and turn on the water tank and the heating equipment of the metal droplet generating device. (b) Setting the temperature of the molten droplet generating device, and generating molten metal droplets after the metal raw material is heated to the point where it can be completely melted, and causing the molten metal droplets to drip through the forward or reverse rotation of the mechanical screw device, thereby maintaining a stable molten metal droplet transition mode. (c) Then, the three-dimensional motion platform is turned on to drive the substrate to move, and the metal droplets solidify on the substrate to form a wall. The droplet generating device is turned off, and the three-dimensional motion mechanism is controlled to return to the initial position, and the metal droplet generating device is turned on to perform the second additive manufacturing, and so on, and finally a precisely formed wall is obtained. (e) By changing the mass of the metal droplets 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; the mechanical screw device can drive the transition speed of the metal droplets by rotating at a certain speed, thereby controlling the amount of metal droplets, the temperature of the droplet generating device, and the rotation speed of the mechanical screw device; and finally obtaining an additively manufactured wall with different shapes and qualities.

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