Measuring device and method for metal droplet solidification morphology at quantitative gradient temperature

Abstract

The invention discloses a device and a method for measuring solidification morphology of molten metal drops at quantitative gradient temperature. The device comprises a molten metal drop regulation and control device, a molten metal drop heating device, a gradient temperature regulation and control device, a high-speed camera, a three-dimensional motion platform, a high-speed camera, an infrared point temperature instrument, a thermocouple temperature measuring instrument, an information acquisition system and the like. The temperature of the generated molten metal drops is accurately regulated and controlled in an infrared temperature measurement mode, a gradient temperature platform is made in a resistance heating and heat insulation material adding mode, and the molten metal drops are dropped on a gradient temperature substrate; the temperature and morphology changes in the molten drop solidification process are collected through a high-speed camera, an infrared thermometer and a thermocouple thermometer, meanwhile, information is fed back to an information collection system, the morphology changes of molten drops under different gradients, different temperatures and different masses are analyzed, and the measurement method for the quantitative gradient temperature regulation and control of the metal molten drop solidification morphology is established. And therefore, the metal droplet solidification morphology reference regulation and control are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of metal droplet additive manufacturing, and in particular to a device and method for measuring the solidification morphology of metal droplets at a quantitative gradient temperature. Background Art

[0002] Metal droplet additive manufacturing is an advanced metal manufacturing technology. Metal materials are melted into liquid metal by laser or electron beam, and then sprayed layer by layer onto the surface of the workpiece through a nozzle in a precise manner to form metal droplets, which gradually accumulate into the required three-dimensional structure. Metal droplet additive manufacturing technology has the advantages of building complex components, saving materials, and rapid manufacturing. It is widely used in aerospace, automobile manufacturing, medical equipment, shipbuilding, mold manufacturing and other fields.

[0003] However, the surface quality of metal droplet additive manufacturing is usually rough. In the process of metal droplet additive manufacturing, the surface quality can be improved and the occurrence of defects can be reduced by adjusting processing parameters such as laser power, scanning speed, droplet injection speed, etc., as well as optimizing the powder spraying and wire spinning methods. Subsequently, the surface quality and roughness of the sample after additive manufacturing are improved by surface polishing, cutting, heat treatment, etc. However, there are relatively few online measurements and controls for the metal droplet forming solidification process. Therefore, it is urgent to accurately measure and control the solidification process of the metal droplet to achieve droplet solidification forming morphology control and provide technical support for the precise control of additive manufacturing forming. Summary of the invention

[0004] The technical purpose of the present invention is to provide a device and method for measuring the solidification morphology of metal droplets at a quantitative gradient temperature, which is used to study the influence of gradient temperature on the entire process of metal droplet flow and solidification, measure the morphological changes of metal droplets during the solidification process, and solve the problem of difficult precise control in the existing metal droplet solidification process. The device and method can measure and precisely control the solidification morphology of metal droplets at a quantitative gradient temperature, providing technical support for the precise forming of metal droplet additive manufacturing.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A measuring device for quantifying the solidification morphology of a metal droplet under a gradient temperature, comprising a metal droplet generating device, a gradient temperature control device, a droplet measuring device, a high-speed camera, a three-dimensional motion platform, an infrared point temperature device, a thermocouple temperature measuring instrument, an information acquisition system, an infrared thermal imager and a thermocouple temperature measuring collector; the metal droplet generating device generates metal droplets by inductive heating, and the temperature of the metal droplets is monitored by the infrared point temperature device and fed back to the information acquisition system; the gradient temperature control device heats two substrates of different temperatures respectively by resistive heating, and the two substrates of different temperatures are heated by the three-dimensional motion platform. The substrates are combined and heat insulation materials are used to prevent heat conduction between the two substrates. Different gradient temperatures are achieved by changing the temperatures of the two substrates. The temperature of the substrates is monitored in real time by a thermocouple temperature collector and fed back to the information acquisition system. The resistance heating device is regulated according to the heat dissipation conditions to ensure the accuracy of the gradient temperature. The molten droplet measurement device collects relevant data such as temperature, flow and disturbance during the solidification process of the metal droplet through a high-speed camera, a thermocouple thermometer, an infrared thermal imager and a thermocouple temperature collector. The relevant data are combined through the information acquisition system to realize the solidification morphology analysis of the metal droplet.

[0007] A method for measuring the solidification morphology of a metal droplet under a quantitative gradient temperature comprises the following steps:

[0008] S1, first clean the metal material to remove oxides and impurities on the surface; put the metal material into a crucible container device, turn on the gas protection device in the container, use vacuum to remove oxygen and water vapor in the container, and fill the container with high-purity argon gas.

[0009] S2, respectively heat the two substrates by means of resistance heating, and realize different temperatures of the two substrates, combine the substrates with different temperatures through a three-dimensional motion platform, use heat-insulating materials at the joint to prevent temperature conduction, and adjust the heating devices of the two substrates in real time according to the thermocouple temperature collector to ensure that the substrate temperature is not changed by the influence of other devices, thereby realizing gradient temperature distribution; adjust the position of the gradient temperature substrate through the three-dimensional motion platform, so that the center point of the gradient temperature distribution substrate is in a straight line with the center point of the metal droplet, so that the metal droplet falls on the center position of the gradient temperature substrate.

[0010] S3, the metal droplet generating device heats the metal material, and adjusts the size of the generated metal droplets through the droplet control device to ensure that the size of the metal droplets can be adjusted at the micron level, and the temperature of the metal droplets is measured by infrared temperature measurement, and the generation of metal droplets with constant temperature and quality is achieved through the collection and control of data information.

[0011] S4, after the generated molten metal drop falls, the molten metal drop falls to the center position of two substrates with different temperatures to solidify, and a monitoring device is used to monitor the solidification forming process and temperature change of the molten metal drop after it falls to the substrate; and the morphology measurement results of the molten metal drop are analyzed according to the data acquisition control system, and the law between the molten metal drop formation and the gradient temperature distribution is analyzed by phase changing the temperature and mass of the molten metal drop and the temperature of the two heated substrates, so as to realize the gradient temperature to adjust the solidification morphology of the molten metal drop.

[0012] Preferably, the crucible container is heated by a droplet heating device and the temperature of the metal droplet is obtained by thermocouple temperature measurement, the generation and temperature of the metal droplet are regulated by a droplet control device, the temperature of the metal droplet is monitored by an infrared point temperature device, and the size of the metal droplet and the heating temperature of the metal droplet are adjusted by the droplet control device according to the collected temperature information to obtain a constant temperature and constant quality metal droplet.

[0013] Preferably, the temperatures of the two resistance-heated substrates are independently controlled, and the two substrates are separated. The two substrates are adjusted on a plane through a three-dimensional motion platform, and the minimum gap is 0.01 mm. The substrates are set at different temperatures respectively, and a thermocouple temperature measuring device is set on the substrate. While monitoring the substrate temperature in real time, the temperature of the molten metal droplet falling and contacting the substrate can also be monitored.

[0014] Preferably, a high-speed camera, an infrared thermal imager and a thermocouple temperature measuring device are used to jointly monitor the solidification process and temperature change of the molten droplet.

[0015] Preferably, a molten droplet control device is used to accurately control the size and temperature of the metal droplets to achieve the generation of constant temperature and constant quality metal droplets. The gas protection device uses a circulating pump and gas pressure detection to achieve a pure argon gas protection environment. The two metal substrates are kept at different temperatures through separate resistance heating. The three-dimensional motion platform is controlled to combine substrates of different temperatures. Insulating materials are used to isolate heat conduction between substrates of different temperatures to achieve gradient temperature distribution.

[0016] Preferably, the gradient temperature is quantified by changing the heating temperature of different substrates, and the three-dimensional motion platform is controlled to ensure that the center point of the gradient temperature distribution substrate is in a straight line with the center point of the metal droplet, and the metal droplet is dropped onto the gradient temperature substrate device. The morphology and temperature changes of the solidification of the metal droplet are monitored by a high-speed camera image detection system, an infrared thermal imager and a thermocouple thermometer, so as to realize the monitoring and feedback of the solidification effect of the metal droplet. The information acquisition system is regulated by the droplet control device and the gradient temperature field according to the feedback information, so as to realize the adjustment of the solidification morphology of the metal droplet.

[0017] The beneficial effects of adopting the above technical solution are:

[0018] (1) The present invention solves the problem of difficulty in controlling the solidification forming of molten metal droplets during the additive manufacturing process. It uses an additional temperature gradient on the deposition substrate to affect the wetting, spreading and solidification behavior of the molten metal droplets without destroying the initial morphology of the molten metal droplets. By controlling the mass of the molten metal droplets, the mass temperature of the molten metal droplets and the gradient temperature field of the substrate, the solidification forming of the molten metal droplets can be controlled, thereby improving the forming accuracy of the molten metal droplets.

[0019] (2) The present invention heats the metal material by a crucible heating method, and heats the metal material in a device filled with argon gas, thereby preventing the loss of the metal material. Due to the thermal conductivity temperature between the materials, in order to reduce the temperature error, the temperature of the metal droplet is measured by an infrared point temperature method, and the temperature and size of the droplet are regulated by a droplet regulation device, thereby achieving precise constant temperature and constant quality of the droplet.

[0020] (3) The temperature gradient device of the present invention realizes a gradient temperature field by regulating the combination of substrates with different temperatures, applies resistive heating to the substrates and realizes a constant temperature, and uses a motion platform to realize the combination of gradient temperatures. For heat conduction between different substrates, heat insulating materials are used to isolate the temperature without affecting the solidification of the molten droplet.

[0021] (4) The present invention monitors the morphology of metal droplets at different gradient temperatures by coordinating the metal droplet formation, infrared thermal imager and thermocouple thermometer, thereby achieving the metal droplet solidification forming effect and feedback, and quantifying the gradient temperature regulation of metal droplet solidification.

[0022] The present invention is described in detail below in conjunction with specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of a device for measuring the solidification morphology of a metal droplet under a quantitative gradient temperature.

[0024] The accompanying drawings are marked as follows: 1-thermocouple temperature controller, 2-metal droplet control device, 3-industrial computer and information acquisition system, 4-argon gas bottle, 5-crucible container, 6-droplet heating device, 7-high-speed camera, 8-thermocouple temperature measuring plate, 9-left resistance heating three-dimensional motion platform, 10-thermal insulation material, 11-infrared point temperature measuring device, 12-infrared thermal imager, 13-thermocouple temperature measurement collector, 14-right resistance heating three-dimensional motion platform, 15-circulation pump. DETAILED DESCRIPTION

[0025] The content of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] like Figure 1 As shown, the device system for quantitatively gradient temperature controlling the solidification morphology of molten metal droplets includes a metal droplet control device 2, a droplet heating device 6, a thermocouple temperature controller 1, a gas pulse signal generator, an industrial computer and information acquisition system 3, a vacuum device, an argon gas bottle 4, a droplet generating device, a high-speed camera, a thermocouple side temperature plate, a resistance heating three-dimensional motion platform, a thermal insulation material 10, an infrared point temperature measuring device 11, an infrared thermal imager 12 and a thermocouple temperature measuring collector 13.

[0027] Among them, the molten droplet heating device heats the metal material by inductive heating, monitors and feedbacks the metal temperature in real time by a thermocouple temperature controller 1, controls the size and temperature of the molten droplet by a molten droplet control device, moves the left and right resistance heating three-dimensional motion platforms to corresponding heights and heats them to different temperatures respectively, adds insulation material between the two and keeps them in the same plane, aligns the center of the thermocouple temperature measuring plate with the center of the molten droplet generating device, and collects the changes in temperature and morphology during the solidification process of the molten droplet by a high-speed camera, an infrared thermometer and a thermocouple thermometer after the molten droplet falls, and feeds back the information to the information collection system, analyzes the morphological changes of the molten droplet under different gradients, different temperatures and different masses, and establishes a method for quantitatively controlling the solidification morphology of the metal molten droplet by gradient temperature, thereby realizing precise control of the solidification morphology of the metal molten droplet.

[0028] The gradient temperature device includes a left resistance heating three-dimensional motion platform 9, a right resistance heating three-dimensional motion platform 14 and thermal insulation materials. By changing the temperature of the left and right resistance heating three-dimensional platforms and adding thermal insulation materials to block the heat radiation between the two different temperature platforms, the gradient temperature is achieved. The thermocouple temperature measuring plate is combined with the heating substrate to ensure real-time monitoring of the substrate temperature. The temperature information is fed back to the acquisition system, and the gradient temperature field is adjusted by changing the heating parameters.

[0029] The specific implementation is as follows: the method of the present invention is used to quantify the temperature gradient to control the solidification morphology of the aluminum alloy molten droplet, including the following steps:

[0030] Step 1. Select 2A12 aluminum alloy bars, remove the surface oxide with sandpaper, and clean the surface impurities with an ultrasonic cleaner. Turn on the circulation pump to remove the water and oxygen inside, fill the equipment with high-purity argon, fill the vacuum device with argon and the pressure value is -0.5-0MPa, and load the bars into the droplet generation device.

[0031] Step 2: Turn on the droplet heating device to melt the aluminum alloy bar into an aluminum alloy solution. At this time, the temperature on the thermocouple temperature controller gradually increases. The aluminum alloy is set to 700°C through the thermocouple temperature controller. When the aluminum alloy solution is 700°C, stop heating and keep warm.

[0032] Step 3. Align the center point of the gradient temperature device with the center point of the droplet generation device, heat the left resistance heating three-dimensional motion platform to 500°C and keep it warm, heat the right resistance heating three-dimensional motion platform to 100°C and keep it warm, insert 0.5mm insulation material between the two, and lay the thermocouple temperature measuring plates on the two platforms respectively. At this time, the temperatures collected on the two plates by the thermocouple collector are 500°C and 100°C respectively.

[0033] Step 4: Adjust the droplet control device to generate aluminum alloy droplets. Use the infrared point temperature measuring device to measure the temperature of the aluminum alloy droplets to be 700°C and feed it back to the acquisition system. Insulate the aluminum alloy droplets by adjusting the heating current.

[0034] Step 5, adjust the molten drop control device to make the aluminum alloy molten drop fall, record the molten drop solidification forming process by a high-speed camera, use an infrared thermal imager to record the temperature change of the molten drop solidification process, and use a thermocouple side temperature collector to collect the temperature change after the solidified molten drop combines with the substrate. It is measured that the aluminum alloy molten drop presents a right-high and left-low inclined morphology after solidification.

[0035] Step 6. In combination with the information acquisition system for the solidification of the molten droplet in step 5, the changes in the morphology and temperature during the solidification process of the aluminum alloy molten droplet can be presented in real time. Combined with the relationship between the two, the influence of the quantified gradient temperature on the solidification of the aluminum alloy molten droplet is expressed in the form of measurement data. By studying the influence of different substrate temperature gradients on the solidification morphology of the aluminum alloy molten droplet, the influence mechanism of the gradient temperature on the solidification morphology and temperature of the molten droplet is established, forming a method for quantitatively controlling the solidification morphology of the aluminum alloy molten droplet by gradient temperature.

Claims

1. A measuring device for quantifying the solidification morphology of a metal droplet under a gradient temperature, characterized in that: It includes a metal droplet generating device, a gradient temperature control device, a droplet measuring device, a high-speed camera, a three-dimensional motion platform, an infrared spot temperature device, a thermocouple temperature meter, an information collection system, an infrared thermal imager and a thermocouple temperature collector; the metal droplet generating device generates metal droplets by inductive heating, and monitors the temperature of the metal droplets by the infrared spot temperature device and feeds back to the information collection system; the gradient temperature control device heats two substrates with different temperatures respectively by resistance heating, combines the two substrates with different temperatures by a three-dimensional motion platform, uses heat insulation materials to prevent heat conduction between the two substrates, realizes different gradient temperatures by changing the temperatures of the two substrates, monitors the temperature of the substrates in real time by a thermocouple temperature collector and feeds back to the information collection system, and controls the resistance heating device according to the heat dissipation situation to ensure the accuracy of the gradient temperature; the droplet measuring device collects temperature, flow and disturbance related data during the solidification process of the metal droplet by a high-speed camera, a thermocouple temperature meter, an infrared thermal imager and a thermocouple temperature collector, and combines the related data by the information collection system to realize the solidification morphology analysis of the metal droplet.

2. A method for measuring the solidification morphology of a metal droplet at a quantitative gradient temperature using the device of claim 1, characterized in that: The following steps are involved: S1, firstly, clean the metal material to remove oxides and impurities on the surface; put the metal material into a crucible container device, turn on the gas protection device in the container, remove the oxygen and water vapor in the container by vacuuming, and fill the container with high-purity argon gas; S2, using resistance heating to heat the two substrates respectively, and achieving different temperatures of the two substrates, combining the substrates with different temperatures through a three-dimensional motion platform, using heat-insulating materials at the joint to prevent temperature conduction, and adjusting the heating devices of the two substrates in real time according to the thermocouple temperature collector to ensure that the substrate temperature is not changed by the influence of other devices, thereby achieving gradient temperature distribution; adjusting the position of the gradient temperature substrate through the three-dimensional motion platform, so that the center point of the gradient temperature distribution substrate is in a straight line with the center point of the metal droplet, so that the metal droplet falls on the center position of the gradient temperature substrate; S3, the metal droplet generating device heats the metal material, and adjusts the size of the generated metal droplets through the droplet control device to ensure that the size of the metal droplets can be adjusted at the micron level, and the temperature of the metal droplets is measured by infrared temperature measurement, and the generation of metal droplets with constant temperature and constant quality is achieved through the collection and control of data information; S4, after the generated molten metal drop falls, the molten metal drop falls to the center position of two substrates with different temperatures to solidify, and a monitoring device is used to monitor the solidification forming process and temperature change of the molten metal drop after it falls to the substrate; and the morphology measurement results of the molten metal drop are analyzed according to the data acquisition control system, and the law between the molten metal drop formation and the gradient temperature distribution is analyzed by phase changing the temperature and mass of the molten metal drop and the temperature of the two heated substrates, so as to realize the gradient temperature to adjust the solidification morphology of the molten metal drop.

3. The method for measuring the solidification morphology of a metal droplet at a quantitative gradient temperature according to claim 1, characterized in that: The crucible container is heated by a droplet heating device and the temperature of the molten metal droplet is obtained by thermocouple temperature measurement. The generation and temperature of the molten metal droplet are regulated by a droplet control device. The temperature of the molten metal droplet is monitored by an infrared point temperature device. The size of the molten metal droplet and the heating temperature of the molten metal droplet are adjusted by the droplet control device according to the collected temperature information to obtain a constant temperature and constant quality molten metal droplet.

4. The method for measuring the solidification morphology of a metal droplet at a quantitative gradient temperature according to claim 1, characterized in that: The temperatures of the two resistance-heated substrates are independently controlled, and the two substrates are separated. The two substrates are adjusted on a plane through a three-dimensional motion platform, and the minimum gap is 0.01mm. The substrates are set at different temperatures respectively, and a thermocouple temperature measuring device is set on the substrate. While monitoring the substrate temperature in real time, it can also monitor the temperature of the metal droplet falling and contacting the substrate.

5. The method for measuring the solidification morphology of a metal droplet at a quantitative gradient temperature according to claim 1, characterized in that: A high-speed camera, an infrared thermal imager and a thermocouple temperature measuring device are used to monitor the solidification process and temperature change of the molten droplet.

6. The method for measuring the solidification morphology of a metal droplet at a quantitative gradient temperature according to claim 1, characterized in that: A molten droplet control device is used to accurately control the size and temperature of the metal droplets to achieve the generation of constant temperature and constant quality metal droplets. The gas protection device uses a circulating pump and gas pressure detection to achieve a pure argon gas protection environment. The two metal substrates are kept at different temperatures through separate resistance heating. The three-dimensional motion platform is controlled to combine substrates of different temperatures. Insulating materials are used to isolate heat conduction between substrates of different temperatures to achieve gradient temperature distribution.

7. The method for measuring the solidification morphology of a metal droplet at a quantitative gradient temperature according to claim 1, characterized in that: The gradient temperature is quantified by changing the heating temperature of different substrates, and the three-dimensional motion platform is controlled to ensure that the center point of the gradient temperature distribution substrate is in a straight line with the center point of the metal droplet. The metal droplet is dropped onto the gradient temperature substrate device, and the morphology and temperature changes of the solidification of the metal droplet are monitored by the high-speed camera image detection system, infrared thermal imager and thermocouple thermometer, so as to realize the monitoring and feedback of the solidification effect of the metal droplet. The information acquisition system is regulated by the droplet control device and the gradient temperature field according to the feedback information, so as to realize the solidification morphology adjustment of the metal droplet.

Images