Transfer device for metal powder machining and operation method of transfer device

Abstract

The invention provides a metal powder processing-oriented transfer device and an operation method thereof, belongs to the technical field of metal powder processing, and solves the problems that accurate control is difficult to realize and the automation degree is low by adopting a gravity dumping method in a metal powder processing technology. Wherein the transfer device comprises a transfer container, an infrared camera, a laser ranging device and a downstream process container; the downstream process container is provided with a funnel-shaped opening, the operation container is used for containing metal in a molten state and pouring the metal into the downstream process container, and the metal in the molten state forms a metal retention area at the thin opening position of the funnel-shaped opening. The laser ranging device is used for measuring the distance between the metal retention area and the downstream metal in the molten state in the downstream process container, and the infrared camera is used for positioning the surface of the downstream metal in the molten state.

Description

Technical Field

[0001] The invention relates to a transfer device for metal powder processing and an operation method thereof, belonging to the technical field of metal powder processing. Background Art

[0002] In the metal powder processing technology, the usual process is to heat and melt the metal powder and then transfer it to the next step. In this transfer process, the gravity pouring method is often used to complete it. The molten powder is usually transferred from one process to another by controlling the tilt angle of the heating container. The structure of this method is relatively simple, but it requires control of key parameters such as pouring speed and pouring angle, which is usually achieved by a hydraulic transfer device. In order to ensure the stability of the transfer process, the control of the pouring speed, pouring angle, and the timing of starting and stopping the pouring is crucial. However, since the heating container and the transfer container are usually made of high-temperature resistant materials such as ceramics, and the high-temperature environment involved in the production process, it is difficult to use weighing measurement to monitor the pouring process. Therefore, it is traditionally relied on manual visual observation, and the pouring speed and angle are adjusted by hydraulic control valves. There are the following defects: 1. It is difficult to achieve precise control: Metal powder in a molten state has fluidity and high-temperature characteristics. The use of gravity pouring is easily affected by the pouring angle and speed, and it is difficult to ensure the uniformity of powder flow. During the pouring process, temperature changes and the surface tension of the molten metal will lead to unstable flow, affecting the quality of subsequent processes; 2. Low degree of automation: Although some mechanical equipment and pumping transfer devices can achieve a certain degree of automation, the existing technology usually requires a lot of manual intervention in the transfer process of high-temperature, molten powder, especially when controlling the flow rate and flow of molten powder, and lacks automatic closed-loop control transfer devices. This not only increases the difficulty of operation, but also easily leads to errors, affecting production efficiency and product quality.

[0003] Therefore, in the transportation of metal powder in a molten state, the existing technology still has deficiencies in terms of precise control, temperature management, automation and material waste, and a more efficient, safe and highly automated solution is urgently needed. The present invention uses infrared thermal imaging technology, spatial positioning technology, and laser measurement technology for observation, and introduces a dynamic closed-door transportation device to complete the linear control of the operation process, thereby ensuring the efficiency and stability of the operation process. Summary of the invention

[0004] The present invention aims to solve the problem that it is difficult to achieve precise control and low automation in the metal powder processing process using the gravity dumping method, and further proposes a transfer device for metal powder processing and an operation method thereof, wherein the transfer device comprises: an operation container, an infrared camera, a laser distance measuring device and a downstream process container;

[0005] A funnel-shaped opening is provided on the downstream process container. The operating container is used to hold metal in a molten state and pour it into the downstream process container. The molten metal forms a metal retention area at the narrow mouth of the funnel opening. The laser distance measuring device is used to measure the distance between the metal retention area and the molten metal in the downstream process container. The infrared camera is used to locate the surface of the molten metal downstream. The pouring angle of the operating container is controlled by a closed loop to complete the operation of the molten metal.

[0006] A method for using a transfer device for metal powder processing, comprising:

[0007] Step 1: Offline calibration is performed on the operating container, infrared camera, laser distance measuring device and downstream process container. The same coordinate system of the observed quantity is established according to the offline parameters of the infrared camera, laser distance measuring device and downstream process container. The physical parameters obtained by the offline calibration of the operating container are measured to complete the initialization parameters of the transfer device.

[0008] Step 2: Calculate the volume of molten metal in the downstream process container online to obtain the dumping speed requirement of the operating container;

[0009] Step 3: Perform online control of the transfer device according to the dumping speed requirement of the operating container to complete the dumping of the metal powder.

[0010] Optionally, the step of completing the initialization parameters of the transfer device in step 1 includes:

[0011] Step 1.1: Record the volume and shape parameters of the operating container, perform mathematical modeling on the inner cavity of the operating container according to the volume and shape parameters, obtain the relationship between the pouring angle and the volume of the liquid flowing out per unit time, and obtain the physical parameters of the operating container;

[0012] Step 1.2: Calibrate the infrared camera's internal parameters through a panel with infrared LED lamp beads, and perform spatial calibration through the infrared camera's camera coordinate system and the physical coordinate system of the downstream container to complete the infrared camera's external parameter calibration;

[0013] Step 1.3: Record the volume and shape parameters of the downstream container, perform mathematical modeling on the inner cavity of the physical parameters of the downstream container according to the volume and shape parameters, and complete the calibration of the physical parameters of the downstream container;

[0014] Step 1.4: Calibrate the zero point of the laser distance measuring device and the physical coordinate system of the downstream container to complete the calibration of the laser distance measuring device;

[0015] Step 1.5: By calibrating the downstream container, laser rangefinder and infrared camera, a unified coordinate system for the observed quantity is established, and by measuring the physical parameters of the operating container, the initialization parameters of the transfer device are completed.

[0016] Optionally, the step of online calculating the volume of metal in a molten state in the downstream process container in step 2 includes:

[0017] Step 2.1: The laser measuring device is directed at a certain angle to the molten metal surface, measures the distance of the molten metal surface, and calculates the position of the molten metal liquid surface in the downstream container at this time;

[0018] Step 2.2: Observe the surface with an infrared camera, accurately locate and model the molten metal surface through spatial positioning technology and offline calibration parameters, and obtain infrared measurement results;

[0019] Step 2.3: Calculate the retained metal volume in the downstream container and the remaining volume redundancy V1 in the downstream container through the laser device measurement results, infrared measurement results and physical parameters of the downstream container;

[0020] Step 2.4: The volume outflow of molten metal per unit time is calculated by mathematical modeling of the operating container, and the volume V2 of free metal liquid in the air that has been poured out of the container and has not reached the downstream container is estimated according to the time;

[0021] Step 2.5: Model the flow transfer device based on the remaining volume redundancy V1 and the estimated volume V2 of free liquid metal in the air, estimate the upper limit Vt of the dumping volume per unit time, combine Vt with the mathematical modeling of the operating container to calculate the upper limit Ang of the dumping angle, and calculate the dumping angle Ang-t' at the next moment through Kalman filtering.

[0022] Optionally, the step of performing online control of the transfer device according to the requirement of the dumping speed of the operating container in step 3 includes:

[0023] Step 3.1: Run the transfer device to automatically control the container to start dumping;

[0024] Step 3.2: All physical parameters of the initial dumping are obtained through step 1, and the transfer device controls the operating container to start dumping at a fixed speed;

[0025] Step 3.3: The transfer device controls the hydraulic mechanism to automatically adjust the dumping angle according to the operating container angle calculated in real time in step 2.5;

[0026] Step 3.4: When the dumping angle is greater than the critical value or the observed volume of the downstream container is greater than the critical value, the transfer device completes the dumping.

[0027] The beneficial effects of the present invention are:

[0028] 1. The present invention can realize automatic dumping, close the dumping process, and ensure the stability and safety of dumping;

[0029] 2. The present invention can use an automated method to perform observations, thus avoiding the instability of manual observations. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic structural diagram of a transfer device for metal powder processing provided by the present invention;

[0031] Figure 2 A flow chart of the operation mode of a transfer device for metal powder processing provided by the present invention. DETAILED DESCRIPTION

[0032] Specific implementation method 1: Combination Figure 1 To illustrate this embodiment, Figure 1 As shown, the structure of a transfer device for metal powder processing described in this embodiment includes: an operating container, an infrared camera, a laser distance measuring device and a downstream process container;

[0033] The infrared camera model used in this embodiment is Hikvision MV-CI003-GL-N6. Hikvision MV-CI003-GL-N6 has the following functions: 1. It adopts a 300,000-pixel, high-sensitivity vanadium oxide uncooled detector; 2. It supports a variety of pseudo-color modes, grayscale alarms, and rich image adjustment functions; 3. It is compact in size and supports four-sided installation; 4. It uses a Gigabit Ethernet interface, and the maximum transmission distance can reach 100m without relaying; 5. It is compatible with the GigE Vision protocol and GenlCam standard.

[0034] The laser distance measuring device used in this embodiment is of model KJT-KDA-TR-II, which has the following functions: 1. It is specially used to measure the height of molten aluminum / molten steel level under various working conditions, and is used for displaying and closed-loop controlling the molten aluminum level; 2. It can maintain high measurement accuracy and reliability in harsh outdoor environments; 3. It uses a visible laser beam, which is easy to aim at the object being measured; 4. The length of the connecting cable can be extended, and the measurement range of the molten aluminum level can reach 10m; 5. Various functional instructions can be input by computer; 6. Different parameters can be used to program the switch output and analog output separately; 7. The alarm distance range can be set arbitrarily; 8. The output unit of the measurement value can be set arbitrarily; 9. An external trigger can be used to realize remote trigger measurement.

[0035] A funnel-shaped opening is provided on the downstream process container. The operating container is used to hold metal in a molten state and pour it into the downstream process container. The molten metal forms a metal retention area at the narrow mouth of the funnel opening. The laser distance measuring device is used to measure the distance between the metal retention area and the molten metal in the downstream process container. The infrared camera is used to locate the surface of the molten metal downstream. The pouring angle of the operating container is controlled by a closed loop, thereby completing the operation of the molten metal.

[0036] Specific implementation method 2: Combination Figure 2 To illustrate this embodiment, Figure 2 As shown, the steps of the operation method of a transfer device for metal powder processing described in this embodiment include:

[0037] a: Offline calibration;

[0038] Since the transfer device is equipped with multiple measurement units, a control unit and multiple containers, and its online operation parameters cannot be directly observed, the transfer device measures and calibrates multiple units by means of offline calibration, so that the measurement and control process can be carried out in the same scale coordinate system during online operation;

[0039] a1: physical parameters of the operating container;

[0040] The physical parameter calibration of the operating container requires recording the volume and shape parameters of the operating container, mathematically modeling the inner cavity of the operating container based on the volume and shape parameters, and completing the relationship between the pouring angle and the volume of the liquid flowing out per unit time.

[0041] a2: infrared camera parameters;

[0042] The parameters of the infrared camera are divided into internal and external parameter calibration. The calibration of the camera's internal parameters is carried out through a panel with infrared LED beads. The calibration of the infrared camera's external parameters mainly completes the spatial calibration of the infrared camera's coordinate system and the physical coordinate system of the downstream container.

[0043] a3: physical parameters of downstream container;

[0044] The physical parameter calibration of the physical parameters of the downstream container requires recording the volume and shape parameters of the downstream container, and mathematically modeling the inner cavity of the physical parameters of the downstream container based on the volume and shape parameters. Since the shape of the downstream container is non-standardized, the retention volume of the metal in the molten state in the downstream container needs to be modeled in order to be coupled with the observed quantity.

[0045] a4: laser distance measuring device parameters;

[0046] The calibration of the laser distance measuring device mainly completes the calibration of the zero point of the laser distance measuring device and the physical coordinate system of the downstream container to ensure that the laser distance measurement result is in the same coordinate system as the downstream container.

[0047] a5: Offline calibration parameters;

[0048] By calibrating the downstream container, laser ranging device and infrared camera, a unified coordinate system for the observed quantity is established, and by measuring the physical parameters of the operating container, the initialization parameters of the control model are completed.

[0049] b: Online calculation;

[0050] The online calculation process mainly completes the measurement of the molten metal volume in the downstream container, and then meets the requirements for control speed.

[0051] b1: laser measurement;

[0052] The laser measuring device will shine directly at the molten metal surface at a certain angle, measure the distance of the molten metal surface, and then calculate the position of the surface in the downstream container at this time.

[0053] b2: infrared measurement;

[0054] Infrared measurement is used to locate the liquid surface. Since the metal surface in a molten state is not a static page, it is necessary to observe the surface with an infrared camera. The observation results are used to accurately locate and model the molten metal surface through spatial positioning technology and offline calibration parameters.

[0055] b3: Calculation of metal volume in the downstream container;

[0056] Through the observation results in b1 and b2, combined with the physical parameters in a3, the retained metal volume in the downstream container can be calculated, and the remaining volume redundancy V1 in the downstream container can be further calculated.

[0057] b4: Estimation of liquid volume in free state;

[0058] Through the pouring model obtained in a1, the volume outflow of molten metal per unit time can be calculated, and then the volume V2 of free metal liquid in the air that has been poured out of the container and has not reached the downstream container can be estimated based on the time parameter.

[0059] b5: Calculation of the operating container angle;

[0060] According to the remaining volume redundancy V1 calculated in b3 and the volume V2 of free liquid metal in the air estimated in b4, the flow transfer device model can be built, and then the upper limit Vt of the dumping volume per unit time can be estimated. By combining Vt with the dumping model calculated in a1, the upper limit Ang of the dumping angle can be obtained. Since the dumping angle Ang-t at this moment can be obtained by automatically controlling the transfer device, the dumping angle Ang-t' at the next moment can be calculated by methods such as Kalman filtering.

[0061] c.Online control;

[0062] The online control module automatically controls the transfer device through the offline calibrated parameters.

[0063] c1: start dumping;

[0064] The start of dumping is the starting moment for the automatic operation of the entire transfer device, which is generally controlled manually.

[0065] c2: fixed initialization speed;

[0066] Since all physical parameters of initial dumping can be obtained from the calibration parameters, the transfer device starts dumping at a fixed speed.

[0067] c3: online speed adjustment;

[0068] According to the operating container angle calculated in real time in b5, the transfer device controls the hydraulic mechanism to automatically adjust the dumping angle.

[0069] c4: Operation completed;

[0070] When the dumping angle is greater than a critical value or the observed volume of the downstream container is greater than a critical value, the transfer device completes the dumping.

[0071] In summary, the present invention can realize automatic dumping, close the dumping process, and ensure the stability and safety of dumping. At the same time, the present invention can adopt an automated way to observe and avoid the instability of manual observation.

[0072] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A transfer device for metal powder processing, characterized in that: The structure of the transfer device for metal powder processing includes: Operating vessels, infrared cameras, laser distance measuring devices and downstream process vessels; The downstream process container is provided with a funnel-shaped opening. The operating container is used to hold the metal in a molten state and pour it into the downstream process container. The metal in a molten state forms a metal retention area at the narrow mouth of the funnel opening. The laser distance measuring device is used to measure the distance between the metal retention area and the metal in a molten state in the downstream of the downstream process container. The infrared camera is used to locate the surface of the metal in a molten state downstream. The pouring angle of the operating container is controlled by a closed loop to complete the operation of the metal in a molten state.

2. A method for using a transfer device for metal powder processing, applied to the transfer device for metal powder processing according to claim 1, characterized in that: include: Step 1: Offline calibration is performed on the operating container, infrared camera, laser distance measuring device and downstream process container. The same coordinate system of the observed quantity is established according to the offline parameters of the infrared camera, laser distance measuring device and downstream process container. The physical parameters obtained by the offline calibration of the operating container are measured to complete the initialization parameters of the transfer device. Step 2: Calculate the volume of molten metal in the downstream process container online to obtain the dumping speed requirement of the operating container; Step 3: Perform online control of the transfer device according to the dumping speed requirement of the operating container to complete the dumping of the metal powder.

3. The method for using a transfer device for metal powder processing according to claim 2, characterized in that: The steps for completing the initialization parameters of the transfer device in step 1 include: Step 1.1: Record the volume and shape parameters of the operating container, perform mathematical modeling on the inner cavity of the operating container according to the volume and shape parameters, obtain the relationship between the pouring angle and the volume of the liquid flowing out per unit time, and obtain the physical parameters of the operating container; Step 1.2: Calibrate the infrared camera's internal parameters through a panel with infrared LED lamp beads, and perform spatial calibration through the infrared camera's camera coordinate system and the physical coordinate system of the downstream container to complete the infrared camera's external parameter calibration; Step 1.3: Record the volume and shape parameters of the downstream container, perform mathematical modeling on the inner cavity of the physical parameters of the downstream container according to the volume and shape parameters, and complete the calibration of the physical parameters of the downstream container; Step 1.4: Calibrate the zero point of the laser distance measuring device and the physical coordinate system of the downstream container to complete the calibration of the laser distance measuring device; Step 1.5: By calibrating the downstream container, laser rangefinder and infrared camera, a unified coordinate system for the observed quantity is established, and by measuring the physical parameters of the operating container, the initialization parameters of the transfer device are completed.

4. The method for using a transfer device for metal powder processing according to claim 2, characterized in that: The step of calculating the volume of metal in the molten state in the downstream process container online in step 2 includes: Step 2.1: The laser measuring device is directed at a certain angle to the molten metal surface, measures the distance of the molten metal surface, and calculates the position of the molten metal liquid surface in the downstream container at this time; Step 2.2: Observe the surface with an infrared camera, accurately locate and model the molten metal surface through spatial positioning technology and offline calibration parameters, and obtain infrared measurement results; Step 2.3: Calculate the retained metal volume in the downstream container and the remaining volume redundancy V1 in the downstream container through the laser device measurement results, infrared measurement results and physical parameters of the downstream container; Step 2.4: The volume outflow of molten metal per unit time is calculated by mathematical modeling of the operating container, and the volume V2 of free metal liquid in the air that has been poured out of the container and has not reached the downstream container is estimated according to the time; Step 2.5: Model the flow system based on the remaining volume redundancy V1 and the estimated volume V2 of free liquid metal in the air, estimate the upper limit Vt of the dumping volume per unit time, combine Vt with the mathematical modeling of the operating container to calculate the upper limit Ang of the dumping angle, and calculate the dumping angle Ang-t' at the next moment through Kalman filtering.

5. The method for using a transfer device for metal powder processing according to claim 2, characterized in that: The step of performing online control of the transfer device according to the requirement of the dumping speed of the operating container in step 3 includes: Step 3.1: Run the transfer device to automatically control the container to start dumping; Step 3.2: All physical parameters of the initial dumping are obtained through step 1, and the transfer device controls the operating container to start dumping at a fixed speed; Step 3.3: The transfer device controls the hydraulic mechanism to automatically adjust the dumping angle according to the operating container angle calculated in real time in step 2.5; Step 3.4: When the dumping angle is greater than the critical value or the observed volume of the downstream container is greater than the critical value, the transfer device completes the dumping.

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