A powder cleaning system for complex flow channels in metal printing

Abstract

The present invention relates to the technical field of metal powder cleaning control, and particularly to a metal printing complex flow channel powder cleaning system, which includes a powder cleaning machine, a powder collection module, a powder cleaning monitoring module, and a powder cleaning control module. The powder cleaning monitoring module includes a dust monitoring unit and a powder monitoring unit, which are used to monitor the inlet dust concentration and the exhaust dust concentration in the powder collection module in real time. The powder monitoring unit is used to capture powder cloud videos at different angles during the powder cleaning process to determine the panoramic powder cloud model. The powder cleaning control module determines the dust characterization state of the part according to the exhaust dust concentration at the first preset time to determine the first adjustment strategy, determines the powder cloud change trend during the powder cleaning process according to the panoramic powder cloud model to determine the powder removal state, and determines the second adjustment strategy according to the powder removal state at the second preset time; the present invention realizes the efficient, precise cleaning and intelligent regulation of residual powder, effectively improving the powder cleaning quality and efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of metal powder cleaning control, and particularly to a metal printing complex flow channel powder cleaning system. Background Art

[0002] Selective Laser Melting (SLM) is an advanced metal additive manufacturing technology that constructs complex-shaped components by melting metal powder layer by layer. During the SLM processing, unmelted metal powder will remain on the surface of the formed part and in internal holes and gaps. If these residual powders are not cleaned in time, they will affect the surface quality, dimensional accuracy, mechanical properties of the part, and subsequent processing, etc. Currently, common powder cleaning methods mainly include manual cleaning, blowing cleaning, vibration cleaning, and chemical cleaning, etc. Manual cleaning has low efficiency and it is difficult to ensure the consistency of the cleaning effect; blowing cleaning is difficult to completely remove the powder in the internal and hidden parts of some complex-shaped parts; vibration cleaning may cause damage to the part; chemical cleaning may introduce new impurities and involve environmental protection issues; therefore, an efficient, thorough and non-destructive post-treatment powder cleaning system for selective laser melting is needed to meet the requirements of industrial production.

[0003] There is a device for internal cavity vibration powder cleaning and internal surface finishing of products formed by selective laser melting disclosed in the prior art. By using a vibration rotation system, a powder cleaning power and recovery system, and an internal surface finishing system, this device can effectively solve the problems of manual knocking to clean the residual powder in the internal cavity of the currently formed wing surface products by selective laser melting and the poor internal surface quality, and can realize the efficient and rapid cleaning of the residual powder in the internal cavity of the complex structure of the wing surface type hollow lattice, greatly improving the powder cleaning efficiency and ensuring the powder cleaning quality of the residual powder in the internal cavity. This invention integrates an electrochemical workstation into the device, and can realize the electrochemical polishing of the internal surface of the wing surface, improving the surface quality of the entire internal cavity of the wing surface. It can be seen that this invention has the following problems:

[0004] This invention cleans the metal powder of different models through fixed modes pre-stored in the device, but fails to intelligently perceive and analyze in real time the differences in aspects such as structure, material, process characteristics, and powder residue conditions of different models, and thus cannot flexibly make adaptive adjustments to the cleaning parameters, resulting in low powder cleaning efficiency for each model. Summary of the Invention

[0005] To this end, the present invention provides a powder cleaning system for complex flow channels in metal printing, which is used to overcome the problem in the prior art that the fixed mode pre-stored in the equipment is used to clean the metal powder of different models, but the differences in structure, material, process characteristics, and powder residue conditions of different models cannot be intelligently perceived and analyzed in real time, and thus the cleaning parameters cannot be flexibly adjusted adaptively, resulting in low powder cleaning efficiency for each model.

[0006] To achieve the above object, the present invention provides a powder cleaning system for complex flow channels in metal printing, including:

[0007] A powder cleaning machine, which is used to vibrate and remove the residual powder on the part and recycle it without pollution;

[0008] A powder collection module, which is connected to the powder cleaning machine, and is used to collect the metal powder cleaned from the part and preliminarily separate the metal powder;

[0009] A powder cleaning monitoring module, which is respectively connected to the powder cleaning machine and the powder collection module, and includes a dust monitoring unit and a powder monitoring unit;

[0010] The dust monitoring unit is used to monitor the inlet dust concentration and exhaust dust concentration at the inlet and outlet of the sealed collection box in the powder collection module in real time;

[0011] The powder monitoring unit includes a number of video shooting components and a video reconstruction component. Each video shooting component is used to shoot the powder cloud videos at different angles during the powder cleaning process of the powder cleaning machine, and the video reconstruction component is used to determine the powder cloud panoramic model according to the powder cloud videos at different angles;

[0012] A powder cleaning control module, which is respectively connected to the powder cleaning machine and the powder cleaning monitoring module, and is used to determine the dust characterization state of the part according to the exhaust dust concentration at the first preset time to determine whether to determine the first adjustment strategy of the first cleaning parameter in combination with the dust concentration difference, determine the change trend of the powder cloud during the powder cleaning process according to the powder cloud panoramic model to determine the powder removal state, and determine the second adjustment strategy of the second cleaning parameter according to the powder removal state at the second preset time;

[0013] Wherein, the first cleaning parameter includes the cleaning power and the negative pressure power, and the second cleaning parameter includes the cleaning time;

[0014] The first start time of the first preset time is the initial powder cleaning start time, and the second end time of the second preset time is the initial powder cleaning end time.

[0015] As a preferred technical solution of the powder cleaning system for complex flow channels in metal printing, the powder collection module includes a sealed collection box and a negative pressure generating device;

[0016] The sealed collection box is used to collect the metal powder cleaned from the parts, and a powder filtering device for preliminarily separating powders of different particle sizes is arranged inside it;

[0017] The negative pressure generating device is connected to the sealed collection box and is used to suck the powder during the cleaning process into the sealed collection box by generating negative pressure.

[0018] As a preferred technical solution of the metal printing complex runner powder cleaning system, in the powder cleaning monitoring module, the dust monitoring unit includes two dust sensors respectively arranged at the air inlet and the air outlet of the sealed collection box.

[0019] As a preferred technical solution of the metal printing complex runner powder cleaning system, the powder cleaning control module determines the first adjustment strategy of the first powder cleaning parameter according to the exhaust dust concentration at the first preset time to determine the dust characterization state of the part, or determines the first adjustment strategy of the first powder cleaning parameter in combination with the dust concentration difference, including,

[0020] If the exhaust dust concentration is greater than the concentration threshold, it is determined that the dust characterization state of the part is an abnormal characterization state and the first adjustment strategy is determined according to the dust concentration difference, where,

[0021] If the dust concentration difference is greater than or equal to the concentration difference reference value, it is determined that the first adjustment strategy is to reduce the powder cleaning power;

[0022] If the dust concentration difference is less than the concentration difference reference value, it is determined that the first adjustment strategy is not formulated, and it is determined that the powder filtering device of the sealed collection box fails;

[0023] If the exhaust dust concentration is less than or equal to the concentration threshold, it is determined that the dust characterization state of the part is a normal characterization state, and it is determined that the first adjustment strategy is not formulated;

[0024] Wherein, the dust concentration difference is determined according to the difference between the inlet dust concentration and the exhaust dust concentration.

[0025] As a preferred technical solution of the metal printing complex runner powder cleaning system, the powder cleaning control module determines whether to formulate the first adjustment strategy secondly according to the dust characterization state after a preset duration of reducing the powder cleaning power, including,

[0026] If the dust characterization state is still an abnormal characterization state, it is determined that the first adjustment strategy is formulated secondly, and the first adjustment strategy formulated secondly is to maintain the reduced powder cleaning power and reduce the negative pressure power.

[0027] As a preferred technical solution of the powder cleaning system for complex flow channels in metal printing, the video reconstruction component converts powder cloud videos at different angles into three-dimensional point cloud data of the powder cloud at each angle through a three-dimensional reconstruction method, and forms a panoramic model of the powder cloud with a spatial structure according to point cloud fusion and rendering techniques.

[0028] As a preferred technical solution of the powder cleaning system for complex flow channels in metal printing, the powder cleaning control module determines the volume time-domain diagram of the powder cloud according to the real-time panoramic model of the powder cloud, and determines the change trend of the powder cloud during the powder cleaning process according to the real-time fluctuation parameters of the volume time-domain diagram to determine the powder removal state, including,

[0029] If the real-time fluctuation parameters at each moment are all less than or equal to the preset fluctuation value, it is determined that the change trend of the powder cloud is a continuous decreasing trend, and it is determined that the powder removal state is a normal state;

[0030] If there is any moment when the real-time fluctuation parameter is greater than the preset fluctuation value, it is determined that the change trend of the powder cloud is a fluctuating change trend, and it is determined that the powder removal state is an abnormal state.

[0031] As a preferred technical solution of the powder cleaning system for complex flow channels in metal printing, the powder cleaning control module determines the real-time volume difference according to the volume of the powder cloud at the current moment and the volume of the powder cloud at the previous moment, and determines the real-time fluctuation parameter according to the percentage of the ratio of the real-time volume difference to the volume of the powder cloud at the current moment.

[0032] As a preferred technical solution of the powder cleaning system for complex flow channels in metal printing, the powder cleaning control module determines the second adjustment strategy of the second powder cleaning parameter according to the powder removal state at the second preset time, including,

[0033] If the powder removal state at the second preset time is an abnormal state, it is determined that the second adjustment strategy is to increase the powder cleaning time;

[0034] If the powder removal state at the second preset time is a normal state, it is determined that the second adjustment strategy is not formulated.

[0035] As a preferred technical solution of the powder cleaning system for complex flow channels in metal printing, the powder cleaning control module determines the increased powder cleaning time according to the volume ratio of the powder cloud at the second end time to the preset volume, where,

[0036] If the volume ratio is less than or equal to the preset ratio, it is determined that the increased powder cleaning time is the standard duration;

[0037] If the volume ratio is greater than the preset ratio, it is determined that the increased powder cleaning time is the product of the standard duration and the volume ratio.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows. The metal printing complex runner powder cleaning system provided by the present invention realizes the efficient, precise cleaning and intelligent regulation of the residual powder of metal printing complex runner parts through the coordinated operation of multiple modules, effectively improving the powder cleaning quality and efficiency, reducing the impact on the environment and ensuring the stable operation of the equipment;

[0039] In particular, the powder collection module collects and preliminarily separates metal powders of different particle sizes through a sealed collection box and an internal powder filtering device. At the same time, it relies on a negative pressure generating device connected to the sealed collection box to generate negative pressure to suck in the powder, and cooperates with dust sensors arranged at the air inlet and outlet by the dust monitoring unit to achieve efficient powder collection, prevent powder from escaping, and preliminarily separate powders of different particle sizes. It is also convenient to monitor the dust concentration, thereby ensuring the orderly progress of the powder cleaning process, improving the powder cleaning quality, reducing dust pollution, and contributing to the stable operation of the system;

[0040] In particular, the powder cleaning control module effectively improves the working efficiency of the powder cleaning system, ensures the powder cleaning quality and environmental protection compliance, and enhances the stability and safety of the equipment operation through precise monitoring and intelligent regulation; among them, the powder cleaning control module accurately determines the dust characterization state of the part based on the comparison of the exhaust dust concentration and the concentration threshold within the first preset time and the relationship between the dust concentration difference and the concentration difference reference value, so as to determine the first adjustment strategy of the powder cleaning power. When the exhaust dust concentration is too high and the dust concentration difference meets the conditions, it can reasonably reduce the powder cleaning power to avoid excessive powder cleaning resulting in dust escape; in case of specific faults, it can be detected and alarmed in time to ensure the normal operation of the system and the powder cleaning effect; this module also flexibly decides whether to formulate a secondary adjustment strategy according to the dust characterization state within the preset time after reducing the powder cleaning power. When necessary (the dust characterization state is still an abnormal characterization state), it maintains the reduced powder cleaning power and reduces the negative pressure power to further optimize the powder cleaning process, so that the powder cleaning parameters always adapt to the actual powder cleaning requirements, improving the powder cleaning efficiency and quality;

[0041] In particular, by virtue of the real-time monitoring and dynamic regulation of the change trend of the powder cloud, the powder cleaning control module can always keep the powder cleaning process in the best state, effectively reducing powder residue, improving the cleanliness and quality of the parts; at the same time, this precise control strategy helps to reduce the energy consumption and wear of the powder cleaning equipment, extend the service life of the equipment, enhance the stability and reliability of the system operation, reduce production interruptions and cost increases caused by incomplete powder cleaning or equipment failures, and improve the comprehensive benefits of the entire metal printing complex runner powder cleaning system. Brief Description of the Drawings

[0042] Figure 1 It is a connection diagram of the metal printing complex runner powder cleaning system according to the embodiment of the present invention;

[0043] Figure 2Connection diagram of the flour cleaning monitoring module according to an embodiment of the present invention;

[0044] Figure 3 Flow chart for determining the first adjustment strategy according to an embodiment of the present invention;

[0045] Figure 4 Flow chart for determining the second adjustment strategy according to an embodiment of the present invention. Detailed implementation manners

[0046] In order to make the objectives and advantages of the present invention more clear and understandable, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0048] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0049] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0050] Please refer to Figure 1 and Figure 2 as shown, which are respectively the connection diagram of the metal printing complex flow channel powder cleaning system according to an embodiment of the present invention and the connection diagram of the flour cleaning monitoring module according to an embodiment of the present invention. An embodiment of the present invention provides a metal printing complex flow channel powder cleaning system, including:

[0051] A flour cleaning machine for vibrating and removing the residual powder on the part and recycling it without pollution;

[0052] A powder collection module connected to the flour cleaning machine for collecting the metal powder cleaned from the part and preliminarily separating the metal powder to prevent powder leakage;

[0053] A powder cleaning monitoring module, which is connected to the powder cleaning machine and the powder collecting module respectively, and includes a dust monitoring unit and a powder monitoring unit;

[0054] The dust monitoring unit is used to monitor the intake dust concentration and exhaust dust concentration at the air inlet and the exhaust port of the sealed collection box in the powder collection module in real time;

[0055] The powder monitoring unit includes a plurality of video shooting components and video reconstruction components, each of which is used to shoot powder cloud videos of the powder purifier at different angles during the powder cleaning process, and the video reconstruction component is used to determine a powder cloud panoramic model based on the powder cloud videos at different angles to determine the spatial structure of the powder cloud;

[0056] In practice, the video shooting component is usually a high-definition motion camera, and the video shooting components are respectively arranged on the inner wall of the powder cleaning machine; at least three video shooting components are included, one video shooting component is located at the center of the inner wall at the top of the powder cleaning machine to obtain a downward-looking powder cloud video, and the other two video shooting components are evenly arranged on the inner wall on the side of the powder cleaning machine to obtain a front-view powder cloud video and a left-view powder cloud video respectively; it is also possible to increase the acquisition of a rear-view powder cloud video and a right-view powder cloud video to obtain a more accurate powder cloud panoramic model;

[0057] a powder cleaning control module, which is connected to the powder cleaning machine and the powder cleaning monitoring module respectively, and is used to determine the dust characterization state of the part according to the exhaust dust concentration at a first preset time to determine whether to determine a first adjustment strategy for a first powder cleaning parameter in combination with the dust concentration difference, determine a powder cloud change trend during the powder cleaning process according to the powder cloud panoramic model to determine a powder cleaning state, and determine a second adjustment strategy for a second powder cleaning parameter according to the powder cleaning state at a second preset time;

[0058] Among them, the first powder cleaning parameter includes powder cleaning power and negative pressure power, and the second powder cleaning parameter includes powder cleaning time; it can be understood that the powder cleaning power refers to the power intensity of the powder cleaning tool in the powder cleaning machine when it is working. If the powder cleaning tool is a brush, the powder cleaning power is the speed of the brush rotating or moving. When the brush contacts the surface of the part at a higher speed to clean the powder, the powder cleaning power is higher; conversely, the powder cleaning power is low at a low speed; if the powder cleaning tool is an ultrasonic vibration head, the powder cleaning power is reflected in the frequency of ultrasonic vibration. A higher frequency means stronger vibration energy, which can make the powder more easily detached from the surface of the part and the inside of the complex flow channel. At this time, the powder cleaning power is higher; and the powder cleaning power generated by a lower frequency is lower; the negative pressure power refers to the intensity of the negative pressure generated by the negative pressure generating device in the powder collection module. The negative pressure power can be adjusted by changing the fan speed, wherein the fan speed is in direct proportion to the negative pressure power;

[0059] The first start time of the first preset time is the initial start time of the flour cleaning, and the second end time of the second preset time is the initial end time of the flour cleaning;

[0060] It can be understood that generally, the duration of the first preset time is less than that of the second preset time; the first preset time is usually from the initial start time of the flour cleaning to the first end time, and the second preset time is usually from the second start time to the initial end time of the flour cleaning; it can be understood that after putting the parts to be cleaned with flour and selecting the flour cleaning mode, there will be a fixed flour cleaning time (from the initial start time of the flour cleaning to the initial end time of the flour cleaning) and fixed flour cleaning parameters. The powder cleaning system provided by the present invention is used to judge whether the mode is appropriate and whether the first flour cleaning parameter and the second flour cleaning parameter need to be adjusted after selecting the flour cleaning mode.

[0061] In practice, the duration of the first preset time is usually ≤3 min; generally, when the flour cleaning equipment starts and the gas in the sealed collection box begins to flow towards the exhaust port, the exhaust dust concentration can be monitored. This time is very short and almost starts synchronously with the flour cleaning process; therefore, only a relatively short first preset time needs to be set to judge whether to adjust the first flour cleaning parameter. However, if the time is too short, the judgment will be too one-sided. Therefore, the duration of the first preset time is preferably set to 2 min;

[0062] In practice, the duration of the second preset time is usually ≤10 min. The second preset time needs to judge the flour cleaning effect in the set flour cleaning mode. If the time is too short, the accuracy of judging the flour cleaning effect cannot be guaranteed, but if the second preset time is too long, it may not reach the end stage of the flour cleaning mode and the judgment will be inaccurate. Therefore, the duration of the second preset time is preferably set to 5 min.

[0063] It can be understood that the flour cleaning monitoring module monitors the dust concentration at the air inlet and outlet of the sealed collection box in real time. The flour cleaning control module determines the part dust characterization state based on the exhaust dust concentration at the first preset time, and then determines the first adjustment strategy for the flour cleaning power and negative pressure power, which can quickly respond to the changes during the flour cleaning process, ensure the balance between the flour cleaning effect and efficiency, and avoid over-cleaning or insufficient cleaning. The powder monitoring unit uses multiple video shooting components to capture powder cloud videos from different angles and the video reconstruction component to construct a panoramic model to determine the spatial structure of the powder cloud. Based on this, the flour cleaning control module can judge the powder removal state according to the change trend of the powder cloud, so as to evaluate the effectiveness of the flour cleaning mode within the second preset time and determine the second adjustment strategy for the flour cleaning time, making the flour cleaning process more targeted and adaptable. The powder collection module is connected to the flour cleaning machine and can perform preliminary separation during the collection of metal powder to prevent powder spillage. Combined with the reasonable regulation of the negative pressure power, it not only ensures the effective recovery of powder, reduces resource waste, but also reduces the environmental pollution caused by dust emissions, meeting the environmental protection requirements. By precisely adjusting the flour cleaning parameters, it avoids damage to parts caused by too high flour cleaning power and the impact on the filtering device of the powder collection module caused by improper negative pressure power, extends the service life of the equipment, maintains the overall stable operation of the system, and reduces the downtime and cost increase caused by equipment failure or maintenance.

[0064] Specifically, the powder collection module includes a sealed collection box and a negative pressure generating device;

[0065] The sealed collection box is used to collect the metal powder cleaned from the parts, and a powder filtering device for preliminary separation of powders with different particle sizes is arranged inside it;

[0066] The negative pressure generating device is connected to the sealed collection box and is used to suck the powder during the cleaning process into the sealed collection box by generating negative pressure.

[0067] Specifically, in the flour cleaning monitoring module, the dust monitoring unit includes two dust sensors respectively arranged at the air inlet and outlet of the sealed collection box.

[0068] It can be understood that the powder collection module collects and preliminarily separates metal powders with different particle sizes through the sealed collection box and the internal powder filtering device, and at the same time relies on the negative pressure generating device connected to the sealed collection box to generate negative pressure to suck in the powder, and cooperates with the dust sensors arranged at the air inlet and outlet by the dust monitoring unit to achieve efficient powder collection, prevent powder spillage and preliminary separation of powders with different particle sizes, and also facilitate the monitoring of dust concentration, thereby ensuring the orderly progress of the flour cleaning process, improving the flour cleaning quality, reducing dust pollution and assisting the stable operation of the system.

[0069] It is understandable that the dust sensor in the present invention can be any dust sensor in the prior art, including: (1) an optical dust sensor. When light irradiates dust particles, scattering occurs. Inside the sensor, there is a light source (such as a laser diode) and a photodetector. The light emitted by the light source irradiates the dust particles passing through the detection area of the sensor, and the scattered light is received by the photodetector. The concentration of dust is calculated based on the intensity of light scattering. Among them, the more dust particles there are, the greater the intensity of scattered light. The optical dust sensor has high sensitivity and can detect tiny dust particles, which is relatively effective for detecting low-concentration dust at the exhaust port. It can detect dust particles with a particle size between 0.1 micrometer and 10 micrometers (this covers the particle size range of most metal powders), and the response speed of the optical dust sensor is relatively fast, capable of reflecting the change of dust concentration in real time. (2) An electrostatic induction dust sensor uses the electrostatic induction generated by dust particles when passing through the sensor to detect the dust concentration. When dust particles pass through the electric field inside the sensor, they will carry charges, and these charged dust particles will generate induced charges on the electrodes. By detecting the magnitude of the induced charges, the dust concentration can be determined. Among them, the more dust particles there are, the more induced charges are generated. This sensor has good adaptability to dust with different particle sizes, high precision, can work in a complex airflow environment, and has strong anti-interference ability. At the exhaust port of the sealed collection box, the airflow velocity and direction may fluctuate to a certain extent, and the electrostatic induction dust sensor can still detect the dust concentration relatively stably. (3) A β-ray absorption dust sensor uses the absorption characteristics of β-rays (electron rays) to measure the dust concentration, including a β-ray source and a detector. When β-rays pass through the airflow containing dust, some rays will be absorbed by the dust particles, and the intensity of the β-rays detected by the detector will decrease. The dust concentration can be calculated based on the attenuation degree of the β-ray intensity. The β-ray absorption dust sensor is a high-precision dust concentration detection device with a wide measurement range. It can effectively detect dust from low concentration to high concentration, and its measurement results are less affected by the physical properties (such as color, shape) of dust particles, and can accurately detect the concentration of metal powders of different materials.

[0070] Please refer to Figure 3 as shown, which is a flowchart for determining the first adjustment strategy in an embodiment of the present invention.

[0071] Specifically, the powder cleaning control module determines the dust characterization state of the part based on the exhaust dust concentration at the first preset time to determine the first adjustment strategy of the first powder cleaning parameter, or determines the first adjustment strategy of the first powder cleaning parameter in combination with the dust concentration difference, including

[0072] If the exhaust dust concentration is greater than the concentration threshold, it is determined that the dust characterization state of the part is an abnormal characterization state, and a first adjustment strategy is determined according to the dust concentration difference, where

[0073] If the dust concentration difference is greater than or equal to the concentration difference reference value, it is determined that the first adjustment strategy is to reduce the powder cleaning power; it can be understood that at the beginning of powder cleaning, the dust concentration at the exhaust port of the sealed collection box will be relatively high because at the beginning of powder cleaning, a large amount of powder originally attached to the surface of the part is cleaned off and quickly sucked into the sealed collection box under the action of negative pressure. At this time, the filtering device in the collection box may not have enough time to effectively intercept all the powder, and some powder will move towards the exhaust port with the air flow, resulting in an increase in the dust concentration at the exhaust port; as the powder cleaning process continues, the dust concentration usually gradually decreases; this is because as time goes by, the filtering device in the collection box gradually plays a role and intercepts more powder in the box; moreover, the amount of powder remaining on the surface of the part is also continuously decreasing, and the amount of powder cleaned and entering the collection box also decreases accordingly, making the dust concentration at the exhaust port show a downward trend; however, within the first preset time, the filtering device has already played a role, and at this time the dust concentration difference should be greater than or equal to the concentration difference reference value; therefore, when the exhaust dust concentration is greater than the concentration threshold and the dust concentration difference is greater than or equal to the concentration difference reference value, it can be determined that the first powder cleaning parameter is too large, resulting in too much powder being discharged at once, so the first powder cleaning parameter needs to be reduced;

[0074] If the dust concentration difference is less than the concentration difference reference value, it is determined that the first adjustment strategy is not formulated, and it is determined that the powder filtering device of the sealed collection box is faulty; it can be understood that the clogging or malfunction of the filtering device of the sealed collection box will also affect the change of the dust concentration. When the filtering device is clogged, the flow of air in the box is blocked, which may cause some powder not to be effectively filtered, resulting in an increase in the dust concentration at the exhaust port; if the filtering device is damaged, such as a cracked filter element, a large amount of the originally intercepted powder will leak to the exhaust port side, which will also cause the dust concentration to rise sharply; therefore, when the exhaust dust concentration is greater than the concentration threshold and the dust concentration difference is less than the concentration difference reference value, it is judged that the powder filtering device of the sealed collection box is faulty / clogged, and an alarm signal needs to be issued and the powder filtering device needs to be repaired;

[0075] wherein, the dust concentration difference is determined according to the difference between the intake dust concentration and the exhaust dust concentration;

[0076] In practice, the concentration difference reference value is determined according to the filtration efficiency of filtration equipment such as the cyclone separator built in the filtering device. The concentration difference reference value is determined by the lowest filtration efficiency during its normal operation, and the concentration difference reference value = lowest filtration efficiency × intake dust concentration;

[0077] In implementation, the concentration threshold is determined according to environmental protection regulations / emission requirements / specifications for dust emission in different industries.

[0078] In implementation, the reduced purifying power = the purifying power before reduction × concentration threshold ÷ exhaust dust concentration;

[0079] If the exhaust dust concentration is less than or equal to the concentration threshold, it is determined that the dust characterization state of the part is a normal characterization state, and it is determined not to formulate the first adjustment strategy.

[0080] Specifically, the purifying control module determines whether to formulate the first adjustment strategy again according to the dust characterization state after a preset duration of reducing the purifying power, including,

[0081] If the dust characterization state is still an abnormal characterization state, it is determined to formulate the first adjustment strategy again, and the first adjustment strategy formulated again is to maintain the reduced purifying power and reduce the negative pressure power; it can be understood that if the exhaust dust concentration is still greater than the concentration threshold after adjusting the purifying power, it means that the adjustment is insufficient, and the negative pressure power of the negative pressure generating device needs to be adjusted to reduce the dust entering the sealed collection box to achieve the effect of reducing the exhaust dust concentration;

[0082] In implementation, the reduced negative pressure power = the negative pressure power before reduction × concentration threshold ÷ exhaust dust concentration;

[0083] If the dust characterization state is a normal characterization state, it is determined not to formulate the first adjustment strategy again, and the purifying is carried out according to the first adjustment strategy formulated for the first time.

[0084] In implementation, the preset duration is set to be equal to the duration of the first preset time, that is, after implementing the first adjustment strategy, the duration of the first preset time is continuously determined, and the dust characterization state is determined according to the exhaust dust concentration during this period;

[0085] It can be understood that the exhaust dust concentration changes with time, so the exhaust dust concentration within a period of time refers to the average value of the exhaust dust concentration during this period.

[0086] It can be understood that the powder cleaning control module accurately determines the powder characterization state of the part based on the comparison between the exhaust dust concentration and the concentration threshold within the first preset time and the relationship between the dust concentration difference and the concentration difference reference value, thereby determining the first adjustment strategy for the powder cleaning power. When the exhaust dust concentration is too high and the dust concentration difference meets the conditions, the powder cleaning power can be reasonably reduced to avoid dust overflow caused by excessive powder cleaning. In case of specific faults, it can be detected in time and an alarm can be issued to ensure the normal operation of the system and the powder cleaning effect. The module also flexibly decides whether to formulate an adjustment strategy for the second time according to the powder characterization state during the preset duration after reducing the powder cleaning power. When necessary (the powder characterization state is still an abnormal characterization state), it maintains the reduced powder cleaning power and reduces the negative pressure power to further optimize the powder cleaning process, so that the powder cleaning parameters always adapt to the actual powder cleaning requirements and improve the powder cleaning efficiency and quality.

[0087] It can be understood that during the process of adjusting the powder cleaning parameters, the powder cleaning control module determines the reduced powder cleaning power and negative pressure power based on a scientific calculation method, which not only effectively controls the powder cleaning effect but also avoids excessive impact or damage to equipment such as the powder cleaning machine and the powder collection module due to improper parameter adjustment, extends the service life of the equipment, reduces equipment failures and maintenance frequencies, lowers operating costs, and ensures the long-term stable operation of the entire powder cleaning system.

[0088] Specifically, the video reconstruction component converts the powder cloud videos from different angles into three-dimensional point cloud data of the powder cloud at each angle through a three-dimensional reconstruction method, and forms a panoramic model of the powder cloud with a spatial structure according to the point cloud fusion and rendering technology.

[0089] It can be understood that both the three-dimensional reconstruction method and the point cloud fusion and rendering technology are existing technologies;

[0090] In implementation, the three-dimensional reconstruction method includes: First, camera calibration is performed to determine the internal parameters (such as focal length, principal point position, etc.) and external parameters (such as the position and attitude of the camera) of each camera, which is the basis for subsequent three-dimensional reconstruction; then a feature extraction algorithm (such as SIFT, SURF, etc.) is used to extract feature points in each video frame; then the corresponding feature points in the video frames from different perspectives are found through a feature matching algorithm; finally, these matched feature points are used for three-dimensional reconstruction to obtain the three-dimensional point cloud model of the powder cloud;

[0091] What is obtained through the previous three-dimensional reconstruction method (such as multi-view geometry or structure from motion) is the three-dimensional point cloud data from each angle. These point cloud data need to be fused to form a complete powder cloud model with a spatial structure. The point cloud fusion technology can register and merge the point clouds from different perspectives, remove duplicate points and fill possible holes, and then convert this fused point cloud model into a panoramic video through the rendering technology, so that it can intuitively display the spatial structure of the powder cloud;

[0092] In implementation, the point cloud fusion and rendering technology includes: First, use a point cloud registration algorithm (such as the ICP algorithm - Iterative Closest Point algorithm) to register point clouds from different perspectives to find the best alignment between them. Then, merge the registered point clouds through a fusion algorithm to obtain a complete powder cloud point cloud model. Next, select a suitable rendering engine (such as OpenGL, Unity, etc.) to render the point cloud model. During the rendering process, set parameters such as light source, viewing angle, and color to generate a panoramic video of the powder cloud with a spatial structure; in specific implementation, the rendering parameters can also be adjusted according to actual requirements, such as emphasizing the density change and movement direction of the powder cloud.

[0093] Please refer to Figure 4 as shown, which is a flowchart for determining the second adjustment strategy in an embodiment of the present invention.

[0094] Specifically, the powder cleaning control module determines a volume time-domain diagram of the powder cloud based on the real-time powder cloud panoramic model, and determines the change trend of the powder cloud during the powder cleaning process based on the real-time fluctuation parameters of the volume time-domain diagram to determine the powder removal status, including,

[0095] If the real-time fluctuation parameters at each moment are all less than or equal to a preset fluctuation value, it is determined that the change trend of the powder cloud is a continuous decreasing trend, and it is determined that the powder removal status is normal;

[0096] If there exists a real-time fluctuation parameter at any moment that is greater than the preset fluctuation value, it is determined that the change trend of the powder cloud is a fluctuating change trend, and it is determined that the powder removal status is abnormal.

[0097] It can be understood that the abscissa of the volume time-domain diagram is time, and the ordinate is the volume of the powder cloud;

[0098] In implementation, the preset fluctuation value ∈ [1%, 5%]. The smaller the preset fluctuation value is set, the more stable the determined continuous decreasing trend is. However, the amount of dust during the powder cleaning process must have fluctuations rather than a straight-line decrease. Therefore, the preset fluctuation value cannot be set too small, and it is preferably set to 5%.

[0099] It can be understood that the powder cleaning control module constructs a volume time-domain diagram of the powder cloud and determines the change trend of the powder cloud and the powder removal status based on the comparison between the real-time fluctuation parameters and the preset fluctuation value. When the real-time fluctuation parameters are all within a reasonable range, it can accurately determine that the powder cloud shows a continuous decreasing trend and the powder removal status is normal, providing a reliable basis for the smooth progress of the powder cleaning process; while in the case of abnormal fluctuations, it can quickly detect and determine it as a fluctuating change trend and an abnormal removal status, and timely discover potential problems in the powder cleaning process.

[0100] Specifically, the purifying control module determines the real-time volume difference based on the powder cloud volume at the current moment and the powder cloud volume at the previous moment, and determines the real-time fluctuation parameter according to the percentage of the ratio of the real-time volume difference to the powder cloud volume at the current moment.

[0101] It can be understood that the real-time fluctuation parameter = (powder cloud volume at the current moment - powder cloud volume at the previous moment) ÷ powder cloud volume at the current moment × 100%.

[0102] Specifically, the purifying control module determines the second adjustment strategy of the second purifying parameter according to the powder removal state at the second preset time, including,

[0103] If the powder removal state at the second preset time is an abnormal state, it means that the powder in the current part has not been completely removed, and there is still powder remaining inside the part, that is, the part has not entered the final stage of the purifying process, but has reached the final stage of the set purifying mode, indicating that the purifying time is insufficient. Therefore, it is determined that the second adjustment strategy is to increase the purifying time;

[0104] If the powder removal state at the second preset time is a normal state, it is determined not to formulate the second adjustment strategy.

[0105] It can be understood that only analyze whether the real-time fluctuation parameters within the second preset time are all less than the preset fluctuation value: if they are all less than the preset fluctuation value, it is determined to be in a normal state and the second adjustment strategy is not specified; if the real-time fluctuation parameters at all times are not less than the preset fluctuation value, it is determined to be in an abnormal state, and the powder removal effect needs to be increased by increasing the purifying time.

[0106] It can be understood that the purifying control module formulates the adjustment strategy of the second purifying parameter based on the powder removal state within the second preset time; when the powder removal state is abnormal, it can scientifically and reasonably determine the increased purifying time based on the ratio relationship between the powder cloud volume and the preset volume, avoiding powder residue caused by insufficient purifying time and effectively improving the thoroughness of purifying; while when the powder removal state is normal, there is no need to adjust the purifying time additionally, ensuring the high efficiency of the purifying process and the reasonable utilization of resources.

[0107] Specifically, the purifying control module determines the increased purifying time according to the volume ratio of the powder cloud volume at the second end time to the preset volume, where,

[0108] If the volume ratio is less than or equal to the preset ratio, it is determined that the increased purifying time is the standard duration;

[0109] If the volume ratio is greater than the preset ratio, it is determined that the increased purifying time is the product of the standard duration and the volume ratio, that is, the increased purifying time = standard duration × volume ratio.

[0110] It is understandable that the standard duration is usually one-tenth of the duration for setting the powder cleaning mode. That is, if the set powder cleaning mode is Mode 1 and the powder cleaning time of Mode 1 is 40 minutes, then the corresponding standard duration is 4 minutes.

[0111] It is understandable that in the ideal state at the end of powder cleaning, the volume of the powder cloud should be close to zero. This is because the purpose of powder cleaning is to completely remove the powder on the surface and inside of the part. When the powder cleaning process is successfully completed, no new powder will be lifted to form a powder cloud. For example, around a simple block part that has been efficiently powder cleaned, no obvious powder cloud should be seen through observation by a high-speed camera or detection by an optical detection device, that is, its volume can be ignored. However, in actual powder cleaning operations, due to the influence of various factors, there may be a small amount of powder residue, resulting in a certain volume (relatively small, usually a few cubic millimeters to a few cubic centimeters) of powder cloud still being observable at the end of powder cleaning. Therefore, in implementation, the preset volume is set to 2 cubic centimeters.

[0112] In implementation, the preset ratio should be greater than 1, but it should be a relatively small value / close to 1. If it is set too large, it will result in a too large difference from the standard at the end of powder cleaning, that is, it cannot be considered that the powder cleaning has ended. Therefore, the preset ratio is preferably set to 1.1.

[0113] It is understandable that the powder cleaning control module determines the way to increase the powder cleaning time based on the volume ratio of the powder cloud at the second end time to the preset volume. It can adjust the powder cleaning time according to the actual powder cleaning situation, avoid insufficient powder cleaning or over-powder cleaning. While effectively improving the powder cleaning effect to approach the ideal state of zero powder residue, it fully considers the characteristics of different powder cleaning modes, reasonably determines the standard duration, and combines the scientific settings of the preset ratio and preset volume to ensure the accuracy and adaptability of the powder cleaning time adjustment, thus guaranteeing the efficient and stable operation of the entire powder cleaning system and the high quality of the parts after powder cleaning.

[0114] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of the devices, methods, and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a part of code, which contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and the combinations of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based device that performs the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0115] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

[0116] The above are only the preferred embodiments of the present invention and are not used to limit the present invention; for those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A metal printing complex flow channel powder cleaning system, characterized in that: include: Powder purifier, used to vibrate and remove residual powder from parts and recycle it without pollution; A powder collection module, which is connected to the powder cleaning machine and is used to collect the metal powder cleaned from the parts and perform preliminary separation of the metal powder; The powder collection module includes a sealed collection box and a negative pressure generating device; The sealed collection box is used to collect the metal powder cleaned from the parts, and a powder filtering device is arranged inside the sealed collection box to perform preliminary separation of powders of different particle sizes; The negative pressure generating device is connected to the sealed collection box and is used to suck the powder in the cleaning process into the sealed collection box by generating negative pressure; A powder cleaning monitoring module, which is connected to the powder cleaning machine and the powder collecting module respectively, and includes a dust monitoring unit and a powder monitoring unit; The dust monitoring unit is used to monitor the intake dust concentration and exhaust dust concentration at the air inlet and the exhaust port of the sealed collection box in the powder collection module in real time; The powder monitoring unit includes a plurality of video shooting components and video reconstruction components, each of which is used to shoot powder cloud videos of the powder purifier at different angles during the powder cleaning process, and the video reconstruction component is used to determine a powder cloud panoramic model according to the powder cloud videos at different angles; a powder cleaning control module, which is connected to the powder cleaning machine and the powder cleaning monitoring module respectively, and is used to determine the dust characterization state of the part according to the exhaust dust concentration at a first preset time to determine a first adjustment strategy for a first powder cleaning parameter, determine a powder cloud change trend during the powder cleaning process according to the powder cloud panoramic model to determine a powder cleaning state, and determine a second adjustment strategy for a second powder cleaning parameter according to the powder cleaning state at a second preset time; Wherein, the first powder cleaning parameter includes powder cleaning power and negative pressure power, and the second powder cleaning parameter includes powder cleaning time; The powder cleaning power refers to the power intensity of the powder cleaning tool in the powder cleaning machine when it is working; The negative pressure power refers to the intensity of the negative pressure generated by the negative pressure generating device in the powder collection module; The first start time of the first preset time is the initial powder cleaning start time, and the second end time of the second preset time is the initial powder cleaning end time.

2. The metal printing complex flow channel powder cleaning system according to claim 1, characterized in that: In the powder cleaning monitoring module, the dust monitoring unit includes two dust sensors respectively arranged at the air inlet and the air outlet of the sealed collection box.

3. The metal printing complex flow channel powder cleaning system according to claim 1, characterized in that: The powder cleaning control module determines the dust characterization state of the part according to the exhaust dust concentration at the first preset time to determine a first adjustment strategy for the first powder cleaning parameter, including: If the exhaust dust concentration is less than or equal to the concentration threshold, it is determined that the dust characterization state of the part is a normal characterization state, and it is determined not to formulate the first adjustment strategy; If the exhaust dust concentration is greater than the concentration threshold, the dust characterization state of the part is determined to be an abnormal characterization state and a first adjustment strategy is determined according to the dust concentration difference, wherein: If the dust concentration difference is greater than or equal to the concentration difference reference value, it is determined that the first adjustment strategy is to reduce the dust cleaning power; If the dust concentration difference is less than the concentration difference reference value, it is determined that the first adjustment strategy is not formulated, and it is determined that the powder filtering device of the sealed collection box is faulty; The dust concentration difference is determined according to the difference between the intake dust concentration and the exhaust dust concentration.

4. The metal printing complex flow channel powder cleaning system according to claim 3 is characterized in that: The powder cleaning control module determines whether to formulate the first adjustment strategy for the second time according to the dust characterization state for a preset time after reducing the powder cleaning power, including: If the dust characterization state is still the abnormal characterization state, it is determined that the first adjustment strategy is formulated for the second time, and the first adjustment strategy formulated for the second time is to maintain the reduced powder cleaning power and reduce the negative pressure power.

5. The metal printing complex flow channel powder cleaning system according to claim 1, characterized in that: The video reconstruction component converts powder cloud videos at different angles into three-dimensional point cloud data of the powder cloud at various angles through a three-dimensional reconstruction method, and forms a powder cloud panoramic model with a spatial structure based on point cloud fusion and rendering technology.

6. The metal printing complex flow channel powder cleaning system according to claim 1, characterized in that: The powder cleaning control module determines the volume time domain diagram of the powder cloud according to the real-time panoramic model of the powder cloud, and determines the powder cloud change trend during the powder cleaning process according to the real-time fluctuation parameter of the volume time domain diagram to determine the powder cleaning state, including: If the real-time fluctuation parameter at each moment is less than or equal to the preset fluctuation value, it is determined that the powder cloud change trend is a continuous decreasing trend, and the powder removal state is determined to be a normal state; If the real-time fluctuation parameter at any moment is greater than the preset fluctuation value, the powder cloud change trend is determined to be a fluctuation change trend, and the powder removal state is determined to be an abnormal state.

7. The metal printing complex flow channel powder cleaning system according to claim 6, characterized in that: The powder cleaning control module determines the real-time volume difference according to the powder cloud volume at the current moment and the powder cloud volume at the previous moment, and determines the real-time fluctuation parameter according to the percentage of the real-time volume difference to the powder cloud volume at the current moment.

8. The metal printing complex flow channel powder cleaning system according to claim 1, characterized in that: The powder cleaning control module determines a second adjustment strategy for a second powder cleaning parameter according to the powder cleaning state at a second preset time, including: If the powder clearing state at the second preset time is an abnormal state, determining that the second adjustment strategy is to increase the powder clearing time; If the powder removal state at the second preset time is a normal state, it is determined that the second adjustment strategy is not formulated.

9. The metal printing complex flow channel powder cleaning system according to claim 8, characterized in that: The powder cleaning control module determines the increased powder cleaning time according to the volume ratio of the powder cloud volume at the second end time to the preset volume, wherein: If the volume ratio is less than or equal to the preset ratio, the increased powder cleaning time is determined to be the standard time; If the volume ratio is greater than a preset ratio, the increased powder cleaning time is determined to be the product of the standard time and the volume ratio.

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