An automatic dustproof method

Abstract

The present application relates to a kind of automatic dustproof methods, belong to laser melting forming technical field, solve the problem that laser window is easily polluted by smoke dust in prior art.The present application includes the following steps: S1: debugging preparation: connecting the pipeline of airflow assembly, arranging sensor and observation camera;S2: starting inert gas supply system, debugging airflow assembly;S3: placing smoke generator, observing airflow;S4: recording parameters, disassembling sensor and observation camera;S5: according to the parameters recorded in step S4, control airflow assembly, realize the automatic dustproof of laser window.The present application uses multiple point sensors and observation cameras to monitor the running state of the airflow generated by the automatic dustproof device, ensuring that the automatic dustproof device for the laser window can generate three kinds of airflow, and the three kinds of airflow can cooperate to prevent smoke dust from polluting the laser window.

Description

Technical Field

[0001] This invention relates to the field of laser selective melting forming technology, and in particular to an automatic dust prevention method. Background Technology

[0002] Selective laser melting (SLM), an advanced additive manufacturing technology, selectively irradiates pre-laid layers of metal powder with a high-precision laser beam, achieving layer-by-layer melting and deposition to construct complex three-dimensional metal parts. Compared to traditional casting and forging processes, SLM technology can generate rapidly solidified non-equilibrium microstructures, characterized by a fine internal grain structure, which endows the parts with excellent comprehensive mechanical properties. Furthermore, this technology has the capability to manufacture components with arbitrarily complex structures, providing innovative pathways for lightweight design, topology optimization, and manufacturing of aircraft, and has become a key development direction for advanced manufacturing technologies in the aerospace field.

[0003] However, a technical problem exists in the actual operation of SLM equipment: when laser energy is locally absorbed by the powder bed, the temperature of the molten pool rises sharply, exceeding the boiling point of the powder material. This high-temperature environment causes a strong vapor jet to be generated on the surface of the molten pool, which not only ejects the vaporized metal but also carries a large number of unmelted powder particles. These vapors subsequently condense into black soot particles, while the carried powder partially agglomerates during the ejection process. Crucially, after the laser beam interacts with the powder bed, these soot particles may rise to the laser window module at the top of the forming chamber and deposit there.

[0004] The accumulation of dust and soot can severely contaminate the laser window, leading to a decrease in laser beam transmittance and consequently reducing the energy density of the laser beam irradiating the powder bed. This significantly impacts print quality and reduces print success rate. Currently, this issue requires periodic shutdowns to clean the laser window module, which undoubtedly sacrifices production efficiency. Therefore, resolving the dust and soot contamination problem at the laser window is crucial for improving the continuous operation capability and print quality of SLM technology. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide an automatic dust prevention method to solve the problem that laser windows are easily contaminated by smoke and dust.

[0006] On one hand, the present invention provides an automatic dust prevention method, comprising the following steps:

[0007] S1: Debugging preparation: Connect the pipelines to the airflow components, set up the sensors and observation cameras;

[0008] S2: Start the inert gas supply system and adjust the airflow components;

[0009] S3: Place the smoke generator and observe the air flow;

[0010] S4: Record the parameters, disassemble the sensor and observe the camera;

[0011] S5: Control the air flow assembly according to the parameters recorded in step S4 to achieve automatic dust prevention of the laser window.

[0012] Further, step S1 specifically includes: S11: connecting the pipeline of the air flow assembly:

[0013] The lateral air flow control valve and the lateral air flow flowmeter are connected in communication with the lateral air inlet in the lateral air flow unit; the cyclone unit air flow control valve and the cyclone unit air flow flowmeter are connected in communication with the cyclone air flow inlet of the cyclone unit; the downward air flow control valve and the downward air flow flowmeter are connected in communication with the downward air flow inlet of the downward air flow unit; the lateral air inlet, the cyclone air flow inlet and the downward air flow inlet are respectively in communication with the inert gas supply system.

[0014] Further, step S1 also includes S12: arranging sensors, which specifically include multi-point lateral air flow flow sensors, multi-point cyclone vortex tangential flow sensors and multi-point longitudinal air flow flow sensors.

[0015] Further, the multi-point lateral air flow flow sensors are respectively placed at the four corners and the center position of the upper surface of the forming substrate for sensing the flow of the lateral air flow.

[0016] Further, the multi-point cyclone vortex tangential flow sensors are arranged in a manner that the center of the forming substrate is taken as the center, the first height from the upper surface of the forming substrate, and the first radius, the second radius and the third radius are respectively taken as the radii of the circumferences.

[0017] Further, the first height is 240mm, the first radius is 80mm, the second radius is 120mm and the third radius is 140mm.

[0018] Further, the multi-point longitudinal air flow flow sensors are arranged in a manner that they are respectively placed at the second height, the third height and the fourth height from the forming substrate and are located on the line connecting the center of the forming substrate and the center of the laser window.

[0019] Further, the second height is 40mm, the third height is 140mm and the fourth height is 240mm.

[0020] Further, in step S1, the observation camera is provided with two, which are respectively arranged at the top and the front of the forming chamber.

[0021] Further, step S2 specifically includes: S21: adjusting the lateral air flow;

[0022] S22: adjusting the cyclone airflow;

[0023] S23: adjusting the downward airflow.

[0024] Further, the step S2 further comprises: S24: monitoring the data fed back by the cyclone vortex tangential flow sensor of the multi-point site and the longitudinal airflow flow sensor of the multi-point site for a preset time period.

[0025] Further, the step S3 specifically comprises: S31: placing the smoke generator to the position where the laser irradiation melts, simulating the working state of the equipment.

[0026] Further, the step S3 further comprises S32: opening the lateral airflow control valve in sequence according to the lateral airflow flow count value recorded in the step S2 and the lateral airflow stable time, the cyclone airflow flow count value and the cyclone airflow stable time, and the downward airflow flow count value and the downward airflow stable time, adjusting the lateral airflow flow meter to the recorded value, keeping the lateral airflow stable for a time, then opening the cyclone unit airflow control valve, adjusting the cyclone unit airflow flow meter to the recorded value, keeping the cyclone airflow stable for a time, then opening the downward airflow control valve, adjusting the downward airflow flow meter to the recorded value, and keeping the downward airflow stable for a time.

[0027] Further, the step S3 further comprises S33: judging whether the airflow meets the standard.

[0028] Further, the automatic dustproof device for the laser window is implemented.

[0029] The automatic dustproof device comprises an inert gas supply system, an airflow assembly, and a control system; wherein the inert gas supply system provides inert gas for the airflow assembly, and the control system controls the operation of the airflow assembly to make the inert gas generate a downward cyclone below the laser window and a lateral airflow below the bottom of the cyclone after passing through the airflow assembly, so as to take out the smoke dust generated in the laser melting process out of the forming chamber.

[0030] The airflow assembly comprises a cyclone unit, a downward airflow unit, and a lateral airflow unit.

[0031] The cyclone unit is arranged around the laser window and is used to generate a cyclone below the laser window.

[0032] The downward airflow unit is arranged between the cyclone unit and the laser window and is used to generate a downward airflow below the laser window.

[0033] The lateral airflow unit is arranged on the opposite two side walls of the forming chamber and is used to generate a lateral airflow below the bottom of the cyclone.

[0034] The control system comprises a controller, a transverse air flow control valve, a transverse air flow flowmeter, a cyclone unit air flow control valve, a cyclone unit air flow flowmeter, a downward air flow control valve and a downward air flow flowmeter.

[0035] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0036] (1) The present application uses a multi-point sensor and an observation camera to monitor the running state of the air flow generated by the automatic dust prevention device, ensuring that the automatic dust prevention device of the laser window can generate three air flows, and the three air flows can cooperate to prevent smoke dust from polluting the laser window.

[0037] (2) The present application realizes the regulation and control of the air flow assembly through multiple control valves and flowmeters, so that the automatic dust prevention device of the laser window of the present application can generate the desired air flow, realize the dust prevention of the laser window, and further discharge the smoke dust out of the forming chamber, improving the quality of laser melting forming.

[0038] (3) The present application uses a smoke generator to simulate the actual working condition, which can directly observe the movement of smoke dust driven by the air flow, avoid damage to sensors and other equipment caused by high temperature, reduce the cost of debugging, and does not need to lay powder, laser melting and wait for cooling, thus shortening the time and improving the efficiency of debugging.

[0039] In the present application, the above technical solutions can be combined with each other to realize more preferred combination schemes. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purpose and other advantages of the present application can be achieved and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0040] The accompanying drawings are included to provide a further understanding of the embodiments, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application, and together with the description serve to explain the principles of the application, and should not be considered limiting of the present application in scope, as numerous embodiments can be made and equivalents can be substituted for specific embodiments without departing from the scope of the application.

[0041] Figure 1 Flow chart of an automatic dust prevention method according to embodiment 1 of the present application;

[0042] Figure 2 Structure diagram of an automatic dust prevention device of a laser window according to embodiment 1 of the present application;

[0043] Figure 3 Structure diagram of an air flow assembly of an automatic dust prevention device of a laser window.

[0044] Reference signs:

[0045] 10 - laser window;

[0046] 20 - air flow assembly; 21 - transverse air flow unit; 211 - transverse air inlet; 212 - transverse air outlet; 22 - cyclone unit; 221 - cyclone air inlet; 222 - top plate; 223 - annular guide channel; 224 - spiral flow channel; 225 - bottom opening; 23 - downward air flow unit; 231 - downward air flow inlet;

[0047] 30 - control system; 31 - transverse air flow control valve; 32 - transverse air flow flowmeter; 33 - cyclone unit air flow control valve; 34 - cyclone unit air flow flowmeter; 35 - downward air flow control valve; 36 - downward air flow flowmeter; 37 - transverse air flow flow sensor; 38 - cyclone vortex tangential flow sensor; 39 - longitudinal air flow flow sensor;

[0048] 40 - inert gas supply system; 50 - forming chamber; 60 - forming substrate. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which constitute a part of this application, and illustrate the principles of the application together with the embodiments thereof, but are not intended to limit the scope of the application.

[0050] Embodiment 1

[0051] This embodiment 1 relates to an automatic dustproof method, which realizes an automatic dustproof device for a laser window in a laser selective melting device. After the automatic dustproof device is debugged, each control parameter of the air flow assembly 20 during operation can be obtained, and in actual production, the device can be controlled through these control parameters, so that the automatic dustproof of the laser window 10 can be realized.

[0052] As shown in Figure 1 , the debugging method of the automatic dustproof device includes the following steps:

[0053] S1: Debugging preparation: connecting the pipeline of the air flow assembly 20, arranging the sensor and the observation camera.

[0054] Specifically, it includes S11: connecting the pipeline of the air flow assembly 20:

[0055] As shown in Figure 2As shown, the lateral air flow control valve 31 and the lateral air flow flowmeter 32 are connected to the lateral air inlet 211 in the lateral air flow unit 21; the cyclone unit air flow control valve 33 and the cyclone unit air flow flowmeter 34 are connected to the cyclone air inlet 221 in the cyclone unit 22; the downward air flow control valve 35 and the downward air flow flowmeter 36 are connected to the downward air inlet 231 in the downward air flow unit 23. The lateral air inlet 211, the cyclone air inlet 221 and the downward air inlet 231 are respectively connected to the inert gas supply system 40.

[0056] S12: arranging sensors: the sensors specifically include multi-point lateral air flow flowmeters 37, multi-point cyclone vortex tangential flowmeters 38 and multi-point longitudinal air flow flowmeters 39.

[0057] As shown, the multi-point lateral air flow flowmeters 37 are respectively arranged at the four corners and the center of the upper surface of the forming substrate 60, for sensing the flow of the lateral air flow. Figure 2

[0058] The multi-point cyclone vortex tangential flowmeters 38 are arranged in the following manner: taking the center of the forming substrate 60 as the center, and placing the sensors at a distance of 240 mm from the upper surface of the forming substrate 60, with radii of 80 mm, 120 mm and 140 mm respectively.

[0059] The multi-point longitudinal air flow flowmeters 39 are arranged in the following manner: placing the sensors at a distance of 40 mm, 140 mm and 240 mm from the upper surface of the forming substrate 60, and on the central axis of the cyclone.

[0060] S13: arranging observation cameras: two observation cameras are arranged at the top and the front of the forming chamber 50.

[0061] S2: starting the inert gas supply system 40, and debugging the air flow assembly 20.

[0062] ​The debugging air flow assembly 20 in step S2 specifically comprises: S21: adjusting the transverse air flow, specifically: opening the transverse air flow control valve 31, and adjusting the transverse air flow flowmeter 32 to 40-50 L / min (the larger the size of the shaped substrate 60, the greater the transverse air flow, and vice versa); obtaining the data fed back by the transverse air flow flow sensors 37 at multiple points and adjusting the transverse air flow flowmeter 32 according to the data, so that the data is about 15 L / min, and the error of each of the 5 sensors is less than 2 L / min; judging the data fed back by the transverse air flow flow sensors 37 at multiple points, when the fluctuation of each data is within the range of ±0.1 L / min and is maintained for more than 3 s, it is considered that the transverse air flow enters a stable state, and after being stabilized, the value of the transverse air flow flowmeter 32 and the transverse air flow stabilization time are recorded, the transverse air flow stabilization time being the time from opening the transverse air flow control valve 31 to the transverse air flow entering the stable state.

[0063] S22: adjusting the cyclone air flow, specifically: opening the cyclone unit air flow control valve 33, and adjusting the cyclone unit air flow flowmeter 34 to 15-20 L / min (the larger the center diameter of the cyclone unit, the greater the flow, and vice versa); obtaining the data fed back by the cyclone vortex tangential flow sensors 38 at multiple points, and adjusting the cyclone unit air flow flowmeter 34 according to the data, under normal circumstances, the data decreases with the increase of the radius of the position where the sensor is located, until the flow at the outermost layer is not less than 2 L / min; judging the data fed back by the cyclone vortex tangential flow sensors 38 at multiple points, when the fluctuation of each data is within the range of ±0.1 L / min and is maintained for more than 3 s, it is considered that the cyclone air flow enters a stable state, and after being stabilized, the value of the cyclone air flow flowmeter and the cyclone air flow stabilization time are recorded, the cyclone air flow stabilization time being the time from opening the cyclone air flow control valve to the cyclone air flow entering the stable state.

[0064] S23: adjusting the downward air flow, specifically: opening the downward air flow control valve 35, and adjusting the downward air flow flowmeter 36 to 8-12 L / min (the farther the downward air flow member is from the bottom surface of the optical assembly, the greater the flow, and vice versa); obtaining the data fed back by the longitudinal air flow flow sensors 39 at multiple points, under normal circumstances, the data decreases in turn from top to bottom, and the downward air flow flowmeter 36 is adjusted according to the data, until the air flow at the uppermost side is greater than 3 L / min and the air flow at the lowermost side is less than 1 L / min; judging the data fed back by the longitudinal air flow flow sensors 39 at multiple points, when the fluctuation of each data is within the range of ±0.1 L / min and is maintained for more than 3 s, it is considered that the downward air flow enters a stable state, and after being stabilized, the value of the downward air flow flowmeter 36 and the downward air flow stabilization time are recorded, the downward air flow stabilization time being the time from opening the downward air flow control valve 35 to the downward air flow entering the stable state.

[0065] S24: monitor the data feedback from the sensors for a period of time. The period of time is preferably 30 seconds to 1 minute. Since the three airflows will have an impact on each other after being fully opened, it is necessary to continue to observe the airflows for a period of time.

[0066] S241: determine whether the multi-point cyclone tangential flow sensor 38 shows no reading or the outermost flow sensor shows a reading less than 2 L / min.

[0067] If so, keep the lateral airflow and downward airflow unchanged, and adjust the cyclone airflow flowmeter 34 to gradually increase the cyclone airflow until a horizontal vortex is generated with the longitudinal axis at the bottom of the optical device, and the outermost flow sensor of the multi-point cyclone tangential flow sensor 38 shows a reading greater than 2 L / min.

[0068] If not, S242: monitor the multi-point longitudinal airflow flow sensor 39 to determine whether the uppermost airflow is less than 3 L / min or the lowermost airflow is greater than 1 L / min.

[0069] If the uppermost airflow is less than 3 L / min, keep the lateral airflow and cyclone airflow unchanged, and adjust the downward airflow flowmeter 36 to increase the downward airflow until the multi-point longitudinal airflow flow sensor 39 feedback shows that the uppermost airflow is greater than 3 L / min.

[0070] If the lowermost airflow is greater than 1 L / min, keep the lateral airflow and cyclone airflow unchanged, and adjust the downward airflow flowmeter 36 to decrease the downward airflow until the multi-point longitudinal airflow flow sensor 39 feedback shows that the lowermost airflow is less than 1 L / min.

[0071] If not, record the lateral airflow flowmeter 32 value at this time, as well as the lateral airflow stabilization time, the cyclone airflow flowmeter value and the cyclone airflow stabilization time, and the downward airflow flowmeter 36 value and the downward airflow stabilization time; continue to the next step.

[0072] S3: place the smoke generator and observe the airflow.

[0073] Specifically including: S31: place the smoke generator at the position where the laser irradiation melts, simulating the working state of the device;

[0074] S32: According to the values recorded in step S2, the lateral air flow meter 32, the lateral air flow stabilization time, the cyclone air flow meter, the cyclone air flow stabilization time, and the downward air flow meter 36, the downward air flow stabilization time, the lateral air flow control valve 31 is opened in turn, the lateral air flow meter 32 is adjusted to the recorded value, the cyclone unit air flow control valve 33 is opened after the lateral air flow is stabilized for the lateral air flow stabilization time, the cyclone unit air flow meter 34 is adjusted to the recorded value, the downward air flow control valve 35 is opened after the cyclone air flow is stabilized for the cyclone air flow stabilization time, the downward air flow meter 36 is adjusted to the recorded value, and the downward air flow is stabilized for the downward air flow stabilization time.

[0075] S33: Determine whether the air flow meets the standard: obtain the picture data fed back by the observation camera placed at the top and front of the forming chamber 50, and compare the picture data with the preset picture data. Specifically, there is no smoke dust impact on the bottom of the laser window 10, and at the same time, there is no downward smoke dust impact on the upper surface of the substrate, and the lateral air flow successfully carries away the smoke dust generated in the printing process.

[0076] S331: Observe the movement of the smoke dust carried by the air flow, and determine whether the smoke dust at the bottom of the optical window presents a cyclone movement or a longitudinal vortex instead of a lateral vortex.

[0077] If the smoke dust does not present a cyclone, or a longitudinal vortex is generated, the lateral air flow rate and the downward air flow rate remain unchanged, the cyclone unit air flow meter 34 is adjusted, and the cyclone air flow is gradually increased until the smoke dust at the bottom of the optical window presents a cyclone movement or a lateral vortex is generated around the optical device.

[0078] S332: Observe the movement of the smoke dust carried by the air flow, and determine whether the smoke dust at the bottom of the optical window presents a cyclone movement downward or a downward vortex is generated to impact the powder (smoke dust) on the upper surface of the substrate.

[0079] If the smoke dust presents a cyclone but does not move downward, the lateral air flow rate and the cyclone air flow rate remain unchanged, the downward air flow meter 36 is adjusted, and the downward air flow is gradually increased until the smoke dust at the bottom of the optical device presents a cyclone downward movement.

[0080] If the downward vortex impacts the powder on the upper surface of the substrate, the lateral air flow rate and the cyclone air flow rate remain unchanged, the downward air flow meter 36 is adjusted, and the downward air flow is gradually reduced until the downward vortex does not impact the powder on the upper surface of the substrate.

[0081] S4: Record the parameters, disassemble the sensors, and the observation camera.

[0082] After step S3 is completed, record the final value of the transverse airflow flow meter 32, the transverse airflow stabilization time, the cyclone airflow flow count value, the cyclone airflow stabilization time, the value of the downward airflow flow meter 36, and the downward airflow stabilization time; disassemble all sensors and observation cameras.

[0083] The data recorded above can be used to control the airflow assembly 20 in actual production.

[0084] S5: When the laser selective melting and forming equipment is working normally, the airflow component is controlled according to the parameters recorded in step S4 to achieve automatic dust prevention of the laser window.

[0085] Compared with the prior art, the debugging method of the automatic dustproof equipment provided in this embodiment is simple and easy to implement. It can clearly and intuitively observe the airflow in the forming chamber 50, ensuring that dustproofing of the laser window 10 can be achieved through three airflows during actual production.

[0086] Example 2

[0087] Embodiment 2 of the present invention relates to an automatic dustproof device for a laser window, used to keep the laser window clean.

[0088] The laser window 10 is set in the laser selective melting and forming equipment. During the operation of the laser selective melting and forming equipment, the laser beam will irradiate the forming substrate 60 through the laser window 10, melt the powder, and thus generate residue and dust.

[0089] like Figure 2 As shown, the laser selective melting forming equipment also includes a forming chamber 50, which includes four side walls, a top plate, and a bottom plate. A forming substrate 60 is disposed on the bottom plate of the forming chamber 50 and is used to lay metal powder. A laser window 10 is disposed on the top plate of the forming chamber 50.

[0090] See Figure 2 The automatic dustproof device includes an inert gas supply system 40, an airflow assembly 20, and a control system 30. The inert gas supply system 40 provides inert gas to the airflow assembly, and the control system 30 controls the operation of the airflow assembly 20 based on real-time monitoring data. This causes the inert gas to generate a downward vortex below the laser window 10 after passing through the airflow assembly 20, while simultaneously generating a transverse airflow below the bottom of the vortex and above the forming substrate 60. This airflow carries the dust generated during laser melting out of the forming chamber 50, thus preventing it from accumulating at the laser window 10.

[0091] Among them, see Figure 3The air flow assembly 20 comprises a cyclone unit 22, a downward air flow unit 23 and a transverse air flow unit 21. The cyclone unit 22 is arranged around the laser window 10 for generating a cyclone below the laser window 10. The downward air flow unit 23 is arranged between the cyclone unit 22 and the laser window 10 for generating a downward air flow below the laser window 10. The transverse air flow unit 21 is arranged on the opposite two side walls of the forming chamber 50 for generating a transverse air flow above the forming substrate 60. The downward air flow is located in the middle of the cyclone and can move downward together with the cyclone. Meanwhile, the cyclone and the downward air flow gradually reduce the flow rate during the downward movement, and basically reduce to zero when reaching the transverse air flow area.

[0092] The cyclone unit 22 comprises a cyclone air flow inlet 221, an annular guide groove 223, a plurality of shunt ports, a spiral flow channel 224 and a bottom opening 225 connected in sequence. The gas enters the cyclone unit 22 from the cyclone air flow inlet 221, exits the cyclone unit 22 from the bottom opening 225, and forms a downward cyclone. The shunt ports are arranged in plurality, and each shunt port corresponds to a spiral flow channel 224. The closer the shunt port is to the cyclone air flow inlet 221, the smaller the size. The spiral flow channel 224 spirally extends downward, and the cross-sectional area of the spiral flow channel 224 gradually decreases from top to bottom.

[0093] The structure of the cyclone unit 22 is shown in Figure 3 The cyclone unit 22 comprises a top plate 222, an outer wall, an inner wall, an inner cylindrical surface and a spiral partition plate.

[0094] The top plate 222 is a circular ring-shaped flat plate located at the top of the cyclone unit 22. The inner diameter of the circular ring is larger than the maximum outer diameter of the laser window 10, so that the laser window 10 can be inserted into the middle of the cyclone unit 22 from the center of the circular ring.

[0095] The outer wall comprises an outer cylindrical surface, an annular step surface and an outer conical surface from top to bottom. The outer cylindrical surface vertically extends downward from the outer periphery of the top plate 222. The annular step surface extends radially inward in the horizontal plane from the bottom of the outer cylindrical surface. The outer conical surface extends obliquely inward and downward from the inner side end of the annular step surface.

[0096] The inner wall is an inner conical surface extending obliquely downward from the inner side of the top plate 222 to a position close to the bottom of the outer conical surface.

[0097] The vertically extending inner cylindrical surface is arranged between the annular step surface and the top plate 222. In the preferred embodiment, the inner diameter of the annular step surface is larger than the inner diameter of the top plate 222. The inner cylindrical surface vertically extends upward from the inner side end of the annular step surface, and the top thereof is connected with the top plate 222.

[0098] The plurality of spiral baffles are evenly distributed along the circumference of the cyclone unit 22. The spiral baffles extend between the top plate 222, the inner cylindrical surface, the inner conical surface and the outer conical surface, and divide the space enclosed by the above surfaces into a plurality of spiral flow channels 224.

[0099] Referring to Figure 3 The outer cylindrical surface is provided with a cyclone gas inlet 221, which is in communication with a gas source. The top plate 222, the outer cylindrical surface, the annular step surface and the inner cylindrical surface enclose an annular groove, which is an annular guide groove 223. The cyclone gas inlet 221 is in communication with the annular guide groove 223. Preferably, the cyclone gas inlet 221 can be provided with two or more, which are evenly distributed along the circumference.

[0100] The inner cylindrical surface is provided with a plurality of shunt ports, which are evenly distributed along the circumference of the inner cylindrical surface and correspond one-to-one to the spiral flow channels 224. In the preferred scheme, the diameters of the shunt ports are not equal, and specifically, the diameter of each shunt port is proportional to the distance between the shunt port and the cyclone gas inlet 221, that is, the closer the shunt port is to the cyclone gas inlet 221, the smaller the diameter of the shunt port. By this arrangement, the gas flow entering each shunt port can be approximately equal.

[0101] Each shunt port is in communication with a spiral flow channel 224. The gas enters the annular guide groove 223 through the cyclone gas inlet 221, then enters the spiral flow channel 224 through the shunt port, moves downward along the spiral flow channel 224, and flows out of the bottom opening 225 of the cyclone unit 22, forming a downward spiral airflow below the laser window 10, preventing black soot particles from adhering to the laser window 10, and achieving self-cleaning of the optical system.

[0102] Referring to Figure 3 The downward airflow unit 23 includes a flat plate body, which is provided with a circular central opening in the middle for the laser window 10 to pass through.

[0103] A downward airflow inlet 231 is arranged on each side of the middle opening, and is in communication with the air source. Obviously, multiple downward airflow inlets 231 can be arranged and evenly distributed around the middle opening. The distance between the center of the middle opening and the center of the downward airflow inlet 231 is less than the inner diameter of the top plate 222 of the cyclone unit 22, and greater than or equal to the maximum outer diameter of the laser window 10. Preferably, the distance between the center of the middle opening and the center of the downward airflow inlet 231 is such that the airflow is tangent to the maximum outer diameter of the laser window 10, i.e. the projection of the downward airflow inlet 231 and the laser window 10 on the horizontal plane is tangent, because the closer to the center of the cyclone, the easier it is to form a vertical downward "cyclone vortex". The downward airflow inlet 231 extends in the vertical direction. The airflow entering from the downward airflow inlet 231 flows vertically downward, and after encountering the inner conical surface of the cyclone unit 22, continues to flow downward along the inner conical surface, and finally forms a downward airflow at the center of the cyclone generated by the cyclone unit 22, further blocking the smoke generated by the melting of the metal powder.

[0104] Referring to Figure 3 The lateral airflow unit 21 includes a lateral airflow inlet 211 and a lateral airflow outlet 212 arranged on two opposite side walls of the forming chamber 50 near the bottom, respectively. The lateral airflow inlet 211 is in communication with the air source and can provide a lateral airflow to the forming chamber 50. The lateral airflow outlet 212 is in communication with the exhaust treatment device and can carry the lateral airflow and the smoke out of the forming chamber 50.

[0105] The lateral airflow can block the downward airflow vortex generated by the cyclone unit 22 and the downward airflow unit 23, avoiding the influence of the metal dust blown by these airflows on the forming, and also can carry the smoke generated by melting out of the forming chamber 50, further improving the cleaning effect.

[0106] In the preferred embodiment, multiple lateral airflow inlets 211 and lateral airflow outlets 212 are arranged and evenly distributed in the horizontal direction. In this way, a partition layer can be formed to avoid the occurrence of turbulent flow affecting the cleaning effect.

[0107] Further, the height of the lateral airflow inlet 211 and the lateral airflow outlet 212 is equal, and is arranged at a position 5-15 mm away from the upper surface of the forming substrate 60, effectively avoiding the influence of the "cyclone vortex" on the powder bed.

[0108] The control system 30 includes a controller, a lateral airflow control valve 31, a lateral airflow flowmeter 32, a cyclone unit airflow control valve 33, a cyclone unit airflow flowmeter 34, a downward airflow control valve 35, and a downward airflow flowmeter 36.

[0109] The transverse air flow control valve 31 and the transverse air flow flowmeter 32 are communicated with the transverse air inlet 211 in the transverse air flow unit 21, and can control the air flow and flow rate of the transverse air inlet 211.

[0110] The cyclone unit air flow control valve 33 and the cyclone unit air flow flowmeter 34 are communicated with the cyclone air flow inlet 221 of the cyclone unit 22, and can control the air flow and flow rate of the cyclone air flow inlet 221, and further control the state of the cyclone.

[0111] The downward air flow control valve 35 and the downward air flow flowmeter 36 are communicated with the downward air flow inlet 231 of the downward air flow unit 23, and can control the air flow and flow rate of the downward air flow inlet 231, and further control the state of the downward air flow.

[0112] The automatic dustproof device of the laser window in the embodiment 2 can generate a downward air flow vortex under the laser window 10 by controlling the air flow, can constantly prevent the upward dust in the printing process, and further constantly performs air flow washing on the surface of the laser window 10 module. In the center of the air flow vortex, a downward air flow can be generated. In addition, a transverse air flow can be generated. Based on the above air flow effect, the laser window 10 is always in a clean state.

[0113] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. An automatic dustproofing method characterized by comprising: The method comprises the following steps: S1: debugging preparation: connecting the pipeline of the airflow assembly, arranging the sensor and the observation camera; S2: starting the inert gas supply system and debugging the airflow assembly; S3: placing the smoke generator and observing the airflow; S4: recording the parameters, dismounting the sensor and the observation camera; S5: controlling the airflow assembly according to the parameters recorded in step S4 to realize automatic dust prevention of the laser window; In step S1, the following steps are included: S11: connecting the pipeline of the airflow assembly: The transverse airflow control valve and the transverse airflow flowmeter are connected with the transverse air inlet in the transverse airflow unit; the cyclone unit airflow control valve and the cyclone unit airflow flowmeter are connected with the cyclone airflow air inlet of the cyclone unit; the downward airflow control valve and the downward airflow flowmeter are connected with the downward airflow air inlet of the downward airflow unit; the transverse air inlet, the cyclone airflow air inlet and the downward airflow air inlet are respectively connected with the inert gas supply system; S12: arranging the sensor, which includes a multi-point transverse airflow flow sensor, a multi-point cyclone vortex tangential flow sensor and a multi-point longitudinal airflow flow sensor; the multi-point transverse airflow flow sensor is arranged at the four corners and the center of the upper surface of the forming substrate to sense the flow of the transverse airflow; the multi-point cyclone vortex tangential flow sensor is arranged in a circular manner with the center of the forming substrate as the center, at a first height from the upper surface of the forming substrate, and with a first radius, a second radius and a third radius as the radii; the multi-point longitudinal airflow flow sensor is arranged at a second height, a third height and a fourth height from the forming substrate and on the line connecting the center of the forming substrate and the center of the laser window; Step S2 specifically includes: S21: adjusting the transverse airflow; S22: adjusting the cyclone airflow; S23: adjusting the downward airflow; S24: monitoring the data fed back by the multi-point cyclone vortex tangential flow sensor and the multi-point longitudinal airflow flow sensor for a preset period of time; Step S3 specifically includes: S31: placing the smoke generator at the position where the laser irradiation melts to simulate the working state of the equipment; S32: opening the transverse airflow control valve in sequence according to the transverse airflow flowmeter count value and the transverse airflow stable time, the cyclone airflow flowmeter count value and the cyclone airflow stable time, and the downward airflow flowmeter count value and the downward airflow stable time recorded in step S2, adjusting the transverse airflow flowmeter to the recorded value, keeping the transverse airflow stable for a period of time, then opening the cyclone unit airflow control valve, adjusting the cyclone unit airflow flowmeter to the recorded value, keeping the cyclone airflow stable for a period of time, then opening the downward airflow control valve, adjusting the downward airflow flowmeter to the recorded value, and keeping the downward airflow stable for a period of time; S33: judging whether the airflow meets the requirements.

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