Valve body laser cutting apparatus and method

Abstract

The application discloses a valve body laser cutting device and method, which comprises the following steps: low-duty-ratio pulse scanning is performed on the outer wall of the valve body to generate a guide groove with surface tension gradient and corrugated texture; inner and outer double-layer pulse air flows are sprayed according to the characteristics of the guide groove, and periodic negative pressure cavities and positive pressure barriers on both sides are formed at the groove bottom; spiral trajectory continuous laser cutting is performed under the action of the double-layer air flows, transverse ultrasonic waves in a three-to-four resonance relationship with the inner layer pulse air flow are applied, and a standing wave guide flow is established on the surface of the molten pool to obtain a cutting seam penetrating through the wall thickness; when the cutting seam is penetrated, the air flow is switched to negative pressure suction and the ultrasonic wave is changed to a traveling wave to remove residual molten droplets; low-power rapid scanning is performed on the inner wall of the cutting seam by using the residual heat of the valve body, and pulsed inert gas flow is injected to make laminar flow and micro-turbulent flow alternately peel off the residual film. The scheme can inhibit slag backflow without increasing additional cooling or chemical treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser processing of metal valves, and particularly relates to a valve body laser cutting device and method. BACKGROUND

[0002] As a key element for pressure bearing and sealing, the valve body usually has a wall thickness of 20-50 mm, and the internal flow channel has a three-dimensional curved or stepped throttle structure. Traditional turning and milling, drilling, etc. are prone to introduce tool vibration marks, thermal cracks and residual stress when machining deep holes, special bevels or curved windows, and multiple tool changes and customized fixtures significantly increase the manufacturing cycle. Laser cutting uses a focused high-energy-density beam to melt metal instantaneously in a very small area, and cooperates with five-axis numerical control to keep the spot perpendicular to the local curved surface at all times, thereby completing the cutting of a narrow slit through the thick wall at one time; the heat-affected zone is only a few hundred microns, which almost does not cause macro deformation, and provides a size and structure controllable base surface for subsequent surfacing, grinding and automatic assembly. Therefore, laser cutting has become an indispensable finishing process in high-end valve manufacturing.

[0003] The existing valve body laser cutting process usually first perforates the outer surface with perpendicular incidence, and then cuts along the pre-programmed trajectory until it breaks through the inner cavity after establishing a slag discharge jet channel. The high-pressure auxiliary gas sprayed coaxially by the cutting head is reflected multiple times on the narrow cavity wall, generating a local reverse shock wave. When the dynamic pressure of the reverse flow and the surface tension of the molten pool are in the critical matching interval, the molten droplets that have not been discharged are sucked back to the inner wall and quickly solidified, forming a resolidified film with a thickness of only a few tens of microns, which is called "molten slag back rolling". Since the film is located inside the valve body and invisible to the naked eye, the current coaxial vision and offline inspection are difficult to identify in time; at the same time, the cutting parameters and the gas flow mode lack real-time coupling control, and when the laser power or gas pressure fluctuates slightly, the back rolling effect is further amplified, eventually leading to a jump in the roughness of the inner wall, potential leakage and increased local flow resistance. SUMMARY

[0004] The main purpose of the present application is to solve the technical problem of molten slag back rolling and resolidification on the inner wall during the existing valve body thick wall laser cutting process, which leads to sealing failure and increased flow resistance.

[0005] The first aspect of the present application provides a valve body laser cutting method, the valve body laser cutting method comprising:

[0006] Pulsed laser is used to scan the outer wall of the valve body along the preset cutting line multiple times, a guide groove with a surface tension gradient is formed on the outer wall of the valve body, and the side wall of the guide groove has corrugated microtexture;

[0007] According to the surface tension gradient and corrugated microtexture of the guide groove, an inner layer pulse air flow and an outer layer pulse air flow are sprayed to the guide groove, the inner layer pulse air flow forms a periodic negative pressure cavity in the guide groove, and the outer layer pulse air flow forms a positive pressure barrier on both sides of the guide groove;

[0008] Under the action of the inner layer pulse air flow and the outer layer pulse air flow, the guide groove is continuously laser cut in a spiral trajectory, and a transverse ultrasonic wave with a preset resonance relationship with the frequency of the inner layer pulse air flow is applied to the cutting area, the transverse ultrasonic wave forms a standing wave on the surface of the molten pool, and the molten metal is guided to flow outwards along the guide groove, forming a slit through the valve body wall thickness;

[0009] When the laser cutting penetrates the valve body wall thickness, the inner layer pulse air flow and the outer layer pulse air flow are switched to a negative pressure suction mode, and the transverse ultrasonic wave is switched from a standing wave to a traveling wave to remove residual molten material in the slit;

[0010] The inner wall of the slit is rapidly scanned by low-power laser using the residual heat of the valve body, and a periodic pulsating inert protective gas is sprayed to the slit, and the residual attachments on the inner wall of the slit are stripped by alternating conversion of laminar flow and micro-turbulent flow of the air flow.

[0011] Preferably, the outer wall of the valve body is scanned multiple times along the preset cutting line by low-duty pulse laser, and a guide groove with a surface tension gradient is formed on the outer wall of the valve body, and the side wall of the guide groove has a corrugated microtexture, which comprises:

[0012] The outer wall of the valve body is scanned for the first time along the preset cutting line by pulse laser, the single pulse energy is set to a first energy level, and the inter-channel offset is half the width of the light spot, forming an initial shallow groove;

[0013] According to the position of the initial shallow groove, the initial shallow groove is scanned by multiple layers of pulse with increasing energy, and a fixed cooling interval is inserted after each layer of scanning, so that the groove bottom forms fine grain layer and columnar grain layer in turn, and step depth and longitudinal surface tension gradient are obtained;

[0014] On the basis of the step depth, the final deep layer scanning is performed at a higher scanning speed than the multiple layer pulse scanning, the local energy density of the center of the groove bottom is reduced, and an energy slope decreasing from the center of the groove to the outlet is formed;

[0015] The groove wall generated by the final deep layer scanning is taken as a reference, and the groove wall is alternately scanned by ±θ lateral polarization pulse, θ represents the included angle between the linear polarization direction of the laser beam and the axis of the guide groove, the transverse amplitude of the fusion wave peak and valley is modulated, and the corrugated microtexture distributed along the longitudinal direction on the side wall of the guide groove is engraved.

[0016] Preferably, the surface tension gradient and corrugated microtexture of the guide groove are used to inject an inner layer of pulsed gas flow and an outer layer of pulsed gas flow into the guide groove, the inner layer of pulsed gas flow forms a periodic negative pressure cavity in the guide groove, and the outer layer of pulsed gas flow forms a positive pressure barrier on both sides of the guide groove, comprising:

[0017] According to the longitudinal period of the corrugated microtexture of the guide groove, a first pulse frequency is set for the inner layer of pulsed gas flow, so that the center positions of the negative pressure cavities of adjacent pulses correspond to adjacent texture troughs one by one;

[0018] A second pulse frequency is set for the outer layer of pulsed gas flow, and the second pulse frequency is kept in a 1:1 ratio with the first pulse frequency, and a 180° phase difference is set between the outer layer of pulsed gas flow and the inner layer of pulsed gas flow, so that the outer layer of positive pressure peak is located at the adjacent texture peak;

[0019] The peak pressure of the inner layer of pulsed gas flow is adjusted incrementally while keeping the first pulse frequency unchanged until the negative pressure valley pressure is lower than the capillary pressure threshold corresponding to the surface tension of the groove bottom, and a stable negative pressure cavity is obtained;

[0020] After the stable negative pressure cavity is obtained, the duty cycle of the outer layer of pulsed gas flow is adjusted decrementally so that the outer layer of positive pressure peak is limited to the texture peak area, forming a positive pressure barrier that continues in the longitudinal direction on both sides of the guide groove.

[0021] Preferably, under the action of the inner layer of pulsed gas flow and the outer layer of pulsed gas flow, the guide groove is continuously laser cut in a spiral trajectory, and a transverse ultrasonic wave with a preset resonance relationship with the frequency of the inner layer of pulsed gas flow is applied to the cutting area, the transverse ultrasonic wave forms a standing wave on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, and forming a slit that penetrates through the valve body wall thickness, comprising:

[0022] According to the groove width and groove depth of the guide groove, the spiral trajectory parameters of the laser cutting head are set to obtain a spiral feed path;

[0023] According to the spiral feed path, power increment control is applied to the continuous laser beam, so that the laser focal point synchronously follows the negative pressure nodes of the inner layer of pulsed gas flow along the spiral feed path, and a synchronous energy distribution is obtained;

[0024] According to the synchronous energy distribution, the driving frequency of the transverse ultrasonic wave is set to be in a 3:4 ratio with the frequency of the inner layer of pulsed gas flow, and the phase of the transverse ultrasonic wave is adjusted so that the antinode of the standing wave corresponds to the position of the negative pressure node, and a standing wave compressed molten pool is obtained;

[0025] According to the standing wave compressed molten pool, the molten metal is discharged in the direction of the guide groove, and a slit profile that penetrates through the valve body wall thickness is obtained.

[0026] Preferably, the spiral trajectory parameters of the laser cutting head are set according to the groove width and groove depth of the guide groove to obtain a spiral feed path, including:

[0027] According to the groove width of the guide groove, the spiral single-turn radial feed amount is determined, so that the spiral single-turn radial feed amount accounts for 2%-5% of the corresponding groove width, to obtain a variable pitch;

[0028] According to the groove depth of the guide groove, the spiral longitudinal step distance is calculated, so that the longitudinal step distance accounts for 1%-3% of the corresponding groove depth, to obtain a segmented axial feed;

[0029] According to the curvature of the valve body outer wall, the inclination angle of the laser cutting head is calculated, so that the laser incidence angle deviates from the normal line of the guide groove by no more than ±3°, to obtain dynamic inclination angle compensation;

[0030] The variable pitch, segmented axial feed and dynamic inclination angle compensation are integrated to generate a spiral feed path.

[0031] Preferably, when the laser cutting penetrates through the valve body wall thickness, the inner layer pulse airflow and the outer layer pulse airflow are switched to a negative pressure suction mode, and at the same time, the transverse ultrasonic wave is switched from a standing wave to a traveling wave, to remove the residual molten material in the slit, including:

[0032] At the moment when the slit is penetrated, a negative pressure suction pulse is applied to the inner layer pulse airflow, the suction period is set to 40ms-60ms, and the suction amplitude is adjusted to 1.2-1.6 times the threshold value of overcoming the cross-sectional tension of the slit, to obtain a first negative pressure wave front;

[0033] During the propagation of the first negative pressure wave front, the transverse ultrasonic wave is switched to a traveling wave, and the propagation direction of the traveling wave is the same as that of the first negative pressure wave front, to obtain gas sound co-directional traction;

[0034] After the gas sound co-directional traction is completed, a closing positive pressure pulse is applied to the outer layer pulse airflow, and the intersection point of the first negative pressure wave front and the inner cavity reflected wave is limited to the slit outlet, to obtain a trapped air curtain;

[0035] According to the trapped air curtain, the linear attenuation of the traveling wave amplitude along the slit length is set, so that the tail of the traveling wave is attenuated to 25%-35% of the initial amplitude at the slit outlet, to obtain a traveling wave gradual extinction segment, and at the same time, the residual molten material in the slit is removed.

[0036] Preferably, the inner wall of the slit is rapidly scanned by low-power laser using the residual heat of the valve body, and at the same time, periodically pulsed inert protective gas is sprayed to the slit, the residual attachments on the inner wall of the slit are stripped by alternating conversion of laminar flow and micro-turbulent flow of the airflow, including:

[0037] Performing low-power laser high-speed reciprocating scanning on the inner wall of the slit, setting the scanning rate to be 3-5 times the cutting rate, to obtain a shallow melting hot layer with a thickness of 5 µm-15 µm;

[0038] According to the temperature distribution of the shallow melting hot layer, setting the pulse frequency of the inert protective gas to be 5 Hz-20 Hz and the duty cycle to be 40 %-60 %, to obtain a pulse base flow;

[0039] In each airflow cycle of the pulse base flow, the gas pulse amplitude is adjusted in two stages, so that the Reynolds number of the pulse rising stage is lower than 1800 to form a laminar flow stage, and the Reynolds number of the pulse peak stage is higher than 2200 to form a micro-turbulent flow stage, to obtain an alternating flow state;

[0040] Using the alternating flow state, the shallow melting hot layer is subjected to shear peeling treatment, to obtain an attachment mixed flow carried by the airflow;

[0041] The attachment mixed flow is subjected to continuous pumping treatment, to obtain a smooth and rough inner wall surface of the slit with a roughness of less than 0.4 µm.

[0042] Preferably, the low-power laser high-speed reciprocating scanning on the inner wall of the slit, setting the scanning rate to be 3-5 times the cutting rate, to obtain a shallow melting hot layer with a thickness of 5 µm-15 µm, comprises:

[0043] In the forward scanning along the direction of the slit, the scanning rate is 3-5 times the cutting rate and the laser power is set to be 15 %-20 % of the rated power, to generate an initial melting layer with a thickness of 3 µm-8 µm;

[0044] In the subsequent reverse scanning, the laser power is set to be 5 %-10 % of the rated power at the same scanning rate, to re-flatten and thicken the initial melting layer to 5 µm-10 µm, to obtain a shallow melting hot layer.

[0045] The second aspect of the present application provides a valve body laser cutting device, which comprises:

[0046] A groove preparation module is configured to perform low-duty pulse laser multiple scanning on the outer wall of the valve body along a preset cutting line, to form a guide groove with a surface tension gradient on the outer wall of the valve body, and the side wall of the guide groove has a corrugated microtexture;

[0047] An airflow construction module is configured to spray inner layer pulse airflow and outer layer pulse airflow into the guide groove according to the surface tension gradient and the corrugated microtexture of the guide groove, the inner layer pulse airflow forms a periodic negative pressure cavity in the guide groove, and the outer layer pulse airflow forms a positive pressure barrier on both sides of the guide groove;

[0048] A spiral cutting module is configured to perform continuous laser cutting along a spiral track on the guide groove under the action of the inner layer pulse airflow and the outer layer pulse airflow, and to apply transverse ultrasonic waves with a preset resonance relationship with the frequency of the inner layer pulse airflow to the cutting area, so that a standing wave is formed on the surface of the molten pool, and the molten metal is guided to flow outward along the guide groove to form a slit through the valve body wall thickness.

[0049] An exhaust and slag removal module is configured to switch the inner layer pulse airflow and the outer layer pulse airflow to a negative pressure suction mode when the laser cutting penetrates through the valve body wall thickness, and to switch the transverse ultrasonic waves from a standing wave to a traveling wave to remove residual molten material in the slit.

[0050] A waste heat polishing module is configured to perform low-power laser rapid scanning on the inner wall of the slit by using the waste heat of the valve body, and to spray periodic pulsed inert protective gas to the slit, so that the residual attachments on the inner wall of the slit are stripped by alternating conversion of laminar flow and micro-turbulent flow of the airflow.

[0051] The third aspect of the present application provides a valve body laser cutting device, comprising a memory and at least one processor, the memory has instructions stored therein, and the memory and the at least one processor are interconnected by a circuit; the at least one processor invokes the instructions in the memory to enable the valve body laser cutting device to perform the steps of the valve body laser cutting method described above.

[0052] The technical scheme provided by the embodiment of the application is that the outer wall of the valve body is first scanned by low-duty-cycle pulses for multiple times, and local melting is formed in the shallow layer to form a groove bottom with fine crystals gradually transitioning to columnar crystals, and longitudinal corrugated textures are engraved on the groove wall. The crystal grain transition zone causes the surface tension to continuously decrease along the groove depth, and the valley-peak sequence of the corrugated texture provides a longitudinal positioning reference for subsequent airflow. The subsequently injected inner and outer double-layer pulse airflow generates a negative pressure cavity at the groove bottom and a positive pressure barrier on both sides under the condition of the geometry and energy, the negative pressure cavity is consistent with the direction of the tension gradient, so that the molten metal naturally tends to be discharged to the center of the groove; the positive pressure barrier locks the airflow from escaping, and maintains the shape and position of the negative pressure cavity. When the spiral trajectory is continuously cut, the laser focal point always advances in the same direction with the center of the negative pressure cavity, and the transverse ultrasonic wave forms a standing wave on the surface of the molten pool, the standing wave antinode suppresses the expansion of the molten pool and gives a thrust, and the molten metal is continuously dragged out along the groove bottom and does not stay on the wall. At the moment when the slit penetrates the thick wall, the double-layer airflow as a whole is changed to short-time negative pressure suction, and the ultrasonic mode is simultaneously changed to a traveling wave; the traveling wave and the suction direction are consistent, which drags the molten droplets and gasification products still in the channel away from the wall, avoiding the reverse shock wave from sucking them back into the cavity. The residual heat of the valve body is then redistributed as a thin molten layer by low-power rapid scanning, and the pulsating inert gas flow periodically converts between laminar flow and micro-turbulent flow: the laminar flow stage stably covers the wall, and the micro-turbulent flow peak stage instantaneously increases the shear stress, which rolls away the micro-film and particles adhering to the surface of the thin molten layer as a whole, and they are taken out of the channel by the air curtain in the next laminar flow stage. Thus, from the initial groove shape induction, the airflow-sound field synergistic deslagging to the residual heat pulsation polishing, the whole process eliminates the conditions for the re-solidification of the molten metal on the inner wall, the inner wall roughness is maintained at micron-level smoothness without leakage risk, and the problems of slag backflow and re-attachment in the laser cutting of the thick-walled valve body are solved from the root. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 An embodiment of the valve laser cutting method in the embodiment of the application is shown in the figure;

[0054] Figure 2 An embodiment of the valve laser cutting device in the embodiment of the application is shown in the figure;

[0055] Figure 3 An embodiment of the valve laser cutting device in the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0056] The technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0057] It should be noted that if the embodiments of the present application involve directionality indication (such as up, down, left, right, front, back, etc.), the directionality indication is only used to explain the relative position relationship, motion condition, etc. between components in a certain posture, and if the certain posture changes, the directionality indication also changes accordingly.

[0058] In addition, the description involving "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" throughout the text includes three schemes, taking A and / or B as an example, including A technical solution, B technical solution, and A and B simultaneously satisfying the technical solution; in addition, the technical solutions of each embodiment can be combined with each other, and it must be based on the realization of the ordinary skill in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of such technical solutions does not exist, nor within the protection scope required by the present application.

[0059] An embodiment of the present application provides a valve body laser cutting method. Figure 1 An embodiment of the present application provides a valve body laser cutting method. In the embodiment, the method comprises:

[0060] Please refer to Figure 1 The low-duty-ratio pulse laser is scanned along the preset cutting line on the outer wall of the valve body multiple times to form a guide groove with a surface tension gradient on the outer wall of the valve body, and the side wall of the guide groove has corrugated microtexture.

[0061] In an embodiment of the present application, the low-duty-ratio pulse laser is scanned along the preset cutting line on the outer wall of the valve body multiple times to form a guide groove with a surface tension gradient on the outer wall of the valve body, and the side wall of the guide groove has corrugated microtexture, which comprises:

[0062] The low-duty-ratio pulse laser is scanned along the preset cutting line on the outer wall of the valve body multiple times to form a guide groove with a surface tension gradient on the outer wall of the valve body, and the side wall of the guide groove has corrugated microtexture.

[0063] According to the position of the initial shallow groove, the initial shallow groove is scanned by multiple layers of pulse with increasing energy, and a fixed cooling interval is inserted after each layer of scanning, so that the groove bottom sequentially forms fine-grained layers and columnar crystal layers, and a stepped depth of penetration and a longitudinal surface tension gradient are obtained.

[0064] On the basis of the stepped depth of penetration, a final deep layer scanning is performed at a scanning speed higher than that of the multiple layer pulse scanning, so as to reduce the local energy density of the center of the groove bottom and form an energy slope decreasing from the center of the groove to the outlet.

[0065] With the groove wall generated by the final deep scanning as the reference, the groove wall is alternately scanned by ±θ lateral polarization pulse, θ represents the included angle between the linear polarization direction of the laser beam and the axis of the guide groove, and the transverse amplitude of the fusion wave crest and trough is modulated to write the corrugated microtexture distributed along the longitudinal direction on the side wall of the guide groove.

[0066] The following is a specific description of the steps involved in the above embodiments:

[0067] The fiber laser is set to pulse mode, the single pulse energy is adjusted to the first energy level of 0.12-0.18 millijoules, the pulse width is controlled within hundreds of nanoseconds, and the heat conduction mode is maintained to avoid plasma formation. The laser beam is focused to a spot diameter of about 80 microns through a 100 millimeter focal length lens, and the galvanometer system (a laser beam deflection device composed of two high-speed rotating mirrors) drives the laser beam to scan along the preset cutting line. The inter-track offset is set to 40 microns, which is half of the spot diameter. According to the geometric relationship of the circular spot, such offset distance makes the melting area of adjacent laser pulses have more than 70% overlapping area, which ensures the formation of continuous melting track. The laser duty cycle is controlled below 10%, so that only 20-30 microns deep melting occurs on the material surface without entering the vaporization state. Under this energy control, the cooling rate of the molten metal reaches 10 6 Kelvin per second, the rapid cooling does not give the crystal nucleus enough time to grow, and a fine-grained layer with an average grain size of less than 5 microns is formed at the groove bottom. The fine-grained layer has a high grain boundary density, and its surface energy is 5-8 millijoules per square meter higher than that of the surrounding base material, providing an identifiable surface tension gradient for the subsequent molten pool movement. The geometric profile of the initial shallow melting groove also provides an accurate laser beam positioning reference for multi-layer scanning.

[0068] A multi-layer pulse scan is performed along the same scan path for 3-5 layers, with the single pulse energy increased by 10-15% for each layer on the basis of the previous layer, while maintaining a 40-micron interpass offset. After each layer scan is completed, a 6-8 millisecond pause is provided by the laser control system, which allows the upper layer to completely solidify, while the lower layer material remains in a supercooled state at 500-600 Kelvin. Under this temperature gradient condition, the heat flow direction is directed from the wall to the groove bottom, and the crystal growth direction is stably controlled to form a columnar crystal structure in the subsequent melting depth area. Columnar crystals refer to columnar structures formed by crystal grains extending and growing in a specific direction, with a length of 40-60 microns, while the upper layer remains in a fine crystal form. As the number of scan layers increases, the grain radius monotonically increases from the notch to the groove bottom, and the corresponding surface free energy monotonically decreases, forming a surface tension gradient of 0.3-0.5 Newton per square meter per centimeter along the longitudinal direction at the groove bottom. This gradient, based on the difference in surface energy of different grain sizes, can continuously drive the molten metal to the center of the groove with higher surface energy, preventing it from spreading to both sides. Multi-layer progressive scanning expands the total melting depth to 1%-1.5% of the valve body wall thickness, and forms a stepped sidewall structure at the groove wall, providing geometric convenience for subsequent laser beam focusing and positioning.

[0069] On the basis of the stepped melting depth structure, the laser scan speed is increased to 1.8 times the aforementioned multi-layer scan speed, while maintaining the laser energy level of the previous layer. The increase in scan speed shortens the interaction time between the laser beam and the material, and reduces the heat input per unit time by about 35%. The heat at the center of the groove bottom is quickly dissipated to the surrounding material through lateral heat conduction, while the temperature at the outlet area is relatively high due to different boundary heat dissipation conditions, thus forming an energy slope distribution with low temperature at the center and high temperature at the outlet. This energy slope restricts the flow of molten metal driven by surface tension differences (i.e., Marangoni convection, which is a fluid flow phenomenon caused by temperature gradients) to the flow channel from the center to the outlet, effectively suppressing the upward flow of molten metal to both sides of the groove wall. At the same time, the higher scan speed controls the heat accumulation to below 200 Joules per square centimeter, avoiding macroscopic thermal deformation of the thick-walled valve body. The decreasing energy slope from the center to the outlet provides a geometric driving force for the molten metal generated during the subsequent spiral cutting process, ensuring that it is quickly discharged in the desired direction without stagnating at the groove bottom.

[0070] The groove wall surface completed by the final deep scanning is taken as a machining reference. The laser polarization direction is controlled by a galvanometer system to switch between pulses within ±θ angle, wherein θ represents the included angle between the linear polarization direction of the laser beam and the axis of the guide groove (i.e. the scanning direction), and is specifically set to ±12°. The interval distance of each group of pulses is set to 0.15 mm. Linearly polarized laser refers to laser whose electric field vector oscillates in a fixed plane, and the energy coupling coefficient of the linearly polarized laser to the metal melt pool changes significantly with the incident angle and the direction of the electric vector. The alternating ±12° polarization direction generates a periodic transverse temperature difference on the groove wall surface, so that the melting depth of the solid-liquid interface at different positions is different, thereby forming a relief structure of wave peaks and wave troughs. After the melting process is completed, a series of ridge-valley structures are left on the groove wall surface, which are distributed along the longitudinal direction, wherein the height difference between the high points and the low points is about 6-8 microns, and the pitch between adjacent ridge-valley structures is stably 18-22 microns, forming regular corrugated micro-texture. The ridge-valley sequence provides accurate geometric locking points for the subsequent double-layer pulsed gas flow: the negative pressure cavity is stably positioned at the wave trough position, and the positive pressure peak is limited by the wave ridge structure, so that the spatial position of the double-layer gas flow will not drift due to accidental disturbance. At the same time, the curvature difference of the micro-texture groove enhances the wall surface wetting angle gradient, so that the melt pool is continuously pushed to the slot under the joint action of the directional surface tension and the gas flow shear force, and will not be solidified and attached to the wall surface.

[0071] Please continue to refer to Figure 1 , according to the surface tension gradient and the corrugated micro-texture of the guide groove, an inner layer pulsed gas flow and an outer layer pulsed gas flow are sprayed into the guide groove, the inner layer pulsed gas flow forms a periodic negative pressure cavity in the guide groove, and the outer layer pulsed gas flow forms a positive pressure barrier on both sides of the guide groove;

[0072] In an embodiment of the present application, the method according to the surface tension gradient and the corrugated micro-texture of the guide groove, an inner layer pulsed gas flow and an outer layer pulsed gas flow are sprayed into the guide groove, the inner layer pulsed gas flow forms a periodic negative pressure cavity in the guide groove, and the outer layer pulsed gas flow forms a positive pressure barrier on both sides of the guide groove, comprises:

[0073] According to the longitudinal period of the corrugated micro-texture of the guide groove, a first pulse frequency is set for the inner layer pulsed gas flow, so that the center positions of the negative pressure cavities of adjacent pulses correspond to the adjacent texture wave troughs one by one;

[0074] A second pulse frequency is set for the outer layer pulsed gas flow, and the second pulse frequency and the first pulse frequency are kept in a 1:1 ratio. A 180° phase difference is set between the outer layer pulsed gas flow and the inner layer pulsed gas flow, so that the outer layer positive pressure peak is located at the adjacent texture wave peak;

[0075] The peak pressure of the inner layer pulse airflow is adjusted incrementally while keeping the first pulse frequency unchanged until the negative pressure valley pressure is lower than the capillary pressure threshold corresponding to the surface tension of the groove bottom, obtaining a stable negative pressure cavity;

[0076] After obtaining the stable negative pressure cavity, the duty cycle of the outer layer pulse airflow is adjusted decrementally so that the outer layer positive pressure peak width is limited to the texture peak region, forming a positive pressure barrier extending longitudinally on both sides of the guide groove.

[0077] The following describes the steps involved in the above embodiments:

[0078] The longitudinal period of the corrugated microtexture formed in the previous steps, i.e. the distance between adjacent peaks or adjacent valleys, is measured by a laser ranging sensor or an optical microscope. According to the measurement results, the longitudinal period of the corrugated microtexture is 18-22 microns. The airflow control system calculates the first pulse frequency of the inner layer pulse airflow based on this period data, and the calculation method is to divide the airflow jet speed by the texture period length. For example, when the airflow jet speed is 20 meters per second and the texture period is 20 microns, the first pulse frequency is set to 1000 Hz. The pulse generator of the inner layer airflow is adjusted by a programmable airflow controller to work at the calculated first pulse frequency. At this frequency, the negative pressure cavity generated by the inner layer pulse airflow will appear at a predetermined time interval and spatial position. The negative pressure cavity refers to the area formed by the airflow pulse in the guide groove at a certain phase, where the pressure is lower than the surrounding environment pressure. By precisely controlling the pulse timing, the center position of each negative pressure cavity accurately corresponds to the valley position of the corrugated microtexture, achieving a one-to-one correspondence between the negative pressure cavity and the texture valley. This precise spatial matching ensures that the airflow dynamics effect can work at the predetermined geometric position, avoiding random drift of the negative pressure cavity position, and provides a stable dynamic foundation for the subsequent directional discharge of molten metal.

[0079] The second pulse frequency of the outer layer pulse gas flow is set to maintain a 1:1 numerical ratio with the first pulse frequency of the inner layer pulse gas flow, that is, the frequency values of the two are exactly the same. The inner and outer layer gas flows are controlled by a double-channel gas flow control system, and the pulse generator of the outer layer gas flow is set to the same frequency value as the inner layer. On the basis of the same frequency, the outer layer pulse gas flow is set to a 180° phase difference relative to the inner layer pulse gas flow through a phase adjuster. The phase difference refers to the time offset relationship of two signals with the same frequency, and a 180° phase difference means that when the inner layer gas flow is at the negative pressure valley value, the outer layer gas flow is exactly at the positive pressure peak value. Phase adjustment is achieved through a delay circuit, and the delay time is equal to half of the pulse period. This phase control makes the positive pressure peak of the outer layer gas flow accurately located at the wave peak position of the corrugated micro-texture, and the positive pressure peak refers to the area where the pressure of the gas pulse is higher than the surrounding environment pressure at a certain phase. For example, when the first pulse frequency is 1000 Hz, the pulse period is 1 ms, and the 180° phase difference corresponds to a time delay of 0.5 ms. Through this spatio-temporal synchronous control, the inner layer negative pressure cavity and the outer layer positive pressure peak form a complementary pressure distribution pattern in space, realizing accurate modulation of the gas flow field in the guide groove.

[0080] Under the premise of keeping the first pulse frequency value unchanged, the peak pressure of the inner layer pulse gas flow is gradually increased by adjusting the pressure regulating valve. The peak pressure refers to the absolute value of the pressure when the gas pulse reaches the maximum negative pressure. The adjustment process adopts a step-by-step pressure increasing method, and the pressure increasing amplitude is controlled at 0.1-0.2 kPa each time, while the actual pressure change at the groove bottom is monitored in real time by a pressure sensor. The capillary pressure threshold refers to the pressure value generated by the surface tension effect, which is equal to the surface tension coefficient divided by twice the bending radius. For 316 stainless steel material, the surface tension coefficient at 1500 degrees Celsius is about 1.6 N / m, and when the curvature radius of the guide groove bottom is 40 microns, the capillary pressure threshold is about 20 kPa. Through continuous monitoring and adjustment, when the negative pressure valley pressure (i.e. the pressure value when the pulse gas flow reaches the maximum negative pressure) is lower than this capillary pressure threshold, it indicates that the negative pressure generated by the gas flow is sufficient to overcome the resistance of the surface tension. At this time, the molten metal at the groove bottom can move stably in the direction of the gas flow under the driving of the negative pressure, forming a stable negative pressure cavity effect. The establishment of the stable negative pressure cavity eliminates the stagnation of the molten metal at the groove bottom, ensuring that the liquid metal generated during cutting can be pumped out in time.

[0081] On the basis of obtaining stable negative pressure cavity, the duty cycle of the outer layer pulse gas flow is gradually reduced by the duty cycle regulator. The duty cycle refers to the percentage of the time that the gas flow is in a positive pressure state within a pulse cycle. The adjustment process starts from an initial duty cycle of 60%, and gradually decreases to a target range of 30-40% with a step size of 5%. The reduction of the duty cycle shortens the duration of the positive pressure peak of the outer layer gas flow, and the positive pressure peak width is limited in the space to the range of the wave peak area of the corrugated micro-texture. The gas flow distribution is monitored by the flow field visualization device to ensure that the spatial coverage of the positive pressure peak does not exceed the boundary of the wave peak area. When the duty cycle is adjusted to a reasonable value, the outer layer gas flow forms a local high pressure area at the wave peak position, while maintaining a relatively low pressure state at the wave valley position. This pressure distribution pattern continuously extends along the longitudinal direction on both sides of the guide groove, forming a positive pressure barrier effect. The positive pressure barrier prevents the low pressure area generated by the inner layer negative pressure cavity from spreading to both sides of the groove wall, and restricts the negative pressure effect to the central area of the groove bottom, while preventing the intrusion of external environment gas flow from interfering with the inner layer gas flow field. This double-layer gas flow pressure distribution pattern creates stable fluid dynamics boundary conditions, providing a continuous and stable pneumatic driving force for the subsequent melting metal discharge during the spiral cutting process.

[0082] Please continue to refer to Figure 1 Under the action of the inner layer pulse gas flow and the outer layer pulse gas flow, the guide groove is continuously laser cut in a spiral trajectory, and a transverse ultrasonic wave with a preset resonance relationship with the frequency of the inner layer pulse gas flow is applied to the cutting area. The transverse ultrasonic wave forms a standing wave on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, forming a cut seam that penetrates through the wall thickness of the valve body.

[0083] In an embodiment of the present application, under the action of the inner layer pulse gas flow and the outer layer pulse gas flow, the guide groove is continuously laser cut in a spiral trajectory, and a transverse ultrasonic wave with a preset resonance relationship with the frequency of the inner layer pulse gas flow is applied to the cutting area. The transverse ultrasonic wave forms a standing wave on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, forming a cut seam that penetrates through the wall thickness of the valve body, comprising:

[0084] According to the groove width and groove depth of the guide groove, the spiral trajectory parameters of the laser cutting head are set to obtain a spiral feed path;

[0085] According to the spiral feed path, power increment control is applied to the continuous laser beam, so that the laser focal point follows the negative pressure node of the inner layer pulse gas flow along the spiral feed path, and a synchronous energy distribution is obtained.

[0086] According to the synchronous energy distribution, the transverse ultrasonic waves are set with a driving frequency in a ratio of 3:4 to the frequency of the inner layer pulsed air flow, and the phase of the transverse ultrasonic waves is adjusted so that the standing wave antinode corresponds to the position of the negative pressure node, thereby obtaining a standing wave compressed molten pool;

[0087] According to the standing wave compressed molten pool, the molten metal is subjected to an ejection process along the direction of the guide groove, thereby obtaining a kerf profile penetrating through the wall thickness of the valve body.

[0088] The following describes the steps involved in the above embodiments in detail:

[0089] The slot width and slot depth data of the guide groove are obtained by measuring instruments. The slot width refers to the width dimension at the opening of the guide groove, and the slot depth refers to the vertical depth from the slot opening to the groove bottom. Based on these geometric parameters, the numerical control system calculates the helical trajectory parameters, including the helical radius, helical pitch, and helical angle. The helical radius is set to 75-85% of the slot width, ensuring that the laser beam does not touch the edge of the groove wall when moving in the groove. The helical pitch refers to the distance between adjacent turns of the helical line in the axial direction, which is set to 2-3% of the slot depth based on the slot depth data. For example, when the slot depth is 2 mm, the helical pitch is set to 0.04-0.06 mm. The helical angle refers to the angle between the helical line and the horizontal plane, which is set to 85-90 degrees based on the valve body wall thickness and the cutting depth requirement, close to vertical cutting to improve the penetration efficiency. The laser cutting head is driven by a six-axis numerical control machine tool, and moves in space according to the calculated helical trajectory parameters to form a helical feed path. The helical feed path refers to the complete path of the laser focal point moving along the helical line trajectory in three-dimensional space. This path design increases the contact area between the laser beam and the molten metal, and provides more space for air flow slagging. Compared with linear cutting, the helical trajectory can significantly reduce the thermal stress concentration during cutting, preventing cracks or deformation of the valve body material in local areas. At the same time, the centrifugal force generated by the helical motion helps to expel the molten metal outward.

[0090] Based on the spatial coordinate information of the helical feed path, the laser control system implements power ramping control on the continuous laser beam. Power ramping control refers to a control mode in which the laser output power gradually increases with the increase of the cutting depth. The initial power is set to 60% of the rated power, and the power increases by 5-8% per millimeter of depth as the helical cutting depth increases. The position sensor monitors the accurate position of the laser focal point on the helical feed path in real time, while the airflow sensor detects the negative pressure node position of the inner layer pulse airflow. The negative pressure node refers to a specific position point where the inner layer pulse airflow forms the maximum negative pressure value in space and time. The numerical control system uses a timing control algorithm to synchronize the movement trajectory of the laser focal point with the movement trajectory of the negative pressure node in space and time, i.e., when the negative pressure node moves to a certain position on the helical path, the laser focal point also reaches that position. This synchronous control is achieved through high-precision servo motors and real-time feedback systems, ensuring that the laser energy input and the airflow suction effect occur simultaneously at the same spatial location. Synchronous energy distribution refers to the state in which the spatial distribution pattern of laser power matches the distribution pattern of airflow negative pressure. This matching ensures that the molten metal is immediately subjected to negative pressure suction, avoiding the stagnation and accumulation of molten metal in the cutting area.

[0091] Based on the spatial distribution characteristics of synchronous energy distribution, the ultrasonic generator sets the drive frequency to be 3 / 4 times the frequency of the inner layer pulse airflow, forming a frequency ratio of 3:4. For example, when the frequency of the inner layer pulse airflow is 1000 Hz, the drive frequency of the transverse ultrasonic wave is set to 750 Hz. This frequency ratio produces a beat frequency effect. Beat frequency refers to the periodic variation in strength that occurs when two vibrations with similar frequencies are superimposed. The frequency of the beat frequency is equal to the difference between the two original frequencies. The phase of the transverse ultrasonic wave is precisely adjusted through a phase adjuster. The goal of phase adjustment is to make the position of the ultrasonic standing wave antinode coincide with the position of the negative pressure node in space. A standing wave is a wave that propagates within a bounded region and is formed by the superposition of reflected and incident waves. The standing wave antinode is the position point with the maximum amplitude in the standing wave. The transverse ultrasonic wave is excited on the guide groove side wall through a piezoelectric transducer array, and the ultrasonic wave reflects back and forth in the groove to form a standing wave field. Phase adjustment is achieved through a delay circuit, with an adjustment accuracy of microseconds, ensuring that the standing wave antinode accurately corresponds to the spatial position of the negative pressure node. The standing wave compresses the molten pool at the standing wave antinode position, where the strong vibration of the ultrasonic wave produces a periodic compression effect on the molten metal, reducing the thickness of the molten pool at that position to 20-30% of the normal thickness. The compressed molten pool is more easily sheared and carried away by the airflow, significantly improving the discharge efficiency of the molten metal and preventing the adhesion of molten metal to the cutting wall.

[0092] The high-efficiency slagging condition generated by the standing wave compression of the molten pool is used to implement directional discharge treatment of the molten metal along the direction of the guide groove. Under the action of the standing wave compression, the molten pool is compressed into a thin layer state, and the surface tension gradient and the negative pressure suction force jointly act to make the molten metal flow rapidly along the longitudinal direction of the guide groove. The discharge treatment is realized by controlling the amplitude of the ultrasonic wave and the suction strength of the air flow, and the amplitude of the ultrasonic wave is adjusted to a level sufficient to overcome the viscous force of the molten metal, and the suction strength of the air flow is set to be 1.5-2 times higher than the surface tension resistance. The molten metal is discharged upward along a spiral trajectory under the driving of multiple forces, and the centrifugal force generated by the spiral motion further promotes the slagging effect. With the continuous spiral cutting, the depth of the cutting seam gradually increases, and when the laser beam completely penetrates the thickness of the valve body, a complete cutting seam profile is formed through the thickness of the valve body. The cutting seam profile presents a spindle-shaped cross-sectional feature with a smooth inner wall, and this cross-sectional shape is the result of the joint action of spiral cutting and standing wave compression. The spindle-shaped cross-section has the smallest fluid resistance, which is beneficial to the smooth flow of the medium during the operation of the valve. The discharge treatment realized by the standing wave compression of the molten pool eliminates the problems of slag adhesion and backflow in traditional laser cutting, ensures that the inner wall of the cutting seam remains clean, and meets the strict requirements of high-precision valves for the surface quality of the inner cavity.

[0093] In an embodiment of the present application, the spiral trajectory parameters of the laser cutting head are set according to the groove width and groove depth of the guide groove, and a spiral feed path is obtained, which includes:

[0094] According to the groove width of the guide groove, the spiral single-turn radial feed amount is determined, and the spiral single-turn radial feed amount accounts for 2 %-5 % of the corresponding groove width, and a variable pitch is obtained;

[0095] According to the groove depth of the guide groove, the spiral longitudinal step distance is calculated, and the longitudinal step distance accounts for 1 %-3 % of the corresponding groove depth, and a segmented axial feed is obtained;

[0096] According to the curvature of the outer wall of the valve body, the inclination angle of the laser cutting head is calculated, and the laser incidence angle deviates from the normal line of the guide groove by no more than ±3°, and a dynamic inclination angle compensation is obtained;

[0097] The variable pitch, the segmented axial feed and the dynamic inclination angle compensation are integrated to generate a spiral feed path.

[0098] The following specifically describes the steps involved in the above-mentioned embodiment:

[0099] The numerical control system calculates the radial feed per single spiral turn based on the measured groove width value. Radial feed refers to the distance the laser cutting head moves towards the groove wall after completing one spiral turn in the direction perpendicular to the cutting depth. The calculation method is to multiply the groove width value by a proportional coefficient of 2-5%, for example, when the groove width is 120 microns, the radial feed per single spiral turn is set to 2.4-6 microns. This feed is controlled by the radial servo motor of the numerical control system, which accurately controls the micro-displacement of the laser cutting head in the radial direction according to the programmed instructions. Since the radial feed per spiral turn is adjusted in real time according to the groove width at the current position, a variable pitch feature is formed. Variable pitch refers to the characteristic that the radial spacing between adjacent spiral turns in the spiral trajectory adjusts with the change in cutting depth, which adapts to the possible width differences of the guide groove at different depths. The proportional range of 2-5% ensures that the laser beam maintains an appropriate distance from the groove wall during the spiral cutting process, avoiding unnecessary material ablation caused by direct contact between the laser beam and the groove wall, while ensuring the continuity and integrity of the cutting.

[0100] Based on the groove depth measurement data of the guide groove, the numerical control system calculates the longitudinal step distance value. Longitudinal step distance refers to the distance increment of the laser cutting head moving downward along the cutting depth direction, that is, the interlayer distance of the spiral trajectory in the vertical direction. The calculation process multiplies the groove depth value by a proportional coefficient of 1-3%, for example, when the groove depth is 2000 microns, the longitudinal step distance is set to 20-60 microns. This step distance value is controlled by the longitudinal feed axis of the numerical control system, which uses high-precision ball screw transmission to ensure the accuracy of each longitudinal movement to the micron level. The control of longitudinal step distance forms a segmented axial feed mode, which refers to the decomposition of the entire cutting depth into multiple small feed segments, each corresponding to a longitudinal step distance of movement distance. This segmented feed method makes the laser cutting process more controllable, and the laser power and airflow parameters in each segment can be independently adjusted. The proportional range of 1-3% ensures the stability of the cutting process, and a too small proportion will lead to a decrease in cutting efficiency, while a too large proportion may cause excessive single feed and affect the cutting quality. Segmented axial feed and variable pitch together form an accurate cutting trajectory that adapts to the geometric characteristics of the guide groove.

[0101] The curvature data of the valve body outer wall is obtained by a coordinate measuring machine or a laser scanner. The curvature refers to the measure of the degree of bending of a curve at a point, and the value is equal to the reciprocal of the radius of curvature at that point. The numerical control system calculates the inclination angle of the laser cutting head according to the curvature of the valve body outer wall. The calculation target is to control the angle of the laser beam deviating from the normal of the guide groove within ±3°. The normal of the guide groove refers to the direction of the straight line perpendicular to the surface of the guide groove, and the laser incidence angle refers to the angle between the laser beam and the normal. When the radius of curvature of the valve body outer wall is small, the laser cutting head needs to adjust the inclination angle accordingly to compensate for the curved surface effect. The adjustment of the inclination angle is realized by the rotation axis of the numerical control system, which drives the laser cutting head to rotate around its own axis. The rotation angle is determined in real time according to the curvature data. Dynamic inclination compensation refers to the control mode that the inclination angle of the laser cutting head is continuously adjusted according to the curvature of the valve body outer wall. This compensation ensures that the laser beam always enters the guide groove surface at a nearly vertical angle. The angle range of ±3° is determined based on the physical characteristics of laser processing. When the incidence angle deviation exceeds 3°, the coupling efficiency of laser energy will be significantly reduced, and at the same time, an asymmetric heat affected zone may be generated on the groove wall. Dynamic inclination compensation eliminates the adverse effects of valve body curved surface geometry on cutting quality, ensuring the effective use of laser energy throughout the cutting process.

[0102] The numerical control system comprehensively processes the three control parameters of variable pitch, segmented axial feed and dynamic inclination compensation to generate a complete helical feed path. The path generation process first combines the variable pitch data with the segmented axial feed data to determine the position coordinate sequence of the laser cutting head in three-dimensional space. Each coordinate point corresponds to a position on the helical trajectory. Then the dynamic inclination compensation data is superimposed into the position coordinate sequence to add corresponding angle posture information to each coordinate point, forming six-dimensional motion instructions containing position and posture. The numerical control system converts these six-dimensional instructions into control signals for each servo motor to drive the laser cutting head to move according to the calculated helical feed path. The generation of the helical feed path ensures that the laser cutting process adapts to the complex geometric features of the valve body while maintaining precise control of the cutting parameters, achieving high-quality kerf forming effect.

[0103] Please continue to see Figure 1 When the laser cutting penetrates the wall thickness of the valve body, the inner layer pulse airflow and the outer layer pulse airflow are switched to negative pressure suction mode, and the transverse ultrasonic wave is switched from standing wave to traveling wave to remove residual molten material in the kerf;

[0104] In an embodiment of the present application, when the laser cutting penetrates the wall thickness of the valve body, the inner layer pulse airflow and the outer layer pulse airflow are switched to negative pressure suction mode, and the transverse ultrasonic wave is switched from standing wave to traveling wave to remove residual molten material in the kerf, comprising:

[0105] At the moment of the cut-through, a negative pressure suction pulse is applied to the inner layer pulsed airflow, the suction period is set to 40-60 ms, and the suction amplitude is adjusted to 1.2-1.6 times the cut-section tension threshold to obtain the first negative pressure wave front;

[0106] During the propagation of the first negative pressure wave front, the transverse ultrasonic wave is switched to a traveling wave, and the propagation direction of the traveling wave is the same as that of the first negative pressure wave front to obtain the same direction air sound traction;

[0107] After the same direction air sound traction is completed, a closing positive pressure pulse is applied to the outer layer pulsed airflow, the intersection point of the first negative pressure wave front and the inner cavity reflection wave is limited to the cut-outlet to obtain the trapped air curtain;

[0108] According to the trapped air curtain, the amplitude of the traveling wave is set to linearly decay along the length of the cut, so that the tail of the traveling wave decays to 25-35% of the initial amplitude at the cut-outlet to obtain the traveling wave fading section, and the residual molten material in the cut is simultaneously removed.

[0109] The following is a specific description of the steps involved in the above embodiment:

[0110] The signal of sudden drop of laser power is detected by the laser power feedback sensor to determine the arrival of the cut-through moment, which refers to the moment when the laser beam completely penetrates the valve body wall thickness and communicates with the inner cavity. After detecting the cut-through signal, the airflow control system immediately applies a negative pressure suction pulse to the inner layer pulsed airflow, which refers to a strong negative pressure airflow pulse superimposed on the original pulsed airflow. The suction period is set to 40-60 milliseconds by a precision timer, and this time window is accurately controlled by a programmable logic controller. The adjustment of the suction amplitude is based on the calculation of the cut-section tension threshold, which refers to the resistance value of the molten metal at the cut-section due to surface tension effect. For 316 stainless steel at 1500 degrees Celsius, it is about 15-20 kilopascals. The suction amplitude is set to 1.2-1.6 times the threshold value by a vacuum pump and a pressure regulating valve, i.e. a negative pressure value of 18-32 kilopascals. For example, when the cut-section tension threshold is 18 kilopascals, the suction amplitude is set to 21.6-28.8 kilopascals. This strong negative pressure pulse generates the first negative pressure wave front in the cut, which refers to the first pressure wave peak formed by the negative pressure suction pulse in the cut channel, which propagates to the inner cavity along the cut direction. The 40-60 millisecond period is set based on the valve body wall thickness and the sound speed propagation characteristics to ensure that the negative pressure wave front has enough time to reach the bottom of the cut, and the 1.2-1.6 times suction amplitude range ensures that the surface tension resistance can be overcome while avoiding excessive suction causing cut deformation.

[0111] At the same time when the first negative pressure wave front starts to propagate, the ultrasonic control system switches the transverse ultrasonic wave from standing wave mode to traveling wave mode. Traveling wave refers to a form of wave motion in which the energy propagates along the medium without forming standing nodes. Unlike standing wave, the energy of traveling wave continuously transfers forward. The switching process is achieved by changing the excitation phase of the piezoelectric transducer array, which results in a phase difference between adjacent transducers and forms a traveling wave propagating along the kerf direction. The propagation direction of the traveling wave is determined by controlling the sign of the phase difference, so that it is consistent with the propagation direction of the first negative pressure wave front, i.e. both propagate along the kerf to the inner cavity. The synchronization of the propagation direction is achieved by monitoring the propagation speed of the negative pressure wave front by the digital signal processor and adjusting the phase speed of the traveling wave accordingly. The same direction traction of gas sound refers to the synergistic dragging effect of the negative pressure wave front and the traveling wave on the residual material in the kerf. The negative pressure wave front provides the driving force of the pressure gradient, and the traveling wave provides the vibration shear force. For example, when the negative pressure wave front propagates at a speed of 300 meters per second, the phase speed of the traveling wave is adjusted to the same value to ensure that the two are synchronized in space and time. This same direction traction effect significantly enhances the cleaning ability of the residual molten material and gasification products in the kerf, preventing these residues from re-solidifying and adhering to the inner cavity wall.

[0112] When the same direction traction of gas sound propagates to the middle section of the kerf, the outer layer pulsed gas flow control system starts the converging positive pressure pulse. The converging positive pressure pulse refers to a short-time high-pressure gas flow pulse applied at the outlet position of the kerf, which forms a pressure barrier at the outlet of the kerf. The pressure value of the positive pressure pulse is set to be 20-30 kilopascals higher than the ambient atmospheric pressure, and the duration is 10-15 milliseconds, which is achieved by a high-pressure gas tank and a fast-responding electromagnetic valve. When the first negative pressure wave front propagates to the inner cavity, it will produce a reflection, forming an inner cavity reflection wave. The reflection wave refers to the return wave formed by the reflection of the negative pressure wave on the inner cavity wall. The timing control of the converging positive pressure pulse makes it meet the inner cavity reflection wave at the outlet position of the kerf, and this meeting point is called the intersection point. Through accurate timing calculation, the intersection point is limited to the outlet of the kerf rather than the inside of the kerf, avoiding the re-entry of the reflection wave into the kerf channel. The trapped air curtain refers to the high-pressure gas flow barrier formed by the converging positive pressure pulse at the outlet of the kerf, which prevents the mutual interference of the inner cavity reflection wave and the external gas flow. For example, when the kerf depth is 25 millimeters and the negative pressure wave propagation speed is 300 meters per second, the converging positive pressure pulse is started about 0.17 milliseconds after the negative pressure wave is emitted, ensuring that the reflection wave returns exactly to meet the positive pressure pulse at the outlet. The establishment of the trapped air curtain eliminates the conditions for the formation of the reverse shock wave, fundamentally preventing the occurrence of slag backflow phenomenon.

[0113] Based on the spatial distribution characteristics of the trapped air curtain, the ultrasonic control system performs linear attenuation adjustment of the traveling wave amplitude along the length of the slit. Linear attenuation refers to a control method in which the amplitude of the traveling wave gradually decreases along the propagation path at a fixed ratio, and the attenuation ratio is achieved through segmented control of a multi-channel power amplifier. The initial amplitude of the traveling wave is set at the entrance of the slit, and as it propagates in the direction of the inner cavity, the amplitude decreases according to a linear law, so that the amplitude of the trailing part of the traveling wave at the outlet of the slit is attenuated to 25%-35% of the initial amplitude. For example, when the initial amplitude is 100 microns, the amplitude at the outlet is controlled within the range of 25-35 microns. This attenuation control is achieved through multiple piezoelectric transducers distributed along the slit, and the driving power of each transducer is independently adjusted according to its position. The traveling wave fading section refers to the region at the end of the slit where the amplitude of the traveling wave gradually attenuates to near zero, and the energy of the traveling wave in this region is just enough to push the residual melt towards the outlet without causing excessive vibration interference. The attenuation range of 25%-35% is determined based on the geometry of the slit and the fluid dynamics characteristics, and excessive attenuation will result in insufficient cleaning effect, while insufficient attenuation will cause strong acoustic reflection at the outlet. Under the action of the traveling wave fading section, the residual melt in the slit is continuously pushed towards the outlet and discharged together with the trapped air curtain, ensuring that the inner wall of the slit remains clean and completely solving the problem of slag backflow.

[0114] Please continue to refer to Figure 1 , using the valve body residual heat to perform low-power laser rapid scanning on the inner wall of the slit, while injecting periodic pulsating inert protective gas into the slit, and alternately converting the residual attachments on the inner wall of the slit through laminar flow and micro-turbulent flow of the gas flow.

[0115] In one embodiment of the present application, the use of valve body residual heat to perform low-power laser rapid scanning on the inner wall of the slit, while injecting periodic pulsating inert protective gas into the slit, and alternately converting the residual attachments on the inner wall of the slit through laminar flow and micro-turbulent flow of the gas flow, comprises:

[0116] Performing high-speed reciprocating scanning of low-power laser on the inner wall of the slit, setting the scanning rate to be 3-5 times the cutting rate, and obtaining a shallow melting heat layer with a thickness of 5 µm-15 µm;

[0117] According to the temperature distribution of the shallow melting heat layer, setting the pulsation frequency of the inert protective gas to be 5 Hz-20 Hz, and setting the duty cycle to be 40 %-60 %, obtaining a pulsating base flow;

[0118] In each gas flow period of the pulsating base flow, two-stage adjustment is performed on the gas pulse amplitude, so that the Reynolds number of the pulsating rising section is less than 1800 to form a laminar flow section, and the Reynolds number of the pulsating peak section is higher than 2200 to form a micro-turbulent flow section, obtaining an alternating flow state;

[0119] The alternating flow state is used to shear and strip the shallow hot layer, obtaining an attached material mixed flow carried by the airflow;

[0120] The attached material mixed flow is continuously pumped out, obtaining a smooth and roughness less than 0.4 µm inner wall surface of the slit.

[0121] The following is a specific description of the steps involved in the above embodiments:

[0122] The laser power is adjusted to 15-20% of the rated power, and the scanning speed is set to 3-5 times the cutting speed, using the residual heat accumulated in the valve body during the cutting process. For example, when the cutting speed is 30 mm / s, the scanning speed is set to 90-150 mm / s. The laser cutting head performs reciprocating scanning motion along the inner wall of the slit. Reciprocating scanning refers to the scanning mode in which the laser beam moves back and forth along the longitudinal direction of the inner wall surface of the slit, including forward and reverse scanning stages. Through precise trajectory control of the numerical control system, the laser focal point moves closely along the inner wall surface of the slit, and the distance between the focal point and the inner wall is kept within 0.1-0.2 mm. Low power setting makes the laser only produce shallow melting on the inner wall surface without causing deep ablation, and high-speed scanning ensures that the laser and material interaction time is short, avoiding excessive heat input. The infrared temperature sensor monitors the inner wall temperature distribution in real time, and when the surface temperature reaches the solidus temperature of the material plus 20-50°C, a shallow hot layer is formed. The shallow hot layer refers to a thin layer structure where the surface of the material is heated by the laser to a semi-molten state, with a thickness controlled within 5-15 µm. This thickness range is achieved by precise matching of laser power and scanning speed, and a thickness that is too small cannot soften the surface roughness peaks, and a thickness that is too large will affect the geometric accuracy of the slit.

[0123] The temperature distribution data of the shallow melt hot layer is obtained by an infrared thermal imager. The temperature distribution refers to the temperature value variation of the shallow melt hot layer at each point in space. Based on the non-uniformity of the temperature distribution, the gas flow control system sets the pulse frequency of the inert protective gas. The inert protective gas is argon, and the pulse frequency is set to 5-20 Hz. The pulse frequency refers to the number of times the gas flow pressure changes periodically within a unit of time. At the same time, the duty cycle of the gas flow is set to 40%-60%. The duty cycle refers to the percentage of the time that the gas flow is in a high-pressure state within a pulse cycle. For example, when the pulse frequency is 10 Hz and the duty cycle is 50%, each pulse cycle is 0.1 seconds, of which 0.05 seconds is the high-pressure stage and 0.05 seconds is the low-pressure stage. The pulse base flow refers to the gas flow mode that changes periodically in pressure according to the set frequency and duty cycle. The gas flow is precisely adjusted by an electromagnetic proportional valve and a flow controller. The frequency range of 5-20 Hz is determined based on the cooling time constant of the shallow melt hot layer. A frequency that is too low will cause the hot layer to cool excessively before the gas flow acts, and a frequency that is too high will not give the hot layer sufficient softening time. The duty cycle range of 40%-60% ensures that the gas flow has enough high-pressure action time to produce a shearing effect on the hot layer, while the low-pressure interval allows the hot layer temperature to adjust naturally.

[0124] In each gas flow cycle of the pulse base flow, the gas pulse amplitude is adjusted in two stages by a programmable pressure regulation system. Two-stage adjustment refers to dividing the gas flow pressure into two different adjustment stages within a single pulse cycle, with each stage corresponding to a different pressure amplitude setting. The first stage is the pulse rising stage, which adjusts the gas pressure amplitude to a lower level, making the Reynolds number of the gas flow below 1800 to form a laminar flow section. The Reynolds number is a dimensionless parameter in fluid mechanics that represents the ratio of inertial force to viscous force. When the Reynolds number is below 1800, the fluid is in a laminar state. The second stage is the pulse peak stage, which adjusts the gas pressure amplitude to a higher level, making the Reynolds number above 2200 to form a micro-turbulent flow section. When the Reynolds number is above 2200, the fluid enters a turbulent state, which appears as micro-turbulent flow in the confined space of the slit. For example, when the slit diameter is 1 mm and the argon density is 1.6 kg / m3, the gas flow speed in the laminar flow section is controlled at 15-20 m / s, and the speed in the micro-turbulent flow section is increased to 35-45 m / s. The alternating flow state refers to the pattern of alternating laminar flow and micro-turbulent flow in time, which is achieved by a precise pressure regulation valve group to switch in real time. The laminar flow section provides stable surface coverage, and the micro-turbulent flow section generates strong shearing force. The alternation of the two can produce a gradual peeling effect on the shallow melt hot layer.

[0125] The shear stripping is a process of separating the softened layer on the surface of the material from the substrate by the tangential force of the airflow. During the laminar flow stage, the stable airflow applies uniform tangential stress on the surface of the shallow melting hot layer, causing plastic deformation of the material in the semi-molten state. During the micro-turbulent flow stage, the turbulent vortex has a strong tearing effect on the deformed material layer, which is completely stripped from the surface of the substrate. The stripped material moves with the airflow in the form of particles and flakes, and forms an attachment mixed flow with the airflow. The attachment mixed flow refers to the two-phase fluid formed after the surface material is stripped and mixed with the carrier gas, wherein the solid phase is micron-sized metal particles and flakes, and the gas phase is the carrier inert protective gas. The high-speed camera system can observe the trajectory of the material particles during the stripping process, and the particle size is controlled in the range of 1-5 microns, ensuring that it can be effectively carried by the airflow. The shear stripping mechanism of the alternating flow state avoids surface damage caused by mechanical contact, and at the same time, the low shear strength characteristics of the material in the semi-molten state are utilized to effectively reduce the surface roughness with the minimum energy input.

[0126] The vacuum exhaust system installed through the slit outlet continuously exhausts the attachment mixed flow. The exhaust process refers to the process of continuously sucking out and collecting the mixed flow from the inside of the slit. The vacuum pump provides negative pressure driving force, and the exhaust flow is controlled in the range of 2-5 cubic meters per minute, ensuring that the attachment mixed flow can be discharged in time without accumulating in the slit. The solid phase particles in the mixed flow are separated from the gas phase through a cyclone separator, and the solid phase particles are collected into a special container, and the gas phase is discharged after filtration. The continuous exhaust process cooperates with the shear stripping effect of the alternating flow state to gradually reduce the micro-unevenness of the inner wall surface of the slit. The surface roughness measuring instrument is used to detect the quality of the processed inner wall surface, and it is confirmed that the roughness value is less than 0.4 microns. The smooth and rough inner wall surface of the slit with a roughness of less than 0.4 microns refers to a high-quality surface state with good surface reflectivity and a micro-undulation height of less than 0.4 microns. Such surface quality meets the strict requirements of high-precision valves for the inner wall surface. The implementation of the continuous exhaust process eliminates the surface defects that may be introduced by traditional mechanical polishing, and realizes non-contact surface finishing by using the principle of airflow dynamics, ensuring that the inner wall of the slit meets the use standards of no leakage and low flow resistance.

[0127] In one embodiment of the present application, the low-power laser high-speed reciprocating scanning is performed on the inner wall of the slit, and the scanning speed is set to be 3-5 times the cutting speed, and a shallow melting hot layer with a thickness of 5 µm-15 µm is obtained, including:

[0128] In the forward scanning along the direction of the slit, the initial melting layer with a thickness of 3 µm-8 µm is generated by setting the scanning speed to be 3-5 times the cutting speed and the laser power to be 15 %-20 % of the rated power;

[0129] In the subsequent backward scan, the laser power is set to 5-10% of the rated power at the same scan rate, the initial molten layer is re-flattened and thickened to 5-10 pm, forming a shallow molten heat layer.

[0130] The following is a specific description of the steps involved in the above embodiments:

[0131] The laser cutting head starts from one end of the kerf and moves in the longitudinal direction of the kerf in a forward scan. Forward scanning refers to the process of moving the laser beam from the starting point to the end point of the kerf in the preset direction. The scan rate is set to 3-5 times the cutting rate by the numerical control system, for example, when the cutting rate is 30 mm / s, the forward scan rate is set to 90-150 mm / s. At the same time, the laser power is adjusted to 15-20% of the rated power by the laser power control module. This low power setting ensures that the laser only produces shallow heating on the inner wall surface of the kerf without causing deep melting. The laser beam moves close to the inner wall surface of the kerf, and the distance between the focal point and the inner wall is kept within 0.1 mm, and the focal point position is monitored in real time by the laser ranging sensor. High-speed scanning combined with low-power output makes the temperature of the inner wall surface of the kerf rise rapidly to 50-100°C above the solidus temperature of the material, and the material surface enters a semi-molten state. The material in this semi-molten state has low viscosity and surface tension, forming an initial molten layer with a thickness of 3-8 pm. The initial molten layer refers to the first layer of semi-molten film formed on the surface of the material after being heated by the laser. This film is still attached to the surface of the substrate but has lost its original solid rigidity. The 3-5 times scan rate is determined based on the thermal diffusion time constant of the material. Too slow speed will cause excessive heating, and too fast speed will not achieve sufficient surface softening effect. The power range of 15-20% ensures that sufficient energy density can be provided to melt the surface material under high-speed scanning conditions, while avoiding excessive heat input that causes deep ablation.

[0132] After the forward scan is completed, the laser cutting head immediately turns to perform a reverse scan, which refers to the scanning process of the laser beam returning from the end point to the starting point of the kerf. The scanning rate remains the same as that of the forward scan, i.e., 3-5 times the cutting rate, ensuring the continuity and consistency of the scan. The laser power is reduced to 5-10% of the rated power through the laser power control system. This lower power setting allows the laser to produce a mild secondary heating effect on the initial molten layer. Under the action of 5-10% low power, the initial molten layer is reheated but does not further melt, but redistributes and flattens. Redistribution refers to the process of semi-molten material spontaneously flowing under the action of surface tension and filling the microscopic concave-convex of the surface, similar to the self-leveling phenomenon of liquid. At the same time, the continuous heating of low power also makes part of the base material reach a semi-molten state, thickening the initial molten layer. The change in molten layer thickness is monitored by a contact thickness gauge or a laser interferometric thickness measurement system, and the reverse scan is completed when the thickness reaches 5-10 microns. The shallow molten heat layer formed after the reverse scan has better uniformity and adhesion, and the surface flatness is significantly improved. The power range of 5-10% is determined based on the secondary heating characteristics of the material. Higher power will destroy the structure of the initial molten layer formed, and lower power will not achieve effective flattening and thickening effect. The process design of bidirectional scanning utilizes the differential effects of different power levels on the material state, and achieves the step-by-step optimization of the surface micro-topography through precise energy control.

[0133] The valve laser cutting method in the embodiments of the present application is described above, and the valve laser cutting device in the embodiments of the present application is described below. Please refer to Figure 2 An embodiment of the valve laser cutting device in the embodiments of the present application includes:

[0134] The groove preparation module 101 is used to perform multiple low-duty pulse laser scans along the preset cutting line on the outer wall of the valve body, forming a guide groove with a surface tension gradient on the outer wall of the valve body, and the side wall of the guide groove has corrugated microtexture.

[0135] The airflow construction module 102 is used to spray inner layer pulse airflow and outer layer pulse airflow into the guide groove according to the surface tension gradient and corrugated microtexture of the guide groove, the inner layer pulse airflow forms periodic negative pressure cavities in the guide groove, and the outer layer pulse airflow forms positive pressure barriers on both sides of the guide groove.

[0136] The spiral cutting module 103 is used to perform continuous laser cutting on the guide groove in a spiral trajectory under the action of the inner layer pulse airflow and the outer layer pulse airflow, and at the same time, transverse ultrasonic waves in a preset resonance relationship with the frequency of the inner layer pulse airflow are applied to the cutting area, the transverse ultrasonic waves form standing waves on the surface of the molten pool, guiding the molten metal to flow outward along the guide groove, and forming a kerf penetrating through the thickness of the valve body wall.

[0137] A suction and slagging module 104 is configured to switch the inner and outer pulse air flows to a negative pressure suction mode when the laser cutting penetrates through the valve body wall thickness, and simultaneously switch the transverse ultrasonic wave from a standing wave to a traveling wave to remove residual molten material in the cut seam;

[0138] A thermal polishing module 105 is configured to perform a low-power laser rapid scanning on the inner wall of the cut seam using the valve body residual heat, and simultaneously spray a periodic pulsating inert protective gas to the cut seam to strip the residual adhesion on the inner wall of the cut seam by alternating the laminar flow and micro-turbulent flow of the air flow.

[0139] The above Figure 2 The valve body laser cutting device in the embodiment of the present application is described in detail from the perspective of a modular functional entity, and the valve body laser cutting device in the embodiment of the present application is described in detail from the perspective of hardware processing.

[0140] Figure 3 is a structural schematic diagram of a valve body laser cutting device provided by the embodiment of the present application. The valve body laser cutting device 200 can have a large difference due to different configurations or performances, and can include one or more processors 210 (for example, one or more processors) and a memory 220, one or more storage media 230 (for example, one or more mass storage device ends) storing an application program 233 or data 232. The memory 220 and the storage medium 230 can be temporary storage or persistent storage. The program stored in the storage medium 230 can include one or more modules (not shown in the figure), and each module can include a series of instruction operations in the valve body laser cutting device 200. Further, the processor 210 can be configured to communicate with the storage medium 230, execute a series of instruction operations in the storage medium 230 on the valve body laser cutting device 200, so as to realize the steps of the valve body laser cutting method described above.

[0141] The valve body laser cutting device 200 can further include one or more power supplies 240, one or more wired or wireless network interfaces 250, one or more input and output interfaces 260, and / or one or more operating systems 231, such as Windows Serve, Mac OS X, Unix, Linux, FreeBSD, and the like. Those skilled in the art can understand that Figure 3 The valve body laser cutting device structure shown does not constitute a limitation on the valve body laser cutting device provided by the present application, and can include more or fewer components than shown, or combine certain components, or different component arrangements.

[0142] The above merely describes the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structural changes made according to the content of the present application specification and drawings, or direct / indirect application in other related technical fields, are included in the patent protection scope of the present application.

Claims

1. A method for laser cutting a valve body, characterized in that, include: The valve body outer wall is scanned multiple times with a low duty cycle pulsed laser along a preset cutting line to form a guide groove with a surface tension gradient on the valve body outer wall. The sidewall of the guide groove has a corrugated microtexture. Based on the surface tension gradient and corrugated microtexture of the guide groove, an inner layer pulsed airflow and an outer layer pulsed airflow are injected into the guide groove. The inner layer pulsed airflow forms a periodic negative pressure cavity in the guide groove, and the outer layer pulsed airflow forms a positive pressure barrier on both sides of the guide groove. Under the action of the inner and outer pulsed airflows, the guide groove is continuously laser-cut in a spiral trajectory. At the same time, transverse ultrasonic waves that resonate with the frequency of the inner pulsed airflow are applied to the cutting area. The transverse ultrasonic waves form a standing wave on the surface of the molten pool, guiding the molten metal outward along the guide groove to form a cut that penetrates the thickness of the valve body wall. When the laser cut penetrates the valve body wall, the inner and outer pulsed airflows are switched to negative pressure suction mode, and the transverse ultrasonic waves are switched from standing waves to traveling waves to remove residual melt in the cut. The residual heat of the valve body is used to perform a low-power laser rapid scan on the inner wall of the cut, while periodically pulsating inert protective gas is sprayed into the cut. The residual deposits on the inner wall of the cut are peeled off by alternating laminar and microturbulent flow.

2. The valve body laser cutting method according to claim 1, characterized in that, The process involves multiple low-duty-cycle pulsed laser scans along a preset cutting line on the outer wall of the valve body to form a guide groove with a surface tension gradient. The sidewall of the guide groove has a corrugated microtexture, including: The valve body outer wall is first pulsed laser scanned along the preset cutting line. The single pulse energy is set to the first energy level and the inter-channel offset is half the spot width to form an initial shallow melt groove. Based on the position of the initial shallow melt pool, the initial shallow melt pool is subjected to multi-layer pulse scanning with increasing energy, and a fixed cooling interval is inserted after each layer scan, so that a fine grain layer and a columnar grain layer are formed sequentially at the bottom of the pool, thereby obtaining a stepped melt depth and a longitudinal surface tension gradient. Based on the stepped melting depth, a final deep scan is performed at a scanning speed higher than that of multi-layer pulse scanning to reduce the local energy density at the center of the tank bottom and form an energy gradient that decreases from the center of the tank to the outlet. Using the groove wall generated by the final deep scan as a reference, the groove wall is alternately scanned with ±θ lateral polarization pulses, where θ represents the angle between the linear polarization direction of the laser beam and the axis of the guide groove. This modulates the lateral amplitude of the melting peaks and troughs, and inscribes corrugated microtextures distributed longitudinally on the sidewall of the guide groove.

3. The valve body laser cutting method according to claim 1, characterized in that, The process involves injecting inner and outer pulsed airflows into the guide groove based on its surface tension gradient and corrugated microtexture. The inner pulsed airflow forms a periodic negative pressure cavity within the guide groove, while the outer pulsed airflow forms a positive pressure barrier on both sides of the guide groove. Based on the longitudinal period of the corrugated microtexture of the guide groove, a first pulse frequency is set for the inner layer pulse airflow, so that the center position of the negative pressure cavity of the adjacent pulse corresponds one-to-one with the valley of the adjacent texture. A second pulse frequency is set for the outer layer pulse airflow, and the second pulse frequency is kept in a 1:1 ratio with the first pulse frequency. A 180° phase difference is set between the outer layer pulse airflow and the inner layer pulse airflow, so that the outer layer positive pressure peak is located at the adjacent texture wave peak. While keeping the first pulse frequency unchanged, the peak pressure of the inner pulse airflow is gradually adjusted until the negative pressure valley pressure is lower than the capillary pressure threshold corresponding to the surface tension of the bottom of the tank, thus obtaining a stable negative pressure chamber. After obtaining the stable negative pressure cavity, the duty cycle of the outer layer pulse airflow is gradually adjusted to limit the width of the outer layer positive pressure peak to the texture wave peak region, forming a positive pressure barrier that extends longitudinally on both sides of the guide groove.

4. The valve body laser cutting method according to claim 1, characterized in that, The process involves continuous laser cutting of the guide groove along a spiral trajectory under the action of the inner and outer pulsed airflows. Simultaneously, transverse ultrasonic waves with a preset resonance relationship to the frequency of the inner pulsed airflow are applied to the cutting area. These transverse ultrasonic waves form a standing wave on the surface of the molten pool, guiding the molten metal outwards along the guide groove, forming a cut that penetrates the valve body wall thickness. This includes: Based on the width and depth of the guide groove, the spiral trajectory parameters are set for the laser cutting head to obtain the spiral feed path; According to the spiral feed path, power increment control is applied to the continuous laser beam so that the laser focus synchronously follows the negative pressure node of the inner layer pulse airflow along the spiral feed path to obtain synchronous energy distribution; Based on the synchronous energy distribution, the driving frequency of the transverse ultrasonic wave is set to be in a 3:4 ratio with the frequency of the inner pulse airflow, and the phase of the transverse ultrasonic wave is adjusted so that the antinode of the standing wave corresponds to the position of the negative pressure node, thereby obtaining a standing wave compression molten pool. Based on the standing wave compression molten pool, the molten metal is discharged along the direction of the guide groove to obtain a slit profile that penetrates the thickness of the valve body wall.

5. The valve body laser cutting method according to claim 4, characterized in that, The step of setting helical trajectory parameters for the laser cutting head based on the width and depth of the guide groove to obtain the helical feed path includes: Based on the width of the guide groove, determine the radial feed amount per turn of the spiral, and make the radial feed amount per turn of the spiral account for 2%-5% of the corresponding groove width to obtain the variable pitch; Based on the depth of the guide groove, calculate the longitudinal step distance of the spiral, and make the longitudinal step distance account for 1%-3% of the corresponding groove depth to obtain segmented axial feed; Based on the curvature of the outer wall of the valve body, the tilt angle of the laser cutting head is calculated so that the laser incident angle deviates from the normal of the guide groove by no more than ±3°, thus obtaining dynamic tilt angle compensation; By combining the variable pitch, segmented axial feed, and dynamic tilt angle compensation, a helical feed path is generated.

6. The valve body laser cutting method according to claim 1, characterized in that, When the laser cut penetrates the valve body wall, the inner and outer pulsed airflows are switched to a negative pressure suction mode, and the transverse ultrasonic waves are switched from standing waves to traveling waves to remove residual molten material from the cut, including: At the moment the cut is completed, a negative pressure suction pulse is applied to the inner layer pulsed airflow, the suction period is set to 40 ms-60 ms, and the suction amplitude is adjusted to 1.2-1.6 times the tension threshold of the cut section to obtain the first negative pressure wavefront; During the propagation of the first negative pressure wavefront, the transverse ultrasonic wave is switched to a traveling wave, and the propagation direction of the traveling wave is in the same direction as the first negative pressure wavefront, so as to obtain air-sound co-directional traction. After the air-sound traction is completed, a converging positive pressure pulse is applied to the outer layer pulse airflow to limit the intersection point of the first negative pressure wavefront and the inner cavity reflected wave at the cut outlet, thus obtaining the intercepting air curtain. According to the intercepting air curtain, the amplitude of the traveling wave is linearly attenuated along the slit length, so that the tail of the traveling wave attenuates to 25%-35% of the initial amplitude at the slit exit, thus obtaining the gradually diminishing section of the traveling wave, and simultaneously removing the residual melt in the slit.

7. The valve body laser cutting method according to claim 1, characterized in that, The process involves using the waste heat of the valve body to perform a low-power laser rapid scan of the inner wall of the cut, while simultaneously injecting a periodically pulsating inert protective gas into the cut. This process, through alternating laminar and micro-turbulent flow, removes residual deposits from the inner wall of the cut. A low-power laser high-speed reciprocating scan is performed on the inner wall of the cut, with the scanning rate set to 3-5 times the cutting rate, to obtain a shallow molten layer with a thickness of 5 µm-15 µm. Based on the temperature distribution of the shallow molten thermal layer, the pulsation frequency of the inert protective gas is set to 5 Hz-20 Hz, and the duty cycle is set to 40%-60%, to obtain the pulsating base current. Within each gas flow cycle of the pulsating base flow, the gas pulse amplitude is adjusted in two stages, so that the Reynolds number of the pulsating rising stage is lower than 1800 to form a laminar flow stage, and the Reynolds number of the pulsating peak stage is higher than 2200 to form a micro-turbulent flow stage, thus obtaining an alternating flow pattern. Using the alternating flow pattern, the shallow molten hot layer is sheared and peeled off to obtain a mixed flow of adhering material carried by the airflow; The mixture of the deposits is continuously pumped out to obtain a smooth inner wall surface of the cut with a roughness of less than 0.4 µm.

8. The valve body laser cutting method according to claim 7, characterized in that, The process of performing low-power laser high-speed reciprocating scanning on the inner wall of the cut, setting the scanning rate to 3-5 times the cutting rate, yields a shallow molten layer with a thickness of 5 µm-15 µm, including: In the forward scanning along the cutting direction, with a scanning rate of 3-5 times the cutting rate and the laser power set to 15%-20% of the rated power, an initial melt layer with a thickness of 3 µm-8 µm is generated. In the subsequent reverse scan, the laser power is set to 5%-10% of the rated power at the same scan rate, and the initial molten layer is flattened and thickened to 5 µm-10 µm to obtain a shallow molten layer.

9. A valve body laser cutting device, characterized in that, The valve body laser cutting device employs the valve body laser cutting method as described in any one of claims 1 to 8, and the valve body laser cutting device comprises: The groove preparation module is used to perform multiple low-duty-cycle pulsed laser scans on the outer wall of the valve body along a preset cutting line to form a guide groove with a surface tension gradient on the outer wall of the valve body. The sidewall of the guide groove has corrugated micro-texture. An airflow construction module is used to inject inner-layer pulsed airflow and outer-layer pulsed airflow into the guide groove according to the surface tension gradient and corrugated microtexture of the guide groove. The inner-layer pulsed airflow forms a periodic negative pressure cavity in the guide groove, and the outer-layer pulsed airflow forms a positive pressure barrier on both sides of the guide groove. The spiral cutting module is used to perform continuous laser cutting of the guide groove in a spiral trajectory under the action of the inner layer pulse airflow and the outer layer pulse airflow. At the same time, transverse ultrasonic waves that form a preset resonance relationship with the frequency of the inner layer pulse airflow are applied to the cutting area. The transverse ultrasonic waves form a standing wave on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, forming a cut that penetrates the thickness of the valve body wall. The suction and slag removal module is used to switch the inner and outer pulse airflows to negative pressure suction mode when the laser cut penetrates the wall thickness of the valve body, and at the same time switch the transverse ultrasonic wave from standing wave to traveling wave to remove the residual melt in the cut. The waste heat polishing module is used to perform low-power laser rapid scanning on the inner wall of the cut using the waste heat of the valve body, while simultaneously spraying periodically pulsating inert protective gas into the cut. The residual deposits on the inner wall of the cut are peeled off by alternating laminar and microturbulent airflow.

10. A valve body laser cutting device, characterized in that, The valve body laser cutting device includes: a memory and at least one processor, wherein the memory stores instructions; The at least one processor invokes the instructions in the memory to cause the valve body laser cutting device to perform the steps of the valve body laser cutting method as described in any one of claims 1 to 8.

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