Valve body laser cutting device and method thereof

Abstract

The invention discloses a valve body laser cutting device and method. The method comprises the steps that low-duty-ratio pulse scanning is conducted on the outer wall of a valve body to generate a guide groove with a surface tension gradient and corrugated textures; spraying inner and outer double-layer pulse airflow according to the characteristics of the guide groove, and respectively forming a periodic negative pressure cavity and positive pressure barriers on two sides at the bottom of the groove; spiral track continuous laser cutting is executed under the action of double-layer airflow, transverse ultrasonic waves forming a three-to-four resonance relation with inner-layer pulse airflow are applied, standing wave diversion is established on the surface of a molten pool, and a kerf penetrating through the wall thickness is obtained; when the kerfs are cut through, the airflow is synchronously switched into negative pressure suction, and ultrasonic waves are changed into traveling waves so as to remove residual molten drops; and low-power rapid scanning is conducted on the inner wall of the kerf through waste heat of the valve body, pulsating inert airflow is injected at the same time, and the residual film is alternately stripped through laminar flow and micro-turbulent flow. According to the scheme, under the condition that extra cooling or chemical treatment is not added, slag rewinding can be restrained.

Description

Technical Field

[0001] The present invention relates to the technical field of metal valve laser processing, and in particular to a valve body laser cutting device and method thereof. Background Art

[0002] As a key component for pressure bearing and sealing, the valve body typically has a wall thickness of 20 to 50 millimeters, and the internal flow channel has a three-dimensional curved or stepped throttling structure. Traditional turning, milling, and drilling are prone to introducing tool chatter marks, thermal cracks, and residual stress when machining deep holes, special-shaped grooves, or curved windows. Multiple tool changes and custom fixtures significantly increase the manufacturing cycle. Laser cutting uses a focused high-energy density beam to instantly melt metal in a very small area. Combined with five-axis CNC, the light spot can always be kept perpendicular to the local curved surface, thereby completing the removal of narrow slits through thick walls in a single operation. Its heat-affected zone is only a few hundred microns, causing almost no macroscopic deformation, providing a base surface with dual controllable size and structure for subsequent surfacing, grinding, and automated assembly. Therefore, laser cutting has become an irreplaceable finishing process in high-end valve manufacturing.

[0003] The existing valve body laser cutting process usually begins by perforating the outer surface at vertical incidence, establishing a slag removal jet channel, and then cutting along a pre-programmed trajectory until the inner cavity is broken through. The high-pressure auxiliary gas coaxially ejected from the cutting head is reflected multiple times on the narrow cavity wall, generating a local reverse shock wave. When the dynamic pressure of this reverse flow and the surface tension of the molten pool are in the critical matching range, the molten droplets that have not yet been discharged are sucked back to the inner wall and rapidly solidify, forming a resolidified film only tens of microns thick. This phenomenon is called "slag rewind." Because this film is located inside the valve body and is invisible to the naked eye, current coaxial visual and offline inspections are difficult to identify in a timely manner. At the same time, the cutting parameters and airflow pattern lack real-time coupling control. When there are slight fluctuations in laser power or air pressure, the rewind effect is further amplified, ultimately leading to a sudden change in inner wall roughness, potential leakage, and increased local flow resistance. Summary of the Invention

[0004] The main purpose of the present invention is to solve the technical problem that during the existing thick-wall laser cutting process of a valve body, slag rolls back and re-solidifies on the inner wall, resulting in sealing failure and increased flow resistance.

[0005] A first aspect of the present invention provides a valve body laser cutting method, the valve body laser cutting method comprising: The outer wall of the valve body is scanned multiple times by a low-duty-cycle pulsed laser along a preset cutting line to form a guide groove with a surface tension gradient on the outer wall of the valve body, wherein the side wall of the guide groove has a corrugated micro-texture; According to the surface tension gradient and corrugated micro-texture of the guide groove, an inner layer of pulsed airflow and an outer layer of pulsed airflow are sprayed into the guide groove, wherein the inner layer of pulsed airflow forms a periodic negative pressure cavity in the guide groove, and the outer layer of pulsed airflow forms a positive pressure barrier on both sides of the guide groove; Under the action of the inner layer pulse airflow and the outer layer pulse airflow, the guide groove is continuously laser cut along a spiral trajectory, and 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 standing waves on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, forming a slit that penetrates the thickness of the valve body wall; 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 the residual melt in the cut; The inner wall of the slit is quickly scanned with a low-power laser using the residual heat of the valve body, and at the same time, an inert protective gas with periodic pulsation is sprayed toward the slit, and residual attachments on the inner wall of the slit are peeled off by alternating laminar flow and micro-turbulence of the airflow.

[0006] Preferably, the outer wall of the valve body 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 outer wall of the valve body, wherein the side wall of the guide groove has a corrugated micro-texture, including: Perform the first pulse laser scan on the outer wall of the valve body along the preset cutting line, set the single pulse energy to the first energy level and the inter-pass offset to half the spot width to form an initial shallow melt groove; According to the position of the initial shallow molten groove, the initial shallow molten groove is subjected to multi-layer pulse scanning with increasing energy, and a fixed cooling interval is inserted after each layer of scanning, so that a fine crystal layer and a columnar crystal layer are sequentially formed at the bottom of the groove, thereby obtaining a step-by-step penetration and a longitudinal surface tension gradient; Based on the step penetration depth, a final deep scan is performed at a scanning speed higher than that of the multi-layer pulse scan to reduce the local energy density at the center of the groove bottom, thereby forming an energy gradient that decreases from the groove center to the outlet; Taking 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. The lateral amplitudes of the melting peaks and troughs are modulated to engrave a corrugated microtexture distributed longitudinally on the side wall of the guide groove.

[0007] Preferably, the method of spraying an inner layer of pulsed airflow and an outer layer of pulsed airflow into the guide groove according to the surface tension gradient and the corrugated microtexture of the guide groove, wherein the inner layer of pulsed airflow forms a periodic negative pressure cavity in the guide groove and the outer layer of pulsed airflow forms a positive pressure barrier on both sides of the guide groove, includes: According to the longitudinal period of the corrugated micro-texture of the guide groove, a first pulse frequency is set for the inner pulse airflow so that the center positions of the negative pressure cavities of adjacent pulses correspond to adjacent texture troughs one by one; Setting a second pulse frequency for the outer pulse airflow, and maintaining a 1:1 ratio between the second pulse frequency and the first pulse frequency, setting a 180° phase difference between the outer pulse airflow and the inner pulse airflow, so that the outer positive pressure peak is located at the adjacent texture wave peak; Under the premise of 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 groove bottom, thereby obtaining a stable negative pressure cavity; After obtaining the stable negative pressure cavity, the duty cycle of the outer pulse airflow is gradually adjusted so that the width of the outer positive pressure peak is limited to the texture wave peak area, forming a positive pressure barrier extending longitudinally on both sides of the guide groove.

[0008] Preferably, under the action of the inner layer pulse airflow and the outer layer pulse airflow, the guide groove is continuously laser cut in a spiral trajectory, and at the same time, a transverse ultrasonic wave having a preset resonance relationship with the frequency of the inner layer pulse airflow is applied to the cutting area, the transverse ultrasonic wave forms a standing wave on the surface of the molten pool, and guides the molten metal to be discharged outward along the guide groove, thereby forming a slit that penetrates the wall thickness of the valve body, including: According to the groove width and groove depth of the guide groove, spiral trajectory parameters are set for the laser cutting head to obtain a spiral feed path; According to the spiral feeding path, power incremental 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 feeding path to obtain synchronous energy distribution; According to the synchronized energy distribution, a driving frequency of the transverse ultrasonic wave is set in a ratio of 3:4 to the frequency of the inner layer pulsed airflow, and a 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; According to 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 wall thickness of the valve body.

[0009] Preferably, the spiral trajectory parameters are set for the laser cutting head according to the groove width and groove depth of the guide groove to obtain the spiral feed path, including: Determine the radial feed amount of a single spiral turn according to the groove width of the guide groove, so that the radial feed amount of the single spiral turn accounts for 2%-5% of the corresponding groove width to obtain a variable pitch; According to the groove depth of the guide groove, the spiral longitudinal pitch is calculated so that the longitudinal pitch accounts for 1%-3% of the corresponding groove depth to obtain segmented axial feed; According to 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 line of the guide groove by no more than ±3°, thereby obtaining dynamic tilt compensation; The variable pitch, segmented axial feed and dynamic inclination compensation are combined to generate a spiral feed path.

[0010] Preferably, 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 a negative pressure suction mode, and the transverse ultrasonic wave is switched from a standing wave to a traveling wave to remove the residual melt in the slit, including: At the moment of the slit penetration, 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 tension threshold of the slit 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 traveling wave propagation direction is made to be in the same direction as the first negative pressure wavefront, thereby obtaining air-acoustic co-directional traction; After the air-acoustic co-directional traction is completed, a closing positive pressure pulse is applied to the outer pulsed airflow, and the intersection point of the first negative pressure wave front and the inner cavity reflected wave is limited to the incision outlet to obtain a trapped air curtain; According to the trapped air curtain, the traveling wave amplitude is set to linearly attenuate along the slit length, so that the tail of the traveling wave decays to 25%-35% of the initial amplitude at the slit exit, obtaining a traveling wave fading section, and simultaneously removing the residual melt in the slit.

[0011] Preferably, the method of utilizing the residual heat of the valve body to rapidly scan the inner wall of the slit with a low-power laser, and simultaneously spraying an inert protective gas superimposed with periodic pulsations toward the slit, and peeling off residual attachments on the inner wall of the slit by alternating laminar flow and micro-turbulence of the gas flow, includes: Performing a low-power laser high-speed reciprocating scan on the inner wall of the slit, setting the scanning rate to 3-5 times the cutting rate, to obtain a shallow melt layer with a thickness of 5 μm-15 μm; According to the temperature distribution of the shallow melting heat layer, the pulsating frequency of the inert shielding gas is set to 5 Hz-20 Hz, and the duty cycle is set to 40%-60% to obtain a pulsating base flow; In each airflow 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, thereby obtaining an alternating flow state; The shallow melt heat layer is subjected to shear stripping treatment by utilizing the alternating flow pattern to obtain a mixed flow of attachments carried by the airflow; The mixed flow of attachments is continuously pumped out to obtain a smooth inner wall surface of the cut with a roughness of less than 0.4 μm.

[0012] Preferably, the method of performing a low-power laser high-speed reciprocating scan on the inner wall of the slit, setting the scanning rate to 3-5 times the cutting rate, and obtaining a shallow melt heat layer with a thickness of 5 μm-15 μm, comprises: In the forward scan along the kerf direction, the scanning rate is 3-5 times the cutting rate and the laser power is set to 15%-20% of the rated power to generate an initial melt layer with a thickness of 3 µm-8 µm; In the subsequent reverse scan, the laser power is set to 5%-10% of the rated power at the same scanning rate, and the initial melt layer is flattened again and thickened to 5 μm-10 μm to obtain a shallow melt layer.

[0013] A second aspect of the present invention provides a valve body laser cutting device, the valve body laser cutting device comprising: A 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, wherein the side wall of the guide groove has a corrugated micro-texture; an airflow construction module, configured to eject an inner layer of pulsed airflow and an outer layer of pulsed airflow into the guide groove according to the surface tension gradient and the corrugated microtexture of the guide groove, wherein the inner layer of pulsed airflow forms a periodic negative pressure cavity within the guide groove, and the outer layer of pulsed airflow forms a positive pressure barrier on both sides of the guide groove; a spiral cutting module, configured to perform continuous laser cutting of the guide groove along a spiral trajectory under the action of the inner layer pulsed airflow and the outer layer pulsed airflow, while simultaneously applying transverse ultrasonic waves having a preset resonance relationship with the frequency of the inner layer pulsed airflow to the cutting area, so that the transverse ultrasonic waves form standing waves on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, thereby forming a slit that penetrates the thickness of the valve body wall; A suction and slag removal module is used to switch the inner layer pulse airflow and the outer layer pulse airflow to a negative pressure suction mode when the laser cutting penetrates the wall thickness of the valve body, and at the same time switch the transverse ultrasonic wave from a standing wave to a traveling wave to remove the residual melt in the slit; The residual heat polishing module is used to use the residual heat of the valve body to quickly scan the inner wall of the slit with a low-power laser, and at the same time spray an inert protective gas with periodic pulsation onto the slit, so as to peel off the residual attachments on the inner wall of the slit by alternating laminar flow and micro-turbulence of the airflow.

[0014] The third aspect of the present invention provides a valve body laser cutting device, comprising: a memory and at least one processor, wherein instructions are stored in the memory, and the memory and the at least one processor are interconnected through lines; the at least one processor calls the instructions in the memory so that the valve body laser cutting device performs the steps of the above-mentioned valve body laser cutting method.

[0015] The technical solution provided by the embodiment of the present application is that the outer wall of the valve body is first subjected to multiple scans of low-duty-cycle pulses, and local melting and solidification are formed in the shallow layer to form a groove bottom that gradually transitions from fine crystals to columnar crystals, while a longitudinal corrugated texture is engraved on the groove wall. The grain transition zone causes the surface tension to continuously decrease along the groove depth, and the trough-peak sequence of the corrugated texture provides a longitudinal positioning reference for the subsequent airflow. The subsequently injected inner and outer double-layer pulsed airflows use this geometric and energy conditions to periodically generate a negative pressure cavity at the bottom of the groove and synchronously generate a positive pressure barrier on both sides. The negative pressure cavity is consistent with the direction of the tension gradient, so that the molten metal naturally tends to discharge outward from the center of the groove; the positive pressure barrier locks the airflow to prevent it from escaping, maintaining the shape and position of the negative pressure cavity. When the spiral trajectory is continuously cut, the laser focus always advances in the same direction as 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 provides thrust. The molten metal is continuously pulled out along the bottom of the groove and does not stay on the wall. At the moment the cut penetrates the thick wall, the double-layer airflow switches to a short-term negative pressure suction, and the ultrasonic mode simultaneously changes to a traveling wave. The traveling wave aligns with the suction direction, dragging any remaining droplets and vaporized products away from the wall, preventing them from being drawn back into the inner cavity by the reverse shock wave. The residual heat of the valve body is then redistributed into a thin melt layer by rapid low-power scanning. The pulsating inert gas flow periodically switches between laminar and micro-turbulent flow: the laminar phase steadily covers the wall, while the micro-turbulent peak momentarily increases shear stress, sweeping away any microfilms and particles adhering to the thin melt layer. These are then carried out of the channel by the air curtain in the next laminar phase. Thus, the entire process, from initial groove induction, airflow-acoustic field synergistic slag removal, to residual heat pulsating polishing, eliminates the conditions for molten metal to resolidify on the inner wall. The inner wall roughness remains smooth at the micron level, without the risk of leakage, fundamentally addressing the problem of slag rollback and reattachment during the laser cutting of thick-walled valve bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of an embodiment of a valve body laser cutting method according to an embodiment of the present invention; Figure 2 A schematic diagram of an embodiment of a valve body laser cutting device in an embodiment of the present invention; Figure 3 This is a schematic diagram of an embodiment of a valve body laser cutting device in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0019] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes technical solution A, technical solution B, and technical solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, and must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0020] An embodiment of the present application provides a valve body laser cutting method. Figure 1 A flow chart of a valve body laser cutting method provided in one embodiment of the present application. In this embodiment, the method includes: See also Figure 1 , a low-duty-cycle pulse laser is scanned multiple times along a preset cutting line on the outer wall of the valve body 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 micro-texture; In one embodiment of the present invention, the outer wall of the valve body is scanned multiple times along a preset cutting line by a low-duty-cycle pulsed laser to form a guide groove with a surface tension gradient on the outer wall of the valve body, wherein the side wall of the guide groove has a corrugated micro-texture, including: Perform the first pulse laser scan on the outer wall of the valve body along the preset cutting line, set the single pulse energy to the first energy level and the inter-pass offset to half the spot width to form an initial shallow melt groove; According to the position of the initial shallow molten groove, the initial shallow molten groove is subjected to multi-layer pulse scanning with increasing energy, and a fixed cooling interval is inserted after each layer of scanning, so that a fine crystal layer and a columnar crystal layer are sequentially formed at the bottom of the groove, thereby obtaining a step-by-step penetration and a longitudinal surface tension gradient; Based on the step penetration depth, a final deep scan is performed at a scanning speed higher than that of the multi-layer pulse scan to reduce the local energy density at the center of the groove bottom, thereby forming an energy gradient that decreases from the groove center to the outlet; Taking 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. The lateral amplitudes of the melting peaks and troughs are modulated to engrave a corrugated microtexture distributed longitudinally on the side wall of the guide groove.

[0021] The following is a detailed description of the steps involved in the above embodiment: A fiber laser is used to set the pulse working mode, and the energy of a single pulse is adjusted to the first energy level of 0.12-0.18 mJ. The pulse width is controlled within the range of hundreds of nanoseconds, and the operation is maintained in the thermal conductivity mode to avoid plasma formation. The laser beam is focused to a spot diameter of about 80 microns through a 100 mm 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 the spot diameter. According to the geometric relationship of the circular spot, such an offset distance causes the melting areas of adjacent laser pulses to produce an overlapping area of more than 70%, ensuring the formation of a continuous melting track. The laser duty cycle is controlled below 10%, so that the surface of the material only melts to a depth of 20-30 microns without entering a vaporized state. Under this energy control, the cooling rate of the molten metal reaches 10 6 With a cooling rate exceeding 1 Kelvin per second, the rapid cooling prevents the crystal nuclei from growing, resulting in a fine-grained layer with an average grain size of less than 5 microns at the bottom of the groove. Due to the high density of grain boundaries, the surface energy of this fine-grained layer is 5-8 millijoules per square meter higher than that of the surrounding parent material, providing a recognizable surface tension gradient for subsequent melt pool movement. The geometric contours of the initial shallow melt groove also provide a precise laser beam positioning reference for multi-layer scanning.

[0022] Multi-layer pulse scanning is performed along the same scanning path for 3-5 layers, with the pulse energy increasing by 10-15% with each layer, while maintaining a constant 40-micron inter-pass offset. After each layer, the laser control system pauses for 6-8 milliseconds. This fixed cooling interval allows the upper melt pool to fully solidify while the lower material remains undercooled at 500-600 Kelvin. Under this temperature gradient, heat flow is directed from the walls to the bottom of the groove, ensuring stable crystal growth and forming a columnar structure within the subsequent melt depth. Columnar crystals are formed by grains extending in a specific direction, reaching lengths of 40-60 microns, while the upper layer retains a fine-grained morphology. As the number of scan layers increases, the grain radius increases monotonically from the groove opening to the bottom, while the corresponding surface free energy decreases monotonically, creating a surface tension gradient of 0.3-0.5 Newtons per square meter per centimeter along the longitudinal direction of the groove bottom. This gradient, driven by the surface energy differences among different grain sizes, continuously drives the molten metal toward the higher surface energy region at the center of the groove, preventing it from spreading to the sides. Multi-layer progressive scanning expands the total penetration depth to 1%-1.5% of the valve body wall thickness and forms a stepped sidewall structure on the groove wall, providing geometric convenience for subsequent laser beam focusing and positioning.

[0023] Based on the stepped penetration structure, the laser scanning speed is increased to 1.8 times the aforementioned multi-layer scanning speed, while maintaining the laser energy level of the previous layer. This increased scanning speed shortens the interaction time between the laser beam and the material, reducing heat input per unit time by approximately 35%. Heat in the center of the groove bottom is rapidly dissipated into the surrounding material through lateral heat conduction, while the groove outlet, due to different heat dissipation conditions at the edges, is relatively high, resulting in an energy gradient distribution with low temperatures at the center and high temperatures at the outlet. This energy gradient confines the molten metal flow driven by surface tension differences (i.e., Marangoni convection, a fluid flow phenomenon caused by surface tension gradients induced by temperature gradients) to the flow channel from the groove center to the outlet, effectively preventing the molten metal from climbing up the groove walls. Furthermore, the high scanning speed keeps heat accumulation below 200 joules per square centimeter, preventing macroscopic thermal deformation in thick-walled valve bodies. The decreasing energy gradient from the groove center to the outlet provides a geometric driving force for the molten metal generated during the subsequent spiral cutting process, ensuring its rapid discharge in the desired direction without stagnating at the groove bottom.

[0024] Using the final deep-scanned groove wall surface as the machining reference, a galvanometer system controls the laser polarization direction, switching pulses between ±θ angles. θ represents the angle of the laser beam's linear polarization relative to the guide groove axis (i.e., the scanning direction), specifically set to ±12°. The interval between each pulse is set to 0.15 mm. Linearly polarized laser light refers to lasers whose electric field vector oscillates within a fixed plane. Its energy coupling coefficient to the molten metal pool varies significantly with the incident angle and the direction of the electric field vector. The alternating ±12° polarization produces periodic lateral temperature rise differences on the groove wall surface, resulting in varying melting depths at the solid-liquid interface at different locations, forming an undulating structure of peaks and troughs. After the solidification process is complete, a series of longitudinally distributed ridges and valleys remain on the groove wall surface. The height difference between the high and low points is approximately 6-8 microns, and the pitch between adjacent ridges and valleys is stable at 18-22 microns, forming a regular corrugated microtexture. This ridge-valley sequence provides a precise geometric locking point for the subsequent double-layer pulsed airflow: the negative pressure cavity is stably positioned at the trough, and the positive pressure peak is confined by the ridge structure, preventing the spatial position of the double-layer airflow from drifting due to occasional disturbances. Simultaneously, the curvature differences of the micro-textured grooves enhance the wall wetting angle gradient, allowing the molten pool to be continuously pushed toward the notch under the combined action of directional surface tension and airflow shear force, without solidifying and adhering to the wall.

[0025] Please continue reading Figure 1 According to the surface tension gradient and corrugated micro-texture of the guide groove, an inner layer of pulsed airflow and an outer layer of pulsed airflow are sprayed into the guide groove, wherein the inner layer of pulsed airflow forms a periodic negative pressure cavity in the guide groove, and the outer layer of pulsed airflow forms a positive pressure barrier on both sides of the guide groove; In one embodiment of the present invention, the inner layer pulse airflow and the outer layer pulse airflow are sprayed into the guide groove according to the surface tension gradient and the corrugated microtexture of the guide groove, wherein 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, including: According to the longitudinal period of the corrugated micro-texture of the guide groove, a first pulse frequency is set for the inner pulse airflow so that the center positions of the negative pressure cavities of adjacent pulses correspond to adjacent texture troughs one by one; Setting a second pulse frequency for the outer pulse airflow, and maintaining a 1:1 ratio between the second pulse frequency and the first pulse frequency, setting a 180° phase difference between the outer pulse airflow and the inner pulse airflow, so that the outer positive pressure peak is located at the adjacent texture wave peak; Under the premise of 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 groove bottom, thereby obtaining a stable negative pressure cavity; After obtaining the stable negative pressure cavity, the duty cycle of the outer pulse airflow is gradually adjusted so that the width of the outer positive pressure peak is limited to the texture wave peak area, forming a positive pressure barrier extending longitudinally on both sides of the guide groove.

[0026] The following is a detailed description of the steps involved in the above embodiment: The longitudinal period of the corrugated microtexture formed in the aforementioned steps—that is, the distance between adjacent peaks or troughs—is measured using a laser rangefinder or optical microscope. The measurement results indicate that the longitudinal period of the corrugated microtexture is 18-22 microns. The airflow control system calculates the first pulse frequency of the inner pulsed airflow based on this period data by dividing the airflow velocity by the texture period length. For example, when the airflow velocity is 20 meters per second and the texture period is 20 microns, the first pulse frequency is set to 1000 Hz. A programmable airflow controller regulates the pulse generator of the inner airflow to operate at the calculated first pulse frequency. At this frequency, negative pressure cavities generated by the inner pulsed airflow appear at predetermined time intervals and spatial locations. Negative pressure cavities are regions within the guide groove where the pressure is lower than the ambient pressure at a specific phase of the airflow pulse. By precisely controlling the pulse timing, the center of each negative pressure cavity precisely corresponds to a trough of the corrugated microtexture, achieving a one-to-one correspondence between negative pressure cavities and texture troughs. This precise spatial matching ensures that the airflow dynamics effect can take effect at the predetermined geometric position, avoiding random drift of the negative pressure cavity position and providing a stable dynamic basis for the subsequent directional discharge of the molten metal.

[0027] A second pulse frequency is set for the outer pulsed airflow, maintaining a 1:1 ratio with the first pulse frequency of the inner pulsed airflow, meaning the two frequencies are identical. A dual-channel airflow control system controls the inner and outer airflows separately, with the outer pulse generator set to the same frequency as the inner pulse. While maintaining the same frequency, a phase adjuster sets a 180° phase difference between the outer pulsed airflow and the inner pulsed airflow. A phase difference refers to the temporal offset between two signals of the same frequency. A 180° phase difference means that when the inner airflow is at a negative pressure valley, the outer airflow is at a positive pressure peak. Phase adjustment is achieved using a delay circuit with a delay equal to half the pulse period. This phase control ensures that the positive pressure peak of the outer airflow is precisely located at the wave crest of the corrugated microtexture. A positive pressure peak is the region where the pressure generated by the airflow pulse at a specific phase is higher than the ambient pressure. For example, when the first pulse frequency is 1000 Hz and the pulse period is 1 millisecond, a 180° phase difference corresponds to a 0.5 millisecond time delay. Through this spatiotemporal synchronous control, the inner negative pressure cavity and the outer positive pressure peak form a complementary pressure distribution pattern in space, achieving precise modulation of the airflow field in the guide groove.

[0028] While maintaining the first pulse frequency constant, the peak pressure of the inner pulsed airflow is gradually increased using a pressure regulating valve. Peak pressure refers to the absolute value of pressure at the point where the airflow pulse reaches its maximum negative pressure. The regulation process utilizes a step-by-step pressure increase method, with each increase controlled within a range of 0.1-0.2 kPa. A pressure sensor simultaneously monitors the actual pressure changes at the trough bottom in real time. The capillary pressure threshold refers to the pressure generated by surface tension effects and is equal to the surface tension coefficient divided by twice the bending radius. For 316 stainless steel, the surface tension coefficient is approximately 1.6 Newtons per meter at 1500 degrees Celsius. When the curvature radius of the guide groove bottom is 40 microns, the capillary pressure threshold is approximately 20 kPa. Through continuous monitoring and adjustment, when the negative pressure valley pressure (i.e., the pressure at the point where the pulsed airflow reaches its maximum negative pressure) falls below this capillary pressure threshold, the negative pressure generated by the airflow is sufficient to overcome the resistance of surface tension. At this point, the molten metal at the trough bottom, driven by the negative pressure, can steadily move toward the airflow, forming a stable negative pressure cavity effect. The establishment of a stable negative pressure chamber eliminates the stagnation of molten metal at the bottom of the groove, ensuring that the liquid metal generated during the cutting process can be sucked and discharged in time.

[0029] After achieving a stable negative pressure cavity, the duty cycle of the outer pulsed airflow is gradually adjusted using a duty cycle adjuster. The duty cycle refers to the percentage of time during a pulse cycle that the airflow remains under positive pressure. The adjustment process begins with an initial duty cycle of 60% and is gradually reduced in 5% increments to a target range of 30-40%. This reduction in duty cycle shortens the duration of the positive pressure peak in the outer layer and spatially confines the peak width to the peak region of the corrugated microtexture. Flow field visualization equipment monitors the airflow distribution to ensure that the spatial coverage of the positive pressure peak does not extend beyond the boundaries of the peak region. When the duty cycle is adjusted to the appropriate value, the outer layer forms a localized high-pressure region at the peak, while maintaining a relatively low-pressure state at the trough. This pressure distribution pattern extends continuously 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 region generated by the inner negative pressure cavity from spreading to the sides of the groove wall, confining the negative pressure effect to the center of the groove bottom and preventing intrusion of external air from disrupting the inner airflow field. This double-layer airflow pressure distribution pattern creates stable fluid dynamic boundary conditions, providing continuous and stable aerodynamic driving force for the discharge of molten metal in the subsequent spiral cutting process.

[0030] Please continue reading Figure 1, under the action of the inner layer pulse airflow and the outer layer pulse airflow, the guide groove is continuously laser cut in a spiral trajectory, and at the same time, a transverse ultrasonic wave that forms a preset resonance relationship with the frequency of the inner layer pulse airflow 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 slit that penetrates the thickness of the valve body wall; In one embodiment of the present invention, the guide groove is continuously laser cut along a spiral trajectory under the action of the inner layer pulse airflow and the outer layer pulse airflow, and transverse ultrasonic waves having 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 be discharged outward along the guide groove, thereby forming a slit that penetrates the wall thickness of the valve body, including: According to the groove width and groove depth of the guide groove, spiral trajectory parameters are set for the laser cutting head to obtain a spiral feed path; According to the spiral feeding path, power incremental 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 feeding path to obtain synchronous energy distribution; According to the synchronized energy distribution, a driving frequency of the transverse ultrasonic wave is set in a ratio of 3:4 to the frequency of the inner layer pulsed airflow, and a 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; According to 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 wall thickness of the valve body.

[0031] The following is a detailed description of the steps involved in the above embodiment: The guide groove width and depth data are obtained using measuring instruments. The groove width refers to the width of the guide groove at its opening, and the groove depth refers to the vertical depth from the groove opening to the bottom. Based on these geometric parameters, the CNC system calculates the spiral trajectory parameters, including the spiral radius, spiral pitch, and spiral angle. The spiral radius is set to 75-85% of the groove width to ensure that the laser beam does not contact the groove wall edges as it moves within the groove. The spiral pitch is the distance between adjacent axial turns of the spiral line. Based on the groove depth data, it is set to 2-3% of the groove depth. For example, for a groove depth of 2 mm, the spiral pitch is set to 0.04-0.06 mm. The spiral angle is the angle between the spiral line and the horizontal plane. Depending on the valve body wall thickness and the required cutting depth, it is set to 85-90 degrees, close to vertical cutting to improve penetration efficiency. The laser cutting head, driven by a six-axis CNC machine tool, moves in space according to the calculated spiral trajectory parameters, forming a spiral feed path. The spiral feed path refers to the complete path along which the laser focus moves in three-dimensional space, following a spiral trajectory. This path design increases the contact area between the laser beam and the molten metal, while also providing more space for airflow to remove slag. Compared to straight-line cutting, a spiral path significantly reduces thermal stress concentration during the cutting process, preventing cracks or deformation in localized areas of the valve body material. The centrifugal force generated by the spiral motion also helps to drain the molten metal.

[0032] Based on the spatial coordinate information of the spiral feed path, the laser control system implements power-increment control on the continuous laser beam. Power-increment control gradually increases the laser output power as the cutting depth increases. Initially set at 60% of the rated power, the power increases at a rate of 5-8% per millimeter of cutting depth. A position sensor monitors the precise position of the laser focus along the spiral feed path in real time, while an airflow sensor detects the location of the negative pressure node of the inner pulsed airflow. The negative pressure node is the specific location in space and time where the inner pulsed airflow generates the maximum negative pressure. The CNC system uses a timing control algorithm to synchronize the trajectory of the laser focus with the negative pressure node in space and time. That is, when the negative pressure node reaches a certain position on the spiral path, the laser focus also reaches that position. This synchronization is achieved through high-precision servo motors and a real-time feedback system, ensuring that laser energy input and airflow suction effects 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 airflow negative pressure distribution pattern. This matching ensures that the molten metal is subjected to negative pressure suction at the moment of generation, avoiding stagnation and accumulation of molten metal in the cutting area.

[0033] Based on the spatial distribution characteristics of synchronized energy distribution, the ultrasonic generator's driving frequency is set to 3 / 4 times the frequency of the inner pulsed airflow, creating a 3:4 frequency ratio. For example, when the inner pulsed airflow frequency is 1000 Hz, the driving 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 fluctuation in strength caused by the superposition of two vibrations of similar frequencies. The beat frequency is equal to the difference between the two original frequencies. A phase adjuster precisely adjusts the phase of the transverse ultrasonic wave. The goal of phase adjustment is to spatially coincide the antinode of the ultrasonic wave's standing wave with the location of the negative pressure node. A standing wave is a waveform formed by the superposition of a sound wave propagating within a bounded area and the incident wave after reflection. The antinode of a standing wave is the point of maximum amplitude within the standing wave. A piezoelectric transducer array excites the transverse ultrasonic wave on the sidewalls of the guide slot. The ultrasonic wave reflects back and forth within the slot, forming a standing wave field. Phase adjustment is achieved through a delay circuit with microsecond accuracy, ensuring that the antinode of the standing wave accurately corresponds to the spatial location of the negative pressure node. Standing wave compression of the melt pool occurs when the intense ultrasonic vibrations at the antinode of the standing wave periodically compress the molten metal, reducing the thickness of the melt pool at that location to 20-30% of its normal thickness. This compressed melt pool is more easily sheared and carried away by the airflow, significantly improving the efficiency of molten metal discharge while preventing it from adhering to the cutting wall.

[0034] Utilizing the efficient slag removal conditions created by standing wave compression of the molten pool, the molten metal is discharged in a targeted manner along the guide groove. The standing wave compresses the molten pool into a thin layer, where the surface tension gradient and negative pressure suction force combine to rapidly flow the molten metal along the longitudinal direction of the guide groove. This discharge process is achieved by controlling the ultrasonic amplitude and airflow suction intensity. The ultrasonic amplitude is adjusted to a level sufficient to overcome the viscous forces of the molten metal, while the airflow suction intensity is set to exceed 1.5-2 times the surface tension resistance. Driven by multiple forces, the molten metal is discharged upward along a spiral trajectory, while the centrifugal force generated by the spiral motion further enhances slag removal. As the spiral cutting process continues, the kerf depth gradually increases. When the laser beam completely penetrates the valve body wall, a complete kerf profile is formed through the valve body wall. The kerf profile exhibits a smooth, spindle-shaped cross-section. This cross-section is the result of the combined effects of spiral cutting and standing wave compression. This spindle-shaped cross-section minimizes fluid resistance, facilitating smooth flow of the medium during valve operation. The slag removal achieved through standing wave compression molten pool technology eliminates the problems of slag adhesion and rewinding in traditional laser cutting, ensuring that the inner wall of the cut remains clean and meeting the strict requirements of high-precision valves for the inner cavity surface quality.

[0035] In one embodiment of the present invention, the step of setting spiral trajectory parameters for the laser cutting head based on the groove width and groove depth of the guide groove to obtain the spiral feed path includes: Determine the radial feed amount of a single spiral turn according to the groove width of the guide groove, so that the radial feed amount of the single spiral turn accounts for 2%-5% of the corresponding groove width to obtain a variable pitch; According to the groove depth of the guide groove, the spiral longitudinal pitch is calculated so that the longitudinal pitch accounts for 1%-3% of the corresponding groove depth to obtain segmented axial feed; According to 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 line of the guide groove by no more than ±3°, thereby obtaining dynamic tilt compensation; The variable pitch, segmented axial feed and dynamic inclination compensation are combined to generate a spiral feed path.

[0036] The following is a detailed description of the steps involved in the above embodiment: The CNC system calculates the radial feed per spiral turn based on the measured groove width. Radial feed refers to the distance the laser cutting head moves toward the groove wall with each completed spiral turn, perpendicular to the cutting depth. This calculation is performed by multiplying the groove width by a scaling factor of 2%-5%. For example, for a groove width of 120 microns, the radial feed per spiral turn is set to 2.4-6 microns. This feed is controlled by the CNC system's radial servo motor, which precisely controls the laser cutting head's radial displacement according to programmed instructions. Because the radial feed for each spiral turn is adjusted in real time based on the current groove width, a variable pitch characteristic is created. Variable pitch refers to the radial spacing between adjacent spiral turns in a spiral trajectory that adjusts with cutting depth. This variation accommodates variations in guide groove width at varying depths. A 2%-5% scaling range ensures that the laser beam maintains an appropriate distance from the groove wall during spiral cutting, preventing direct contact with the groove wall and unnecessary material ablation, while ensuring continuous and complete cutting.

[0037] Based on the measured depth data of the guide groove, the CNC system calculates the longitudinal stepover value for the spiral. The longitudinal stepover refers to the incremental distance the laser cutting head moves downward along the cutting depth, or the vertical distance between layers along the spiral trajectory. The calculation multiplies the groove depth by a scaling factor of 1%-3%. For example, for a groove depth of 2000 microns, the longitudinal stepover value is set to 20-60 microns. This stepover value is controlled by the CNC system's longitudinal feed axis, which utilizes a high-precision ball screw drive to ensure micron-level accuracy for each longitudinal movement. This longitudinal stepover control creates a segmented axial feed mode, which divides the entire cutting depth into multiple smaller feed segments, each corresponding to a longitudinal stepover distance. This segmented feed method enhances the controllability of the laser cutting process, allowing for independent adjustment of laser power and airflow parameters within each segment. A scaling range of 1%-3% ensures cutting stability. A smaller scaling factor can reduce cutting efficiency, while a larger scaling factor can result in excessive feed per pass, impacting cutting quality. The segmented axial feed combined with the variable pitch together constitutes a precise cutting trajectory adapted to the geometric characteristics of the guide groove.

[0038] The curvature data of the valve body's outer wall is acquired using a coordinate measuring machine or laser scanner. Curvature is a measure of the degree of curvature of a curve at a specific point, and its value is equal to the inverse of the radius of curvature at that point. The CNC system calculates the tilt angle of the laser cutting head based on the curvature of the valve body's outer wall. The goal is to keep the laser beam's angle of incidence within a ±3° range from the guide groove normal. The guide groove normal is the line perpendicular to the guide groove surface, and the laser incident angle is the angle between the laser beam and the normal. When the radius of curvature of the valve body's outer wall is small, the laser cutting head's tilt angle must be adjusted accordingly to compensate for the curved surface. Tilt adjustment is achieved using the CNC system's rotary axis, which drives the laser cutting head around its own axis. The rotation angle is determined in real time based on the curvature data. Dynamic tilt compensation is a control method that continuously adjusts the laser cutting head's tilt angle as the curvature of the valve body's outer wall changes. This compensation ensures that the laser beam always enters the guide groove surface at a near-perpendicular angle. The ±3° angle range is determined by the physical properties of laser processing. When the incident angle deviates by more than 3°, the coupling efficiency of the laser energy is significantly reduced, and an asymmetric heat-affected zone may be generated on the groove wall. Dynamic tilt compensation eliminates the adverse effects of the valve body surface geometry on cutting quality, ensuring efficient use of laser energy throughout the cutting process.

[0039] The CNC system comprehensively processes the three control parameters of variable pitch, segmented axial feed, and dynamic inclination compensation to generate a complete spiral 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, with each coordinate point corresponding to a position on the spiral trajectory. The dynamic inclination compensation data is then superimposed on the position coordinate sequence, and the corresponding angle posture information is added to each coordinate point to form a six-dimensional motion instruction containing position and posture. The CNC system converts these six-dimensional instructions into control signals for each servo motor, driving the laser cutting head to move according to the calculated spiral feed path. The generation of the spiral 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 to achieve high-quality slit forming effects.

[0040] Please continue reading 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 the residual melt in the cut; In one embodiment of the present invention, when the laser cutting penetrates the wall thickness of the valve body, the inner layer pulsed airflow and the outer layer pulsed airflow 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 the residual melt in the slit, including: At the moment of the slit penetration, 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 tension threshold of the slit 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 traveling wave propagation direction is made to be in the same direction as the first negative pressure wavefront, thereby obtaining air-acoustic co-directional traction; After the air-acoustic co-directional traction is completed, a closing positive pressure pulse is applied to the outer pulsed airflow, and the intersection point of the first negative pressure wave front and the inner cavity reflected wave is limited to the incision outlet to obtain a trapped air curtain; According to the trapped air curtain, the traveling wave amplitude is set to linearly attenuate along the slit length, so that the tail of the traveling wave decays to 25%-35% of the initial amplitude at the slit exit, obtaining a traveling wave fading section, and simultaneously removing the residual melt in the slit.

[0041] The following is a detailed description of the steps involved in the above embodiment: The laser power feedback sensor detects a sudden drop in laser power, signaling the moment of slit penetration. This moment is defined as the moment when the laser beam completely penetrates the valve body wall and connects with the inner cavity. Upon detecting the penetration signal, the airflow control system immediately applies a negative pressure suction pulse to the inner pulsed airflow. This negative pressure suction pulse is a strong negative pressure pulse superimposed on the existing pulsed airflow. A precision timer sets the suction period to 40-60 milliseconds, a time window precisely controlled by a programmable logic controller. The suction amplitude is adjusted based on the slit cross-sectional tension threshold, which refers to the resistance of the molten metal to the slit due to surface tension effects. For 316 stainless steel, this threshold is approximately 15-20 kPa at 1500°C. The suction amplitude is set to 1.2-1.6 times this threshold, or a negative pressure of 18-32 kPa, using a vacuum pump and pressure regulating valve. For example, when the slit cross-sectional tension threshold is 18 kPa, the suction amplitude is set to 21.6-28.8 kPa. This strong negative pressure pulse generates an initial negative pressure wavefront within the slit. This initial negative pressure wavefront refers to the first pressure peak formed by the negative pressure suction pulse within the slit channel, which propagates along the slit toward the inner cavity. The 40-60 millisecond time interval is determined based on the valve body wall thickness and sound propagation characteristics to ensure that the negative pressure wavefront has sufficient time to reach the bottom of the slit. The 1.2-1.6 times suction amplitude range ensures that the surface tension resistance is overcome while avoiding slit deformation caused by excessive suction.

[0042] As the initial negative pressure wavefront begins to propagate, the ultrasonic control system switches the transverse ultrasonic wave from standing wave mode to traveling wave mode. A traveling wave is a wave pattern in which vibration energy propagates through the medium without forming stationary nodes. Unlike standing waves, traveling waves continuously transfer energy forward. This switching process is achieved by varying the excitation phase of the piezoelectric transducer array, creating a phase difference between adjacent transducers, forming a traveling wave that propagates along the slit. The propagation direction of the traveling wave is determined by controlling the sign of the phase difference, ensuring that it aligns with the propagation direction of the initial negative pressure wavefront, that is, both propagate along the slit toward the inner cavity. Synchronization of propagation directions is achieved by monitoring the propagation velocity of the negative pressure wavefront via a digital signal processor and adjusting the phase velocity of the traveling wave accordingly. Air-acoustic co-traction refers to the synergistic drag effect exerted by the negative pressure wavefront and the traveling wave on the residual material within the slit in the same direction. The negative pressure wavefront provides the pressure gradient driving force, while the traveling wave provides the vibration shear force. For example, when the negative pressure wavefront propagates at a speed of 300 meters per second, the phase velocity of the traveling wave is adjusted to the same value to ensure spatial and temporal synchronization between the two. This unidirectional pulling effect significantly enhances the ability to remove residual melt and gasification products in the cut, preventing these residues from re-solidifying and adhering to the inner cavity wall.

[0043] When the co-directional air-acoustic traction reaches the mid-slit, the outer pulsed airflow control system activates a closing positive pressure pulse. This pulse is a short, high-pressure airflow pulse applied at the slit exit, creating a pressure barrier. The positive pressure pulse is set to 20-30 kPa above ambient atmospheric pressure, with a duration of 10-15 milliseconds. This is achieved using a high-pressure gas tank and a fast-response solenoid valve. When the initial negative pressure wavefront propagates into the inner cavity, it is reflected, forming an inner cavity reflection wave. This reflection wave is the return wave formed by the negative pressure wave reflecting off the inner cavity wall. The timing of the closing positive pressure pulse is controlled so that it meets the inner cavity reflection wave at the slit exit. This meeting point is called the intersection point. Through precise timing calculation, the intersection point is confined to the slit exit, not inside the slit, preventing the reflection wave from re-entering the slit channel. The interception air curtain is the high-pressure airflow barrier formed by the closing positive pressure pulse at the slit exit. This barrier prevents interference between the inner cavity reflection wave and the external airflow. For example, when the kerf depth is 25 mm and the negative pressure wave propagation speed is 300 meters per second, the closing positive pressure pulse is initiated approximately 0.17 milliseconds after the negative pressure wave is emitted, ensuring that the reflected wave returns and coincides with the positive pressure pulse at the exit. The establishment of the trapped air curtain eliminates the conditions for the formation of a reverse shock wave, fundamentally preventing the occurrence of slag rollback.

[0044] Based on the spatial distribution of the trapped air curtain, the ultrasonic control system linearly attenuates the traveling wave amplitude along the length of the slit. Linear attenuation refers to a control method in which the traveling wave amplitude gradually decreases at a fixed rate along the propagation path. This attenuation rate is achieved through segmented control of a multi-channel power amplifier. The initial amplitude of the traveling wave is set at the slit entrance. As it propagates toward the inner cavity, the amplitude decreases linearly, so that the amplitude of the traveling wave tail at the slit exit is attenuated to 25%-35% of the initial amplitude. For example, when the initial amplitude is 100 microns, the amplitude at the exit is controlled within the range of 25-35 microns. This attenuation control is achieved using multiple piezoelectric transducers distributed along the slit, with the drive power of each transducer independently adjusted based on its position. The traveling wave extinction segment refers to the region at the end of the slit where the traveling wave amplitude gradually decays to near zero. The traveling wave energy in this region is just sufficient to propel the residual melt toward the exit without causing excessive vibration interference. The 25%-35% attenuation range is determined based on the kerf geometry and fluid dynamics. Excessive attenuation results in insufficient cleaning, while insufficient attenuation can produce strong acoustic reflections at the outlet. The fading phase of the traveling wave continuously pushes the residual melt in the kerf toward the outlet and out with the trapped air curtain, ensuring the kerf's inner wall remains clean and completely eliminating the problem of slag rollback.

[0045] Please continue reading Figure 1The residual heat of the valve body is used to quickly scan the inner wall of the slit with a low-power laser, and at the same time, an inert protective gas with periodic pulsation is sprayed into the slit, and the residual attachments on the inner wall of the slit are peeled off by alternating laminar flow and micro-turbulence of the airflow.

[0046] In one embodiment of the present invention, the method of utilizing the residual heat of the valve body to rapidly scan the inner wall of the slit with a low-power laser, and simultaneously spraying an inert protective gas superimposed with periodic pulsations toward the slit, and stripping residual attachments from the inner wall of the slit by alternating laminar flow and micro-turbulence, includes: Performing a low-power laser high-speed reciprocating scan on the inner wall of the slit, setting the scanning rate to 3-5 times the cutting rate, to obtain a shallow melt layer with a thickness of 5 μm-15 μm; According to the temperature distribution of the shallow melting heat layer, the pulsating frequency of the inert shielding gas is set to 5 Hz-20 Hz, and the duty cycle is set to 40%-60% to obtain a pulsating base flow; In each airflow 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, thereby obtaining an alternating flow state; The shallow melt heat layer is subjected to shear stripping treatment by utilizing the alternating flow pattern to obtain a mixed flow of attachments carried by the airflow; The mixed flow of attachments is continuously pumped out to obtain a smooth inner wall surface of the cut with a roughness of less than 0.4 μm.

[0047] The following is a detailed description of the steps involved in the above embodiment: Utilizing the residual heat accumulated in the valve body during the aforementioned cutting process, the laser power is adjusted to 15-20% of the rated power, and the scanning rate is set to 3-5 times the aforementioned cutting rate. For example, at a cutting rate of 30 mm / s, the scanning rate is set to 90-150 mm / s. The laser cutting head performs a reciprocating scanning motion along the inner wall of the slit. Reciprocating scanning involves the laser beam moving back and forth longitudinally along the inner wall surface, consisting of two phases: forward scanning and reverse scanning. Precision trajectory control by the CNC system ensures that the laser focus moves closely to the inner wall surface, maintaining a distance of 0.1-0.2 mm from the focus point. The low power setting ensures that the laser only produces shallow melting of the inner wall surface without causing deep ablation. The high-speed scanning ensures that the laser interaction time with the material is short, avoiding excessive heat input. An infrared temperature sensor monitors the inner wall temperature distribution in real time. When the surface temperature reaches the material solidus temperature plus 20-50 degrees Celsius, a shallow melt layer is formed. A shallow melt layer is a thin layer of material on the surface that has been heated to a semi-molten state by the laser. Its thickness is controlled within the 5-15 micron range. This thickness range is achieved through precise matching of laser power and scanning speed. A thickness that is too small will not soften the surface roughness peaks, while a thickness that is too large will affect the geometric accuracy of the kerf. The 3-5x scanning rate setting is determined based on the heat conduction time constant to ensure that the surface material reaches the desired semi-molten state under the laser's action without completely liquefying or vaporizing.

[0048] The temperature distribution data of the shallow melt layer is obtained using an infrared thermal imager. The temperature distribution refers to the temperature variation of the shallow melt layer at various points in space. Based on the uneven temperature distribution characteristics, the airflow control system sets the pulsation frequency of the inert shielding gas. Argon is used as the inert shielding gas, and the pulsation frequency is set to 5-20 Hz. The pulsation frequency refers to the number of times the airflow pressure changes periodically per unit time. At the same time, the duty cycle of the airflow is set to 40%-60%. The duty cycle refers to the percentage of time that the airflow is in a high-pressure state during a pulsation cycle to the total cycle time. For example, when the pulsation frequency is 10 Hz and the duty cycle is 50%, each pulsation 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 pulsating base flow refers to an airflow pattern in which the pressure changes periodically according to the set frequency and duty cycle. The airflow is precisely regulated by an electromagnetic proportional valve and a flow controller. The frequency range of 5-20 Hz is based on the cooling time constant of the shallow melt layer. A frequency too low will cause the layer to cool too quickly before the airflow acts, while a frequency too high will not give the layer sufficient time to soften. A duty cycle range of 40%-60% ensures sufficient high-pressure airflow time to shear the layer, while retaining low-pressure intervals to allow the layer's temperature to naturally adjust.

[0049] During each airflow cycle of the pulsating base flow, the gas pulse amplitude is adjusted in two stages through a programmable pressure regulation system. Two-stage regulation means dividing the airflow pressure into two different regulation stages within a single pulsating cycle, with each stage corresponding to a different pressure amplitude setting. The first stage is the pulsating rise stage, in which the gas pressure amplitude is adjusted to a lower level so that the Reynolds number of the airflow is lower than 1800, forming a laminar flow stage. The Reynolds number is a dimensionless parameter in fluid mechanics that characterizes the flow state. Its value is equal to the ratio of inertial force to viscous force. When the Reynolds number is lower than 1800, the fluid exhibits a laminar flow state. The second stage is the pulsating peak stage, in which the gas pressure amplitude is adjusted to a higher level so that the Reynolds number is higher than 2200, forming a micro-turbulent stage. When the Reynolds number is higher than 2200, the fluid enters a turbulent state, exhibiting micro-turbulence within 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 laminar flow velocity is controlled at 15-20 m / s, while the slightly turbulent flow velocity is increased to 35-45 m / s. Alternating flow refers to a temporal alternation between laminar and slightly turbulent flow, a process achieved in real time by a precise pressure-regulating valve assembly. The laminar flow provides stable surface coverage, while the slightly turbulent flow generates strong shear forces. The alternating flow pattern produces a progressive stripping effect on the shallow melt layer.

[0050] Alternating flow patterns are used to shear-strip the shallow melt layer. Shear stripping involves separating the softened surface layer of the material from the substrate through the tangential force of the airflow. During the laminar flow phase, the steady airflow applies uniform tangential stress to the surface of the shallow melt layer, causing the semi-molten material to undergo plastic deformation. During the microturbulent phase, turbulent vortices exert a strong tearing effect on the deformed material layer, completely stripping it from the substrate. The stripped material, in the form of particles and flakes, is carried along by the airflow and mixed with the airflow to form a deposited mixed flow. This deposited mixed flow is a two-phase fluid formed by the mixture of the stripped surface material and the carrier gas. The solid phase consists of micron-sized metal particles and flakes, while the gas phase is the inert shielding gas. A high-speed camera system monitors the movement of the material particles during the stripping process. Particle size is controlled within the range of 1-5 microns to ensure effective transport by the airflow. The alternating flow shear stripping mechanism avoids surface damage that could be caused by mechanical contact. It also leverages the low shear strength of the semi-molten material to effectively reduce surface roughness with minimal energy input.

[0051] A vacuum extraction system installed at the slit outlet continuously extracts the mixed flow of deposits. This extraction process involves continuously aspirating and collecting the mixed flow from within the slit. A vacuum pump provides negative pressure, controlling the extraction flow rate within a range of 2-5 cubic meters per minute to ensure the timely discharge of the mixed flow and prevent it from accumulating within the slit. A cyclone separator separates the solid phase from the gas phase in the mixed flow. The solid phase is collected in a dedicated container, while the gas phase is filtered and discharged. This continuous extraction process, combined with the shearing and exfoliating action of the alternating flow patterns, gradually reduces the microscopic roughness of the slit's inner wall surface. The treated inner wall surface quality is tested using a surface roughness meter, confirming a roughness value below 0.4 microns. A smooth slit inner wall surface with a roughness below 0.4 microns represents a high-quality surface with excellent reflectivity and microscopic undulations less than 0.4 microns in height, meeting the stringent surface requirements for high-precision valves. The implementation of continuous extraction treatment eliminates surface defects that may be introduced by traditional mechanical polishing, and uses the principles of air flow dynamics to achieve non-contact surface finishing, ensuring that the inner wall of the cut meets the use standards of no leakage and low flow resistance.

[0052] In one embodiment of the present invention, the method of performing a low-power laser high-speed reciprocating scan on the inner wall of the slit, setting the scanning rate to 3-5 times the cutting rate, and obtaining a shallow melt heat layer with a thickness of 5 μm-15 μm, comprises: In the forward scan along the kerf direction, the scanning rate is 3-5 times the cutting rate and the laser power is set to 15%-20% of the rated power to generate an initial melt layer with a thickness of 3 µm-8 µm; In the subsequent reverse scan, the laser power is set to 5%-10% of the rated power at the same scanning rate, and the initial melt layer is flattened again and thickened to 5 μm-10 μm to obtain a shallow melt layer.

[0053] The following is a detailed description of the steps involved in the above embodiment: Starting from one end of the kerf, the laser cutting head performs a forward scanning motion along the longitudinal direction of the kerf. Forward scanning refers to the process of moving the laser beam in a preset direction from the starting point to the end point of the kerf. The CNC system sets the scanning rate to 3-5 times the cutting rate. For example, at a cutting rate of 30 mm / s, the forward scanning rate is set to 90-150 mm / s. The laser power control module also adjusts the laser power to 15%-20% of the rated power. This low power setting ensures that the laser only shallowly heats the inner surface of the kerf without causing deep melting. The laser beam moves closely to the inner surface of the kerf, maintaining a distance of 0.1 mm from the focal point. The focal position is monitored in real time by a laser rangefinder. The combination of high-speed scanning and low power output rapidly raises the inner surface temperature of the kerf to 50-100°C above the solidus temperature of the material, causing the material surface to enter a semi-molten state. This semi-molten state exhibits low viscosity and surface tension, forming an initial melt layer with a thickness of 3-8 microns. The initial melt layer refers to the first semi-molten film formed on the material surface after laser heating. This film remains attached to the substrate but has lost its original solid rigidity. The 3-5x scan rate setting is determined based on the material's thermal diffusion time constant. Too slow a speed will lead to overheating, while too fast a speed will not achieve sufficient surface softening. A power range of 15%-20% ensures sufficient energy density to melt the surface material under high-speed scanning conditions while avoiding deep ablation caused by excessive heat input.

[0054] After completing the forward scan, the laser cutting head immediately turns to perform a reverse scan. Reverse scanning refers to the process in which the laser beam returns from the end point of the kerf to the starting point. The scanning rate is maintained at the same value as the forward scan, i.e., 3-5 times the cutting rate, to ensure continuous and consistent scanning. The laser power control system reduces the laser power to 5%-10% of the rated power. This lower power setting allows the laser to gently reheat the initial molten layer. At this low power setting, the initial molten layer is reheated but does not melt further. Instead, it redistributes and flattens. Reflattening occurs when the semi-molten material spontaneously flows under surface tension to fill microscopic surface irregularities, similar to the self-leveling phenomenon of liquids. Simultaneously, continued low-power heating causes portions of the base material to reach a semi-molten state, merging with the initial molten layer and increasing its thickness. The molten layer thickness is monitored using a contact thickness gauge or laser interferometry thickness measurement system. The reverse scan is completed when the thickness reaches 5-10 microns. The shallow molten layer formed after the reverse scan exhibits improved uniformity and adhesion, with significantly improved surface flatness. The power range of 5%-10% is determined based on the secondary heating characteristics of the material. Excessively high power can damage the initial melt layer structure, while too low power prevents effective flattening and thickening. The bidirectional scanning process design utilizes the differential effects of different power levels on the material state, achieving gradual optimization of the surface microtopography through precise energy control.

[0055] The above describes the valve body laser cutting method according to the embodiment of the present invention. The following describes the valve body laser cutting device according to the embodiment of the present invention. Figure 2 An embodiment of the valve body laser cutting device of the present invention includes: The groove preparation module 101 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, wherein the side wall of the guide groove has a corrugated micro-texture; an airflow construction module 102 for spraying an inner layer of pulsed airflow and an outer layer of pulsed airflow into the guide groove according to the surface tension gradient and the corrugated micro-texture of the guide groove, wherein the inner layer of pulsed airflow forms a periodic negative pressure cavity within the guide groove, and the outer layer of pulsed airflow forms a positive pressure barrier on both sides of the guide groove; The spiral cutting module 103 is configured to perform continuous laser cutting of the guide groove along a spiral trajectory under the action of the inner layer pulsed airflow and the outer layer pulsed airflow, while applying transverse ultrasonic waves having a preset resonance relationship with the frequency of the inner layer pulsed airflow to the cutting area. The transverse ultrasonic waves form standing waves on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, thereby forming a slit that penetrates the thickness of the valve body wall. The suction and slag removal module 104 is used to switch the inner layer pulse airflow and the outer layer pulse airflow to a negative pressure suction mode when the laser cutting penetrates the wall thickness of the valve body, and simultaneously switch the transverse ultrasonic wave from a standing wave to a traveling wave to remove the residual melt in the cut; The residual heat polishing module 105 is used to use the residual heat of the valve body to quickly scan the inner wall of the slit with a low-power laser, and at the same time spray an inert protective gas with periodic pulsation superimposed on the slit, so as to peel off the residual attachments on the inner wall of the slit by alternating the laminar flow and micro-turbulence of the airflow.

[0056] above Figure 2 The valve body laser cutting device in the embodiment of the present invention is described in detail from the perspective of modular functional entities. The valve body laser cutting equipment in the embodiment of the present invention is described in detail from the perspective of hardware processing.

[0057] Figure 3 The figure is a schematic diagram of the structure of a valve body laser cutting device provided by an embodiment of the present invention. The valve body laser cutting device 200 may vary significantly depending on its configuration or performance. It may include one or more processors 210 (e.g., one or more processors), a memory 220, and one or more storage media 230 (e.g., one or more mass storage devices) storing application programs 233 or data 232. The memory 220 and storage media 230 may be either transient or persistent storage. The program stored in the storage medium 230 may include one or more modules (not shown), each of which may include a series of instructions for operating the valve body laser cutting device 200. Furthermore, the processor 210 may be configured to communicate with the storage medium 230, and the valve body laser cutting device 200 may execute the series of instructions stored in the storage medium 230 to implement the steps of the valve body laser cutting method described above.

[0058] The valve body laser cutting device 200 may 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 Server, Mac OS X, Unix, Linux, FreeBSD, etc. It will be understood by those skilled in the art that Figure 3 The structure of the valve body laser cutting equipment shown does not constitute a limitation on the valve body laser cutting equipment provided by the present invention, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0059] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A valve body laser cutting method, characterized in that: include: The outer wall of the valve body is scanned multiple times by a low-duty-cycle pulsed laser along a preset cutting line to form a guide groove with a surface tension gradient on the outer wall of the valve body, wherein the side wall of the guide groove has a corrugated micro-texture; According to the surface tension gradient and corrugated micro-texture of the guide groove, an inner layer of pulsed airflow and an outer layer of pulsed airflow are sprayed into the guide groove, wherein the inner layer of pulsed airflow forms a periodic negative pressure cavity in the guide groove, and the outer layer of pulsed airflow forms a positive pressure barrier on both sides of the guide groove; Under the action of the inner layer pulse airflow and the outer layer pulse airflow, the guide groove is continuously laser cut along a spiral trajectory, and 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 standing waves on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, forming a slit that penetrates the thickness of the valve body wall; 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 the residual melt in the cut; The inner wall of the slit is quickly scanned with a low-power laser using the residual heat of the valve body, and at the same time, an inert protective gas with periodic pulsation is sprayed toward the slit, and residual attachments on the inner wall of the slit are peeled off by alternating laminar flow and micro-turbulence of the airflow.

2. The valve body laser cutting method according to claim 1, characterized in that: The outer wall of the valve body is scanned multiple times by a low-duty-cycle pulse laser along a preset cutting line to form a guide groove with a surface tension gradient on the outer wall of the valve body, wherein the side wall of the guide groove has a corrugated micro-texture, including: Perform the first pulse laser scan on the outer wall of the valve body along the preset cutting line, set the single pulse energy to the first energy level and the inter-pass offset to half the spot width to form an initial shallow melt groove; According to the position of the initial shallow molten groove, the initial shallow molten groove is subjected to multi-layer pulse scanning with increasing energy, and a fixed cooling interval is inserted after each layer of scanning, so that a fine crystal layer and a columnar crystal layer are sequentially formed at the bottom of the groove, thereby obtaining a step-by-step penetration and a longitudinal surface tension gradient; Based on the step penetration depth, a final deep scan is performed at a scanning speed higher than that of the multi-layer pulse scan to reduce the local energy density at the center of the groove bottom, thereby forming an energy gradient that decreases from the groove center to the outlet; Taking 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. The lateral amplitudes of the melting peaks and troughs are modulated to engrave a corrugated microtexture distributed longitudinally on the side wall of the guide groove.

3. The valve body laser cutting method according to claim 1, characterized in that: The method comprises: spraying an inner layer of pulsed airflow and an outer layer of pulsed airflow into the guide groove according to the surface tension gradient and the corrugated micro-texture of the guide groove, wherein the inner layer of pulsed airflow forms a periodic negative pressure cavity in the guide groove, and the outer layer of pulsed airflow forms a positive pressure barrier on both sides of the guide groove. According to the longitudinal period of the corrugated micro-texture of the guide groove, a first pulse frequency is set for the inner pulse airflow so that the center positions of the negative pressure cavities of adjacent pulses correspond to adjacent texture troughs one by one; Setting a second pulse frequency for the outer pulse airflow, and maintaining a 1:1 ratio between the second pulse frequency and the first pulse frequency, setting a 180° phase difference between the outer pulse airflow and the inner pulse airflow, so that the outer positive pressure peak is located at the adjacent texture wave peak; Under the premise of 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 groove bottom, thereby obtaining a stable negative pressure cavity; After obtaining the stable negative pressure cavity, the duty cycle of the outer pulse airflow is gradually adjusted so that the width of the outer positive pressure peak is limited to the texture wave peak area, forming a positive pressure barrier extending longitudinally on both sides of the guide groove.

4. The valve body laser cutting method according to claim 1, characterized in that: The guide groove is continuously laser cut in a spiral trajectory under the action of the inner layer pulse airflow and the outer layer pulse airflow, and transverse ultrasonic waves having 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 be discharged outward along the guide groove, thereby forming a slit that penetrates the wall thickness of the valve body, including: According to the groove width and groove depth of the guide groove, spiral trajectory parameters are set for the laser cutting head to obtain a spiral feed path; According to the spiral feeding path, power incremental 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 feeding path to obtain synchronous energy distribution; According to the synchronized energy distribution, a driving frequency of the transverse ultrasonic wave is set in a ratio of 3:4 to the frequency of the inner layer pulsed airflow, and a 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; According to 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 wall thickness of the valve body.

5. The valve body laser cutting method according to claim 4, characterized in that: The method of setting spiral trajectory parameters for the laser cutting head according to the groove width and groove depth of the guide groove to obtain a spiral feed path includes: Determine the radial feed amount of a single spiral turn according to the groove width of the guide groove, so that the radial feed amount of the single spiral turn accounts for 2%-5% of the corresponding groove width to obtain a variable pitch; According to the groove depth of the guide groove, the spiral longitudinal pitch is calculated so that the longitudinal pitch accounts for 1%-3% of the corresponding groove depth to obtain segmented axial feed; According to 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 line of the guide groove by no more than ±3°, thereby obtaining dynamic tilt compensation; The variable pitch, segmented axial feed and dynamic inclination compensation are combined to generate a spiral feed path.

6. The valve body laser cutting method according to claim 1, characterized in that: 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 a negative pressure suction mode, and the transverse ultrasonic wave is switched from a standing wave to a traveling wave to remove the residual melt in the slit, including: At the moment of the slit penetration, a negative pressure suction pulse is applied to the inner layer pulse 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 slit 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 traveling wave propagation direction is made to be in the same direction as the first negative pressure wavefront, thereby obtaining air-acoustic co-directional traction; After the air-acoustic co-directional traction is completed, a closing positive pressure pulse is applied to the outer pulsed airflow, and the intersection point of the first negative pressure wave front and the inner cavity reflected wave is limited to the incision outlet to obtain a trapped air curtain; According to the trapped air curtain, the traveling wave amplitude is set to linearly attenuate along the slit length, so that the tail of the traveling wave decays to 25%-35% of the initial amplitude at the slit exit, obtaining a traveling wave fading section, and simultaneously removing the residual melt in the slit.

7. The valve body laser cutting method according to claim 1, characterized in that: The method utilizes the residual heat of the valve body to rapidly scan the inner wall of the slit with a low-power laser, and simultaneously sprays an inert protective gas superimposed with periodic pulsations toward the slit, and peels off residual attachments on the inner wall of the slit by alternating laminar flow and micro-turbulence of the gas flow, including: Performing a low-power laser high-speed reciprocating scan on the inner wall of the slit, setting the scanning rate to 3-5 times the cutting rate, to obtain a shallow melt layer with a thickness of 5 μm-15 μm; According to the temperature distribution of the shallow melting heat layer, the pulsating frequency of the inert shielding gas is set to 5 Hz-20 Hz, and the duty cycle is set to 40%-60% to obtain a pulsating base flow; In each airflow 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, thereby obtaining an alternating flow state; The shallow melt heat layer is subjected to shear stripping treatment by utilizing the alternating flow pattern to obtain a mixed flow of attachments carried by the airflow; The mixed flow of attachments 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 method of performing a low-power laser high-speed reciprocating scan on the inner wall of the slit, setting the scanning rate to 3-5 times the cutting rate, and obtaining a shallow melt heat layer with a thickness of 5 μm-15 μm, comprises: In the forward scan along the kerf direction, the scanning rate is 3-5 times the cutting rate and the laser power is set to 15%-20% of the rated power to generate an initial melt layer with a thickness of 3 µm-8 µm; In the subsequent reverse scan, the laser power is set to 5%-10% of the rated power at the same scanning rate, and the initial melt layer is flattened again and thickened to 5 μm-10 μm to obtain a shallow melt layer.

9. A valve body laser cutting device, characterized in that: The valve body laser cutting device adopts the valve body laser cutting method according to any one of claims 1 to 8, and the valve body laser cutting device includes: A 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, wherein the side wall of the guide groove has a corrugated micro-texture; an airflow construction module, configured to eject an inner layer of pulsed airflow and an outer layer of pulsed airflow into the guide groove according to the surface tension gradient and the corrugated microtexture of the guide groove, wherein the inner layer of pulsed airflow forms a periodic negative pressure cavity within the guide groove, and the outer layer of pulsed airflow forms a positive pressure barrier on both sides of the guide groove; a spiral cutting module, configured to perform continuous laser cutting of the guide groove along a spiral trajectory under the action of the inner layer pulsed airflow and the outer layer pulsed airflow, while simultaneously applying transverse ultrasonic waves having a preset resonance relationship with the frequency of the inner layer pulsed airflow to the cutting area, so that the transverse ultrasonic waves form standing waves on the surface of the molten pool, guiding the molten metal to be discharged outward along the guide groove, thereby forming a slit that penetrates the thickness of the valve body wall; A suction and slag removal module is used to switch the inner layer pulse airflow and the outer layer pulse airflow to a negative pressure suction mode when the laser cutting penetrates the wall thickness of the valve body, and at the same time switch the transverse ultrasonic wave from a standing wave to a traveling wave to remove the residual melt in the slit; The residual heat polishing module is used to use the residual heat of the valve body to quickly scan the inner wall of the slit with a low-power laser, and at the same time spray an inert protective gas with periodic pulsation onto the slit, so as to peel off the residual attachments on the inner wall of the slit by alternating laminar flow and micro-turbulence of the 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 calls the instructions in the memory to enable the valve body laser cutting device to perform the steps of the valve body laser cutting method according to any one of claims 1 to 8.

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