Magnesium alloy automobile skylight anti-oxidation laser cutting device

Abstract

The invention discloses an anti-oxidation laser cutting device for a magnesium alloy automobile skylight, which belongs to the technical field of automobile skylight cutting and comprises a base, a longitudinal guide rail mounted on the base, a carrier plate in sliding fit with the longitudinal guide rail, a supporting block mounted at the top of the carrier plate, a bracket erected on the base and a transverse guide rail mounted on the bracket. The annular plate is arranged on the outer side of the bottom end of the laser cutting head, the annular air grooves integrally formed in the annular plate and the lower spraying holes evenly distributed form a surrounding type air channel, high-purity inert gas is continuously guided into the annular plate in cooperation with the air connector, and then the protective cover mechanism composed of the inner protective plate, the outer protective plate, the metal elastic pieces, the fixing blocks and the balls is matched; a surrounding protection area can be constructed below a laser cutting head, accurate wrapping of a cutting operation area and a high-temperature cutting seam which is just cut is achieved, and the problem of secondary oxidation caused by focus switching is thoroughly solved.

Description

Technical Field

[0001] This invention relates to a laser cutting device, and more particularly to a magnesium alloy automotive sunroof anti-oxidation laser cutting device, belonging to the field of automotive sunroof cutting technology. Background Technology

[0002] When cutting magnesium alloy car sunroofs using laser cutting, in order to solve the oxidation problem during the cutting process and the residual heat stage after cutting, existing laser cutting devices have adopted a technical solution of adding a rear protective gas nozzle. By linking the rear protective gas nozzle with the laser cutting head, it moves synchronously with the rear of the cutting head to spray inert gas into the high-temperature cut that has just been cut, so as to isolate the air, cool down, and avoid secondary oxidation caused by residual heat. However, in the actual application of this existing technology to magnesium alloy car sunroofs, the cutting path of the car sunroof workpiece contains a large number of irregular contours and corner structures. The laser cutting head needs to frequently change its moving direction, which makes it difficult for the follow-up path of the rear protective air nozzle to accurately fit the cutting trajectory. Especially in the corner area, the air nozzle is prone to interference with the edge of the workpiece or deviating from the center of the cutting, forming a protective dead angle. This makes it impossible for the high-temperature cutting in this area to be effectively covered by inert gas, ultimately resulting in local oxidation. Secondly, the thickness of different components of magnesium alloy car sunroofs varies greatly. During the cutting process, the focus mode needs to be switched according to the plate thickness. Thin materials are cut with zero focus, while thick materials are cut with negative focus. However, the relative position of the rear protective gas nozzle and the laser cutting head is currently fixed. When switching from zero focus to negative focus cutting, the height of the laser head needs to be adjusted downwards. The distance between the rear gas nozzle and the cutting surface will decrease accordingly, resulting in a smaller coverage area of ​​the inert gas jet. The effective protection time of the cutting is insufficient, and the residual heat cannot be quickly reduced below the oxidation threshold, which will still cause secondary oxidation. In addition, existing rear-mounted protective gas nozzles only spray inert gas from the top of the workpiece. The narrow kerf formed by laser cutting will hinder the downward penetration of gas, making it difficult to form an effective gas barrier layer at the bottom and lower surface of the kerf. Air can easily enter from the bottom gap and react with the high-temperature kerf to form an oxidation reaction, further reducing the anti-oxidation effect.

[0003] To address this issue, a laser cutting device for preventing oxidation of magnesium alloy automotive sunroofs was designed. Summary of the Invention

[0004] The main objective of this invention is to provide a laser cutting device for preventing oxidation of magnesium alloy automotive sunroofs. By installing an annular plate on the outer side of the bottom of the laser cutting head, an integrally formed annular air groove and evenly distributed lower spray holes form a surrounding air path. High-purity inert gas is continuously introduced through a gas connector. Combined with a protective cover mechanism consisting of an inner protective plate, an outer protective plate, metal elastic sheets, fixing blocks, and ball bearings, a surrounding protective area can be constructed below the laser cutting head. This achieves precise protection of the cutting work area and the newly cut high-temperature kerf. On one hand, the protective area can move synchronously with the laser cutting head, closely conforming to the irregular contours and corner trajectories of the automotive sunroof, effectively avoiding the interference and deviation problems of traditional rear-mounted air nozzles in corner areas and eliminating blind spots. On the other hand, when the cutting mode changes from zero-focal-length cutting… When switching to negative focus cutting, the protective plate is squeezed outward, which drives the protective cover mechanism to automatically expand outward, increasing the coverage area of ​​the inert gas injection, extending the effective protection time of the cut, and allowing the residual heat to quickly drop below the oxidation threshold of the magnesium alloy, completely solving the problem of secondary oxidation caused by focus switching. The lower isolation mechanism at the top of the carrier plate, consisting of an air chamber, air pipe, air guide plate, air guide groove, strip groove, air hole, return spring, limit rod and cover plate, can control the area of ​​the bottom isolation area of ​​the plate according to the coverage area of ​​the sunroof plate, forming the bottom oxygen isolation. This structure, together with the top annular area limiting protection, forms a coordinated protection effect, completely blocking the path of air intrusion from the bottom gap, solving the defect of poor isolation effect of traditional single top air blowing on the bottom of the cut, and achieving all-round anti-oxidation protection of the entire surface of the cut.

[0005] The objective of this invention can be achieved by adopting the following technical solution: A laser cutting device for preventing oxidation of magnesium alloy car sunroof includes a base, a longitudinal guide rail mounted on the base, a carrier plate slidably fitted to the longitudinal guide rail, a support block mounted on the top of the carrier plate, a bracket mounted on the base, a transverse guide rail mounted on the bracket, a transverse slide plate slidably fitted to the transverse guide rail, a vertical guide rail mounted on the transverse slide plate, a vertical slide plate slidably fitted to the vertical guide rail, and a laser cutting head fixed to the vertical slide plate. A fixed plate is fixed to the outer side of the bottom end of the laser cutting head. A ring plate is provided below the fixed plate, and the outer edge of the ring plate is inclined upward. A ring-shaped gas groove is opened inside the ring plate. Several downward spray holes communicating with the ring-shaped gas groove are evenly opened at the bottom of the ring plate. A gas connector communicating with the ring-shaped gas groove is provided at the top of the fixed plate. The gas connector is used to connect inert gas. The outer side of the annular plate is equipped with a protective cover mechanism, which is used to form an adaptively expandable inert gas protection area to adapt to the focus mode switching of the laser cutting head. The top of the carrier plate is equipped with a lower isolation mechanism, which is used to adaptively form a bottom inert gas isolation layer according to the coverage area of ​​the magnesium alloy skylight panel.

[0006] Preferably, the protective cover mechanism includes an inner protective plate, an outer protective plate, metal elastic sheets, fixing blocks, and ball bearings. The inner protective plate is uniformly hinged to the outside of the annular plate along the circumference, and the outer protective plate is uniformly hinged to the bottom of the fixing disk along the circumference. The outer protective plate covers the outside of the adjacent inner protective plate. Metal elastic sheets are installed between the top of the outer outer protective plate and the bottom of the fixing disk. Fixing blocks are fixed at the middle position of the inner side of the inner protective plate. Ball bearings are rotatably installed at the bottom end of the fixing blocks, and the ball bearings protrude from the bottom end of the inner protective plate. The bottom end of the ball bearings is located on the same plane as the laser focus.

[0007] Preferably, both the inner and outer protective plates are arc-shaped structures, with the inner arc of the inner protective plate matching the outer arc of the annular plate, and the inner arc of the outer protective plate matching the outer arc of the inner protective plate.

[0008] Preferably, the lower isolation mechanism includes an air chamber, an air pipe, an air guide plate, an air guide groove, and a switching component. The air chamber is located inside the carrier plate. The side of the carrier plate is provided with an air pipe that communicates with the inside of the air chamber. The air guide plate is uniformly fixed inside the air chamber, and the top of the air guide plate extends to the outside of the carrier plate. The air guide plate is parallel to the width direction of the carrier plate and is located between the support blocks. The inside of the air guide plate is uniformly provided with air guide grooves along the length direction, and the air guide grooves communicate with the outside of the carrier plate. The bottom of each air guide groove is provided with a switching component for releasing and blocking gas flow.

[0009] Preferably, the on / off assembly includes a strip groove, an air hole, and a return spring. The strip groove is parallel to the length direction of the air guide plate and is opened on the top of the carrier plate. The support block slides vertically inside the strip groove, and the sides of the support blocks inside the strip groove are in contact with each other. The support blocks correspond to the air guide grooves on the bottom side of the air guide plate. Each support block is provided with an air hole that cooperates with the air guide groove. The air hole is initially misaligned with the air guide groove. The side of the support block is in contact with the side of two sets of adjacent air guide plates. A return spring is provided between the bottom end of the support block and the bottom of the air chamber.

[0010] Preferably, a limiting rod is fixedly installed at the bottom of each support block. In the initial state, the bottom of the limiting rod is spaced apart from the bottom of the air chamber to limit the downward movement distance of the support block and to vertically limit the return spring.

[0011] Preferably, a baffle is fixedly installed on the top of the air guide plate along its length. The width of the baffle is greater than the width of the top of the air guide plate, and both sides of the baffle protrude to the outer side of the top of the air guide plate.

[0012] Preferably, the top of the support block has a serrated shape, and the top of the support block is coated with an anti-rust coating.

[0013] Preferably, the lower spray holes are evenly distributed in a ring array at the bottom of the annular air groove, and the bottom opening of the lower spray holes is funnel-shaped.

[0014] Preferably, the metal elastic sheet is V-shaped, and the tip of the metal elastic sheet faces the laser cutting head.

[0015] The beneficial effects of this invention are as follows: This invention provides a magnesium alloy automotive sunroof anti-oxidation laser cutting device. By setting an annular plate on the outer side of the bottom of the laser cutting head, an integrally formed annular gas groove and evenly distributed lower spray holes form a surrounding gas path. High-purity inert gas is continuously introduced through a gas connector. Combined with a protective cover mechanism consisting of an inner protective plate, an outer protective plate, metal elastic sheets, fixing blocks, and ball bearings, a surrounding protective area can be constructed below the laser cutting head. This achieves precise protection of the cutting work area and the newly cut high-temperature slit. On one hand, the protective area can move synchronously with the laser cutting head, closely conforming to the irregular contours and corner trajectories of the automotive sunroof, effectively avoiding the interference and deviation problems of traditional rear-mounted air nozzles in corner areas and eliminating protection blind spots. On the other hand, when the cutting mode switches from zero-focus cutting to negative-focus cutting, the protective plate is squeezed outwards, which can drive the protective cover mechanism to automatically expand outwards, increasing the coverage area of ​​the inert gas spray, extending the effective protection time of the slit, and allowing residual heat to quickly drop below the magnesium alloy oxidation threshold, completely solving the problem of secondary oxidation caused by focus switching.

[0016] The lower isolation mechanism at the top of the carrier plate consists of an air chamber, air pipe, air guide plate, air guide groove, strip groove, air hole, return spring, limit rod and cover plate. It can control the area of ​​the isolation area at the bottom of the plate according to the coverage area of ​​the skylight plate, forming an isolation of oxygen at the bottom. This structure, together with the top annular area protection, forms a coordinated protection effect, completely blocking the path of air intrusion from the bottom gap. It solves the defect of poor isolation effect of traditional single top air blowing on the bottom of the cut, and achieves all-round anti-oxidation protection of the entire surface of the cut. Attached Figure Description

[0017] Figure 1 This is the front view of the present invention; Figure 2 This is a front view of the bottom end of the laser cutting head of the present invention; Figure 3 This is a cross-sectional view of the bottom end of the laser cutting head of the present invention; Figure 4 This is a front view of the annular plate in its installed state according to the present invention; Figure 5 This is a structural diagram of the inner side of the inner protective plate of the present invention; Figure 6 This is a partial cross-sectional view of the carrier plate of the present invention; Figure 7 This is a shape diagram of the air guide plate of the present invention; Figure 8 This is a partial structural diagram of the top of the carrier plate of the present invention; Figure 9This is a surface structure diagram of the support block of the present invention.

[0018] In the diagram: 1. Base; 2. Longitudinal guide rail; 3. Carrier plate; 4. Support block; 5. Lower isolation mechanism; 501. Air chamber; 502. Air tube; 503. Air guide plate; 504. Air guide groove; 505. Strip groove; 506. Air hole; 507. Return spring; 508. Limiting rod; 509. Cover plate; 6. Bracket; 7. Horizontal guide rail; 8. Horizontal slide plate; 9. Vertical guide rail; 10. Vertical slide plate; 11. Laser cutting head; 12. Fixing plate; 13. Annular plate; 14. Annular air groove; 15. Lower spray hole; 16. Gas connector; 17. Protective cover mechanism; 1701. Inner protective plate; 1702. Outer protective plate; 1703. Metal elastic sheet; 1704. Fixing block; 1705. Ball bearing. Detailed Implementation

[0019] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0020] Example 1 like Figures 1-9 As shown, this embodiment provides a magnesium alloy automotive sunroof anti-oxidation laser cutting device, including a base 1, a longitudinal guide rail 2 mounted on the base 1, a carrier plate 3 slidably fitted to the longitudinal guide rail 2, a support block 4 mounted on the top of the carrier plate 3, a bracket 6 mounted on the base 1, a transverse guide rail 7 mounted on the bracket 6, a transverse slide plate 8 slidably fitted to the transverse guide rail 7, a vertical guide rail 9 mounted on the transverse slide plate 8, a vertical slide plate 10 slidably fitted to the vertical guide rail 9, and a laser cutting head 11 fixed to the vertical slide plate 10; A fixed plate 12 is fixed to the outer side of the bottom end of the laser cutting head 11. An annular plate 13 is provided below the fixed plate 12, and the outer side of the annular plate 13 is inclined upward. An annular gas groove 14 is opened inside the annular plate 13. Several lower spray holes 15 that communicate with the annular gas groove 14 are evenly opened at the bottom of the annular plate 13. A gas connector 16 that communicates with the annular gas groove 14 is provided at the top of the fixed plate 12. The gas connector 16 is used to connect inert gas. The outer side of the annular plate 13 is provided with a protective cover mechanism 17, which is used to form an adaptively expandable inert gas protection area to adapt to the focus mode switching of the laser cutting head 11. The top of the carrier plate 3 is provided with a lower isolation mechanism 5, which is used to adaptively form a bottom inert gas isolation layer according to the coverage area of ​​the magnesium alloy skylight panel.

[0021] Before cutting, the magnesium alloy car sunroof workpiece is placed on the support block 4 of the carrier plate 3. The carrier plate 3 can move longitudinally along the longitudinal guide rail 2 of the base 1. The transverse slide plate 8 on the bracket 6 can slide laterally along the transverse guide rail 7. The vertical slide plate 10 can move vertically along the vertical guide rail 9 of the transverse slide plate 8. The three work together to drive the laser cutting head 11 fixed to the vertical slide plate 10 to complete the three-dimensional space cutting motion, adapting to the cutting needs of different positions and contours of the workpiece.

[0022] Before cutting, high-purity inert gas is introduced into the device through gas connector 16. The gas flows into the annular gas groove 14 of the annular plate 13 through the fixed plate 12, and is then evenly sprayed out from the lower spray hole 15 at the bottom of the annular plate 13. Together with the protective cover mechanism 17, a top inert gas protective layer is formed in the cutting area below the laser cutting head 11, initially isolating air from contact with the high-temperature cut. The protective cover mechanism 17 on the outside of the annular plate 13 can move synchronously with the laser cutting head 11, avoiding the interference and deviation problems of traditional rear-mounted gas nozzles, and can adaptively expand the protective area when the focus mode of the laser cutting head 11 is switched. At the same time, the lower isolation mechanism 5 on the top of the carrier plate 3 will automatically adjust according to the workpiece coverage area to form a bottom inert gas isolation layer. The top protection and bottom isolation work together to completely block the path of air entering the cut from all directions, achieving anti-oxidation protection throughout the cutting process and the residual heat stage, and finally completing the precise cutting of the magnesium alloy car sunroof.

[0023] Example 2 The solution in Example 1 will be further described below with reference to its specific working method. In this embodiment, the protective cover mechanism 17 includes an inner protective plate 1701, an outer protective plate 1702, a metal elastic sheet 1703, a fixing block 1704, and a ball bearing 1705. The inner protective plate 1701 is uniformly hinged to the outer side of the annular plate 13 along the circumferential direction. The outer protective plate 1702 is uniformly hinged to the bottom of the fixing disk 12 along the circumferential direction, and the outer protective plate 1702 covers the outer side of the adjacent inner protective plate 1701. A metal elastic sheet 1703 is installed between the top of the outer side of the outer protective plate 1702 and the bottom of the fixing disk 12. A fixing block 1704 is fixed at the middle position of the inner side of the inner protective plate 1701. A ball bearing 1705 is rotatably installed at the bottom end of the fixing block 1704, and the ball bearing 1705 protrudes from the bottom end of the inner protective plate 1701. The bottom end of the ball bearing 1705 is located on the same plane as the laser focus.

[0024] During the cutting operation, the ball bearing 1705 at the bottom of the fixing block 1704 on the inner side of the inner protective plate 1701 is in close contact with the workpiece surface and rolls as the laser cutting head 11 moves, ensuring that the protective cover mechanism 17 always fits against the workpiece surface and maintains the protected area. When the cutting mode is switched from zero focal length to negative focal length, the laser cutting head 11 needs to be adjusted downwards. The ball bearing 1705 is squeezed by the workpiece and generates an upward force, which drives the inner protective plate 1701 to unfold outwards. The outer protective plate 1702 expands outwards synchronously under the push of the inner protective plate 1701. The metal elastic sheet 1703 undergoes elastic deformation, maintaining the fit between the outer protective plate 1702 and the inner protective plate 1701. At this time, the protected area expands, prolonging the coverage time of the inert gas on the high-temperature cut and avoiding secondary oxidation caused by residual heat.

[0025] In this embodiment, both the inner protective plate 1701 and the outer protective plate 1702 are arc-shaped structures. The inner arc of the inner protective plate 1701 is adapted to the outer arc of the annular plate 13, and the inner arc of the outer protective plate 1702 is adapted to the outer arc of the inner protective plate 1701.

[0026] The inner protective plate 1701 adopts an arc-shaped structure that matches the outer curvature of the annular plate 13, ensuring a tight fit between the inner protective plate 1701 and the annular plate 13 and reducing the leakage of inert gas from the gaps. The outer protective plate 1702 adopts an arc-shaped structure that matches the outer curvature of the inner protective plate 1701, so that the outer protective plate 1702 can completely cover the gap between the adjacent inner protective plates 1701, forming a continuous surrounding protective barrier, further improving the sealing of the protected area, and ensuring that the inert gas is concentrated on the cutting area and the cut.

[0027] In this embodiment, the lower isolation mechanism 5 includes an air chamber 501, an air pipe 502, an air guide plate 503, an air guide groove 504, and a switching component. The air chamber 501 is opened inside the carrier plate 3. The side of the carrier plate 3 is provided with an air pipe 502 that communicates with the inside of the air chamber 501. The air guide plate 503 is uniformly fixed inside the air chamber 501, and the top end of the air guide plate 503 extends to the outside of the carrier plate 3. The air guide plate 503 is parallel to the width direction of the carrier plate 3 and is located between the support blocks 4. The air guide groove 504 is uniformly opened along the length direction inside the air guide plate 503, and the air guide groove 504 communicates the air chamber 501 with the outside of the carrier plate 3. The bottom end of the air guide groove 504 is provided with a switching component for releasing and blocking gas flow.

[0028] The air pipe 502 is connected to an external inert gas source, introducing inert gas into the air chamber 501 inside the carrier plate 3. Evenly distributed air guide plates 503 inside the air chamber 501 are parallel to the width direction of the carrier plate 3 and located between the support blocks 4. Air guide grooves 504 inside the air guide plates 503 connect the air chamber 501 to the outside of the carrier plate 3, providing a channel for gas delivery. The on / off assembly controls the opening and closing of the air guide grooves 504 according to the workpiece coverage, ensuring that the inert gas is released only at the bottom of the workpiece coverage area, forming a targeted bottom isolation layer. This ensures both anti-oxidation effect and avoids inert gas waste.

[0029] In this embodiment, the on / off component includes a strip groove 505, an air hole 506, and a return spring 507. The strip groove 505 is parallel to the length direction of the air guide plate 503 and is opened on the top of the carrier plate 3. The support block 4 slides vertically inside the strip groove 505, and the sides of the support block 4 inside the strip groove 505 are in contact with each other. The support block 4 corresponds to the air guide groove 504 on the bottom side of the air guide plate 503. Each support block 4 is provided with an air hole 506 that cooperates with the air guide groove 504. In the initial state, the air hole 506 is misaligned with the air guide groove 504. The side of the support block 4 is in contact with the side of two adjacent air guide plates 503. A return spring 507 is provided between the bottom end of the support block 4 and the bottom of the air cavity 501.

[0030] Initially, the support block 4 is in a high position under the support of the return spring 507. The air hole 506 on the support block 4 is misaligned with the air guide groove 504 of the air guide plate 503, and the side of the support block 4 is in contact with the side of the adjacent air guide plate 503, sealing the air guide groove 504 and preventing gas from escaping. When the workpiece is placed on the support block 4, the weight of the workpiece causes the support block 4 to move vertically downward along the strip groove 505, and the return spring 507 is compressed. As the support block 4 moves downward, the air hole 506 gradually aligns with the air guide groove 504. At this time, the inert gas in the air chamber 501 is discharged to the bottom of the workpiece through the air hole 506 and the air guide groove 504 in sequence. When the workpiece is removed, the return spring 507 returns to its original deformation, pushes the support block 4 upward to reset, and the air hole 506 and the air guide groove 504 are misaligned again, blocking the gas flow.

[0031] In this embodiment, a limiting rod 508 is fixedly installed at the bottom of each support block 4. The bottom of the limiting rod 508 initially leaves a gap with the bottom of the air cavity 501, which is used to limit the downward movement distance of the support block 4 and vertically limit the reset spring 507.

[0032] When the support block 4 moves downward under the weight of the workpiece, the limiting rod 508 moves downward accordingly. When the bottom end of the limiting rod 508 contacts the bottom of the air chamber 501, it restricts the support block 4 from moving further downward, preventing the return spring 507 from being damaged due to excessive compression. At the same time, it ensures that when the support block 4 moves downward to the set stroke, the air hole 506 can be precisely aligned with the air guide groove 504, ensuring stable gas discharge.

[0033] In this embodiment, a baffle 509 is fixedly installed on the top of the air guide plate 503 along the length direction. The width of the baffle 509 is greater than the width of the top of the air guide plate 503, and both sides of the baffle 509 protrude to the outer side of the top of the air guide plate 503.

[0034] The baffle 509 can block the debris generated during cutting, preventing the debris from clogging the air guide channel 504.

[0035] In this embodiment, the top of the support block 4 has a serrated structure. The serrated design increases the gap between the workpiece and the support, effectively reducing the possibility of laser reflection, thereby avoiding the problem of the lower surface of the workpiece being scorched. In addition, the top of the support block 4 is coated with an anti-rust coating to prevent rust from contaminating the surface of the workpiece and to extend the service life of the support block 4.

[0036] In this embodiment, the lower spray holes 15 are evenly distributed in a ring array at the bottom of the annular gas groove 14 to ensure that the inert gas is sprayed out from the bottom of the annular plate 13 in all directions and evenly, without any spray dead angles. The bottom opening of the lower spray holes 15 is funnel-shaped, which can expand the gas spray range, so that the inert gas can quickly cover the cutting area and the newly formed high-temperature cut, improve the gas utilization rate, and enhance the top anti-oxidation protection effect.

[0037] In this embodiment, the metal elastic sheet 1703 is V-shaped, and the tip of the metal elastic sheet 1703 faces the laser cutting head 11.

[0038] The metal elastic sheet 1703 adopts a V-shaped structure and has excellent elastic recovery performance. When the protective cover mechanism 17 is deployed due to focus switching or trajectory change, the metal elastic sheet 1703 is stretched or squeezed and undergoes elastic deformation, generating a reverse elastic force, which pushes the outer protective plate 1702 to always fit against the inner protective plate 1701. The inner protective plate 1701 fits against the workpiece surface through the fixing block 1704 and the ball bearing 1705.

[0039] Example 3 The solutions in Embodiment 1 and Embodiment 2 will be further described below with reference to their specific working methods. The magnesium alloy car sunroof workpiece to be cut is placed stably on the support block 4 of the carrier plate 3. Under the action of the workpiece's gravity, the support block 4 in the area covered by the workpiece moves vertically downward along the strip groove 505. The return spring 507 is compressed, and the limiting rod 508 at the bottom of the support block 4 moves downward accordingly until the bottom of the limiting rod 508 contacts the bottom of the air chamber 501. The support block 4 stops moving downward. At this time, the air hole 506 on the support block 4 is precisely aligned with the air guide groove 504 of the air guide plate 503. The support block 4 not covered by the workpiece is kept at its initial high position under the elastic support of the return spring 507. The air hole 506 is misaligned with the air guide groove 504, and the air guide groove 504 is in a closed state. Subsequently, high-purity inert gas is introduced into the air cavity 501 inside the carrier plate 3 through the air pipe 502. The gas is evenly distributed in the air cavity 501 and discharged to the bottom of the workpiece through the air guide groove 504 of the air guide plate 503 and the air hole 506 of the support block 4. This allows the gas to quickly form a uniform and dense bottom inert gas isolation layer between the bottom of the workpiece and the carrier plate 3, blocking the path of air to invade the cut from the bottom.

[0040] High-purity inert gas is supplied to the fixed plate 12 through the gas connector 16. The gas flows through the fixed plate 12 and enters the annular gas groove 14 of the annular plate 13, and then is ejected from the lower spray holes 15 arranged in a ring array at the bottom of the annular plate 13. The trumpet-shaped opening of the lower spray holes 15 expands the gas spray range, so that the inert gas forms a top inert gas protective layer that covers the entire cutting area below the laser cutting head 11, which works together with the bottom isolation layer to form a closed anti-oxidation space. At the same time, the ball bearings 1705 of the protective cover mechanism 17 contact the workpiece surface. Under the elastic force of the metal elastic sheet 1703, the inner protective plate 1701 and the outer protective plate 1702 form an inert gas protection area at the edge of the cutting area.

[0041] The cutting control system is activated. The carrier plate 3 moves longitudinally along the longitudinal guide rail 2 of the base 1, the transverse slide plate 8 on the bracket 6 slides laterally along the transverse guide rail 7, and the vertical slide plate 10 moves vertically along the vertical guide rail 9. These three components work together to drive the laser cutting head 11 to move in three-dimensional space, precisely adapting to the irregular contour cutting trajectory of the magnesium alloy car sunroof. During the cutting process, the protective cover mechanism 17 moves synchronously with the laser cutting head 11, and the ball bearings 1705 roll on the workpiece surface to reduce frictional resistance; ensuring that the protected area always closely fits the cutting trajectory and eliminating blind spots.

[0042] When cutting workpieces of different thicknesses, the focus mode needs to be switched. If switching from zero-focus cutting to negative-focus cutting, the laser cutting head 11 moves downward along the vertical guide rail 9. The ball bearings 1705 of the shield mechanism 17 are squeezed by the workpiece surface and generate an upward force, which drives the inner shield plate 1701 to expand outward. The outer shield plate 1702 expands outward synchronously under the push of the inner shield plate 1701. The metal elastic sheet 1703 undergoes elastic deformation to maintain the contact state between the outer shield plate 1702 and the inner shield plate 1701. The protected area automatically expands, prolonging the coverage time of the inert gas on the high-temperature cut, so that the residual heat of the cut quickly drops below the oxidation threshold of magnesium alloy, and completely solves the problem of secondary oxidation caused by focus switching.

[0043] After the workpiece is cut, the laser cutting head 11 is turned off, and inert gas is continued to be introduced for a period of time to ensure that the cut has completely cooled to a safe temperature before the gas supply is stopped. The workpiece is removed, and the support block 4 moves upward and resets under the elastic action of the return spring 507. The air hole 506 and the air guide groove 504 are misaligned, and the air guide groove 504 is closed. The metal elastic plate 1703 of the protective cover mechanism 17 returns to its original shape, causing the inner protective plate 1701 and the outer protective plate 1702 to retract to their initial positions, completing one cutting operation. Throughout the process, the top surrounding gas jet and the bottom adaptive gas isolation layer work together to achieve all-round anti-oxidation protection on the entire surface of the cut, ensuring the cutting quality of the magnesium alloy car sunroof.

[0044] The above description is merely a further embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A magnesium alloy automobile sunroof anti-oxidation laser cutting device, comprising a base (1), a longitudinal guide rail (2) mounted on the base (1), a carrier plate (3) slidingly fitted in the longitudinal guide rail (2), a support block (4) mounted on the top of the carrier plate (3), a bracket (6) erected on the base (1), a transverse guide rail (7) mounted on the bracket (6), a transverse sliding plate (8) slidingly fitted in the transverse guide rail (7), a vertical guide rail (9) mounted on the transverse sliding plate (8), a vertical sliding plate (10) slidingly fitted in the vertical guide rail (9), and a laser cutting head (11) fixed to the vertical sliding plate (10); characterized in that: a fixed disc (12) is fixed to the bottom end of the laser cutting head (11), an annular plate (13) is arranged below the fixed disc (12), the outer side of the annular plate (13) is inclined upward, a ring-shaped gas groove (14) is arranged in the annular plate (13), a plurality of lower spray holes (15) are evenly arranged in the bottom of the annular plate (13) and communicated with the ring-shaped gas groove (14), a gas joint (16) is arranged on the top of the fixed disc (12) and communicated with the ring-shaped gas groove (14), and the gas joint (16) is used for connecting inert gas; a shield mechanism (17) is arranged on the outside of the annular plate (13), and the shield mechanism (17) is used for forming an inert gas protection area which can be self-adaptively expanded to adapt to the focal point mode switching of the laser cutting head (11); a lower insulation mechanism (5) is arranged on the top of the carrier plate (3), and the lower insulation mechanism (5) is used for self-adaptively forming a bottom inert gas insulation layer according to the coverage area of the magnesium alloy sunroof plate.

2. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 1, characterized in that: The shield mechanism (17) comprises an inner shield plate (1701), an outer shield plate (1702), a metal elastic sheet (1703), a fixed block (1704), and a ball (1705), the inner shield plate (1701) is circumferentially and uniformly hinged and mounted on the outside of the annular plate (13), the outer shield plate (1702) is circumferentially and uniformly hinged and mounted on the bottom of the fixed disc (12), and the outer shield plate (1702) covers the outside of the adjacent inner shield plate (1701), the metal elastic sheet (1703) is arranged between the top of the outer side of the outer shield plate (1702) and the bottom of the fixed disc (12), the fixed block (1704) is fixed to the inner side of the inner shield plate (1701), the ball (1705) is rotatably mounted at the bottom end of the fixed block (1704), and the ball (1705) protrudes from the bottom end of the inner shield plate (1701), and the bottom end of the ball (1705) and the focal point of the laser are located in the same plane.

3. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 2, characterized in that: The inner shield plate (1701) and the outer shield plate (1702) are both arc-shaped structures, the inner side curvature of the inner shield plate (1701) is adapted to the outer side curvature of the annular plate (13), and the inner side curvature of the outer shield plate (1702) is adapted to the outer side curvature of the inner shield plate (1701).

4. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 1, characterized in that: The lower isolation mechanism (5) comprises an air cavity (501), an air pipe (502), a gas guide plate (503), a gas guide groove (504) and an on-off assembly. The air cavity (501) is arranged in the interior of the carrier plate (3), and the side of the carrier plate (3) is provided with the air pipe (502) in communication with the interior of the air cavity (501). The gas guide plate (503) is uniformly fixed in the interior of the air cavity (501), and the top end of the gas guide plate (503) extends to the exterior of the carrier plate (3). The gas guide plate (503) is parallel to the width direction of the carrier plate (3) and is located between the support blocks (4). The interior of the gas guide plate (503) is uniformly provided with the gas guide groove (504) along the length direction, and the gas guide groove (504) is in communication with the exterior of the carrier plate (3). The bottom end of the gas guide groove (504) is provided with the on-off assembly for releasing and blocking the gas flow.

5. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 4, characterized in that: The on-off assembly comprises a strip-shaped groove (505), a gas hole (506) and a reset spring (507). The strip-shaped groove (505) is parallel to the length direction of the gas guide plate (503) and is arranged on the top of the carrier plate (3). The support block (4) vertically slides in the interior of the strip-shaped groove (505), and the side edges of the support blocks (4) in the interior of the strip-shaped groove (505) are mutually attached. The support block (4) is respectively provided with the gas hole (506) matched with the gas guide groove (504) on the bottom side of the gas guide plate (503). The gas hole (506) is dislocated with the gas guide groove (504) in the initial state. The side edges of the support block (4) are attached with the side edges of the two groups of adjacent gas guide plates (503). The bottom end of the support block (4) is provided with the reset spring (507) between the inner bottom of the air cavity (501).

6. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 5, characterized in that: The bottom end of the support block (4) is fixedly installed with the limiting rod (508). The bottom end of the limiting rod (508) is spaced apart from the inner bottom of the air cavity (501) in the initial state, so as to limit the downward distance of the support block (4) and vertically limit the reset spring (507).

7. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 4, characterized in that: The top of the gas guide plate (503) is fixedly installed with the shutter (509) along the length direction. The width of the shutter (509) is greater than that of the top of the gas guide plate (503), and the two sides of the shutter (509) are protruded to the outside of the top of the gas guide plate (503).

8. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 1, characterized in that: The top of the support block (4) is in a sawtooth structure, and the top end of the support block (4) is coated with an anti-rust coating.

9. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 1, characterized in that: The lower spray holes (15) are uniformly distributed in the bottom of the annular air groove (14) in an annular array, and the bottom end opening of the lower spray hole (15) is in a horn shape.

10. The magnesium alloy sunroof anti-oxidation laser cutting device according to claim 2, characterized in that: The metal elastic sheet (1703) is in a V shape, and the tip of the metal elastic sheet (1703) faces the laser cutting head (11).

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