Aircraft skin laser cutting method and device capable of accurately controlling heat affected zone

Abstract

The invention relates to the technical field of aircraft skin manufacturing, and particularly discloses an aircraft skin laser cutting method and device capable of accurately controlling a heat affected zone. The device comprises a mechanical arm, a laser head and a synchronous chilling device. The synchronous chilling device is fixedly connected to the laser head in a circular ring shape and synchronously moves along with the laser head; a plurality of nozzles are annularly distributed on the lower surface of the spraying end and can spray a cooling medium to the surface of a workpiece, and an annular cooling area with a laser spot as the center is formed. By adjusting the distance between the chilling device and the workpiece, the radius of the cooling area can be accurately controlled, so that the width of a heat affected zone HAZ generated by laser cutting is limited within a preset range. According to the method, the maximum width of the HAZ can be preset and controlled without later detection, accurate control and cutting of the HAZ layer are achieved, the problems that in the prior art, HAZ control is difficult, material loss is large, and efficiency is low are effectively solved, and the cutting quality and economic benefits are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of aircraft skin manufacturing technology, specifically a method and apparatus for precisely controlling the heat-affected zone of aircraft skin laser cutting. Background Technology

[0002] In the aerospace manufacturing industry, laser cutting technology has become the mainstream process for skin contour processing due to its non-contact and high-precision characteristics. The high-power irradiation of the laser beam causes the material to heat up instantaneously, causing the irradiated material to melt, vaporize, or ablate rapidly. The cut edge forms a heat-affected zone (HAZ) due to the increased temperature, which is characterized by microstructural degradation, decreased mechanical properties, and reduced corrosion resistance, posing a serious threat to the safety and lifespan of the aircraft.

[0003] Currently, the industry's solution for eliminating the adverse effects of the heat-affected zone (HAZ) is to add a machining process after laser cutting to physically remove the HAZ layer. However, precise removal of the HAZ layer relies on a known HAZ width. Currently, there is no method for rapid, non-destructive online monitoring of the HAZ layer; hardness or metallographic testing is only possible through destructive sampling, making it difficult to determine the HAZ width in actual production. Due to differences in material type, specifications, and process parameters, the HAZ width fluctuates significantly, making it difficult to control the amount of HAZ layer removed. Insufficient removal fails to eliminate the heat-affected zone, while excessive removal increases material loss and waste.

[0004] Current research attempts to use auxiliary gas cooling or pulsed laser control for HAZ, but these methods still face bottlenecks in aircraft skin processing: gas cooling provides insufficient control over HAZ depth, while pulsed lasers reduce cutting efficiency and cannot meet the needs of mass production, and neither can achieve precise control over HAZ width.

[0005] In summary, this invention addresses the existing problems by designing a method and apparatus for precisely controlling the heat-affected zone in laser cutting of aircraft skin. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for precisely controlling the heat-affected zone (HAZ) in aircraft skin laser cutting, thereby solving the problems in the prior art. This invention achieves active and precise control of the HAZ width by controlling the temperature gradient of the cutting area, thus achieving precise removal of the HAZ layer. It can even directly obtain a cut surface that meets aerospace standards, avoiding problems caused by insufficient or excessive removal, and achieving improved efficiency and cost savings.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method and apparatus for precisely controlling the heat-affected zone of aircraft skin using laser cutting includes a robotic arm, a laser head, and a synchronous cooling device. The laser head is fixedly connected to the robotic arm, and the synchronous cooling device is fixedly connected to the laser head in a circular shape and can move synchronously with the laser head.

[0008] The synchronous cooling device includes a control end, a spray end, and a telescopic rod connecting the two. The telescopic rod is controlled by the control end and is used to adjust the distance between the spray end and the workpiece surface without changing the position of the laser head itself.

[0009] The lower surface of the spray end has multiple equally spaced cooling medium nozzles arranged in a ring. These nozzles spray cooling medium onto the workpiece at a specific angle, so that the cooling medium sprayed from each nozzle reaches the workpiece in an arc shape. When all nozzles are open simultaneously, the cooling medium forms a complete circular cooling area on the workpiece surface centered on the laser spot, thereby strictly confining the high-temperature heat-affected zone within this circular area.

[0010] The cooling medium can be liquid nitrogen, coolant, cooling water, etc., ensuring that the temperature in its directly affected area is reduced below the HAZ formation temperature. The injection speed and flow rate of the cooling medium can be adjusted via a control terminal.

[0011] The device of this invention can also independently control the opening and closing, injection speed and flow rate of each nozzle in real time, and can achieve automated operation through program settings.

[0012] A laser cutting method based on the above-mentioned device includes the following steps: Step 1: The robotic arm drives the laser head and synchronous cooling device to the processing position.

[0013] Step 2: Based on the target HAZ width, adjust the telescopic rod through the control end to set the distance between the spray end and the workpiece surface, thereby determining the radius of the cooling circle formed by the cooling medium on the workpiece.

[0014] Step 3: Start the laser head to cut, and at the same time start the synchronous cooling device so that the circular area formed by the cooling medium moves synchronously with the laser spot.

[0015] Step 4: Through the rapid cooling effect of the cooling medium, the heat-affected zone is precisely limited to a preset circular range, thereby achieving precise control of the HAZ width.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Precise and controllable: Through physical structure design, the maximum width of HAZ can be directly preset and controlled, eliminating the need for complex and time-consuming offline detection.

[0017] 2. High quality and high efficiency: It can effectively ensure the cutting quality and avoid rework caused by HAZ problems, while avoiding the efficiency loss caused by pulsed laser and other methods, making it suitable for mass production.

[0018] 3. Material saving: It enables precise control and removal of the HAZ layer, fundamentally avoiding material loss caused by improper estimation of the amount to be removed.

[0019] 4. Flexible and intelligent: The nozzle can be controlled independently to adapt to different processing paths; the whole process is programmable and automated, with a high degree of intelligence.

[0020] The above method solves the problem of efficient and accurate identification of aircraft connectors. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall laser cutting device; Figure 2 Enlarged view of a portion of the laser head; Figure 3 This is a schematic diagram of a synchronous quenching device.

[0022] In the diagram: 1. Robotic arm; 2. Laser head; 3. Synchronous cooling device; 201. Laser nozzle connector; 205. Laser nozzle; 301. Control end; 302. Spray end; 303. Telescopic rod; 304. Lower surface of spray end; 305. Cooling medium nozzle; 306. Control end signal input port; 307. Spray end signal input port; 308. Cooling medium channel. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] This invention provides a laser cutting device for aircraft skin that precisely controls the heat-affected zone, comprising a robotic arm, a laser head, and a synchronous cooling device. The laser head is fixedly connected to the robotic arm, and the synchronous cooling device is fixedly connected to the laser head in a circular shape and can move synchronously with the laser head.

[0025] The synchronous quenching device includes a control end, a jetting end, and a telescopic rod connecting the two. The telescopic rod is controlled by the control end and is used to adjust the distance between the jetting end and the workpiece surface without changing the position of the laser head itself.

[0026] The lower surface of the spray end has multiple equally spaced cooling medium nozzles arranged in a ring. These nozzles spray cooling medium onto the workpiece at a specific angle, so that the cooling medium sprayed from each nozzle reaches the workpiece in an arc shape. When all nozzles are open simultaneously, the cooling medium forms a complete circular cooling area on the workpiece surface centered on the laser spot, thereby strictly confining the high-temperature heat-affected zone within this circular area.

[0027] The cooling medium can be liquid nitrogen, coolant, cooling water, etc., ensuring that the temperature in its directly affected area is reduced below the HAZ formation temperature. The injection speed and flow rate of the cooling medium can be adjusted via a control terminal.

[0028] The device of this invention can also independently control the opening and closing, injection speed and flow rate of each nozzle in real time, and can achieve automated operation through program settings.

[0029] A laser cutting method based on the above-mentioned device includes the following steps: Step 1: The robotic arm drives the laser head and synchronous cooling device to the processing position.

[0030] Step 2: Based on the target HAZ width, adjust the telescopic rod through the control end to set the distance between the spray end and the workpiece surface, thereby determining the radius of the cooling circle formed by the cooling medium on the workpiece.

[0031] Step 3: Start the laser head to cut, and at the same time start the synchronous cooling device so that the circular area formed by the cooling medium moves synchronously with the laser spot.

[0032] Step 4: Through the rapid cooling effect of the cooling medium, the heat-affected zone is precisely limited to a preset circular range, thereby achieving precise control of the HAZ width.

[0033] like Figure 1 As shown, the laser head 2 is fixedly connected to the end of the robotic arm 1 by bolts. The synchronous cooling device 3 is fixedly mounted on the laser head 2 by a threaded connection.

[0034] like Figure 2 As shown, the outer wall of the laser nozzle connector 201 of the laser head 2 is machined with external threads, which cooperate with the internal threads of the cooling device 3 body to achieve a tight and reliable connection.

[0035] like Figure 3As shown, the control terminal 301 of the synchronous cooling device 3 is fixed to the laser head 2 and connected to the spray end 302 via a telescopic rod 303. A control signal is input through port 306 to control the extension and retraction of the telescopic rod 303, thereby precisely adjusting the distance between the spray end 302 and the workpiece. Nozzles 305 distributed on the lower surface 304 of the spray end spray cooling medium at a specific angle, forming a cooling circle centered on the laser spot on the workpiece surface. By adjusting the distance, the radius of the cooling circle can be changed, thus precisely setting the maximum width of the HAZ. The cooling medium enters the spray end 302 through channel 308, and its flow rate and volume can be controlled by a signal input through port 307, achieving precise adjustment of the cooling intensity.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laser cutting device for precisely controlling the heat-affected zone of aircraft skin, characterized in that, The device includes a robotic arm (1); a laser head (2) is fixedly connected to the end of the robotic arm (1) for emitting laser for cutting; a synchronous cooling device (3) includes a control end (301), a spray end (302) and a telescopic rod (303) connecting the control end (301) and the spray end (302); the telescopic rod (303) is controlled by the control end (301) and is used to adjust the distance of the spray end (302) relative to the workpiece surface; the lower surface (304) of the spray end (302) is provided with a ring of cooling medium nozzles (305), each of the nozzles (305) is configured to spray cooling medium onto the workpiece at a specific angle, so that the cooling medium sprayed by all the nozzles (305) together form a ring-shaped cooling area centered on the laser spot on the workpiece surface.

2. The apparatus according to claim 1, characterized in that, The synchronous cooling device (3) is fixed to the laser nozzle connector (201) of the laser head (2) by means of a threaded connection.

3. The apparatus according to claim 1 or 2, characterized in that, By controlling the telescopic rod (303) to change the distance between the spray end (302) and the workpiece surface, the radius of the annular cooling area on the workpiece can be adjusted.

4. The apparatus according to claim 1, characterized in that, The control terminal (301) is configured to independently control the opening, closing, injection speed and flow rate of each of the cooling medium nozzles (305).

5. The apparatus according to claim 1, characterized in that, The cooling medium is liquid nitrogen, coolant, or cooling water, etc.

6. A method for laser cutting aircraft skin using the apparatus described in any one of claims 1-5, characterized in that, Includes the following steps: Step S1: The robotic arm (1) drives the laser head (2) and the synchronous cooling device (3) to the processing position; Step S2: Based on the target heat-affected zone width, adjust the telescopic rod (303) through the control end (301) and set the distance between the spray end (302) and the workpiece surface to determine the radius of the annular cooling zone; Step S3: Start the laser head (2) to cut, and at the same time start the synchronous cooling device (3) so that the annular cooling area moves synchronously with the laser spot, and the heat-affected zone generated during the processing is precisely limited to the range defined by the annular cooling area.

7. The method according to claim 6, characterized in that, In step S3, the injection speed and flow rate of the cooling medium are controlled by the control terminal (301) to adjust the cooling intensity of the annular cooling zone.

8. The method according to claim 6, characterized in that, In step S3, the cooling medium nozzles (305) at specific locations are selectively closed or opened via the control terminal (301) according to the geometric characteristics of the cutting path.

9. A laser processing system for aircraft skin, characterized in that, include: The laser cutting apparatus as described in any one of claims 1-5; a control unit, which is signal-connected to the control terminal (301) of the robotic arm (1), the laser head (2) and the synchronous cooling device (3), wherein the control unit is programmed to perform the method as described in any one of claims 6-8.

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