Laser etching device for increasing dyne value of surface of magnesium-aluminum die casting and using method of laser etching device

Abstract

The invention discloses a laser etching device for increasing the dyne value of the surface of a magnesium-aluminum die casting and a using method of the laser etching device, and belongs to the technical field of magnesium-aluminum die casting surface treatment.The laser etching device comprises a pretreatment unit, a collaborative laser etching unit, a secondary activation unit, a post-treatment unit and a quality detection unit. Through the pretreatment unit, the cooperative laser etching unit, the secondary activation unit, the post-treatment unit and the quality detection unit, cooperative control over laser etching texture forming and surface dyne value increasing is achieved, and the technical problem that laser etching texture forming and surface dyne value increasing are mutually restricted in the traditional technology is solved; through the combined design of sectional laser etching and plasma secondary activation and in combination with dyne value online feedback control, the surface activity and the process stability are remarkably improved, and it is ensured that the dyne value is stably larger than or equal to 42 dyn / cm; and by arranging the collaborative laser etching unit, plasma activation parameters and laser etching parameters are optimized according to the surface characteristic difference of the magnesium alloy and the aluminum alloy, and it is ensured that the treatment effects of magnesium-aluminum die castings made of different materials are stable and consistent.

Description

Technical Field

[0001] This invention belongs to the field of surface treatment technology for magnesium-aluminum die-cast parts, specifically relating to a laser engraving device and its method for improving the dyne value of magnesium-aluminum die-cast parts. Background Technology

[0002] Magnesium-aluminum alloys, with their low density, high specific strength, and excellent thermal and electrical conductivity, are widely used in the automotive, electronics, and aerospace industries. Die casting enables the efficient mass production of complex structural parts, meeting the demands for lightweight and precision industrial products. Laser engraving, a non-contact, high-precision surface processing technology, is commonly used for texture shaping and marking on magnesium-aluminum die-cast parts. It offers advantages such as high processing efficiency, controllable textures, and no mechanical damage, significantly improving the appearance and functionality of die-cast parts.

[0003] The dyne value (surface tension coefficient) is a key indicator for measuring the wettability and adhesion of a material surface, directly affecting the quality stability of subsequent coating, bonding, and film-coating processes for magnesium-aluminum die-cast parts. When the dyne value is too low, coatings and adhesives are prone to defects such as peeling, blistering, and sagging, failing to meet the long-term use requirements of the product. Magnesium-aluminum die-cast parts themselves have low surface energy. In traditional die-casting processes, mold release agents, oxide layers, and micropores easily remain on the surface of the castings. Subsequent conventional laser engraving processes can only achieve surface texture processing and are difficult to effectively remove surface contaminants and oxide layers. In fact, improper laser engraving parameters may even lead to the formation of a molten and resolidified layer on the surface, further reducing surface activity. As a result, the dyne value of the surface of the die-cast parts after laser engraving is usually below 34 dyn / cm, which cannot meet the requirements of subsequent processing.

[0004] Currently, the main methods used in the industry to improve the dyne value of magnesium-aluminum die-cast parts include chemical etching, plasma treatment, and sandblasting. Among these, chemical etching can easily cause uneven surface roughness of the castings, and the waste liquid generated can pollute the environment, which is inconsistent with the concept of green production; plasma treatment equipment is expensive and complex to operate, making it difficult to adapt to mass production scenarios, and the treatment effect is greatly affected by environmental humidity and gas purity, resulting in poor stability; sandblasting can damage the surface precision of die-cast parts, making it unsuitable for surface treatment after precision texture laser engraving, and it is easy to generate new impurities on the surface, affecting the dyne value improvement effect.

[0005] Meanwhile, in existing technologies, laser engraving and dyne enhancement are independent processes, lacking coordinated design: performing laser engraving first and then dyne enhancement can easily lead to damage to the laser-engraved texture and blurred edges, affecting the appearance quality; performing dyne enhancement first and then laser engraving can result in molten material and residue generated during laser engraving covering surface active sites, causing a significant drop in dyne value and failing to achieve the dual goals of texture formation and dyne enhancement. Furthermore, magnesium alloys and aluminum alloys have different surface properties (magnesium alloys have lower liquid surface tension than aluminum alloys, making them prone to oxidation and mold sticking), and existing processes do not optimize parameters to address these differences, resulting in uneven and unstable dyne enhancement effects after laser engraving of magnesium-aluminum die-cast parts.

[0006] Therefore, in view of the technical problems existing in the prior art, such as low surface dyne value of magnesium-aluminum die-cast parts after laser engraving, inability to achieve texture formation and dyne value improvement in a coordinated manner, poor environmental friendliness of the processing technology, insufficient adaptability, and low feasibility of mass production, there is an urgent need to develop a laser engraving device and its usage method that can improve the surface dyne value of magnesium-aluminum die-cast parts by taking into account both the quality of laser engraving texture and the improvement of surface dyne value, and is environmentally friendly, efficient, and adaptable to mass production. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a laser engraving device and its method of use for improving the dyne value of magnesium-aluminum die-cast parts.

[0008] The technical solution adopted to solve the above technical problems is: a laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts, including a pretreatment unit, a collaborative laser engraving unit, a secondary activation unit, a post-treatment unit and a quality inspection unit. The collaborative laser engraving unit adopts a segmented laser engraving process, and the secondary activation unit is equipped with an online dyne value detection module.

[0009] Furthermore, the pretreatment unit includes a degreasing tank, a washing tank, a drying oven, and an atmospheric low-temperature plasma activation device arranged in sequence.

[0010] The above technical solution removes mold release agent, oil, oxide layer and impurities from the surface of the blank, while improving surface activity, laying the foundation for subsequent laser engraving and dyne value improvement.

[0011] Furthermore, the collaborative laser engraving unit includes a body on which a fiber laser and a flexible anti-slip fixture are mounted. The flexible anti-slip fixture is located below the fiber laser, and a negative pressure adsorption system is connected below the flexible anti-slip fixture. A wind-cooled temperature control system is provided on one side of the flexible anti-slip fixture. A silicone pad is provided at the contact area between the flexible anti-slip fixture and the workpiece, and negative pressure adsorption holes are distributed on the surface of the flexible anti-slip fixture.

[0012] Using the above technical solution, the pre-treated magnesium-aluminum die-cast blank is fixed on the flexible anti-slip fixture of the laser engraving equipment. According to the preset texture requirements, the fiber laser uses a segmented laser engraving process to perform laser engraving. At the same time, through laser engraving parameter optimization, while achieving texture formation, the residual oxide layer on the surface is further removed, the surface active sites are activated, and the surface dyne value is improved.

[0013] Furthermore, the secondary activation unit includes a low-temperature plasma generator. The top of the low-temperature plasma generator is provided with a moving guide rail, a direct injection nozzle, an online dyne detection probe, and a temperature controller. The direct injection nozzle is installed on the moving guide rail, the online dyne detection probe is installed on the side wall of the direct injection nozzle, and the online dyne detection probe is electrically connected to the temperature controller.

[0014] Through the above technical solution, after laser engraving is completed, the direct injection nozzle of the low-temperature plasma generator immediately performs low-temperature plasma secondary activation treatment on the die-casting part. The online dyne value detection probe monitors the surface dyne value in real time. Once the standard is met, the activation automatically stops, removing impurities such as molten residue and carbides generated during the laser engraving process, further activating surface active groups, and stabilizing and improving the surface dyne value.

[0015] Furthermore, the post-processing unit includes a vacuum cooling chamber and a hot air circulating drying box, with a support plate between the vacuum cooling chamber and the hot air circulating drying box, and an anhydrous ethanol container and a dust-free cloth on the support plate.

[0016] Using the above technical solution, the magnesium-aluminum die-cast parts that have undergone secondary activation treatment are sequentially subjected to vacuum cooling, anhydrous ethanol wiping, and drying to remove residual impurities and moisture from the surface, ensuring surface cleanliness, and finally obtaining magnesium-aluminum die-cast parts with both precise laser engraving texture and high surface dyne value.

[0017] Furthermore, the quality inspection unit includes a workbench on which a microscope and a dyne pen are placed.

[0018] Using the above technical solutions, the laser-engraved texture is observed under a microscope to ensure that the texture is clear, the edges are neat, and there are no burrs or defects; the dyne value is detected by a dyne pen to ensure that the average dyne value is ≥42 dyn / cm and the individual detection point is ≥40 dyn / cm.

[0019] A method for using a laser engraving device to improve the dyne value of the surface of magnesium-aluminum die-cast parts includes the following steps; Step 1: Pre-treatment of die-cast blanks. Magnesium-aluminum die-cast blanks are placed in a degreasing tank, a water washing tank, and a drying oven in sequence for degreasing, water washing, and drying. Then, atmospheric low-temperature plasma activation equipment is used to activate the surface of the blanks for pre-treatment. The plasma power, treatment time, and gas ratio are set according to the magnesium alloy or aluminum alloy material. Step 2: Perform collaborative laser engraving. Fix the pre-treated blank onto a flexible anti-slip fixture, start the negative pressure adsorption system and fiber laser, and perform rough engraving and fine engraving stages in sequence. The air-cooled temperature control system controls the surface temperature in real time. Step 3: Activation treatment after laser engraving. After laser engraving is completed, the low-temperature plasma generator is immediately started. The moving guide rail drives the direct injection nozzle to move. The direct injection nozzle performs a secondary activation treatment on the blank. The online dyne value detection probe and temperature controller monitor the surface dyne value in real time. The activation automatically stops after the standard is met. Step 4: Post-processing. The activated die casting is sent to a vacuum cooling chamber to cool to room temperature. Then, the die casting is placed on a support plate and the surface of the die casting is wiped with anhydrous ethanol and a lint-free cloth. After that, the surface of the casting is sent to a hot air circulating drying oven for drying. Step 5: Conduct quality inspection. Use a microscope to inspect the clarity and dimensional accuracy of the laser-engraved texture, and use a dyne pen to check the dyne value of the surface, ensuring that the average dyne value is ≥42 dyn / cm and the value of a single test point is ≥40 dyn / cm.

[0020] Furthermore, in step two, the laser power in the rough carving stage is 30-50W and the scanning speed is 800-1200mm / s, while the laser power in the fine carving stage is 15-30W and the scanning speed is 1500-2000mm / s.

[0021] Furthermore, in step three, the online dyne detection probe monitors the surface dyne value in real time, and the target value is 42 dyn / cm. When the detected value reaches the target value, the activation process is automatically stopped. The beneficial effects of this invention are as follows: (1) By setting up a pre-processing unit, a collaborative laser engraving unit, a secondary activation unit, a post-processing unit, and a quality inspection unit, the collaborative control of laser engraving texture forming and surface dyne value improvement is realized, which solves the technical problem of mutual constraint between the two in the traditional process. Moreover, the device has a high degree of automation, is easy to operate, is suitable for mass production, and significantly improves production efficiency and product qualification rate. (2) By combining segmented laser engraving and plasma secondary activation, and with online feedback control of dyn value, the surface activity and process stability are significantly improved, ensuring that the dyn value is stable at ≥42 dyn / cm; (3) By setting up a collaborative laser engraving unit and a secondary activation unit, the plasma activation parameters and laser engraving parameters are optimized respectively to address the differences in surface characteristics between magnesium alloy and aluminum alloy. At the same time, it adapts to the zonal processing requirements of magnesium-aluminum composite die castings, solves the problems of poor adaptability of existing processes and uneven improvement of dyne values, ensures that the processing effect of magnesium-aluminum die castings of different materials is stable and consistent, and expands the application range of the process. (4) Through the pretreatment unit, the entire process adopts environmentally friendly degreasing agent and physical surface modification technology, with no harmful waste liquid discharge, which meets the requirements of green manufacturing. Attached Figure Description

[0022] Figure 1 This is a perspective view of a laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts and its usage method according to the present invention. Figure 2 This is a perspective view of the pretreatment unit of a laser engraving device and its application method for improving the dyne value of magnesium-aluminum die-cast parts according to the present invention. Figure 3 This is a three-dimensional view of the collaborative laser engraving unit of the laser engraving device and its method for improving the dyne value of magnesium-aluminum die-cast parts according to the present invention. Figure 4 This is a three-dimensional view of the secondary activation unit of a laser engraving device and its usage method for improving the dyne value of magnesium-aluminum die-cast parts according to the present invention. Figure 5 This is a perspective view of the post-processing unit of a laser engraving device and its method for improving the dyne value of magnesium-aluminum die-cast parts according to the present invention. Figure 6 This invention relates to a laser engraving device and its usage method for improving the dyne value of magnesium-aluminum die-cast parts, and is a quality inspection unit.

[0023] Reference numerals: 1. Pre-treatment unit; 2. Collaborative laser engraving unit; 3. Secondary activation unit; 4. Post-treatment unit; 5. Quality inspection unit; 101. Degreasing tank; 102. Washing tank; 103. Drying oven; 104. Atmospheric low-temperature plasma activation equipment; 201. Machine body; 202. Fiber laser; 203. Flexible anti-slip tooling fixture; 204. Negative pressure adsorption system; 205. Air-cooled temperature control system; 301. Low-temperature plasma generator; 302. Moving guide rail; 303. Direct injection nozzle; 304. Dyne value online detection probe; 305. Temperature controller; 401. Vacuum cooling chamber; 402. Hot air circulating drying oven; 403. Support plate; 404. Anhydrous ethanol container; 405. Cleanroom cloth; 501. Workbench; 502. Microscope; 503. Dyne pen. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Example 1: As Figures 1-6As shown, a laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts in this embodiment includes a pretreatment unit 1, a collaborative laser engraving unit 2, a secondary activation unit 3, a post-treatment unit 4, and a quality inspection unit 5. The collaborative laser engraving unit 2 adopts a segmented laser engraving process, and the secondary activation unit 3 is equipped with an online dyne value detection module. The pretreatment unit 1 includes a degreasing tank 101, a washing tank 102, a drying oven 103 and an atmospheric low-temperature plasma activation device 104 arranged in sequence to remove mold release agent, oil stains, oxide layer and impurities from the surface of the blank, while improving surface activity and laying the foundation for subsequent laser engraving and dyne value improvement. The collaborative laser engraving unit 2 includes a body 201, on which a fiber laser 202 and a flexible anti-slip fixture 203 are mounted. The flexible anti-slip fixture 203 is located below the fiber laser 202. A negative pressure adsorption system 204 is connected to the bottom of the flexible anti-slip fixture 203. A wind-cooled temperature control system 205 is provided on one side of the flexible anti-slip fixture 203. A silicone pad is provided at the contact part between the flexible anti-slip fixture 203 and the workpiece. Negative pressure adsorption holes are distributed on the surface of the flexible anti-slip fixture 203. The pre-treated magnesium-aluminum die-cast blank is fixed on the flexible anti-slip fixture 203 of the laser engraving equipment. According to the preset texture requirements, the fiber laser 202 uses a segmented laser engraving process to perform laser engraving. At the same time, through laser engraving parameter optimization, while achieving texture formation, the residual oxide layer on the surface is further removed, the surface active sites are activated, and the surface dyne value is improved. The secondary activation unit 3 includes a low-temperature plasma generator 301. The top of the low-temperature plasma generator 301 is equipped with a moving guide rail 302, a direct injection nozzle 303, a dyne value online detection probe 304, and a temperature controller 305. The direct injection nozzle 303 is installed on the moving guide rail 302, and the dyne value online detection probe 304 is installed on the side wall of the direct injection nozzle 303. The dyne value online detection probe 304 is electrically connected to the temperature controller 305. After laser engraving is completed, the direct injection nozzle 303 of the low-temperature plasma generator 301 immediately performs low-temperature plasma secondary activation treatment on the die-casting part. The dyne value online detection probe 304 monitors the surface dyne value in real time. After reaching the standard, the activation is automatically stopped to remove impurities such as molten residue and carbides generated during laser engraving, further activate surface active groups, and stably improve the surface dyne value. Post-processing unit 4 includes a vacuum cooling chamber 401 and a hot air circulating drying box 402. A support plate 403 is provided between the vacuum cooling chamber 401 and the hot air circulating drying box 402. An anhydrous ethanol container 404 and a dust-free cloth 405 are provided on the support plate 403. The magnesium-aluminum die castings that have undergone secondary activation treatment are sequentially subjected to vacuum cooling, anhydrous ethanol wiping, and drying treatment to remove residual impurities and moisture on the surface, ensure surface cleanliness, and finally obtain magnesium-aluminum die castings with both precise laser engraving texture and high surface dyne value. The quality inspection unit 5 includes a workbench 501, on which a microscope 502 and a dyne pen 503 are placed. The microscope 502 observes the laser engraving texture to ensure that the texture is clear, the edges are neat, and there are no burrs or defects. The dyne pen 503 detects the dyne value to ensure that the average dyne value is ≥42 dyn / cm and the single detection point is ≥40 dyn / cm. A method for using a laser engraving device to improve the dyne value of the surface of magnesium-aluminum die-cast parts includes the following steps; Step 1: Pre-treatment of die-cast blanks. Select aluminum alloy die-cast blanks (material: 6061 aluminum alloy) and place them in degreasing tank 101 with an environmentally friendly alkaline degreasing agent for degreasing treatment. The degreasing temperature is 50℃ and the degreasing time is 15min. The environmentally friendly alkaline degreasing agent consists of the following components by mass fraction: sodium hydroxide 6%, sodium carbonate 4%, trisodium phosphate 3%, surfactant 1.5%, and deionized water balance. After degreasing, wash the blanks three times with deionized water in water washing tank 102, with each wash lasting 4min, to remove any degreasing agent residue. Then place the blanks in drying oven 103 and dry them at 80℃ for 25min to ensure that the surface moisture content is ≤0.5%. After drying, use atmospheric low-temperature plasma activation equipment 104 for activation pre-treatment. The plasma power is 120W, the treatment time is 60s, the gas is a mixture of argon and oxygen with a mixing volume ratio of 3:1, and the treatment distance is 8mm, acting uniformly on the surface of the blanks. Step 2: Perform collaborative laser engraving. Fix the pre-treated aluminum alloy die-cast blank onto the flexible anti-slip fixture 203. Use the negative pressure adsorption system 204 to assist in fixing the negative pressure at 0.05MPa. Place silicone pads at the contact points of the fixture. Use a fiber laser 202 to perform segmented laser engraving. The preset texture is a grid texture (grid size 0.1mm × 0.1mm). Rough engraving stage: The laser wavelength is 1064nm, the laser power is 40W, the scanning speed is 1000mm / s, the spot diameter is 0.15mm, the pulse frequency is 30kHz, and the engraving depth is 0.08mm. During the laser engraving process, the surface temperature is controlled to not exceed 100℃ by the air-cooled temperature control system 205. Fine carving stage: Keep the laser wavelength constant, adjust the laser power to 25W, the scanning speed to 1800mm / s, the spot diameter to 0.08mm, the pulse frequency to 50kHz, and the carving depth to 0.02mm to accurately form the grid texture; Step 3: Post-laser engraving activation treatment. After laser engraving is completed, the low-temperature plasma generator 301 is immediately started. The moving guide rail 302 drives the direct injection nozzle 303 to move. The direct injection nozzle 303 performs a secondary activation treatment on the blank. The treatment temperature is 40℃, the treatment time is 30s, the gas is a mixture of oxygen and nitrogen with a mixing volume ratio of 1:3, the plasma power is 80W, and the direct injection method is adopted. The distance between the nozzle of the direct injection nozzle 303 and the surface of the die-casting part is 5mm, the nozzle moving speed is 80mm / s, and the dyne value online detection probe 304 detects the surface dyne value in real time. When the dyne value is ≥42 dyn / cm, the activation is stopped. Step 4: Post-processing. Place the die-cast part after secondary activation into the vacuum cooling chamber 401 and cool it to room temperature under a vacuum of 0.08MPa. Then place the die-cast part on the support plate 403 and wipe the surface of the die-cast part with anhydrous ethanol from the anhydrous ethanol container 404 using a lint-free cloth 405 to remove residual impurities. Then send the surface of the casting part into the hot air circulating drying oven 402 and dry it at 70℃ for 20 minutes with a hot air velocity of 1.5m / s. Step 5: Conduct quality inspection. Use a 502 microscope to observe the laser-engraved texture. The grid texture is clear, the edges are neat, there are no burrs or defects, and the texture size error is ≤ ±0.01mm. Use a 503 dyn pen to detect the surface dyn value. Select 5 detection points, and the detection values ​​are 43 dyn / cm, 44 dyn / cm, 42 dyn / cm, 45 dyn / cm, and 43 dyn / cm, respectively. The average dyn value is 43.4 dyn / cm, and the dyn value of each detection point is ≥40 dyn / cm. The surface is free of impurities and oxidation spots, which indicates that it is a qualified product.

[0026] Example 2: The difference from Example 1 is that a method for using a laser engraving device to improve the dyne value of the surface of magnesium-aluminum die-cast parts includes the following steps; Step 1: Pre-treatment of die-cast blanks. Select magnesium alloy die-cast blanks (material: AZ91D magnesium alloy), place them in degreasing tank 101 with environmentally friendly alkaline degreasing agent for degreasing treatment, the degreasing temperature is 45℃, and the degreasing time is 12min; the environmentally friendly alkaline degreasing agent is the same as in Example 1; after degreasing, wash twice with deionized water in water washing tank 102, each time for 3min; then place them in drying oven 103 and dry at 75℃ for 22min to ensure surface moisture content ≤0.5%; after drying, use atmospheric low-temperature plasma activation equipment 104 for activation pre-treatment, the plasma power is 100W, the treatment time is 45s, the gas is a mixture of argon and oxygen, the mixing volume ratio is 4:1, and the treatment distance is 6mm; Step 2: Perform collaborative laser engraving. Fix the pre-treated magnesium alloy die-cast blank onto the flexible anti-slip fixture 203. Use the negative pressure adsorption system 204 to assist in fixing it (negative pressure is 0.04MPa). Use a fiber laser 202 to perform segmented laser engraving. The preset texture is stripes (texture stripe width 0.08mm, spacing 0.1mm). Rough engraving stage: The laser wavelength is 1064nm, the laser power is 35W, the scanning speed is 900mm / s, the spot diameter is 0.12mm, the pulse frequency is 25kHz, and the engraving depth is 0.06mm. During the laser engraving process, the surface temperature is controlled to not exceed 80℃ by the air-cooled temperature control system 205. Fine carving stage: Keep the laser wavelength constant, adjust the laser power to 20W, the scanning speed to 1600mm / s, the spot diameter to 0.06mm, the pulse frequency to 45kHz, and the carving depth to 0.015mm to accurately form stripe textures; Step 3: Post-laser engraving activation treatment. After laser engraving is completed, the low-temperature plasma generator 301 is immediately started. The moving guide rail 302 drives the direct injection nozzle 303 to move. The direct injection nozzle 303 performs a secondary activation treatment on the blank. The treatment temperature is 35℃, the treatment time is 25s, the gas is a mixture of oxygen and nitrogen with a mixing volume ratio of 1:2.5, the plasma power is 70W, the direct injection method is used, the distance between the direct injection nozzle 303 and the surface of the die-casting part is 4mm, the nozzle moving speed is 60mm / s, and the dyne value online detection probe 304 detects the dyne value in real time. Activation is stopped after the standard is met. Step 4: Post-processing. Place the die-cast part after secondary activation into the vacuum cooling chamber 401 and cool it to room temperature under a vacuum of 0.06 MPa. Then place the die-cast part on the support plate 403 and wipe the surface of the die-cast part with anhydrous ethanol from the anhydrous ethanol container 404 using a lint-free cloth 405 to remove residual impurities. Then send the surface of the casting part into the hot air circulating drying oven 402 and dry it at 65°C for 18 minutes with a hot air velocity of 1.2 m / s. Step 5: Quality inspection was conducted. Microscopic observation with a 502 microscope showed that the stripe texture was clear, the edges were neat, there were no burrs or defects, and the texture size error was ≤ ±0.01mm. Five points were tested with a dyne pen with 503, and the measured values ​​were 42 dyn / cm, 43 dyn / cm, 44 dyn / cm, 42 dyn / cm, and 43 dyn / cm, with an average dyn / cm value of 42.8 dyn / cm, all of which met the qualification requirements. The surface was clean and free of oxidation spots, indicating that it was a qualified product. Example 3: The difference from Example 1 is that a method for using a laser engraving device to improve the dyne value of the surface of magnesium-aluminum die-cast parts includes the following steps; Step 1: Pre-treatment of die-cast blanks. Select magnesium-aluminum composite die-cast blanks (magnesium alloy area material is AZ31B, aluminum alloy area material is 5052), and place them in the environmentally friendly alkaline degreasing agent in degreasing tank 101 for degreasing at 55℃ for 18 minutes. The degreasing agent is the same as in Example 1. After degreasing, wash with deionized water three times in water washing tank 102 for 5 minutes each time. Dry at 85℃ for 28 minutes until the moisture content is ≤0.5%. Activation pre-treatment is performed using atmospheric low-temperature plasma activation equipment 104: magnesium alloy area uses magnesium alloy parameters (power 110W, time 50s, argon:oxygen = 4.5:1, processing distance 7mm), and aluminum alloy area uses aluminum alloy parameters (power 130W, time 70s, argon:oxygen = 3.5:1, processing distance 8mm). Step 2: Perform collaborative laser engraving. Fix the pre-treated composite die-casting part onto the flexible anti-slip fixture 203 with a negative pressure adsorption pressure of 0.05MPa. Use a fiber laser 202 for segmented laser engraving. The preset texture is a combination of logo and grid texture. Rough carving stage: laser power 45W, scanning speed 1100mm / s, spot diameter 0.18mm, pulse frequency 35kHz, carving depth 0.09mm, air-cooled temperature control system 205 controls the temperature of magnesium alloy area ≤80℃ and aluminum alloy area ≤100℃. Fine carving stage: laser power 28W, scanning speed 1900mm / s, spot diameter 0.09mm, pulse frequency 55kHz, carving depth 0.025mm, accurately forming combined textures; Step 3: Post-laser engraving activation treatment. After laser engraving, the secondary activation adopts a zoned treatment with a temperature of 45℃, a time of 35s, a gas oxygen:nitrogen ratio of 1:3.5, a power of 90W, a direct injection nozzle of 303 with a nozzle distance of 6mm, a moving speed of 90mm / s, and a dyne value online detection probe of 304 to detect the dyne value in real time, ensuring that the dyne value in both zones is ≥42 dyn / cm. Step 4: Post-processing. Place the die-cast parts after secondary activation into the vacuum cooling chamber 401 and cool them to room temperature under vacuum at 0.09MPa. Wipe with anhydrous ethanol, and then send the surface of the castings into the hot air circulating drying oven 402 and dry them with hot air at 75℃ for 25 minutes at a wind speed of 1.8m / s. Step 5: Conduct quality inspection. Microscopic observation with a 502 microscope shows that the combined texture is clear, the edges are neat, and the dimensional error is ≤±0.01mm. Dyne pen testing shows that the average dyn value of the magnesium alloy area is 43.2 dyn / cm, and the average dyn value of the aluminum alloy area is 44.1 dyn / cm, both of which meet the requirements. The surface is clean and free of impurities, indicating that it is a qualified product.

[0027] Comparative Experiment: The same aluminum alloy die-casting parts as in Example 1 and the same magnesium alloy die-casting parts as in Example 2 were selected and treated using traditional processes (conventional laser engraving + chemical etching to enhance dyne value), serving as control group 1 and control group 2. The same magnesium-aluminum composite die-casting parts as in Example 3 were selected and treated using existing synergistic processes (activation before laser engraving, without segmented laser engraving), serving as control group 3. The laser engraving texture quality, surface dyne value, environmental friendliness, and processing efficiency of each group were tested, and the results are shown in the table below: As can be seen from the above comparative tests, the products of Examples 1-3 of the present invention have significantly better laser engraving texture quality, surface dyne value, environmental friendliness, processing efficiency and pass rate than the control group. This fully demonstrates that the technical solution of the present invention can effectively solve the shortcomings of the prior art, achieve synergistic optimization of texture forming and dyne value improvement, and has significant technical advantages and industrial application value.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts, characterized in that, It includes a pre-processing unit (1), a collaborative laser engraving unit (2), a secondary activation unit (3), a post-processing unit (4), and a quality detection unit (5). The collaborative laser engraving unit (2) adopts a segmented laser engraving process, and the secondary activation unit (3) is equipped with an online dyne detection module.

2. The laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts according to claim 1, characterized in that, The pretreatment unit (1) includes a degreasing tank (101), a washing tank (102), a drying oven (103), and an atmospheric low-temperature plasma activation device (104) arranged in sequence.

3. The laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts according to claim 1, characterized in that, The collaborative laser engraving unit (2) includes a body (201), on which a fiber laser (202) and a flexible anti-slip fixture (203) are mounted. The flexible anti-slip fixture (203) is located below the fiber laser (202). A negative pressure adsorption system (204) is connected below the flexible anti-slip fixture (203). A wind-cooled temperature control system (205) is provided on one side of the flexible anti-slip fixture (203). A silicone pad is provided at the contact part between the flexible anti-slip fixture (203) and the workpiece. Negative pressure adsorption holes are distributed on the surface of the flexible anti-slip fixture (203).

4. The laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts according to claim 1, characterized in that, The secondary activation unit (3) includes a low-temperature plasma generator (301). The low-temperature plasma generator (301) is provided with a moving guide rail (302), a direct injection nozzle (303), a dyne value online detection probe (304), and a temperature controller (305) on its top. The direct injection nozzle (303) is installed on the moving guide rail (302). The dyne value online detection probe (304) is installed on the side wall of the direct injection nozzle (303). The dyne value online detection probe (304) is electrically connected to the temperature controller (305).

5. The laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts according to claim 1, characterized in that, The post-processing unit (4) includes a vacuum cooling chamber (401) and a hot air circulating drying box (402). A support plate (403) is provided between the vacuum cooling chamber (401) and the hot air circulating drying box (402). An anhydrous ethanol container (404) and a dust-free cloth (405) are provided on the support plate (403).

6. The laser engraving device for improving the dyne value of magnesium-aluminum die-cast parts according to claim 1, characterized in that, The quality inspection unit (5) includes a workbench (501) on which a microscope (502) and a dyne pen (503) are placed.

7. A method of using the laser engraving device for increasing the dyne value of magnesium-aluminum die-cast parts as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Pre-treatment of die-cast blanks. Magnesium-aluminum die-cast blanks are placed in a degreasing tank (101), a water washing tank (102), and a drying box (103) in sequence for degreasing, water washing, and drying. Then, an atmospheric low-temperature plasma activation device (104) is used to activate the surface of the blanks for pre-treatment. The plasma power, treatment time, and gas ratio are set according to the magnesium alloy or aluminum alloy material. Step 2: Perform collaborative laser engraving. Fix the pre-treated blank onto the flexible anti-slip fixture (203). Start the negative pressure adsorption system (204) and fiber laser (202) to perform rough engraving and fine engraving stages in sequence. The air-cooled temperature control system (205) controls the surface temperature in real time. Step 3: Laser engraving and activation treatment. After laser engraving is completed, the low-temperature plasma generator (301) is immediately started. The moving guide rail (302) drives the direct injection nozzle (303) to move. The direct injection nozzle (303) performs secondary activation treatment on the blank. The online detection probe (304) and temperature controller (305) monitor the surface dyne value in real time. The activation is automatically stopped after the standard is met. Step 4: Post-processing: The activated die casting is sent into a vacuum cooling chamber (401) to cool to room temperature. Then the die casting is placed on a support plate (403), and the surface of the die casting is wiped with anhydrous ethanol and a lint-free cloth (405). Then the surface of the casting is sent into a hot air circulating drying oven (402) for drying. Step 5: Conduct quality inspection. Use a microscope (502) to inspect the clarity and dimensional accuracy of the laser-engraved texture, and use a dyne pen (503) to inspect the surface dyne value to ensure that the average dyne value is ≥42 dyn / cm and the single inspection point is ≥40 dyn / cm.

8. The method of use according to claim 7, characterized in that: In step two, the laser power in the rough carving stage is 30-50W and the scanning speed is 800-1200mm / s, while the laser power in the fine carving stage is 15-30W and the scanning speed is 1500-2000mm / s.

9. The method of use according to claim 7, characterized in that, In step three, the online dyne detection probe (304) monitors the surface dyne value target value in real time, which is 42 dyn / cm. When the detection value reaches the target value, the activation process is automatically stopped.

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