Electrostatic powder spraying process and device for aluminum alloy processing

Abstract

The invention relates to the field of aluminum alloy door and window enterprises, and discloses an electrostatic powder spraying process and device for aluminum alloy machining, and the electrostatic powder spraying process comprises the following steps: pretreatment: pretreating an aluminum alloy base material, the pretreatment comprises polishing, cleaning and preheating treatment; powder treatment is conducted, specifically, a treatment agent accounting for 5%-10% of the mass of the powder base material is added into the powder base material, high-speed stirring is conducted, spraying powder is obtained, and the treatment agent is composed of a low-Tg polyester resin modifier and nano titanium dioxide; and electrostatic spraying is conducted, specifically, powder spraying is conducted on the surface of the pretreated aluminum alloy base material through electrostatic powder spraying equipment through spraying powder. Powder added with a treating agent is sprayed to an aluminum alloy base material, low-temperature rapid curing is conducted, the curing process of the coating is rapidly completed at the relatively low temperature through stage gradient temperature curing and auxiliary curing, and the curing efficiency and quality are further improved through ultraviolet light and microwave auxiliary curing.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy door and window enterprises, and specifically to an aluminum alloy processing electrostatic powder spraying process and device. Background Art

[0002] Existing aluminum alloy door and window companies usually process aluminum alloy plates through processes such as melting, extrusion and coloring. Coloring mainly includes oxidation, electrophoretic coating, fluorocarbon spraying, powder spraying, wood grain transfer and other processes. During the powder spraying process, a high voltage (generally a negative voltage) is applied to the spray gun through an electrostatic generator to make the powder coating carry a negative charge. When the negatively charged powder coating is sprayed from the spray gun, the powder coating will be adsorbed onto the surface of the aluminum alloy profile. During the adsorption process, the powder will gradually accumulate on the surface of the aluminum alloy to form a coating. After curing treatment, the powder coating is melted, leveled and solidified into a hard and uniform coating, thereby achieving the protection and decoration of the aluminum alloy.

[0003] The traditional electrostatic powder spraying process for aluminum alloy processing usually needs to be carried out at a high temperature of 180-220℃ during the curing process. This high temperature and long-term curing method will cause a large amount of energy consumption and increase production costs. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an aluminum alloy processing electrostatic powder spraying process and device, which solves the problem that the traditional aluminum alloy processing electrostatic powder spraying process will cause a large amount of energy consumption and increase production costs during the curing process.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: an aluminum alloy processing electrostatic powder spraying process, comprising the following steps:

[0006] S1. Pretreatment: pretreatment of the aluminum alloy substrate, including grinding, cleaning and preheating;

[0007] S2, powder treatment: adding a treatment agent of 5% to 10% of the mass of the powder substrate to the powder substrate, and stirring at high speed to obtain a spray powder, wherein the treatment agent is composed of a low Tg polyester resin modifier and nano titanium dioxide;

[0008] S3, electrostatic spraying: using electrostatic powder spraying equipment to spray the spray powder on the surface of the pretreated aluminum alloy substrate;

[0009] S4, curing treatment: the sprayed aluminum alloy substrate is subjected to low-temperature rapid curing, and during the curing process, a heating element and a circulating fan are used for hot air circulation and temperature control. The low-temperature rapid curing includes stage gradient temperature curing and auxiliary curing. The temperature of the stage gradient temperature curing is 120°C-160°C.

[0010] Preferably, the polishing in S1 is to polish the surface of the aluminum alloy substrate with 200-400 mesh sandpaper, and the roughness Ra is 0.8μm-1.6μm, the cleaning is to clean the surface of the aluminum alloy substrate with acetone to make the surface of the aluminum alloy substrate free of oil and impurities, and the preheating treatment is to preheat the aluminum alloy substrate with a hot air circulation oven, the temperature is 40℃-60℃, and the preheating time is 5-10 minutes.

[0011] Preferably, the Tg of S2 is 40-60° C., and the preparation method of the treatment agent comprises the following steps:

[0012] S201, modifying the terminal hydroxyl groups of the low Tg polyester resin to make the hydroxyl value reach 30-50 mgKOH / g, to obtain a low Tg polyester resin modifier;

[0013] S202, weighing a low Tg polyester resin modifier and nano titanium dioxide with a particle size of 20-30 nm in a mass ratio of 4:1-6:1, placing the mixture in a high-speed mixer, and premixing the mixture at a speed of 600-800 rpm for 5-8 minutes to obtain a premixed material;

[0014] S203, grinding the premixed material into a particle size of 15-25 μm by a grinder to obtain a treatment agent.

[0015] Preferably, the electrostatic powder spraying equipment in S3 includes an electrostatic spray gun, the spray gun voltage is 60-80 kV, the powder spraying amount is 100-200 g / min, the distance between the electrostatic spray gun and the surface of the aluminum alloy substrate during the powder spraying is maintained at 15-25 cm, and the coating thickness is 80-120 μm.

[0016] Preferably, the low temperature rapid curing in S4 comprises the following steps:

[0017] S401, the first stage: the aluminum alloy substrate is initially cured at 120°C to 130°C for 3 minutes to 5 minutes by infrared heating tube, and the ultraviolet lamp is turned on to assist in curing. The power of the ultraviolet lamp is 80W / m 2 Up to 200W / m 2 ;

[0018] S402, second stage: then further curing is performed at 140° C. to 150° C. for 5 to 8 minutes, and a microwave generator is turned on to assist in curing, wherein the frequency of the microwave generator is 2.45 GHz and the power is 0.8 kW to 2.5 kW;

[0019] S403, the third stage: then post-curing is performed at 150° C. to 160° C. for 2 minutes to 3 minutes, thereby completing low-temperature rapid curing.

[0020] An aluminum alloy processing electrostatic powder spraying device comprises a support frame, an air curtain machine is fixedly arranged on one side of the support frame, a protective shell is fixedly connected to the other side of the support frame, an electric push rod is fixedly connected to the inner wall of the protective shell, an output end of the electric push rod is fixedly connected to a slider, a first rack is fixedly connected to one side of the slider, a first gear is meshingly connected to the tooth end of the first rack, a connecting pipe is fixedly connected to the bottom of the first gear, a connecting plate is fixedly connected to the bottom of the connecting pipe, a groove is arranged inside the connecting plate, and an adjustment structure is arranged in the groove inside the connecting plate.

[0021] Preferably, the adjustment structure includes a rotating shaft, the bottom end of the rotating shaft is rotatably connected to the bottom of the inner wall of the groove of the connecting plate, the bottom of the outer wall of the rotating shaft is fixedly connected to a second gear, the tooth end of the second gear is symmetrically meshingly connected to a second rack, the side of the second rack away is fixedly connected to a movable plate, one end of the movable plate is fixedly connected to a connecting column, and a hook is fixedly provided at the bottom of the connecting column.

[0022] Preferably, the outer wall of the movable plate is slidably connected to the inner wall of the groove of the connecting plate, and the second gear is located inside the groove.

[0023] Preferably, an air outlet is provided at the bottom of the air curtain machine, a filter is fixedly provided at the air inlet of the air curtain machine, and the air curtain machine is used to generate a wind curtain with a wind speed of 3-5m / s and forms an angle of 30-60 degrees with the spraying direction.

[0024] Preferably, a protective box is fixedly connected to the top of the support frame, a servo motor is fixedly arranged inside the protective box, the output end of the servo motor is fixedly arranged at the top of the rotating shaft, a slide groove is arranged on one side of the support frame, the slider is slidably connected to the inside of the slide groove, the first gear is located inside the slide groove, and the top of the connecting pipe is rotatably connected to the top of the inner wall of the slide groove of the support frame.

[0025] Working principle: When using the device, the servo motor drives the rotating shaft to rotate, thereby driving the second gear to rotate, thereby driving the two second racks and the moving plate to move inside the groove, thereby driving the connecting columns to move closer to or away from each other, thereby adjusting the position of the hook according to the width of the aluminum alloy plate, and hanging the aluminum alloy plate to be sprayed by the hook, and then spraying.

[0026] When the angle of the aluminum alloy plate needs to be adjusted during spraying, the electric push rod drives the slider and the first rack to move inside the slide slot, thereby driving the first gear to rotate, thereby driving the connecting pipe to rotate, thereby driving the connecting plate to rotate, thereby driving the adjustment structure to rotate, so as to adjust the rotation of the aluminum alloy plate according to the spraying requirements, and when rotating, the servo motor cooperates to operate so that the rotating shaft follows the connecting pipe to rotate synchronously, ensuring the stable suspension of the plate.

[0027] When one or both sides of the aluminum alloy plate need to be sprayed with different powders, the wind curtain machine generates a wind curtain with a wind speed of 3-5m / s and forms an angle of 30-60 degrees with the spraying direction, thereby blocking the sprayed powder and preventing the powder from being adsorbed on the area where different powders need to be sprayed. The electric push rod can also be used to drive the adjustment structure to rotate and adjust the size of the area where different powders need to be sprayed.

[0028] The present invention provides an electrostatic powder spraying process for aluminum alloy processing, which has the following beneficial effects:

[0029] 1. The present invention sprays the powder added with the treatment agent onto the aluminum alloy substrate, performs low-temperature rapid curing, and performs stage gradient temperature curing and auxiliary curing, thereby quickly completing the curing process of the coating at a relatively low temperature, and further improves the curing efficiency and quality by using ultraviolet and microwave assisted curing, thereby reducing the curing energy consumption, shortening the curing time and improving the coating performance, thereby solving the problem of the traditional aluminum alloy processing electrostatic powder spraying process causing a large amount of energy consumption and increased production costs during the curing process.

[0030] 2. The present invention adds a treatment agent to the powder substrate so that the powder coating has the performance of low-temperature rapid curing, better ultraviolet absorption and weather resistance, improves the fluidity and reactivity of the powder at low temperatures through a low Tg polyester resin modifier, and uses nano-titanium dioxide to exert photoinitiation and anti-aging effects, thereby improving the comprehensive performance of the coating and improving the poor effect of traditional powder coatings when cured at low temperatures and the easy aging of the coating.

[0031] 3. The present invention performs preliminary curing of the aluminum alloy substrate at 120°C to 130°C for 3 minutes to 5 minutes, and simultaneously turns on an ultraviolet lamp for auxiliary curing, and utilizes ultraviolet rays to excite nano-titanium dioxide to produce free radicals, which quickly triggers the curing reaction of the powder coating, and starts the cross-linking process at a relatively low temperature. Infrared heating provides basic thermal energy for the reaction, causing the powder to begin to soften and react preliminarily. The two synergistically improve the initial rate of the curing reaction, thereby shortening the overall curing time and reducing energy consumption, thereby solving the problems of low efficiency and high energy consumption in the initial stage of traditional high-temperature and long-term curing.

[0032] 4. The present invention further cures at 140°C to 150°C for 5 to 8 minutes, and at the same time turns on the microwave generator, so that the polar molecules inside the powder coating vibrate at high speed and generate heat by friction with the help of microwaves, thereby achieving uniform and rapid heating from the inside to the outside, accelerating the formation of a cross-linked network of the coating, further improving the curing speed and coating quality, and achieving the goal of efficiently constructing a high-quality coating structure at a relatively low temperature and enhancing the density and mechanical properties of the coating, thereby improving the uneven heat transfer, limited curing speed, and easy defects in the coating in the traditional single thermal curing method.

[0033] 5. The present invention performs post-curing at 150°C to 160°C for 2 to 3 minutes to finally improve and strengthen the coating, so that the various properties of the coating reach an optimal balance, ensuring that the coating can maintain good performance during long-term use, and solving the problem that traditional curing treatment is difficult to quickly obtain high-quality coatings under low temperature conditions. At the same time, it reduces the adverse effects of high-temperature and long-term curing on the microstructure and properties of the aluminum alloy substrate.

[0034] 6. The present invention drives the connecting plate to rotate through the operation of the electric push rod, thereby driving the adjustment structure to rotate, so that the aluminum alloy plate can be adjusted to rotate according to the spraying requirements without manual flipping, thereby enhancing the spraying efficiency.

[0035] 7. When one or both sides of the aluminum alloy plate need to be sprayed with different powders, the present invention generates a wind curtain with a wind speed of 3-5m / s through the wind curtain machine and forms an angle of 30-60 degrees with the spraying direction, thereby blocking the powder and preventing the powder from passing through the wind curtain and being adsorbed on the area where different powders need to be sprayed. The size of the area where different powders need to be sprayed can be adjusted by adjusting the rotation of the structure, thereby enhancing the practicality of the device.

[0036] 8. The present invention drives the second gear to rotate through a servo motor, so that the connecting columns move closer to or away from each other, and the position of the hook is adjusted according to the width of the aluminum alloy plate. The aluminum alloy plate to be sprayed is hung by the hook, so that the device can hang aluminum alloy plates of different widths, thereby enhancing the applicability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A method flow chart of an electrostatic powder spraying process for aluminum alloy processing proposed by the present invention;

[0038] Figure 2 This is a structural stereogram of an aluminum alloy processing electrostatic powder spraying device proposed by the present invention;

[0039] Figure 3 This is a schematic diagram of the rear structure of an aluminum alloy processing electrostatic powder spraying device proposed by the present invention;

[0040] Figure 4 This is a schematic diagram of the local structure of a slideway of an aluminum alloy processing electrostatic powder spraying device proposed by the present invention;

[0041] Figure 5 This is a schematic diagram of the partial structure of the first gear of an aluminum alloy processing electrostatic powder spraying device proposed by the present invention;

[0042] Figure 6 A schematic diagram of the partial structure of a protective shell of an aluminum alloy processing electrostatic powder spraying device proposed by the present invention;

[0043] Figure 7 This is a schematic diagram of the partial structure of the second gear of an aluminum alloy processing electrostatic powder spraying device proposed by the present invention.

[0044] Among them, 1. support frame; 2. protective shell; 3. protective box; 4. air curtain machine; 5. electric push rod; 6. slider; 7. slide groove; 8. servo motor; 9. first rack; 10. first gear; 11. connecting pipe; 12. connecting plate; 13. moving plate; 14. second rack; 15. connecting column; 16. hook; 17. rotating shaft; 18. groove; 19. second gear; 20. air outlet. DETAILED DESCRIPTION

[0045] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Example:

[0047] Please see attached Figure 1 The embodiment of the present invention provides an aluminum alloy processing electrostatic powder spraying process, comprising the following steps:

[0048] S1. Pretreatment: Pretreatment of the aluminum alloy substrate, including grinding, cleaning and preheating;

[0049] S2. Powder treatment: adding a treatment agent of 5% to 10% of the mass of the powder substrate to the powder substrate and stirring at high speed to obtain a spray powder, wherein the treatment agent is composed of a low Tg polyester resin modifier and nano titanium dioxide;

[0050] S3, electrostatic spraying: using electrostatic powder spraying equipment to spray the spray powder on the surface of the pretreated aluminum alloy substrate;

[0051] S4. Curing treatment: The sprayed aluminum alloy substrate is rapidly cured at low temperature, and a heating element and a circulating fan are used to circulate hot air and control the temperature during the curing process. The low-temperature rapid curing includes stage gradient temperature curing and auxiliary curing. The temperature of the stage gradient temperature curing is 120°C-160°C.

[0052] Specifically, by pre-treating the aluminum alloy substrate, impurities and oil stains on the surface of the aluminum alloy substrate are removed and the surface state is improved, the surface roughness is increased, and the adhesion ability of subsequent powders is improved, providing a good foundation for electrostatic powder spraying.

[0053] By adding a treatment agent of 5% to 10% of the mass of the powder substrate into the powder substrate and stirring it at high speed, a spray powder is obtained, so that the powder coating has the performance of low-temperature rapid curing, better ultraviolet absorption and weather resistance, the low Tg polyester resin modifier improves the fluidity and reactivity of the powder at low temperatures, and nano-titanium dioxide plays a photo-initiating and anti-aging role, thereby improving the comprehensive performance of the coating and improving the poor effect of traditional powder coatings when cured at low temperatures and the easy aging of the coating.

[0054] The surface of the pretreated aluminum alloy substrate is powder-sprayed with spray powder by electrostatic powder spraying equipment, so that the charged powder is uniformly adsorbed on the surface of the aluminum alloy substrate to form a preliminary coating structure.

[0055] The sprayed aluminum alloy substrate is rapidly cured at low temperature, and heating elements and circulating fans are used for hot air circulation and temperature control during the curing process. The low-temperature rapid curing includes stage gradient temperature curing and auxiliary curing. The stage gradient temperature curing temperature is 120℃-160℃, so that the curing process of the coating is completed quickly at a relatively low temperature. Ultraviolet and microwave assisted curing are used to further improve the curing efficiency and quality, thereby reducing curing energy consumption, shortening curing time and improving coating performance, thereby solving the problem of traditional aluminum alloy processing electrostatic powder spraying process, which will cause a lot of energy consumption and increase production costs during curing treatment.

[0056] In S1, the grinding is to grind the surface of the aluminum alloy substrate with 200-400 mesh sandpaper, and the roughness Ra is 0.8μm-1.6μm. The cleaning is to clean the surface of the aluminum alloy substrate with acetone to make the surface of the aluminum alloy substrate free of oil stains and impurities. The preheating treatment is to preheat the aluminum alloy substrate in a hot air circulation oven, the temperature is 40℃-60℃, and the preheating time is 5-10 minutes.

[0057] Specifically, the surface of the aluminum alloy substrate is polished with 200-400 mesh sandpaper, the surface of the aluminum alloy substrate is cleaned with acetone, and the aluminum alloy substrate is preheated in a hot air circulation oven, thereby effectively removing various pollutants and defects on the surface of the aluminum alloy substrate, forming a suitable microscopic surface morphology, and improving surface energy. An ideal adhesion interface is created for subsequent powder spraying, and the bonding force between the powder and the substrate is enhanced, ensuring the long-term stability and reliability of the coating on the aluminum alloy surface, reducing the occurrence of undesirable phenomena such as coating peeling and blistering caused by substrate surface problems, and improving the overall quality and appearance consistency of aluminum alloy products.

[0058] The Tg of S2 is 40-60°C, and the preparation method of the treating agent comprises the following steps:

[0059] S201, modifying the terminal hydroxyl groups of the low Tg polyester resin to make the hydroxyl value reach 30-50 mgKOH / g, to obtain a low Tg polyester resin modifier;

[0060] S202, weighing a low Tg polyester resin modifier and nano titanium dioxide with a particle size of 20-30 nm in a mass ratio of 4:1-6:1, placing the mixture in a high-speed mixer, and premixing the mixture at a speed of 600-800 rpm for 5-8 minutes to obtain a premixed material;

[0061] S203, grinding the premixed material into a particle size of 15-25 μm by a grinder to obtain a treatment agent.

[0062] Specifically, by modifying the terminal hydroxyl groups of a low Tg polyester resin so that its hydroxyl value reaches 30-50 mgKOH / g, a low Tg polyester resin modifier is obtained, thereby increasing the reactive sites of the polyester resin, enabling it to more effectively undergo cross-linking reactions with other components during low-temperature curing, thereby improving the curing efficiency of the powder coating and the cross-linking density of the coating, thereby forming a dense and tough coating at a relatively low temperature, enhancing the mechanical properties of the coating such as hardness and wear resistance, and at the same time improving the adhesion between the coating and the aluminum alloy substrate, thereby reducing the risk of coating shedding.

[0063] The low Tg polyester resin modifier and nano titanium dioxide with a particle size of 20-30 nm are weighed in a mass ratio of 4:1-6:1, placed in a high-speed mixer, and premixed at a speed of 600-800 rpm for 5-8 minutes to obtain a premixed material, so that the nano titanium dioxide is uniformly dispersed in the low Tg polyester resin modifier, ensuring that in the subsequent curing process, the nano titanium dioxide can give full play to its photoinitiating effect, efficiently generate free radicals under ultraviolet irradiation, accelerate the start of the curing reaction, and at the same time its ultraviolet absorption characteristics are uniformly reflected, effectively protecting the coating from ultraviolet aging and degradation, thereby achieving the goals of improving the curing speed, enhancing the weather resistance of the coating and ensuring the uniformity of the coating quality, so that the coating can maintain a good appearance and performance for a long time in an outdoor environment or under ultraviolet exposure conditions.

[0064] The treating agent is obtained by grinding the premixed material through a grinder to a particle size of 15-25μm, thereby optimizing the particle size distribution of the treating agent, so that it can be more evenly dispersed when mixed and stirred with the powder substrate to avoid agglomeration, ensuring that the powder can stably carry an electric charge and be evenly adsorbed on the surface of the aluminum alloy substrate during the electrostatic spraying process to form a coating with uniform thickness and smooth surface, thereby achieving the goal of improving the electrostatic spraying effect and enhancing the flatness and aesthetics of the coating, and helping to produce aluminum alloy electrostatic powder spraying products with high appearance quality and stable performance.

[0065] The electrostatic powder spraying equipment in S3 includes an electrostatic spray gun, the spray gun voltage is 60-80kV, the powder spraying amount is 100-200g / min, the distance between the electrostatic spray gun and the surface of the aluminum alloy substrate is maintained at 15-25cm during powder spraying, and the coating thickness is 80-120μm.

[0066] S4 medium and low temperature rapid curing includes the following steps:

[0067] S401, the first stage: the aluminum alloy substrate is initially cured at 120℃ to 130℃ for 3 minutes to 5 minutes by infrared heating tube, and the ultraviolet lamp is turned on to assist the curing at the same time. The power of the ultraviolet lamp is 80W / m 2 Up to 200W / m 2 ;

[0068] S402, second stage: then further curing is performed at 140° C. to 150° C. for 5 to 8 minutes, and a microwave generator is turned on to assist in curing, wherein the frequency of the microwave generator is 2.45 GHz and the power is 0.8 kW to 2.5 kW;

[0069] S403, the third stage: then post-curing is performed at 150° C. to 160° C. for 2 minutes to 3 minutes, thereby completing low-temperature rapid curing.

[0070] Specifically, the aluminum alloy substrate is initially cured at 120°C to 130°C for 3 to 5 minutes through an infrared heating tube, and the ultraviolet lamp is turned on for auxiliary curing, so that ultraviolet rays are used to excite nano-titanium dioxide to produce free radicals, which quickly trigger the curing reaction of the powder coating and start the cross-linking process at a lower temperature. Infrared heating provides basic thermal energy for the reaction, causing the powder to begin to soften and react initially. The two synergistically increase the starting rate of the curing reaction, thereby achieving the goal of shortening the overall curing time and reducing energy consumption, thereby solving the problems of low efficiency and high energy consumption in the initial stage of traditional high-temperature and long-term curing.

[0071] By further curing at 140°C to 150°C for 5 to 8 minutes and turning on the microwave generator to assist in curing, the polar molecules inside the powder coating can be vibrated at high speed by microwaves to generate heat through friction, thereby achieving uniform and rapid heating from the inside to the outside, promoting in-depth curing reactions, complementing infrared heating, accelerating the formation of a cross-linked network of the coating, and further improving the curing speed and coating quality. It also achieves the goal of efficiently constructing a high-quality coating structure at a relatively low temperature and enhancing the density and mechanical properties of the coating, improving the uneven heat transfer, limited curing speed, and easy defects inside the coating in the traditional single thermal curing method.

[0072] By post-curing at 150°C to 160°C for 2 to 3 minutes, low-temperature rapid curing is completed, thereby completing and strengthening the coating, so that the various properties of the coating reach the best balance. For example, the hardness, adhesion, impact resistance and other properties are fully stable, ensuring that the coating can maintain good performance during long-term use, achieving the goal of obtaining an aluminum alloy surface coating with excellent comprehensive performance that meets the needs of various application scenarios, and solving the problem that traditional curing treatments are difficult to quickly obtain high-quality coatings under low temperature conditions. At the same time, it reduces the adverse effects of high-temperature and long-term curing on the microstructure and properties of the aluminum alloy substrate.

[0073] Please see attached Figure 2 -Attached Figure 7, an aluminum alloy processing electrostatic powder spraying device, comprising a support frame 1, an air curtain machine 4 is fixedly arranged on one side of the support frame 1, a protective shell 2 is fixedly connected to the other side of the support frame 1, an electric push rod 5 is fixedly connected to the inner wall of the protective shell 2, an output end of the electric push rod 5 is fixedly connected to a slider 6, a first rack 9 is fixedly connected to one side of the slider 6, a first gear 10 is meshedly connected to the tooth end of the first rack 9, a connecting pipe 11 is fixedly connected to the bottom of the first gear 10, a connecting plate 12 is fixedly connected to the bottom of the connecting pipe 11, a groove 18 is fixedly connected to the inside of the connecting plate 12, and an adjustment structure is arranged in the groove 18 inside the connecting plate 12; the adjustment structure comprises a rotating shaft 17, the bottom end of the rotating shaft 17 is rotatably connected to the bottom of the inner wall of the groove 18 of the connecting plate 12, a second gear 19 is fixedly connected to the bottom of the outer wall of the rotating shaft 17, a second gear 19 is symmetrically meshedly connected to the tooth end of the second gear 19, and the second rack 14 is symmetrically meshedly connected to the tooth end of the second gear 19. 4 is fixedly connected to a moving plate 13 on the side away from each other, one end of the moving plate 13 is fixedly connected to a connecting column 15, and a hook 16 is fixedly arranged at the bottom of the connecting column 15; the outer wall of the moving plate 13 is slidably connected to the inner wall of the groove 18 of the connecting plate 12, and the second gear 19 is located inside the groove 18; an air outlet 20 is arranged at the bottom of the air curtain machine 4, and a filter is fixedly arranged at the air inlet of the air curtain machine 4. The air curtain machine 4 is used to generate a wind curtain with a wind speed of 3-5m / s and forms an angle of 30-60 degrees with the spraying direction; a protective box 3 is fixedly connected to the top of the support frame 1, a servo motor 8 is fixedly arranged inside the protective box 3, and the output end of the servo motor 8 is fixedly arranged at the top of the rotating shaft 17, a slide groove 7 is arranged on one side of the support frame 1, a slider 6 is slidably connected inside the slide groove 7, a first gear 10 is located inside the slide groove 7, and the top of the connecting pipe 11 is rotatably connected to the top of the inner wall of the slide groove 7 of the support frame 1.

[0074] Specifically, the operation of the electric push rod 5 drives the slider 6 and the first rack 9 to move inside the slide groove 7, thereby driving the first gear 10 to rotate, thereby driving the connecting pipe 11 to rotate, thereby driving the connecting plate 12 to rotate, thereby driving the adjustment structure to rotate, so that the aluminum alloy plate can be adjusted to rotate according to the spraying requirements without manual flipping, thereby enhancing the spraying efficiency, and when rotating, through the coordinated operation of the servo motor 8, the rotating shaft 17 follows the connecting pipe 11 to rotate synchronously, thereby ensuring the stable suspension of the plate.

[0075] The wind curtain machine 4 generates a wind curtain with a wind speed of 3-5m / s and forms an angle of 30-60 degrees with the spraying direction. Therefore, when different powders need to be sprayed on one side or both sides of the aluminum alloy plate (such as different colors), the powder is blocked to prevent the powder from passing through the wind curtain and being adsorbed on the area where different powders need to be sprayed. The size of the area where different powders need to be sprayed can be adjusted by adjusting the rotation of the structure, thereby enhancing the practicality of the device.

[0076] The operation of the servo motor 8 drives the rotating shaft 17 to rotate, thereby driving the second gear 19 to rotate, thereby driving the two second racks 14 and the movable plate 13 to move inside the groove 18, thereby driving the connecting column 15 to move closer to or away from each other, so that the position of the hook 16 can be adjusted according to the width of the aluminum alloy plate, and the aluminum alloy plate to be sprayed can be hung by the hook 16, so that the device can hang aluminum alloy plates of different widths, thereby enhancing the applicability of the device.

[0077] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An electrostatic powder spraying process for aluminum alloy processing, characterized in that: The following steps are involved: S1. Pretreatment: pretreatment of the aluminum alloy substrate, including grinding, cleaning and preheating; S2, powder treatment: adding a treatment agent of 5% to 10% of the mass of the powder substrate to the powder substrate, and stirring at high speed to obtain a spray powder, wherein the treatment agent is composed of a low Tg polyester resin modifier and nano titanium dioxide; S3, electrostatic spraying: using electrostatic powder spraying equipment to spray the spray powder on the surface of the pretreated aluminum alloy substrate; S4, curing treatment: the sprayed aluminum alloy substrate is subjected to low-temperature rapid curing, and during the curing process, a heating element and a circulating fan are used for hot air circulation and temperature control. The low-temperature rapid curing includes stage gradient temperature curing and auxiliary curing. The temperature of the stage gradient temperature curing is 120°C-160°C.

2. The electrostatic powder spraying process for aluminum alloy processing according to claim 1 is characterized in that: The grinding in S1 is to grind the surface of the aluminum alloy substrate with 200-400 mesh sandpaper, and the roughness Ra is 0.8μm-1.6μm. The cleaning is to clean the surface of the aluminum alloy substrate with acetone to make the surface of the aluminum alloy substrate free of oil and impurities. The preheating treatment is to preheat the aluminum alloy substrate in a hot air circulation oven, the temperature is 40℃-60℃, and the preheating time is 5-10 minutes.

3. The electrostatic powder spraying process for aluminum alloy processing according to claim 1 is characterized in that: The Tg of S2 is 40-60°C, and the preparation method of the treatment agent comprises the following steps: S201, modifying the terminal hydroxyl groups of the low Tg polyester resin to make the hydroxyl value reach 30-50 mgKOH / g, to obtain a low Tg polyester resin modifier; S202, weighing a low Tg polyester resin modifier and nano titanium dioxide with a particle size of 20-30 nm in a mass ratio of 4:1-6:1, placing the mixture in a high-speed mixer, and premixing the mixture at a speed of 600-800 rpm for 5-8 minutes to obtain a premixed material; S203, grinding the premixed material into a particle size of 15-25 μm by a grinder to obtain a treatment agent.

4. The electrostatic powder spraying process for aluminum alloy processing according to claim 1 is characterized in that: The electrostatic powder spraying equipment in S3 includes an electrostatic spray gun, the spray gun voltage is 60-80 kV, the powder spraying amount is 100-200 g / min, the distance between the electrostatic spray gun and the surface of the aluminum alloy substrate during the powder spraying is maintained at 15-25 cm, and the coating thickness is 80-120 μm.

5. The electrostatic powder spraying process for aluminum alloy processing according to claim 1 is characterized in that: The low temperature rapid curing in S4 comprises the following steps: S401, the first stage: the aluminum alloy substrate is initially cured at 120°C to 130°C for 3 minutes to 5 minutes by infrared heating tube, and the ultraviolet lamp is turned on to assist in curing. The power of the ultraviolet lamp is 80W / m 2 Up to 200W / m 2 ; S402, second stage: then further curing is performed at 140° C. to 150° C. for 5 to 8 minutes, and a microwave generator is turned on to assist in curing, wherein the frequency of the microwave generator is 2.45 GHz and the power is 0.8 kW to 2.5 kW; S403, the third stage: then post-curing is performed at 150° C. to 160° C. for 2 minutes to 3 minutes, thereby completing low-temperature rapid curing.

6. An electrostatic powder spraying device for aluminum alloy processing, characterized in that: An electrostatic powder spraying process for aluminum alloy processing as described in any one of claims 1 to 5, comprising a support frame (1), a wind curtain machine (4) is fixedly arranged on one side of the support frame (1), a protective shell (2) is fixedly connected to the other side of the support frame (1), an electric push rod (5) is fixedly connected to the inner wall of the protective shell (2), an output end of the electric push rod (5) is fixedly connected to a slider (6), one side of the slider (6) is fixedly connected to a first rack (9), a tooth end of the first rack (9) is meshingly connected to a first gear (10), the bottom of the first gear (10) is fixedly connected to a connecting pipe (11), the bottom of the connecting pipe (11) is fixedly connected to a connecting plate (12), a groove (18) is arranged inside the connecting plate (12), and an adjustment structure is arranged in the groove (18) inside the connecting plate (12).

7. The electrostatic powder spraying device for aluminum alloy processing according to claim 6 is characterized in that: The adjustment structure comprises a rotating shaft (17), the bottom end of the rotating shaft (17) is rotatably connected to the bottom of the inner wall of the groove (18) of the connecting plate (12), the bottom of the outer wall of the rotating shaft (17) is fixedly connected to a second gear (19), the tooth end of the second gear (19) is symmetrically meshed with a second rack (14), the side of the second rack (14) away from the second rack (14) is fixedly connected to a moving plate (13), one end of the moving plate (13) is fixedly connected to a connecting column (15), and the bottom of the connecting column (15) is fixedly provided with a hook (16).

8. The electrostatic powder spraying device for aluminum alloy processing according to claim 7, characterized in that: The outer wall of the movable plate (13) is slidably connected to the inner wall of the groove (18) of the connecting plate (12), and the second gear (19) is located inside the groove (18).

9. The electrostatic powder spraying device for aluminum alloy processing according to claim 6, characterized in that: The bottom of the air curtain machine (4) is provided with an air outlet (20), the air inlet of the air curtain machine (4) is fixedly provided with a filter screen, and the air curtain machine (4) is used to generate an air curtain with a wind speed of 3-5 m / s and forms an angle of 30-60 degrees with the spraying direction.

10. The aluminum alloy processing electrostatic powder spraying device according to claim 6, characterized in that: The top of the support frame (1) is fixedly connected to a protection box (3), the interior of the protection box (3) is fixedly provided with a servo motor (8), the output end of the servo motor (8) is fixedly provided at the top of the rotating shaft (17), a slide groove (7) is provided on one side of the support frame (1), the slider (6) is slidably connected to the interior of the slide groove (7), the first gear (10) is located inside the slide groove (7), and the top of the connecting pipe (11) is rotatably connected to the top of the inner wall of the slide groove (7) of the support frame (1).

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