Busbar electrostatic spraying process and device

Abstract

This application relates to the field of electrostatic spraying technology, specifically disclosing an electrostatic spraying process and apparatus for busbars. It includes six steps: busbar acceptance and cleaning, protection of non-sprayed areas, electrostatic spraying, coating leveling, cleaning and inspection, and curing. The newly added coating leveling process first pre-cures the epoxy powder, followed by coating appearance inspection and thickness measurement. Because the coating is not fully cured at this stage, coating removal is simple. This solves the technical problem in existing processes where unqualified busbars are tightly bonded to the coating, making coating removal difficult, time-consuming, and severely impacting production progress.

Description

Technical Field

[0001] This invention relates to the field of electrostatic spraying technology, specifically to an electrostatic spraying process and apparatus for busbars. Background Technology

[0002] Busbars are a common electrical component in power supply systems. They are mainly composed of multi-layered laminated metal or conductors. This laminated structure can significantly reduce the number of cable connections and gather current. They are mainly used to carry and distribute electrical energy and are an important component of modern power supply systems.

[0003] Busbars are also widely used in the aviation field. They are key components in the aircraft's electrical system for power output, transmission, and distribution to various electrical devices, and they play an important role in aircraft.

[0004] On large passenger aircraft, the power distribution system transmits power through various busbars. However, in recent years, the fixed weight of aircraft has been continuously reduced, and the volume occupied by each part of the power supply system has also been reduced accordingly. In order to save space, the aircraft's power system has to adopt a multi-line parallel structure. This structure causes the current passing through the busbars per unit volume to become larger, and the voltage difference between them also becomes larger, making it easier for the busbars to break down into air and cause short circuits. Therefore, the aviation industry has to put forward higher requirements for the insulation between the busbars.

[0005] To meet the insulation requirements of busbars in the aviation industry, companies typically use epoxy powder to spray the electroplated busbars to form an insulating coating. After spraying, in the existing electrostatic spraying technology for busbars, the sprayed busbars still need to be baked at high temperature to fully bond with the powder. However, the baked coating has strong adhesion and complete powder bonding. If the coating thickness cannot meet the requirements in one spraying, or if the busbar needs to be reworked due to unqualified coating appearance, the tightly bonded coating makes it difficult and time-consuming to remove, seriously affecting the production schedule. Summary of the Invention

[0006] The purpose of this invention is to provide a busbar electrostatic spraying process and apparatus to solve the technical problem mentioned above in the prior art where unqualified busbars are tightly bonded to the coating, making coating removal difficult, time-consuming, and seriously affecting production progress.

[0007] To solve the above problems, the technical solution adopted by the present invention is as follows: an electrostatic spraying process for busbars.

[0008] Includes the following steps:

[0009] Step 1: Busbar Acceptance and Cleaning: Use compressed air to blow away dust from the busbar. After blowing away dust, inspect the appearance of the electroplated busbar surface. Busbars with a smooth surface and no appearance defects are considered to be accepted. After acceptance, use anhydrous ethanol solution to clean the accepted busbar to remove excess material from the surface of the busbar and let it air dry at room temperature.

[0010] Step 2, Protection of non-coated areas: Protect the non-coated areas of the busbar that were dried in Step 1 with high-temperature resistant insulating tape;

[0011] Step 3, electrostatic spraying: Turn on the powder electrostatic spraying assembly, adjust the distance between the spray gun and the workpiece to 100~200mm, and in the "constant current" state, control the current below 30uA, or in the "constant voltage" (normal) state, control the voltage below 70KV to start spraying epoxy powder onto the busbar until the busbar no longer adsorbs powder.

[0012] Step 4, Coating leveling: The sprayed manifold is fed into the leveling device for leveling. The leveling temperature is controlled at 100℃-130℃. The rotation speed of the manifold in the leveling device is 40r / min during leveling.

[0013] Step 5: Cleaning and Inspection: Clean the high-temperature tape off the busbar and perform a surface inspection on the melted busbar to ensure there are no leaks or defects.

[0014] Step 6, Curing: Send the qualified busbars from Step 5 into the curing equipment for high-temperature curing at a temperature of 170℃~190℃.

[0015] In step five, defective busbars are sent to the decoating process. In the decoating process, a professional cleaning agent (JX-1) and tools are used to remove the coating completely. The busbars with the coating removed are then sent to step one, and steps one through six are repeated.

[0016] The beneficial effects of this implementation plan are as follows:

[0017] 1. In the prior art, epoxy powder is directly cured after spraying, and the spraying effect is only inspected after curing. If unqualified products are found, they are returned to the stripping process and electrostatic spraying is performed again. However, after high-temperature curing, the epoxy powder is fully bonded, and the adhesion between the coating and the busbar is strong. This makes it difficult and time-consuming to remove the coating when stripping the busbar, which seriously affects the production schedule. However, the inventor of this application makes the epoxy powder basically formed at 100℃~120℃ in the melting and leveling section. After forming, the coating on the surface of the busbar is inspected. If the appearance quality or thickness of the coating on the busbar is found to be unqualified, it can be directly returned to the stripping section. This is because the epoxy powder is not fully cured, and the adhesion between the coating and the coating on the surface of the busbar is small. The coating can be easily removed during stripping. The stripping process is simple and efficient.

[0018] 2. Because the coating is tightly bonded to the plating on the busbar surface after curing, greater force is required to remove the coating. However, excessive force can cause the removal tool to not only scrape off the coating but also damage the plating underneath, resulting in damage to the plating on some of the busbars and requiring re-plating. In contrast, the inventors of this application have achieved basic molding of the epoxy powder at 100℃~120℃ in the leveling section. After molding, the coating on the busbar surface is inspected. If the appearance quality or thickness of the coating on the busbar is found to be unqualified, it can be directly returned to the removal section. This is because the epoxy powder is not fully cured, the bonding force between the coating and the plating on the busbar surface is small, and less force is required for coating removal, which will not cause scratches to the coating. This reduces the cost and time of re-plating the busbar when the plating is scratched during removal, improves production efficiency, and reduces the production cost of re-plating.

[0019] 3. Compared with the prior art, this application does not directly cure the coating at high temperature after electrostatic spraying. Instead, the coating is initially solidified at a temperature of 100℃~120℃ and then cured at a high temperature of 170℃~190℃. This allows the coating bonding process to go through two temperature stages. Uniaxial tensile test shows that the toughness of the coating is greatly improved after passing through the two temperature stages.

[0020] 4. In the existing technology, the high-temperature tape on the busbar is only cleaned after the coating has cured. This makes the adhesive material between the high-temperature tape and the busbar bond more tightly with the busbar coating at high temperature, making it impossible to clean completely. These uncoated areas on the busbar are the lamination bonding areas later. The adhesive material on the surface of the busbar prevents the busbars from making good contact during lamination, resulting in poor lamination bonding effect.

[0021] Furthermore, the powder electrostatic spraying assembly in step three includes a frame, an electrical system mounted on the frame, a powder supply system electrically connected to the electrical system, and a manual high-pressure powder spraying gun that imparts a negative charge to the epoxy powder in the powder supply system. The powder supply system includes a powder suction device that can adjust the amount of epoxy powder drawn in.

[0022] Furthermore, the powder suction device includes a conveying gas channel through which the conveying gas passes. The conveying gas channel has a Venturi structure with both ends larger than the middle throat. The middle throat of the conveying gas channel is connected to the powder suction channel and the dilution gas channel.

[0023] Furthermore, the powder supply system also includes an oil-water separation pressure reducing valve that can remove oil and moisture from external compressed air.

[0024] Furthermore, the oil-water separator pressure reducing valve is connected to a gas diversion valve that can split compressed air into four streams.

[0025] Furthermore, the melting temperature in step four is 120°C.

[0026] Furthermore, the fusion leveling device includes a hinged conveyor belt for transmitting busbars. The hinged conveyor belt is located at the top of the fusion leveling device. The hinged conveyor belt is equipped with a conveyor block that engages with the hinged conveyor belt. The lower end of the conveyor block is equipped with a busbar hoisting device for the busbar to be attached.

[0027] Furthermore, the conveyor block is equipped with a drive motor that can drive the busbar to rotate during hoisting. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the powder electrostatic assembly device according to an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the manual high-pressure powder spraying gun according to an embodiment of the present invention.

[0030] Figure 3 This is a cross-sectional view of the powder suction device according to an embodiment of the present invention.

[0031] Figure 4 This is a side view of the welding and leveling device according to an embodiment of the present invention.

[0032] Figure 5 This is a schematic diagram of the melting and drying device in an embodiment of the present invention. Detailed Implementation

[0033] The following detailed description illustrates the specific implementation method:

[0034] The reference numerals in the accompanying drawings include: frame 11, vertical frame 111, horizontal plate 112, electrical system 12, control panel 121, powder supply system 13, oil-water separator pressure reducing valve 131, fluidizing air inlet pipe 132, dilution air pipe 133, conveying air pipe 134, fluidized bed 135, air chamber 1351, powder hopper 1352, powder overflow port 1353, powder suction device 136, conveying air channel 1361, dilution air channel, powder suction channel 1363, powder supply pipe 137, manual high-pressure powder spraying gun 14, gun body 141, nozzle 142, powder supply pipe interface 143, power cord 144, high-voltage electrostatic switch 145, control air pipe 146, leveling device 21, support 201, housing 202, heater 203, conveyor block 204, busbar hoisting 2041, hinged conveyor belt 205, drying device 22, and inspection platform 206.

[0035] Implementation, for example, attached Figures 1-4 As shown: A busbar electrostatic spraying process includes the following steps:

[0036] Step 1: Busbar Acceptance and Cleaning: Use compressed air to blow away dust from the busbar. After blowing away dust, inspect the appearance of the electroplated busbar surface. Busbars with a smooth surface and no appearance defects are considered to be accepted. After acceptance, use anhydrous ethanol solution to clean the accepted busbar to remove excess material from the surface of the busbar and let it air dry at room temperature.

[0037] After electroplating or stripping, the busbar is placed on the operating platform. The platform's light source emits white light, making the plating on the busbar surface clearer. The inspection personnel visually inspect the plating for any defects, including pinholes, pitting, bumps, peeling, blistering, flaking, uneven plating, spots, scorching, shadows, dendritic and spongy deposits, and scratches. If no defects are found, the busbar is considered acceptable. Acceptable busbars are then cleaned with anhydrous ethanol. After cleaning, the busbar is hung on aluminum wire and allowed to air dry at room temperature.

[0038] Step 2, Protection of non-coated areas: Protect the non-coated areas of the busbar that were dried in Step 1 with high-temperature resistant insulating tape;

[0039] After the busbars are dried, the protective workers divide them into coated and uncoated areas based on whether they are coated. The uncoated area is the connection area where the busbars will be laminated and welded together later. To prevent this area from being covered by the coating and making it impossible to connect later, tape is used to cover and protect the uncoated area. Since the coating is epoxy powder, it needs to be heated at high temperature to bond and cure. Ordinary tape is prone to deformation at high temperatures, so high-temperature tape is used to protect the uncoated area.

[0040] Step 3, electrostatic spraying: Turn on the powder electrostatic spraying assembly, adjust the distance between the spray gun and the workpiece to 100~200mm, and in the "constant current" state, control the current below 30uA, or in the "constant voltage" (normal) state, control the voltage below 70KV to start spraying epoxy powder onto the busbar until the busbar no longer adsorbs powder.

[0041] After the protection is completed, place the busbar in the spraying area and start the powder electrostatic spraying assembly to spray.

[0042] like Figures 1-3 As shown, the powder electrostatic assembly includes a frame 11, a manual high-pressure powder spraying gun 14, a powder supply system 13, and an electrical system 12. The frame 11 is divided into two parts: a vertical frame 111 and a horizontal plate 112. The horizontal plate 112 is a flat steel plate with omnidirectional wheels at the lower end, allowing the horizontal plate 112 to slide on the ground. The vertical frame 111 is located on the left end of the horizontal plate 112. The vertical frame 111 is a frame structure made of alloy material, with a horizontal placement plate at the upper end, so that the manual high-pressure powder spraying gun 14 can be hung on the placement plate of the vertical frame 111 when not in use.

[0043] The upper end of the vertical frame 111 is welded with the housing of the electrical system 12. The electrical system 12 mainly provides electrical energy for the electrostatic field in the spraying process, provides driving power for each valve, and monitors the status of each part. The right end of the electrical system 12, which is slightly raised, is the control panel, which mainly houses the electromagnetic switches of multiple control valves on the powder electrostatic assembly device, and the pressure monitoring instruments in the pipelines of each valve.

[0044] On the left end face of the vertical frame 111, the oil-water separator pressure reducing valve 131 is fixed to the mounting plate of the vertical frame 111 by welding a mounting plate and bolts. The oil-water separator pressure reducing valve 131 is provided with an air inlet for connecting to an external air compressor and an air outlet for supplying high-pressure gas to the entire device. The air outlet is connected to a gas diversion valve through a pipe. The gas diversion valve is fixed to the placement plate on the vertical frame 111 by bolts. The gas diversion valve divides the gas into four streams, which are fluidizing gas, conveying gas, dilution gas and control gas according to their functions. The gas diversion valve is electrically connected to the electrical system 12, so the electrical system 12 can monitor and control the flow rate and pressure of each gas.

[0045] The gas diversion valve uses a pipeline to send fluidizing gas to the lower end of the vertical frame 111, and then enters the gas chamber 1351 of the powder supply system 13 through the fluidizing air inlet pipe 132. A powder hopper 1352 is set at the upper end of the gas chamber 1351. A microporous plate is used to separate the powder hopper 1352 from the gas chamber 1351. Therefore, the fluidizing gas will pass through the microporous plate from the gas chamber 1351 into the powder hopper 1352, fluidizing the epoxy powder in the hopper and entering the fluidized bed 13.

[0046] The conveying gas separated by the gas diversion valve enters the powder suction device 136 via the conveying gas pipe 134, and the dilution gas enters the powder suction device 136 via the dilution gas pipe 133. The internal structure of the powder suction device 136 is as follows: Figure 3 As shown, it is divided into a conveying gas channel 1361 for the flow of conveying gas, a dilution gas channel 1362 for the entry of dilution gas, and a powder suction channel 1363 connected to the fluidized bed 135. Since the diameters at both ends of the conveying gas channel 1361 are larger, and the diameter at its throat suddenly decreases, according to Bernoulli's principle, when the conveying gas passes through the conveying gas channel 1361, the velocity increases and the pressure decreases as it passes through the throat. Figure 3 As shown, since both the powder suction channel 1363 and the dilution gas channel 1362 are connected to the throat of the conveying gas channel 1361, a negative pressure is generated within the powder suction channel 1363 and the dilution gas channel 1362. This negative pressure draws the epoxy powder from the fluidized bed 135 into the conveying gas channel 1361, where it enters the powder supply pipe 137 and is conveyed by the conveying gas to the manual high-pressure powder spraying gun 14. The dilution gas channel 1362 is also connected to the conveying gas channel 1361, and dilution gas can also enter the throat of the conveying gas channel 1361 to supplement the negative pressure at the throat. Therefore, the flow rate of dilution gas entering the conveying gas channel 1361 can be controlled by the electrical system 12, thereby controlling the magnitude of the negative pressure within the powder suction channel 1363 and thus controlling the amount of epoxy powder sucked in.

[0047] Manual high-pressure powder spraying gun 14 Figure 2 As shown, it includes a gun body 141, within which a gun barrel is housed. The front end of the gun barrel is a nozzle 142, which is a pipe structure. A high-voltage electrostatic field electrostatic device surrounds the nozzle, connected to a power supply line 144. This device is controlled by a high-voltage electrostatic switch 145. A powder supply pipe interface 143, connected to the nozzle 142, is also provided between the gun body 141 and the nozzle 142. The powder supply pipe interface 143 is connected to a powder supply pipe 137, allowing epoxy powder to be continuously supplied to the nozzle by the powder supply system. A control air pipe 146, connected to the rear end of the gun body and the gun barrel, is also provided at the rear end of the gun body. The control air pipe 146 is connected to a gas diversion valve, allowing control air diverted from the gas diversion valve to enter the gun body 141. Its magnitude can be controlled by a switch on the electrical system 12, thereby adjusting the spraying distance and powder dispersion shape of the epoxy powder during spraying.

[0048] In use, connect the outlet pipe of the external air compressor to the oil-water separator pressure reducing valve 131. The oil-water separator pressure reducing valve 131 reduces the oil and moisture content of the compressed air to meet the requirements of the electrostatic field. Control the pressure of the oil-water separator pressure reducing valve at 0.5-0.6 MPa. Then, use the control switch on the control panel 121 on the electrical system 12 to open the fluidizing gas switch valve on the gas diversion valve, controlling the fluidizing gas to enter the gas chamber 1351 of the powder supply system 13, so that the epoxy powder in the powder hopper 1352 is fluidized in the fluidized bed 135. The gas pressure is controlled at approximately 0.25 MPa. After the fluidized bed has been operating for 5-10 minutes, the overflow of epoxy powder is observed through the overflow port 1353. The optimal fluidized gas pressure is when a small amount of epoxy powder floats out of the overflow port 1353. The delivery gas switch valve on the gas diversion valve is opened using the electrical system 12, allowing the delivery gas to enter the powder suction device 136 and begin drawing in epoxy powder. The dilution gas switch valve on the gas diversion valve is then opened and adjusted to ensure stable delivery and atomization of the drawn-in epoxy powder, without any violent boiling or shaking. When the epoxy powder enters the nozzle of the manual high-pressure powder spray gun 14, the spraying distance is controlled by adjusting the gas flow through the gas diversion valve, and spraying begins.

[0049] Step 4, Coating leveling: The sprayed manifold is sent into a high-temperature drying tunnel for leveling. The leveling temperature is controlled at 100℃-130℃ and the leveling speed is 40r / min.

[0050] When melting, the coated manifold should be placed as follows: Figure 4 The welding and leveling process is performed within the welding and leveling device 21 shown. Therefore, workers use the busbar hoist 2041 to hang the busbar on the conveyor block 204. The conveyor block 204 contains a drive motor that allows the busbar hoist 2041 to rotate around the conveyor block 204. Figure 5 As shown, the conveyor block 204 engages with the hinge conveyor belt 205, so when the hinge conveyor belt 205 operates, the conveyor block 204 can move together with the hinge conveyor belt 205. Since the hinge conveyor belt 205 is installed at the upper middle part of the remelting and leveling device 21, the busbar can be transported into the remelting and leveling device 21 using the hinge conveyor belt 205.

[0051] The lower end face of the leveling device 21 is bolted to the bracket 201 and is lifted by the bracket 201. The leveling device is a rectangular box structure. Figure 5The direction is described in terms of orientation. Both ends of the housing 202 are equipped with openable doors. A hinged conveyor belt 205 is located on the top surface of the housing 202 and runs through it from both sides. Therefore, the hinged conveyor belt 205 can convey the busbars to the leveling device 21 and also convey the busbars out of the leveling device. Heaters 203 are provided on the front and rear side walls of the housing 202, and the leveling temperature is controlled at 120°C using these heaters.

[0052] Step 5: Cleaning and Inspection: Clean the high-temperature tape off the busbar and perform a surface inspection on the melted busbar to ensure there are no leaks or defects.

[0053] After the leveling process is completed, the busbar in the leveling device 21 can be transported out using the hinged conveyor belt 205. The worker removes the busbar from the busbar hoisting 2041, removes the high-temperature tape protecting the non-sprayed area, and then checks the appearance and thickness of the coating on the inspection platform 206. Busbars with unqualified appearance and thickness are returned for stripping. In the stripping process, a professional cleaning agent (JX-1) is used to soften the coating. After softening, the coating is removed cleanly using a stripping scraper. After stripping, the work is returned to step one for re-spraying.

[0054] Step 6, Curing: Send the qualified busbars from Step 5 into the curing equipment for high-temperature curing at a temperature of 170℃~190℃.

[0055] The qualified manifold strips from step five are reattached to the hinged conveyor belt 205 and transported by the hinged conveyor belt 205 to the high-temperature fixed drying device 22 for curing. The high-temperature curing temperature is controlled between 170℃ and 190℃. The drying device 22 and the melting and leveling device 21 have the same structure, both being box structures that can provide high temperatures. The manifold strips rotate on the conveyor block 204 of the hinged conveyor belt 205 to heat the coating, thereby curing the coating.

[0056] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A busbar electrostatic spraying process, characterized in that: It includes the following steps: Step 1, bus bar acceptance and cleaning: Use compressed air to blow dust on the bus bar. After blowing dust, check the surface appearance of the electroplated bus bar. The bus bar with a flat surface and no appearance defects is regarded as qualified for acceptance. After acceptance, clean the bus bar qualified for acceptance with anhydrous ethanol solution to remove the excess substances on the surface of the bus bar and dry it at room temperature; Step 2, protection of non-spraying area: Protect the non-spraying area of the bus bar dried in Step 1 with high-temperature resistant insulating tape; Step 3, electrostatic spraying: Open the powder electrostatic spraying combination device, adjust the distance between the spray gun and the workpiece to 100 - 200 mm. Under the constant current state, control the current below 30 μA, or under the constant voltage state, control the voltage below 70 kV to start spraying epoxy powder on the bus bar until the bus bar no longer adsorbs powder; Step 4, coating leveling: Send the bus bar after spraying into the leveling device for leveling. Control the leveling temperature at 100℃ - 130℃. When leveling, the rotation speed of the bus bar in the leveling device is 30 - 40 r / min; Step 5, cleaning and inspection: Clean the high-temperature tape on the bus bar, and conduct an appearance inspection on the bus bar after leveling. The bus bar with no coating leakage points and defects in appearance is qualified for inspection; Step 6, curing: Send the bus bar qualified for inspection in Step 5 into the curing equipment for high-temperature curing, and the curing temperature is 170℃ - 190℃; The bus bar with defects in Step 5 is sent to the paint stripping process. In the paint stripping process, use a cleaning agent and tools to completely remove the coating. The bus bar with the coating completely stripped is sent to Step 1 to repeat the above Steps 1 to 6; The powder electrostatic spraying combination device in Step 3, the leveling device in Step 4, and the curing device in Step 5. The powder electrostatic spraying combination device includes a machine frame, an electrical system arranged on the machine frame, a powder supply system electrically connected to the electrical system, and a manual high-pressure powder spray gun that imparts a negative charge to the epoxy powder in the powder supply system. The powder supply system includes a powder suction device for adjusting the inhalation amount of epoxy powder.

2. The electrostatic spraying process for busbars according to claim 1, characterized in that: The powder suction device includes a conveying gas passage for the conveying gas to pass through. The conveying gas passage is a Venturi structure with the sizes of both ends larger than the middle throat. The middle throat of the conveying gas passage is connected to a powder suction passage and a dilution gas passage.

3. The electrostatic spraying process for busbars according to claim 1, characterized in that: The powder supply system further includes an oil-water separation pressure reducing valve for removing oil and moisture from the external source compressed air.

4. The electrostatic spraying process for busbars according to claim 3, characterized in that: The oil-water separation pressure reducing valve is connected to a gas distribution valve that divides the compressed air into four strands.

5. The electrostatic spraying process for busbars according to claim 1, characterized in that: The leveling temperature in Step 4 is 120℃.

6. The electrostatic spraying process for busbars according to claim 1, characterized in that: The leveling device in Step 4 includes a hinge conveyor belt for transporting the bus bar. The hinge conveyor belt is arranged on the top of the leveling device. There are transfer blocks engaged with the hinge conveyor belt on the hinge conveyor belt, and a bus bar hanging device for the bus bar to hang on is provided at the lower end of the transfer block.

7. The electrostatic spraying process for busbars according to claim 6, characterized in that: A driving motor for driving the rotation of the bus bar hanging device is provided on the transfer block.

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