A processing technology of capacitor film-coated aluminum shell

Abstract

The present application belongs to the technical field of electrolytic capacitor, and particularly relates to a processing technology of capacitor film-coated aluminum shell, which comprises five steps: S1, film-coated aluminum roll into warehouse, inspection and slitting; S2, waiting for stamping aluminum belt to be drawn into semi-finished product film-coated aluminum shell; S3, cleaning of semi-finished product film-coated aluminum shell; S4, curing of semi-finished product film-coated aluminum shell to obtain finished product film-coated aluminum shell; and S5, inspection, packaging, warehousing and delivery of finished product film-coated aluminum shell. The present application can not only improve the insulation and aesthetic degree of the aluminum shell, but also save the sleeve process, save materials, simplify the process, reduce the cost, and make the PU insulating film quickly and tightly adhere to the surface of the aluminum shell, improve the adhesion between the PU insulating film and the aluminum shell, solve the problem of film peeling caused by poor adhesion of the PU insulating film, and ensure the processing quality of the finished product film-coated aluminum shell.

Description

Technical Field

[0001] This invention belongs to the technical field of electrolytic capacitors, and specifically relates to a processing technology for a coated aluminum shell for capacitors. Background Technology

[0002] Electrolytic capacitors are polarized capacitors whose anode or positive plate is made of metal. There are three main types of electrolytic capacitors: aluminum electrolytic capacitors, tantalum electrolytic capacitors, and niobium electrolytic capacitors, with aluminum electrolytic capacitors being the most widely used. To improve the aesthetics and insulation properties of aluminum electrolytic capacitors, a protective paint film is sprayed onto the outer surface of the aluminum casing. Currently, the process of spraying this protective paint film on the aluminum casing suffers from problems such as exposed substrate, high-gloss paint peeling, and oxidation discoloration, which seriously affect the processing quality of the aluminum casing.

[0003] Existing technologies address issues such as exposed substrate, paint peeling at high gloss levels, and color bleeding during the coating of protective films on aluminum shells. For example, patent application CN112760695A describes a processing method for a stretched aluminum alloy shell. This method involves electrophoresis followed by baking paint, and then oxidation, resulting in a stronger adhesion between the paint and the electrophoretic base film. This prevents paint peeling and flaking during high-gloss application and also forms a protective undercoat after electrophoresis, solving the problems of paint peeling at high gloss levels, color bleeding at high gloss levels, and color difference after baking paint. However, existing stretched aluminum shell processing methods only involve stretching before baking paint or coating, resulting in complex procedures and high costs. Further research is needed on processing aluminum strips coated with an insulating film before deep drawing them into aluminum shells to ensure adhesion between the aluminum shell and the insulating film and prevent film detachment during production. Therefore, a new technical solution is required to address these technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a processing technology for coated aluminum shells of capacitors, in order to solve the problem that the current aluminum shell processing technology mentioned in the background art only involves stretching or deep drawing before baking paint or coating, which is complex and costly. However, for the processing technology of deep drawing aluminum strips coated with insulating film into aluminum shells, further research is needed to ensure the adhesion between the aluminum shell and the insulating film, so that the aluminum shell will not detach from the film during the production process.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a processing technology for a capacitor coated aluminum shell, characterized by comprising the following specific steps:

[0006] S1. First, aluminum coils with an aluminum strip thickness of 0.25 to 0.50 mm and a PU insulating film with a thickness of 7 to 13 micrometers are put into the warehouse and inspected. Then, the aluminum coils that have passed the inspection are cut into aluminum coils to be stamped.

[0007] The specific steps for aluminum coil slitting are as follows: First, the aluminum coils that have been stored and inspected are hoisted onto the uncoiler by a crane or overhead crane for uncoiling; second, the uncoiled aluminum strips are slitting by a slitting machine, and the aluminum strips are simultaneously wound by a coiling machine to form aluminum coils to be stamped; finally, the aluminum coils to be stamped are weighed and labeled.

[0008] The aluminum strip needs to be wrapped with a layer of insulating tape at the 1-meter mark after being wound by the coiling machine. The insulating tape can also be wrapped around the 1-meter mark where the aluminum strip is damaged.

[0009] S2. Install the aluminum coil to be stamped onto the stamping machine and stamp and draw the aluminum strip to be stamped on the aluminum coil to form a semi-finished coated aluminum shell.

[0010] The specific steps of aluminum strip stamping and deep drawing are as follows: First, the aluminum coil to be stamped is installed on the material rack of the stamping machine by a crane or overhead crane; second, the aluminum strip to be stamped on the aluminum coil is pulled onto the stamping die of the stamping machine by a feeding machine; third, the stamping machine is started to stamp and draw the aluminum strip on the stamping die to form a semi-finished coated aluminum shell; finally, the semi-finished coated aluminum shell is discharged into a turnover basket through the discharge port or can be directly discharged into a cleaning mesh bucket.

[0011] The aluminum strip to be stamped needs to be oiled before it is pulled to the stamping die;

[0012] S3. Place the semi-finished coated aluminum shell into the cleaning mesh bucket and clean the semi-finished coated aluminum shell using hydrocarbon cleaning agent and ultrasonic waves.

[0013] The specific steps for cleaning the semi-finished coated aluminum shells are as follows: First, the semi-finished coated aluminum shells are loaded into a cleaning mesh bucket; second, a robotic arm is used to place the cleaning mesh bucket containing the semi-finished coated aluminum shells into a cleaning tank containing a hydrocarbon cleaning agent for ultrasonic cleaning; third, a robotic arm is used to remove the cleaning mesh bucket containing the semi-finished coated aluminum shells after cleaning; finally, the semi-finished coated aluminum shells in the cleaning mesh bucket are slowly rotated and poured into a turnover box.

[0014] The heating temperature setting range of the hydrocarbon cleaning agent is 60-70℃. The hydrocarbon cleaning agent in the cleaning tank needs to be replaced once after cleaning 8-10 barrels of semi-finished coated aluminum shells.

[0015] S4. The cleaned semi-finished coated aluminum shell is sent into a drying tunnel with a curing temperature of 170-220℃ and a conveying speed of 8-20m / s to cure the PU insulating film on the surface of the aluminum shell at high temperature for 450-650 seconds to obtain the finished coated aluminum shell.

[0016] S5. Inspect the structural dimensions, appearance, chloride ion content, resistivity, and performance indicators of the finished coated aluminum shell. After passing the inspection, it can be packaged, put into storage, and shipped out.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. This invention uses aluminum strips coated with PU insulating film to produce aluminum shells. This not only further improves the insulation and aesthetics of the aluminum shells, but also eliminates the need for sleeve manufacturing during the production process, effectively saving raw materials required for aluminum shell production, simplifying the processing technology, and reducing production costs. Utilizing hydrocarbon cleaning agents and ultrasonic cleaning processes, the semi-finished coated aluminum shells can be cleaned of oil stains and dirt more quickly, effectively improving cleaning efficiency and effectiveness. By transferring the cleaned semi-finished coated aluminum shells into a drying tunnel for high-temperature curing, the PU insulating film can adhere to the aluminum shell surface more quickly and tightly, effectively improving the adhesion between the PU insulating film and the aluminum shell. This effectively avoids the problem of film detachment caused by poor adhesion of the PU insulating film, thereby ensuring the processing quality of the finished coated aluminum shells.

[0019] 2. By using an insulating tape to cover the aluminum strip, the present invention enables the sensing mechanism on the stamping machine to detect the tail end or damaged part of the aluminum strip in a timely manner during the stamping and drawing process. This allows the stamping machine to stop in time when the position of the insulating tape is detected, effectively improving the safety of the stamping process. It also effectively avoids the problem of the tail end or damaged part of the aluminum strip being affected by the stamping and drawing process, thus ensuring the quality and efficiency of the semi-finished coated aluminum shell production.

[0020] 3. This invention improves the lubricity and toughness of the aluminum strip by oiling it before it is drawn to the stamping die, making it easier to form under the deep drawing process of the stamping machine. This effectively improves the production quality of the semi-finished coated aluminum shells. The setting of replacing the hydrocarbon cleaning agent after cleaning 8 to 10 barrels of semi-finished coated aluminum shells ensures that the cleaning tank maintains a good cleaning effect, effectively improving the cleaning effect of the semi-finished coated aluminum shells. Then, ultrasonic cleaning is used to further improve the cleaning efficiency of the semi-finished coated aluminum shells.

[0021] 4. This invention uses a drying tunnel at 170-220℃ and a conveying speed of 8-20m / s to cure the semi-finished coated aluminum shell, which allows the PU insulating film to adhere to the surface of the aluminum shell more quickly and tightly, effectively improving the adhesion between the PU insulating film and the aluminum shell, effectively avoiding the problem of delamination caused by poor adhesion of the PU insulating film, thereby ensuring the processing quality of the finished coated aluminum shell. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of the aluminum shell coating process of the present invention. Detailed Implementation

[0023] The following examples are used to further illustrate the content of the present invention and do not limit the application of the present invention. Example 1:

[0024] The specific steps of the capacitor coating aluminum shell processing technology are as follows:

[0025] S1. First, aluminum coils with a thickness of 0.25-0.50 mm and a PU insulating film with a thickness of 7-13 microns are put into storage and inspected. Then, the aluminum coils that have passed the storage and inspection are hoisted to the uncoiler by a crane or overhead crane and uncoiled. Then, the uncoiled aluminum strip is cut by a slitting machine. At the same time as the aluminum strip is cut, it is wound into a coil to be stamped by a coiling machine. A layer of isolation tape needs to be wrapped on the surface of the aluminum strip 1 meter after it is wound by the coiling machine. The isolation tape can also be wrapped on the 1 meter of the aluminum strip surface where there is damage. Finally, the aluminum coil to be stamped is weighed and labeled.

[0026] S2. First, the aluminum coil to be stamped is installed on the material rack of the stamping machine by a crane or overhead crane. Then, the aluminum strip to be stamped on the aluminum coil is pulled to the stamping die of the stamping machine by a feeding machine. The aluminum strip to be stamped needs to be oiled before being pulled to the stamping die. Then, the stamping machine is turned on to stamp and draw the aluminum strip to be stamped on the stamping die to form a semi-finished coated aluminum shell. Finally, the semi-finished coated aluminum shell is discharged into the turnover basket through the discharge port or can be directly discharged into the cleaning net bucket.

[0027] S3. First, transfer the semi-finished coated aluminum shells in the turnover basket into the cleaning net bucket. Then, use a robotic arm to place the cleaning net bucket containing the semi-finished coated aluminum shells into a cleaning tank containing hydrocarbon cleaning agent and heated at 60-70°C for ultrasonic cleaning. The hydrocarbon cleaning agent in the cleaning tank needs to be replaced after cleaning 8-10 buckets of semi-finished coated aluminum shells. After cleaning, use a robotic arm to remove the cleaning net bucket containing the semi-finished coated aluminum shells. Finally, slowly rotate and pour the semi-finished coated aluminum shells in the cleaning net bucket into the turnover box.

[0028] S4. First, send the semi-finished coated aluminum shell in the turnover box into the drying tunnel with a curing temperature of 170-220℃ and a conveying speed of 8-20m / s to cure the PU insulating film on the surface of the semi-finished coated aluminum shell at high temperature for 450-650 seconds. The semi-finished coated aluminum shell entering the drying tunnel needs to be isolated with isolation square tubes with an isolation distance of 25-35 cm to obtain the finished coated aluminum shell.

[0029] S5. First, the structural dimensions, appearance, and pressure release of the finished coated aluminum shell are inspected batch by batch. Then, the chloride ion content and resistivity of the finished coated aluminum shell are inspected by sampling. After that, the performance indicators (including high pressure resistance, printability, scratch resistance, and coating peeling test) of the finished coated aluminum shell are inspected by batch sampling. After all the above inspections are qualified, the shell can be packaged, put into storage, and shipped out.

[0030] The structural dimensions, appearance, and release pressure of the finished coated aluminum shells obtained in S4 above are sampled according to the batch-by-batch inspection method in S5. The sampling standard is based on GB2828.1-2003, and a single sampling plan is used. The inspection items, inspection levels, and acceptance quality limits (AQL) are shown in Table 1 below. The single sampling plan for normal inspection is shown in Table 2 below, and the single sampling plan for tightened inspection is shown in Table 3 below.

[0031] ; ; ;

[0032] As shown in Tables 1, 2 and 3 above, if the product's dimensions, appearance and oil pressure are inspected according to the sampling plan for normal inspection, and if two out of five consecutive batches or fewer than five batches of a certain specification of finished coated aluminum shells fail the normal inspection, then the next batch of finished coated aluminum shells should be subject to stricter inspection. When stricter inspection is carried out, if five consecutive batches pass the initial inspection, then the next batch should be subject to normal inspection. Finished coated aluminum shells that were judged as unqualified in the previous batch or reworked and re-inspected should be subject to stricter inspection.

[0033] When the quality of the chloride ion content and resistivity of the finished coated aluminum shell obtained in S4 above is stable, the normal inspection plan in Table 2 shall be followed, that is, sampling at 1% of the total batch. When normal inspection is carried out, if one batch fails the inspection, the next batch shall be switched to the tightened inspection, that is, sampling at 25%. When 10 consecutive batches pass the tightened inspection, the normal inspection plan shall be followed.

[0034] The performance indicators of the finished coated aluminum shells obtained in S4 above (performance indicators include high pressure resistance, printability, scratch resistance, and coating peeling test) are sampled according to the batch sampling method in S5, and the sampling standards are shown in Table 4 below:

[0035] ;

[0036] As shown in the table above, the finished coated aluminum shells in each batch are considered qualified if they can withstand 500V without breakdown. The printability needs to be tested with a dyne pen, and 36 dynes or above is considered qualified. The scratch resistance is considered qualified if the aluminum shell is torn open without peeling off the film. The coating peeling test is considered qualified if there is no peeling off the film.

[0037] For each batch of inspected products, the number of non-conforming items should be less than or equal to the acceptance number. If the number of non-conforming items is greater than the acceptance number, the batch of products is considered non-conforming. In all inspected samples, the number of fatal defects should be zero. If the number is greater than zero, the batch of products is considered non-conforming and must be inspected again. For each batch of inspected products, all sampled items must be inspected according to regulations, and the inspection data or results (minimum value, maximum value, including non-conforming data) of two samples must be recorded. Only after all items pass the inspection can the product leave the factory. Example 2:

[0038] The processing technology of the capacitor coated aluminum shell in this embodiment is the same as that in Embodiment 1, the only difference being that the specifications and dimensions of the capacitor coated aluminum shell are different.

Claims

1. A processing technology for a capacitor coated aluminum shell, characterized in that, The specific steps are as follows: S1. First, aluminum coils coated with PU insulating film are put into storage and inspected. Then, the aluminum coils that have passed the storage and inspection are cut into aluminum coils to be stamped. The specific steps of cutting the aluminum coils are as follows: First, the aluminum coils that have passed the storage and inspection are hoisted to the uncoiler by a crane or overhead crane for uncoiling. Second, the uncoiled aluminum strip is cut by a slitting machine. At the same time as the aluminum strip is cut, it is wound into aluminum coils to be stamped by a coiling machine. Finally, the aluminum coils to be stamped are weighed and labeled. When the aluminum strip is wound by the coiling machine, a layer of isolation tape needs to be wrapped on the surface for 1 meter. The isolation tape can also be wrapped on the damaged 1 meter of the aluminum strip surface. S2. The aluminum coil to be stamped is installed on the stamping machine. The aluminum strip to be stamped on the aluminum coil is then stamped and drawn to form a semi-finished coated aluminum shell. The specific steps of the aluminum strip stamping and drawing are as follows: First, the aluminum coil to be stamped is installed on the material rack of the stamping machine by a crane or overhead crane; second, the aluminum strip to be stamped on the aluminum coil is pulled onto the stamping die of the stamping machine by a feeding machine; third, the stamping machine is started to stamp and draw the aluminum strip to be stamped on the stamping die to form a semi-finished coated aluminum shell; finally, the semi-finished coated aluminum shell is discharged into a turnover basket through the discharge port or can be directly discharged into a cleaning net bucket. The setting of wrapping the aluminum strip with isolation tape allows the end of the aluminum strip or the damaged part to be detected by the sensing mechanism on the stamping machine in time during the stamping and drawing process, so that the stamping machine can stop in time when the position of the isolation tape is detected. S3. Place the semi-finished coated aluminum shell into the cleaning mesh bucket and clean the semi-finished coated aluminum shell using hydrocarbon cleaning agent and ultrasonic waves. S4. The cleaned semi-finished coated aluminum shell is sent into the drying tunnel to cure the PU insulating film on the surface of the aluminum shell at high temperature to obtain the finished coated aluminum shell. S5. Inspect, package, store, and ship finished coated aluminum shells.

2. The processing technology for a capacitor coated aluminum shell according to claim 1, characterized in that, In S1, the thickness of the PU insulating film is 7–13 micrometers, and the thickness of the aluminum strip on the aluminum coil is 0.25–0.50 millimeters.

3. The processing technology for a capacitor coated aluminum shell according to claim 1, characterized in that, The aluminum strip to be stamped needs to be oiled before being pulled to the stamping die.

4. The processing technology for a capacitor coated aluminum shell according to claim 1, characterized in that, In S3, the specific steps for cleaning the semi-finished coated aluminum shell are as follows: First, the semi-finished coated aluminum shell is loaded into the cleaning mesh bucket; second, the cleaning mesh bucket containing the semi-finished coated aluminum shell is placed into the cleaning tank containing hydrocarbon cleaning agent by a robotic arm for ultrasonic cleaning; third, the cleaning mesh bucket containing the semi-finished coated aluminum shell is removed by a robotic arm; finally, the semi-finished coated aluminum shell in the cleaning mesh bucket is slowly rotated and poured into the turnover box.

5. The processing technology for a capacitor coated aluminum shell according to claim 4, characterized in that, The heating temperature setting range of the hydrocarbon cleaning agent is 60-70℃. The hydrocarbon cleaning agent in the cleaning tank needs to be replaced once after cleaning 8-10 barrels of semi-finished coated aluminum shells.

6. The processing technology for a capacitor coated aluminum shell according to claim 1, characterized in that, In S4, the curing temperature of the drying tunnel is 170–220℃, the conveying speed of the drying tunnel is 8–20 m / s, and the curing time of the drying tunnel is 450–650 seconds.

7. The processing technology for a capacitor coated aluminum shell according to claim 1, characterized in that, In S5, the finished coated aluminum shells need to be inspected for their structural dimensions, appearance, chloride ion content, resistivity and performance indicators. After passing the inspection, they can be packaged, put into storage and shipped out.

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