Method for improving identification degree of aluminum foil welding seam

Abstract

The method comprises the following steps that S1, in the slitting production process, an aluminum foil roll needing to be welded is welded through an ultrasonic welding machine, and the welding seam is in a linear shape in the width direction of aluminum foil; s2, after welding is completed, a high-temperature-resistant adhesive tape parallel to a welding seam is attached to the center of the position 3-10 mm away from the welding seam, the length of the high-temperature-resistant adhesive tape is smaller than that of the welding seam, and a certain distance is formed between the two ends of the high-temperature-resistant adhesive tape and the S3, the two ends of the high-temperature-resistant adhesive tape are smeared with alcohol, and two aluminum foil pieces with the thickness smaller than or equal to 0.006 mm and the width larger than that of the high-temperature-resistant adhesive tape are taken to cover the two ends correspondingly; and S4, continuous slitting is conducted according to normal slitting and coiling operation, and the slit aluminum foil roll is subjected to oil removal, annealing and packaging. The recognition degree of the automatic product inspection machine is improved by increasing the color difference between the aluminum foil and the high-temperature-resistant adhesive tape, operation is easier and more convenient, and damage to the aluminum foil roll is smaller.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-thin aluminum foil production, and in particular relates to a method for improving the recognition of aluminum foil welds. Background Art

[0002] Aluminum foil has the advantages of moisture-proof, airtight, light-shielding, abrasion-resistant, fragrance-retaining, non-toxic and odorless. Especially after aluminum foil is compounded with plastic and paper, the shielding property of aluminum foil is integrated with the strength of paper and the heat sealing property of plastic, which further improves the shielding performance against water vapor, air, ultraviolet rays and bacteria, which is necessary as a packaging material, and becomes an important material in the packaging industry such as food, medicine and cigarettes.

[0003] The thickness of aluminum foil is very small, mostly in the micron level, and the thinnest can reach 0.004mm. Therefore, during the aluminum foil slitting process, the aluminum foil may break due to various factors. The main reasons for the breakage of aluminum foil are as follows: quality problems of aluminum foil blanks, the blanks may have defects such as inclusions, airways, metal or non-metallic pressed objects, etc.; problems in the rolling process, the tension during rolling is too high, and foreign objects such as aluminum powder, broken aluminum foil, mosquitoes, and oil sludge are brought in.

[0004] When the aluminum foil breaks during the rolling process, it will produce aluminum coils of different sizes. In order to meet the customer's meter requirements, a welding machine is usually required to neatly weld the front and rear aluminum foils, such as by ultrasonic welding, welding the two aluminum foils together, and then continuing to cut them into the required meters. For example, patent document CN102284799A discloses a welding method for a double-zero aluminum foil joint, in which the double-zero aluminum foil joint is separated from the upper and lower sheets, and is respectively overlapped on the upper and lower anvil rollers coated with a welding medium, and the overlap area is retained; the double-zero aluminum foil on the upper and lower winding shafts is overlapped on the upper and lower double-zero aluminum foils respectively by overlapping joints, and the welding medium is applied between the double-zero aluminum foil on the upper winding shaft and the upper double-zero aluminum foil, and between the double-zero aluminum foil on the lower winding shaft and the lower double-zero aluminum foil; after fixing the joint, the welding process parameters are adjusted, the welding machine is started, and the welding medium is applied to the overlap area of ​​the double-zero aluminum foil. After the welding pad passes through the overlap area coated with the welding medium, a weld with a smooth surface is formed, and the welding medium is a volatile organic solvent.

[0005] The welding strength of the aluminum coil welded by ultrasonic welding is basically the same as the original strength of the aluminum foil; for the aluminum coil with joints, customers can use the composite normally without stopping the machine at the joints, which improves production efficiency and yield rate. For the composite aluminum foil products, customers will use the inspection machine to check and remove the aluminum foil weld position in the subsequent cutting and bag making processes. However, after the two aluminum foils are welded, the color of the weld is close to that of the aluminum foil, and the welding is single-seam welding, the weld is very small, usually only 2mm, which makes it difficult for the inspection machine to identify the weld joint during the subsequent processing of the customer, and there is a situation where the joint defects are not picked out, resulting in the outflow of defective products, thus affecting the quality of the client's products.

[0006] In order to improve the recognition rate of welding joints by the inspection machine, the patent document CN108526739A discloses a welding method for aluminum foil joints, including the following steps: S1: placing the first aluminum foil and the second aluminum foil to be overlapped on the welding roller in sequence, retaining the first overlap area corresponding to the first aluminum foil and the second overlap area corresponding to the second aluminum foil, starting the welding machine for welding, and forming a smooth weld; S2: pasting tape on the first overlap area corresponding to the first aluminum foil, and folding the first overlap area back and pasting it on the tape; S3: rotating the curling roller, moving the weld to the curling roller, pasting tape on the second overlap area corresponding to the second aluminum foil, and folding the second overlap area back and pasting it on the tape. The document adopts the method of folding the first overlap area and the second overlap area back and pasting them on the tape, and increasing the thickness and width on both sides of the weld position to increase the recognition rate of the welded joint. However, (1) since the color of the aluminum foil remains after folding, this method is not suitable for automated monitoring equipment that detects color differences (grayscale contrast); (2) During the slitting and winding process of the aluminum foil, a pressure of 1.5-4N / mm will be applied by the flattening roller to ensure the quality of the aluminum foil winding. However, the reserved space on both sides of the weld in this document is relatively large, especially after the aluminum foil is folded back at the pasting position, the thickness of the two layers of aluminum foil and one layer of tape is increased here, which will cause the thickness of the aluminum foil to suddenly become seriously thicker when it enters the flattening roller, which will not only cause deep pressure damage to the aluminum coil, but also cause the tape to break when entering the flattening roller due to the thin aluminum foil, making it impossible to achieve normal production, especially in the field of double zero foil, which is impossible to achieve; (3) The aluminum foil after slitting needs to undergo high-temperature annealing and degreasing treatment, and the tape in this document may melt and seep out, causing the aluminum foil at the welding point to be unable to be opened normally. Once it flows to the end face of the aluminum coil, the entire coil will be stuck and cannot be opened, resulting in scrap. Summary of the invention

[0007] The purpose of the present invention is to provide a method for improving the recognition of aluminum foil welds after compounding, so as to improve the recognition rate of welding joints by inspection machines and solve the problems of low machine inspection recognition rate, easy crushing or belt breakage, etc. in the prior art.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for improving the recognition of aluminum foil weld after lamination of the present invention comprises the following steps:

[0010] S1. During the slitting production process, the aluminum foil rolls that need to be welded are welded using an ultrasonic welding machine, and the weld is straight along the width direction of the aluminum foil;

[0011] S2. After welding is completed, a high-temperature resistant tape is pasted in the middle 3 to 10 mm away from the weld and parallel to the weld. The length of the tape is less than the length of the weld and both ends are at a certain distance from the edge of the aluminum foil. The high-temperature resistant tape has a color with a gray value that is obviously different from that of the aluminum foil and has a temperature resistance of ≥260°C.

[0012] S3, apply alcohol on the two ends of the high temperature resistant tape, take 2 pieces of aluminum foil with a thickness of ≤0.006mm and a width greater than the width of the high temperature resistant tape, and cover the two ends of the high temperature resistant tape respectively;

[0013] S4. Continue slitting according to normal slitting and coiling operations, degrease and anneal the slit aluminum foil coils, and then package them.

[0014] Preferably, the high temperature resistant tape has a temperature resistance of 260-400°C, a thickness of ≤0.025mm, a width of 7-15mm, a cloth adhesive width of ≥6mm and centered, and a cloth adhesive thickness of ≤0.0075mm; preferably, it is Runhai brand gold finger brown high temperature resistant tape, which must be flat and wrinkle-free during pasting, and the aluminum foil must not be damaged; the aluminum foil roll needs to undergo annealing and degreasing process, and the tape is required to have no changes in performance and shape during heating at 260-400°C.

[0015] Preferably, both ends of the high temperature resistant tape are 5 to 15 mm away from the edge of the aluminum foil, more preferably 10 mm away from the edge of the aluminum foil.

[0016] Preferably, in step S3, the covered portion of the end of the high temperature resistant tape occupies 1 / 3 to 2 / 3 of the area of ​​the aluminum foil.

[0017] Preferably, in step S3, the alcohol is alcohol with a purity of ≥95%.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The present invention improves the recognition of the automatic inspection machine and the automation production efficiency by increasing the color difference (grayscale contrast) between the aluminum foil and the high temperature resistant tape; only one layer of high temperature resistant tape is flatly pasted on the surface of the aluminum foil, there is no folded part, and the thickness of the high temperature resistant tape is limited, so that the aluminum foil will not be crushed or broken; the temperature resistance, adhesive amount and adhesive width of the high temperature resistant tape are limited, so that melting and seepage will not occur during high temperature annealing, causing adhesion between aluminum foil layers. The present invention is simpler and more convenient to operate, less harmful to the aluminum foil roll, and has obvious advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Photo of an ultrasonically welded weld of aluminum foil.

[0021] Figure 2 A photo of a piece of high temperature resistant tape placed next to the weld and parallel to the weld.

[0022] Figure 3 This is a photo of the two ends of the high temperature resistant tape being covered with aluminum foil. DETAILED DESCRIPTION

[0023] The present invention is further described below by means of specific embodiments, which are only used to illustrate the present invention rather than to limit the present invention.

[0024] Example 1

[0025] A method for improving the recognition of aluminum foil weld after compounding, comprising the following steps:

[0026] S1, 0.006*1281mm aluminum coil is cut into 23500 meters and welded with the incoming aluminum coil by conventional ultrasonic welding. The weld is straight along the width of the aluminum foil (see attached Figure 1 );

[0027] S2. After welding is completed, stick a piece of high temperature resistant tape parallel to the weld at a distance of 5 mm from the weld (see attached Figure 2 ), the width of the tape is 10mm, the thickness is 0.025mm, the width of the cloth adhesive is 6mm and centered, its length is less than the length of the weld and the two ends are 10mm away from the edge of the aluminum foil; the high temperature resistant tape is Runhai brand gold finger brown high temperature resistant tape, temperature resistant ≥260℃; it must be smooth and wrinkle-free when pasting;

[0028] S3. Apply alcohol with a purity of ≥95% on both ends of the high temperature resistant tape, take 2 pieces of aluminum foil with a thickness of 0.006mm and a width greater than the width of the high temperature resistant tape, and cover the two ends of the high temperature resistant tape respectively (see attached Figure 3 ); prevent the end surface of the high temperature resistant tape from leaking glue and causing adhesion, the aluminum foil piece should be as small as possible and ensure that the aluminum foil is flat and wrinkle-free, and the covered part of the end of the high temperature resistant tape occupies 1 / 2 of the area of ​​the aluminum foil piece;

[0029] S4. Continue slitting according to the normal slitting and coiling operation. After slitting to the required number of meters, 65,000 meters, unload the frame, degrease and anneal the slit aluminum foil rolls, and then package them.

[0030] The aluminum coil welding position was inspected and the weld position was opened normally without any adhesion. The surface indentation of the aluminum coil caused by the tape was light, and the coil could be opened normally without any wrinkles during the coiling process.

[0031] Example 2

[0032] A method for improving the recognition of aluminum foil weld after compounding, comprising the following steps:

[0033] S1, 0.007*880mm aluminum coil is cut into 5800 meters and welded with the incoming aluminum coil by conventional ultrasonic welding. The weld is straight along the width of the aluminum foil (see attached Figure 1 );

[0034] S2. After welding, a piece of high-temperature resistant tape parallel to the weld is pasted in the middle 3mm away from the weld. The width of the tape is 15mm, the thickness is 0.015mm, the width of the tape is 10mm and it is centered. Its length is less than the length of the weld and the two ends are 8mm away from the edge of the aluminum foil. The high-temperature resistant tape is Runhai brand gold finger brown high-temperature resistant tape with a temperature resistance of ≥260℃. It must be smooth and wrinkle-free when pasting.

[0035] S3. Apply alcohol with a purity of ≥95% on both ends of the high temperature resistant tape, take 2 pieces of aluminum foil with a thickness of 0.0051 mm and a width greater than the width of the high temperature resistant tape, and cover the two ends of the high temperature resistant tape respectively; prevent the end surface of the high temperature resistant tape from leaking glue and causing adhesion. The aluminum foil should be as small as possible and ensure that the aluminum foil is flat and wrinkle-free. The covered part of the end of the high temperature resistant tape accounts for 2 / 3 of the area of ​​the aluminum foil;

[0036] S4. Continue slitting according to the normal slitting and coiling operation. After slitting to the required number of meters, 12100 meters, unload the frame, degrease and anneal the slit aluminum foil rolls, and then package them.

[0037] The aluminum coil welding position was inspected and the weld position was opened normally without any adhesion. The surface indentation of the aluminum coil caused by the tape was light, and the coil could be opened normally without any wrinkles during the coiling process.

[0038] Comparative Example 1

[0039] S1, 0.007*920mm aluminum coil is cut into 7100 meters and welded with the incoming aluminum coil by conventional ultrasonic welding. The weld is straight along the width of the aluminum foil.

[0040] S2. After welding, a piece of high-temperature resistant tape parallel to the weld is pasted in the middle at 5mm away from the weld. The width of the tape is 10mm, the thickness is 0.025mm, the width of the tape is 10mm and centered, and the length is 920mm. Both ends are flush with the edge of the aluminum foil. The high-temperature resistant tape is Runhai brand gold finger brown high-temperature resistant tape, with a temperature resistance of ≥260℃. It must be smooth and wrinkle-free when pasting.

[0041] S3. Continue slitting according to normal slitting and coiling operations. After slitting to the required number of meters, 12,100 meters, unload the frame, degrease and anneal the slit aluminum foil rolls, and then package them.

[0042] During the coil guide inspection of the aluminum coil welding position, it was found that the tape was too long and the glue width was too wide, resulting in a small amount of melted glue seeping out from the edge of the tape after high-temperature annealing, causing the aluminum foil weld to stick and be unable to be opened.

[0043] Comparative Example 2

[0044] S1, 0.0063*1290mm aluminum coil is cut into 31300 meters, and conventional ultrasonic welding is performed with the incoming aluminum coil. The weld is straight along the width direction of the aluminum foil;

[0045] After welding is completed, a piece of high-temperature resistant tape parallel to the weld is pasted in the middle 5mm away from the weld. The width of the tape is 10mm, the thickness is 0.06mm, the width of the tape is 6mm and it is centered. Its length is less than the length of the weld and the two ends are 10mm away from the edge of the aluminum foil. The high-temperature resistant tape is Runhai brand gold finger brown high-temperature resistant tape with a temperature resistance of ≥260℃. It must be smooth and wrinkle-free when pasting;

[0046] S3. Apply alcohol with a purity of ≥95% on both ends of the high temperature resistant tape, take 2 pieces of aluminum foil with a thickness of 0.006 mm and a width greater than the width of the high temperature resistant tape, and cover the two ends of the high temperature resistant tape respectively; prevent the end surface of the high temperature resistant tape from leaking glue and causing adhesion. The aluminum foil should be as small as possible and ensure that the aluminum foil is flat and wrinkle-free. The covered part of the end of the high temperature resistant tape accounts for 2 / 3 of the area of ​​the aluminum foil;

[0047] S4. Continue slitting according to the normal slitting and coiling operation. After slitting to the required number of meters, 65,000 meters, unload the frame, degrease and anneal the slit aluminum foil rolls, and then package them.

[0048] The aluminum coil welding position is inspected for coil guiding. The weld position is opened normally without adhesion. The tape is too thick, resulting in obvious indentations on the surface of the aluminum coil at the tape. Transverse wrinkles will be generated during coil guiding. The tape thickness needs to be reduced.

Claims

1. A method for improving the recognition of aluminum foil welds after lamination, characterized in that: The following steps are involved: S1. During the slitting production process, the aluminum foil rolls that need to be welded are welded using an ultrasonic welding machine, and the weld is straight along the width direction of the aluminum foil; S2. After welding is completed, a high-temperature resistant tape is pasted in the middle 3 to 10 mm away from the weld and parallel to the weld. The length of the tape is less than the length of the weld and both ends are at a certain distance from the edge of the aluminum foil. The high-temperature resistant tape has a color with a gray value that is obviously different from that of the aluminum foil and has a temperature resistance of ≥260°C. S3, apply alcohol on the two ends of the high temperature resistant tape, take 2 pieces of aluminum foil with a thickness of ≤0.006mm and a width greater than the width of the high temperature resistant tape, and cover the two ends of the high temperature resistant tape respectively; S4. Continue slitting according to normal slitting and coiling operations, degrease and anneal the slit aluminum foil coils, and then package them.

2. The method for improving the recognition of aluminum foil weld after lamination according to claim 1, characterized in that: The high temperature resistant adhesive tape has a temperature resistance of 260-400°C, a thickness of ≤0.025mm, a width of 7-15mm, a cloth adhesive width of ≥6mm and centered, and a cloth adhesive thickness of ≤0.0075mm.

3. The method for improving the recognition of aluminum foil weld after lamination according to claim 1, characterized in that: The high temperature resistant tape is Runhai brand gold finger brown high temperature resistant tape.

4. The method for improving the recognition of aluminum foil weld after lamination according to claim 1, characterized in that: The two ends of the high temperature resistant tape are respectively 5 to 15 mm away from the edge of the aluminum foil.

5. The method for improving the recognition of aluminum foil weld after lamination according to claim 1, characterized in that: The two ends of the high temperature resistant tape are respectively 10 mm away from the edge of the aluminum foil.

6. The method for improving the recognition of aluminum foil weld after lamination according to claim 1, characterized in that: In the step S3, the covered portion of the end of the high temperature resistant tape occupies 1 / 3 to 2 / 3 of the area of ​​the aluminum foil.

7. The method for improving the recognition of aluminum foil weld after lamination according to claim 1, characterized in that: In step S3, the alcohol is alcohol with a purity of ≥95%.

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