As people’s lives continue to improve, aluminum products are becoming more and more extensive in our lives. The issue of improving the quality of electronic aluminum foil is especially important. The production process of electronic aluminum foil is divided into two parts: calendering and finishing. In recent years, the market demand for electronic aluminum foil has gradually changed to higher quality and greater difference. The finishing technology represented by cleaning, shearing, rewinding, annealing and other processes has become very important, involving stability and improvement. The big problem of product quality and the ability to improve the ability of enterprises to meet the needs of customers has become a key issue for enterprises to survive and develop.

1 defects in the surface of aluminum foil

1.1 crater

After the aluminum foil is cleaned, it must be awakened and dried. Because of the flammable and explosive materials of the rolling mill and the cleaning agent, the ignition point is around 200 °C. The crater is in the drying process, the aluminum foil is cut by the air ball, the heat exchanger, the drying box and the like, and the solid particles are cut and the small particles are entangled between the steel roller and the aluminum foil, and the embossing is generally formed on the foil surface. Defects, reducing product quality; large particles can even cut through the foil surface, causing scrapping

1.2 oil spots

During the cleaning and rinsing process of the aluminum foil, the nozzle sprays the cleaning agent to the foil surface through a certain pressure and flow. After the cleaning agent reaches the foil surface and rebounds to the four walls, a large amount of high-concentration oil mist is generated, and the oil spot is formed over time. .

1.3 abrasions

Scratch is a common quality problem of all finishing equipment including cleaning. The mechanism is that the aluminum foil is slippery on the thin surface and the roll surface during the cleaning process, but the cause of the slip is related to machinery, electrical appliances, crafts, etc. Various aspects.

1.4 wrinkles

The thickness of the electronic aluminum foil entering the cleaning pass is generally about 0.1 mm. Due to the thinness of the incoming material, the fluctuation of the plate type, the occurrence of waves and waves, etc., the material in the cleaning process passes through the pinch roller and the squeeze roller. Wrinkles appear.

2 Measures to improve the foil surface

2.1 Improvement measures for pressure pits

The control of the crater is divided into two steps: the early stage equipment is used only in the later stage and the later stage. High-temperature oxidation of the drying equipment is unavoidable, but the oxidation-resistant stainless steel material is used in the early equipment manufacturing process, and a protective gas welding process such as argon arc welding is used, which may reduce the oxidation of the material surface and the welded portion in use in the future. The possibility. In the later stage of use, a multi-layer stainless steel filter is added to the air duct. In order to reduce the clogging of the filter and reduce the air volume, the filter can be periodically cleaned or replaced for routine maintenance.

2.2 Oil spot improvement measures

During the cleaning and rinsing process of the aluminum foil, a large amount of high-concentration oil mist will be generated in the tank body and eventually fall on the foil surface to cause pollution. Since a large amount of mist will consume cleaning agents, increase the cost of the enterprise, and the effect is not satisfactory, it is only considered to block the oil droplets to the foil surface. It is found that the oil droplets are mainly installed with an arc-shaped baffle at the top of the tank at the distance from the squeezing roller to the rinsing tank, and an oil sump is installed at the top of the rinsing tank outlet to guide the oil droplets to both sides, thereby eliminating the foil surface oil spot. .

2.3 Improvement measures for scratches and scratches

The causes of scratches are mechanical structure, electrical control and process selection.

1 For each roller not synchronized, check whether the synchronous toothed belt is tight and the bearing is lubricated in place;

2 Electrically adjust the motor parameters so that the individual drive rollers are not synchronized, and the correction of the winding diameter error control mode selects simple tension control and speed control.

3 The process tension and speed settings should match the front and rear passes, and a reasonable range should be selected.

2.4 Wrinkle improvement measures

For the poor type of material, the following measures are taken: 1. Adding several sets of S-shaped U-shaped rolls on both sides of the unwinding and winding to correct the effect; 2. Installing the plate-type adjusting rolls on both sides of the unwinding and winding. Eliminate the edge waves by adjusting the level and parallelism of the roller; 3. Eliminate the mid-wave by increasing the rubber roller or other convexity.

3 electronic aluminum foil cleaning

3.1 Status analysis

3.1.1 Importance of cleaning

Electronic aluminum foil belongs to deep processing technology, and the surface quality has a great influence on the electronic storage capacity. The small defects caused by the previous process on the surface of the aluminum foil will be amplified in the subsequent process. Therefore, only the quality of the foil surface is performed in each process in the production process. strict control.

3.1.2 Cleaning process

The cleaning process of the aluminum foil is as follows: the strip enters the device from the uncoiler and the inlet deflector roller, first passes through the lower brush roller, and a cleaning liquid is sprayed between the lower brush roller and the strip to wash the lower surface of the strip. Next, the strip passes through the upper roller, and a cleaning liquid is also sprayed between the upper roller and the strip to wash the upper surface of the strip. The strip then enters the rinse tank. Still use the same cleaning solution to spray the upper and lower surfaces of the strip. The cleaning oil on the surface of the strip was squeezed through a 2# dry roll. After the strip exits the rinsing tank, it enters the drying box, and the residual cleaning liquid on the strip is evaporated under the hot air purging. Later, the strip passes through the outlet deflecting roller and is circulated by the coiler into a roll. The cleaning is over.

4 cutting of electronic aluminum foil

4.1 Description of the status of equipment and quality defects

The shearing machines are available in different models. These devices are available in both narrow and wide widths. They have both trimming and drawing, and both single and double shafts. No matter what type of shearing machine is mainly used for unwinding, slitting, The volume is composed of three parts. As customers’ demand for aluminum foil rolls is changing to large volume, high quality, short delivery time and multiple specifications. The cutters, shafts, rollers, and dies of the shearing machine are subject to problems such as increased wear, reduced accuracy, and frequent replacement. The shearing part may cause scratches, craters, burrs and other quality defects due to the fabrication and fitting accuracy of the disc knives and knives. Due to the use and design problems of the surface roller, the take-up shaft and the die, the coiling portion may cause quality defects such as flanging, split layer, and unstable internal stress.

4.2 Causes and improvement of shear quality defects

4.2.1 Scratch

Reason: The problem of scratching is a common problem in the shearing process, and it is also a problem that is difficult to solve completely. The main cause of scratches is that the end face is misaligned by the disc knife or the knife pad when it is assembled with the knife shaft. When the aluminum foil slides over the sharp corner, the material of the lower knife or the knife pad is harder than the aluminum foil, at a specific rotation speed. Extremely small slippage occurs in a very short period of time, reflected in the point or line scratches on the material surface. Since everyone pays more attention to the machining accuracy and assembly precision of disc knives, knives and knives, we will not discuss the scratches caused by the above reasons. This paper mainly studies the following cases that are easily overlooked. Since the disc cutter becomes dull after a period of use, it is necessary to replace the new knife frequently, and the knife pad is generally fixed. The equipment and quality defects of the disc knife and the knife pad will be described each time a new disc knife is replaced. There are many different types of aluminum foil shearing machines in our company. These devices have both narrow and wide widths. Both the trimming and the long-term accumulation of the strips will cause the outer diameter of the mat to be relatively small. A batch of old disc knives is used up, and the problem of sharp corners will be more prominent after replacing a batch of new disc knives. 2 Design link problem: Aluminum foil is prone to flanging and embossing during the slitting process, mainly due to the aluminum powder sticking knife. There are two sources of aluminum powder, one is the aluminum powder attached to the surface of the aluminum foil; the other is the aluminum powder produced during the shearing process. The two parts of aluminum powder gather on the tip of the knife to make the knife dull, which causes the material surface to be turned over. When the aluminum powder falls to the material surface, a crater is generated. Improvement measures: New knives need to be replaced frequently, and the knives are generally fixed. Each time a new disc knives is replaced, the equipment and quality defects of the disc knives and knives will be polished.

4.2.2 Flanging and pressing

Reason: Aluminum foil is prone to flanging and embossing during the slitting process, mainly due to the aluminum powder sticking knife. There are two sources of aluminum powder, one is the aluminum powder attached to the surface of the aluminum foil; the other is the aluminum powder produced during the shearing process. The two parts of aluminum powder gather on the tip of the knife to make the knife dull, which causes the material surface to be turned over. When the aluminum powder falls to the material surface, a crater is generated. Improvement measures: 1 Add a set of aluminum powder purging device, purify the tool in the opposite direction, and remove the aluminum powder attached to the tool; 2 pad the felt with kerosene, diesel and other light oil and stick it on the knife. When cutting, the felt is wiped on the surface to prevent the aluminum powder from collecting. 3 Soak the knife in the inside with 5 NaOH alkali solution, heat it to 60-70 ° C, remove it, rinse it with water, and dry it. This method can be used in the knife. A protective layer is formed on the surface to reduce the amount of aluminum foil sticking.

4.2.3 Uneven surface layer and roll density uneven

Reason: The cause of the inconsistency between the end-face staggered layer and the roll density is mainly on the take-up shaft. When using the air-expansion shaft to cut the heavier roll, whether it is an inflatable pressure-holding inflatable shaft or a continuous aerated air-expansion shaft, when When the weight of the coil exceeds the support force provided by the air pressure, the weight of the coil is too large, which may cause the core to sag and the coil to be eccentric, affecting the density of the coil and the quality of the end surface. Improvement measures: The simpler measure is to replace the knife pad in time, and the second step can adopt the structure of the outer rubberized knife pad. The outer diameter is larger than the outer diameter of the disk cutter by 0.01ram-0.05ram, and the upper part is rounded and rounded. The radius is about 0.01 ram – 0.15 ram, the rubber is urethane rubber, and the hardness is ≥ HS85. The upper and lower knives usually use an external gear transmission. The number of teeth and the modulus of the upper cutter drive gear can be adjusted according to the change of the upper cutter diameter to achieve the matching purpose.

4.2.4 Jumping and toothing

Cause: Jumping and toothing are prone to problems during tool use. After the grinding of the upper knife, the total outer diameter will be reduced by 6-8 ram, and only the clearance of the upper and lower cutter transmission gears will be used for the elastic fit, and the overlap of the upper and lower knives cannot be guaranteed, so that the inner wall of the steel pipe core can provide the support and torque structure. Instead of providing the support by the shaft, the drive pin provides the structure of the rotational torque, both of which cause equipment damage and waste. Improvement measures: The upper and lower knives usually adopt external gear transmission. The number of teeth and the modulus of the upper cutter drive gear can be adjusted according to the change of the upper cutter diameter to achieve the matching purpose. By improving the winding shaft, the transmission and support functions are separated, and bearing support can ensure smooth rotation of the shaft and improve the quality of the winding. By using clutch transmission, frequent replacement caused by cone wear can be eliminated, and equipment maintenance costs can be reduced.

5 electronic aluminum foil rewinding

5.1 Technical requirements for aluminum foil rewinder

In order to ensure that the paper roll does not deform or crack during transportation and storage, it can run smoothly on printing equipment or other processing equipment. The finished paper roll must have sufficient hardness, and the inner tightness is loose and the radial hardness is evenly distributed. Therefore, the rewinder must have the following functions: 1 Set the integrator of the support roller torque so that the input speed signal is a smoothly rising ramp signal, rather than a sudden amount. By changing the integral of the given integrator to the constant, the slope of the E-slope of the ramp signal can be changed. When the system starts, the speed acceleration is smaller than when no integrator is given; 2 the pressure of the platen roller is adjusted and squeezed; 3 the “disturbance” start of the electric drive and the appropriate speed program control; 4 the indirect or the tension Control, etc.

Research on improving the quality of electronic aluminum foil

Figure 1: Aluminum foil rewinding machine

5.2 Composition of the electronic control system

The front bottom roller, the rear bottom roller and the paper ejection roller of the winder are respectively driven by a separate AC motor, and the slitting circular cutter adopts an AC variable frequency transmission, and maintains a 5%–20% speed difference with the rear bottom roller. The auxiliary drive consists of two parts, a pneumatic and hydraulic system, which are used to control the movement of the auxiliary drive mechanism and cooperate with the main drive. The entire electronic control system is mainly composed of three partial volumes, and the chain of the bottom roller is adjusted to be smaller by the town.

5.3 Control of the back roll tension

The control of the rollback tension affects the shape of the finished roll. Stable web tension can avoid lateral deflection of the web. Appropriate web tension can improve the quality of the paper roll to a certain extent, reduce breakage and keep the winder stable. Therefore, web tension control is an important part of the electronic control system.

5.4 Dynamic compensation in the tension control of the eject roller

In the actual operation of the system, the diameter of the ejected paper roll is getting smaller and smaller. Due to the inertia of the system, during the process of accelerating the unwinding, decelerating and stopping and running at a steady speed, the electromagnetic torque of the inertia should be positively added. Moment M. To compensate for the energy that needs to be absorbed.

6 Effect of annealing system on the performance of aluminum foil

Research on improving the quality of electronic aluminum foil

6.1 Effect of thickness on the performance of aluminum foil products

When the metal undergoes cold deformation, the internal energy of the metal will rise, and the atom will be in an unstable state. Naturally, there is a tendency to change in a stable state. Most metal materials refuse to complete this transformation at room temperature, when the metal back is heated, Increasing the mobility of the atom and accelerating the diffusion rate of the atom can complete the transition of the atom to a stable state. This is the internal cause of the fly-off and recrystallization of the cold-deformed metal during annealing. However, the heat energy provided by the cold-deformed metal back is sufficient to overcome the bonding force between the atoms, allowing the atoms to migrate and freely diffuse to occur in the crystallization. The recrystallization temperature depends on the atomic migration to re-form the nucleus and The higher the activation energy required to grow up, the higher the activation energy required and the higher the recrystallization temperature. The first scheme is to carry out intermediate annealing of aluminum foil blank at a thickness of 1.5 mm (cold deformation processing rate is about 80%). The second scheme is to perform intermediate annealing of aluminum foil blank at a thickness of 2.5 mm (cold deformation processing rate is about 65%). The processing rate of the second produced blank is smaller. The activation energy required for recrystallization of the metal is higher, the recrystallization temperature is higher, and the strength is higher. On the other hand, the 2.5 mm intermediate annealed aluminum foil blank is processed into According to the metallurgical theory, the storage energy retained in the dislocation form in the metal structure is the driving force for recrystallization during annealing. The nucleation rate in the recrystallization process increases with the increase of the metal deformation. Therefore, 2.5 is used. Mm intermediate annealed aluminum foil blanks, the aluminum foil obtained by rolling has a greater amount of deformation during annealing, and the storage energy accumulated in the form of dislocations is also larger. The nucleation rate in the original aluminum foil is greatly increased during recrystallization. Therefore, the aluminum foil can obtain a finer grain structure after the finish annealing, and thus the strength and elongation are higher.

6.2 Effect of temperature on the performance of aluminum foil products

For the aluminum foil blank produced by the casting and rolling method, the cooling and solidification and deformation of the metal during casting and rolling are all completed in the casting and rolling zone with a roll diameter of 650 mm – 700 mm. The length of the larger casting zone is about 50 mm. The length of the casting zone is only about ten millimeters. The solidification crystallization of Yuan metal is only about 1 s. The speed of this solidification is about 2 orders of magnitude higher than that of semi-continuous casting. The various impurities and alloying elements in the aluminum alloy are The solid solubility in aluminum varies with temperature. For example, according to the equilibrium phase diagram, the solubility of iron in aluminum at eutectic temperature (655 °C) is about 0.052%. The solubility decreases to 0.002% at room temperature. The faster the cooling rate deviates from the equilibrium state, the more severe it is. Therefore, the intragranular segregation of the billet produced by the casting method and the degree of supersaturation of the solid solution are more serious than those of the semi-continuous casting. If the annealing temperature is high (to reach the homogenization temperature) during the intermediate annealing, the supersaturated element in the metal can be promoted. According to the analysis, the decrease of solid solubility in the phase increases the self-diffusion coefficient of the atom, which is beneficial to the nucleation and growth of the new nucleus during annealing. The recrystallization temperature of the material is reduced. If the temperature does not reach the homogenization effect during the intermediate annealing. However, only the plastic recovery of the metal can be satisfied. At this time, the supersaturated solid solution of the metal is not fully analyzed.