Research on Improving the Quality of Electronic Aluminum Foil
With the continuous improvement of people's lives, aluminum products in our lives are more and more widely, to improve the quality of electronic foil is particularly important. Electronic aluminum foil production process as long as divided into two parts of rolling and finishing. In recent years, the demand for electronic aluminum foil in the market has gradually shifted to higher quality and greater differences. The finishing technology, which is represented by processes such as cleaning, shearing, rewinding and annealing, has become very important and involves stability and improvement. Product quality and improve the ability of enterprises to meet customer demand for large problems, has become the survival and development of enterprises must face the key issues.
1 aluminum foil surface defects
1.1 pressure pit
Aluminum foil must be cleaned after cleaning up the drying process, due to rolling mill and cleaning agent flammable and explosive materials, the ignition point of about 200 ℃. Pie pit is in the drying process, the aluminum foil by the duct, heat exchanger, drying box and other welding body stripping the solid particles cut small particles are involved in the steel roll and aluminum foil after the general formation in the foil surface bump Defects, reduce product quality; large particles even cut off the foil surface, resulting in scrapped
1.2 oil spots
Aluminum foil in the cleaning, rinsing process, the nozzle will be a certain pressure and flow through the jet to the foil surface, cleaning agent to reach the wall and rebound to the walls will produce a large number of high concentrations of oil mist, over time to form a grease
The scratches are a common quality problem for all finishing equipment, including cleaning. The mechanism is that the aluminum foil is slippery on the surface and the roll surface during the cleaning process, but the cause of slipping is related to machinery, electrical appliances, Various aspects.
Into the cleaning pass the thickness of the electronic foil is generally about 0.1mm, due to incoming thin, version of the type of large fluctuations, waves and waves in the emergence of such problems in the cleaning process through the pinch roll and squeeze roll Appear wrinkled.
2 measures to improve the foil surface
2.1 improvement measures of pressure pit
The control of the pit is divided into pre-equipment only two steps in the maintenance of the later and later. Drying equipment, high temperature oxidation is inevitable, but in the early stage of the equipment used in the selection of oxidation-resistant stainless steel, and the use of argon arc welding and other protective gas welding process, may reduce the use of materials in the surface and the welding site oxidation The possibility of. Later use in the duct to increase the multi-layer stainless steel filter, in order to reduce the filter block to reduce air volume, the filter can be regularly cleaned or replaced included in the daily maintenance.
2.2 improvement measures of oil spots
Aluminum foil in the cleaning, rinsing process, the box will produce a large number of high concentrations of oil mist eventually fall on the foil surface caused by pollution. As a large number of fog will consume cleaning agents, increase business costs, and the effect is not ideal, so can only consider blocking the oil droplets to the foil surface. Found that the oil droplets are mainly in the squeeze roller to rinse box within the distance from the top of the box to install the arc baffle, and in the top of the rinse tank outlet to install the oil tank, the oil droplets to the sides, you can eliminate the foil surface oil spots
2.3 measures to improve the scratches
The reasons for scratches are three aspects: mechanical structure, electrical control and process selection.
① for each roller is not synchronized to check whether the sync belt is appropriate, the bearing is lubricated in place;
② electrical adjustment of the motor parameters so that each active roller is not synchronized, calibration roll diameter error control mode to select a simple tension control and speed control.
③ process tension and speed settings should be matched with the previous pass, select the most reasonable range.
2.4 wrinkle improvement measures
For the type of poor material, take the following measures: 1. In the open book, coiling on both sides to increase the number of S-shaped U-shaped roller to play a correction role; 2 in the open, coiling on both sides of the plate-type adjustment roller. By adjusting the level of the roller and parallelism to eliminate the waves; 3. by increasing the roller or other convex to eliminate the waves.
3 electronic foil cleaning
3.1 Analysis of the status quo
3.1.1 The importance of cleaning
Electronic foil is a deep processing technology, the surface quality of the electronic storage capacity of a larger process in the aluminum foil surface caused by minor defects in the subsequent process will be enlarged, so only in the production process of each process on the foil quality 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 guide roller. First, through the lower brush roll, a cleaning solution is sprayed between the lower brush roller and the strip to wash the lower surface of the strip. The strip is then passed through the upper roll and a cleaning fluid is sprayed between the upper roll and the strip to wash the upper surface of the strip. Then the strip enters the rinse box. Or use the same cleaning solution to spray the upper and lower surfaces of the strip. After passing the 2 # agent dry roll, the cleaning oil on the strip surface is squeezed. Strip out of the rinse box into the drying box, the residue on the cleaning solution in the hot air under the purge was evaporated. Finally, the strip passes through the exit guide roller and is rolled up by the coiler. The cleaning is over.
4 cut aluminum foil
4.1 Description of the status of equipment and quality defects
Shears are different models, these devices are both narrow and wide, both trimming and pumping, both single and double, regardless of what type of shear mainly by the open book, cutting, Coil three parts. With the customer demand for aluminum foil rolls to large volume, high quality, short delivery time, more specifications change. Cutting machine knives, shafts, rollers, dies and other components are faced with increased wear and tear, reduced accuracy, frequent replacement and other issues. Shear part of the disc knife and knife pad because of the production and with the accuracy of the problem will cause scratches, pressure pit, burr and other quality defects. Coiling part due to surface pressure roller, take-up shaft and die use and design problems will cause flanging, fault layer, internal stress instability and other quality defects.
4.2 Causes and improvements in quality defects of cutting
Reason: scratches the problem is the most common problem of cutting process, but also the most difficult to completely solve the problem. The main reason for the scratches is due to the fact that the end of the disc knife or knife pad and the knife shaft are misaligned and the aluminum foil slips from the sharp corners. As the material of the knife or knife pad is harder than the aluminum foil, at a specific speed, In a very short period of time there is a very small slip, reflected in the material surface is dotted or linear scratches. As a result of everyone on the disc knife, knife pad, knife shaft machining accuracy and assembly accuracy of more attention, not to discuss the above reasons caused by scratches, this paper mainly study the following are easy to overlook the situation ① the use of links: As the disc knife used for some time will become blunt, need to constantly replace the new knife, and the knife pad is generally fixed, each time the new disc knife will be polished disc knife and knife pad equipment and quality defects description of the status quo I have a number of different types of aluminum foil shears, these devices are both narrow and wide, both trimming and pumping a long period of cumulative will cause the knife pad in the joint part of the outer diameter is relatively small, when A number of old disk knife run out, put on a number of new disc knife sharp angle problem will be more prominent. ② design aspects of the problem: aluminum foil in the cutting process prone to flanging and pressure pit, the main reason is caused by aluminum powder sticks. There are two sources of aluminum powder, aluminum foil surface attached to the aluminum powder; Second, the process of cutting aluminum powder. These two parts of the aluminum powder on the tip of the knife after the knife blunt, resulting in material surface flanging, when the aluminum powder fall to the surface will produce pressure pit. Improvements: need to constantly replace the new knife, and the knife pad is generally fixed, each time the new disc knife will be grinding disc knife and knife pad equipment and quality defects status quo.
4.2.2 Flanging and pressing pit
Reason: aluminum foil in the cutting process prone to flanging and pressure pit, the main reason is caused by aluminum powder sticks. There are two sources of aluminum powder, aluminum foil surface attached to the aluminum powder; Second, the process of cutting aluminum powder. These two parts of the aluminum powder on the tip of the knife after the knife blunt, resulting in material surface flanging, when the aluminum powder fall to the surface will produce pressure pit. Improve the measures: ① increase a set of aluminum powder purge device, the tool in the opposite direction of the purge, remove the tool attached to the aluminum powder; ② blankets filled with kerosene, diesel and other light oil on the knife, Cut the blanks on the line to clean the blade to prevent the accumulation of aluminum powder; ③ 5 ‰ NaOH alkali solution will be soaked in the inside of the tool, heated to 60-70 ℃, remove the rinse with water, dry, the method can be in the knife The surface layer of a protective layer to reduce the amount of aluminum foil sticks.
4.2.3 End face fault and volume density is not uniform
Reason: the cause of the end of the wrong layer and the density of the main reason is mainly in the coiling axis, the use of inflatable shaft cutting heavier weight of the volume, whether it is inflatable inflatable inflation or continuous inflatable inflatable inflatable shaft, when When the weight of the roll exceeds the support force provided by the air pressure, the weight of the roll is too large, which causes the die to sag and the eccentricity of the roll, which affects the roll density and the end face quality. Improve the measures: the easiest measure is to replace the knife pad in time, followed by the outer package can be taken to the structure of the knife pad, diameter larger than the disc knife diameter 0.01ram - 0.05ram, higher part of the rounded corners Radius of about 0.01ram - 0.15ram ,, plastic for the polyurethane rubber, hardness ≥ HS85. The upper and lower knives are usually driven by external gears. Can be based on the diameter of the knife can be adjusted on the knife drive gear teeth and modulus to achieve the purpose of matching.
4.2.4 jump knife and teeth
Reason: jump knife and tooth is a tool in the use of the process prone to the problem. On the knife after grinding several times the cumulative diameter will be reduced by 6-8ram, just rely on the gap between the upper and lower knife gears for elastic fit, can not guarantee the amount of overlap between the upper and lower knife, so that the steel pipe wall to provide support and torque structure To be provided by the axis of the cross, by the transmission pin to provide the structure of the torque, these two problems will cause equipment damage and waste. Improvement measures: the upper and lower knives are usually used external gear transmission. Can be based on the diameter of the knife can be adjusted on the knife drive gear teeth and modulus to achieve the purpose of matching. Through the winding shaft to improve the transmission and support functions, the use of bearings to support the shaft can be achieved when the smooth rotation to improve the quality of sub-volume. Through the use of clutch transmission can eliminate the frequent wear caused by cone wear, reducing equipment maintenance costs.
5 rewinding of aluminum foil
5.1 aluminum foil rewinder technical requirements
In order to ensure that the paper roll in the transport, storage process is not deformed, no crack, in the printing equipment or other processing is not ready to run smoothly, the finished paper roll must have sufficient hardness, and the outer loose, radial hardness distribution. Therefore, the rewinder must have the following functions: ① support roller torque set the given integrator, so that the input speed signal is a smooth rise of the ramp signal, rather than a sudden amount. By changing the integral of the given integrator, the slope of the slope signal can be changed by changing the slope. When the system is started, the speed acceleration is smaller than that of the given integrator. (2) The adjustment and pressing of the pressure of the platen roller are carried out. (3) The power-driven "disturbance" is activated and the appropriate speed is programmed. Control and so on.
5.2 The composition of the electronic control system
The front roller, rear bottom roller and eject roller of the rewinder are driven by a separate AC motor, and the vertical cutting knife adopts AC variable frequency drive and maintains 5% - 20% speed difference with the rear bottom roller. Auxiliary drive, including pneumatic and hydraulic system in two parts, respectively, used to control the auxiliary transmission machinery is not prepared action, with the main drive for. The entire electronic control system is mainly composed of three parts of the volume, the town by adjusting the front and rear bottom roller chain is also smaller.
5.3 Control of roll tension
The control of the tension of the paper roll affects the shape of the finished paper roll. Stable web tension can avoid the lateral shift of the web, the appropriate web tension can improve the paper roll quality to a certain extent, reduce the breakage and keep the rewinder stable. Therefore, the paper tension control is the electrical control system mushroom links.
5.4 Dynamic compensation in roll tension control
In the actual operation of the system, the paper roll diameter is getting smaller and smaller, due to its own inertia, the paper roll in the acceleration of the volume, deceleration stop and steady speed operation, there is inertia electromagnetic torque should be added positive dynamic Moment M. To compensate for the energy needed to absorb.
6. Effect of thickness on the performance of aluminum foil
Metal cold deformation occurs, the metal will increase the internal energy, the atoms in an unstable state, naturally have to change the trend of steady state, most of the metal materials at room temperature refused to complete this change, when the metal back heating, Increase the ability of atomic activity, accelerate the diffusion rate of atoms in order to complete the transition from atomic to steady state. This is the cold deformation of the metal in the annealing occurs when the fly and recrystallization of internal factors. But in the cold deformation of the metal back to the temperature of the heat to provide sufficient heat to overcome the atomic force between the atoms, so that the atoms migrate and free diffusion in order to occur in the crystallization, recrystallization temperature depends on the atomic migration to re-form nuclei and The size of the activation energy required to grow up, the higher the activation energy required, the higher the recrystallization temperature. The first is to anneal the aluminum foil blank at a thickness of 1.5 mm (cold deformation processing rate of about 80%), the second is the aluminum foil in the 2.5 mm thickness of the middle annealing (cold deformation processing rate of about 65%) due to the program Second, the processing of the blank processing rate of small metal recrystallization required for the higher activation energy of its recrystallization temperature is higher and its strength is even higher on the other hand 2.5 mm in the middle of the aluminum foil blank processing its processing to According to the theory of metal deformation, the storage energy retained in the form of dislocations mainly in the form of dislocations is the driving force of recrystallization during the annealing process and the nucleation rate in the recrystallization process increases with the increase of the amount of metal deformation. mm intermediate annealed aluminum foil blanks The resulting aluminum foil finished product obtained during the annealing is more deformed in the form of dislocations. The nucleation rate in the primary aluminum foil during the recrystallization process will be greatly increased So that the aluminum foil after the finished product can be more fine grain structure, so its strength and elongation is even higher.
6.1The effect of temperature on the finished product of aluminum foil
The casting and rolling of the aluminum foil produced by the casting process are all about 650mm to 700mm in the casting area. The maximum casting area is about 50mm. Area length of only about ten millimeters Yuan metal solidification crystallization only in about 1s time to complete this cooling and solidification speed compared with semi-continuous casting about two orders of magnitude and aluminum alloy in a variety of impurities and alloying elements in the aluminum The solubility in the aluminum is about 0.052% at room temperature, and the solubility is reduced to 0.002% at room temperature. At the time of eutectic temperature (655 ° C) The faster the cooling rate is, the worse the degree of deviation from the equilibrium state. Therefore, the intragranular segregation of the billet produced by the casting process and the degree of supersaturation of the solid solution are more severe than that of the semi-continuous casting. If the annealing temperature is high (reaching the homogenization temperature) in the intermediate annealing, the supersaturated element Sufficient precipitation, the phase of the solid solubility decreases the increase in the atomic self-diffusion coefficient is conducive to the annealing of the new nucleus nucleation and growth of the material to reduce the recrystallization temperature of the same reason if the intermediate annealing temperature does not achieve uniform effect And only can only meet the plastic recovery of the metal at this time the metal supersaturated solid solution also failed to fully precipitate.
Therefore, the use of aluminum produced by the program three, in the finished product annealing, under the same conditions of annealing more likely to occur in the crystallization, and due to homogenization of the segregation and solid solution of the full precipitation, the number of internal nucleation of the material increased Grain structure is more small, so the elongation of the finished product is also higher, ordinary intermediate annealing aluminum foil rolling surface into a higher strength, it is due to the middle of the annealing temperature is not enough, the internal structure of the material within the segregation 2 and the solid solution can not be completely precipitated, the aluminum foil produced a solid solution strengthening effect, but in the finished product annealing if the temperature continues to rise, it may be due to grain growth continues, resulting in sharp decline in strength and elongation.
7 concluding remarks
Electronic aluminum foil is a relatively high quality control requirements of the product, so the details of the process must pay attention. Equipment in the design, manufacturing pre-use, the use of maintenance personnel to take the initiative to participate in the equipment will congenital defects to a minimum, for future equipment use, maintenance to create favorable prerequisites.
The main way to solve the scratching of aluminum strip is to improve the accuracy of cleaning agents. According to the different production of aluminum foil, so to use the aluminum foil rewinder is not the same, according to the characteristics of aluminum foil produced in the production process to help the problem.
According to the needs of industrial control of aluminum foil annealing furnace, the defects and improvement measures in annealing were studied. The temperature of the furnace gas temperature and the temperature of the temperature of the aluminum foil annealing furnace were tested by the industrial test. The temperature control system was able to meet the aluminum foil annealing furnace industry Production requirements.