Wet towel packaging machinery has been used for a long time, especially in the case of continuous work and overload, it is prone to some electrical and mechanical faults, such as: unstable sealing, running and stopping of the machine, fuse breaking when starting, squeaking during operation, uncontrollable temperature, deformation and bending of the finished bag at the sealing, knife sealing. There are bubbles or irregular marks on the impression.
Combining with the practical experience of packaging machine, this paper analyzes the causes of several faults, puts forward corresponding solutions, and expounds the maintenance of continuous sealing machine, hoping to be helpful to enterprises and individuals using continuous sealing machine.
1. sealing is not firmly sealed is one of the common faults of continuous sealing machine. The seal is not solid. There are three meanings:
(1) the sealing area of the bag can not be sealed.
2. Under the pressure of the sealing knife, the bag mouth is sealed, but it is slightly squeezed or torn off, and the seal is cracked.
(3) When peeling test was carried out at the sealing place, the phenomenon of half sealing firmly and half separating was found. The sealing quality of such bags was still unqualified because the contents could easily be leaked out by extrusion during storage and transportation. This situation often occurs when composite lining is OPP and blow molding PE.
The main reasons for the first failure are the following.
(1) When the heat sealing temperature is not enough, the temperature of the composite bag with OPP as the lining material should reach 170-180 C when the total thickness of the bag is 80-90_ m, and that of the composite bag with PE as the lining material should be controlled at 180-200 C when the total thickness of the bag is 85-100_ M. As long as the total thickness of the bag is increased, the heat sealing temperature must be raised accordingly.
(2) the sealing speed is too fast and the sealing speed is too fast. If the speed is too fast, the seal has not yet been heated by the traction roll to the cold pressure for cooling treatment, naturally can not meet the quality requirements of the heat seal.
(3) The pressure of cold-pressed rubber wheels is not suitable. Each of them has its upper and lower parts. The pressure between them should be moderate. When adjusting the pressure, it is only necessary to clamp the spring.
(4) The quality of hot sealing film is not a problem with the quality of hot sealing film sealing is also related to the quality of hot sealing film, if the composite lining corona treatment is not uniform, the effect is not good, and just appear in the sealing place, certainly can not seal. This situation is rare, but once it appears, the product will inevitably be scrapped. Therefore, in the color printing and packaging industry, is the next process to supervise the last process, a quality problem found, must be timely analysis of the causes and solve. If the seal is water and dirty, it will also cause poor sealing. In short, to solve the first sealing problem, generally can properly increase the heat sealing temperature, and then reduce the heat sealing speed, while increasing the pressure of cold-pressed rubber wheels.
The main reasons leading to second kinds of sealing failure are as follows.
(1) the heat sealing temperature is not enough, only the proper heat seal temperature can be solved.
(2) The surface of the hot sealing knife is not smooth enough. The hot sealing knife is divided into two parts, the upper and the lower. Thermoelectric coupling is usually installed in the knife to induce temperature transfer. There are three screws on the hot sealing knife. The middle screw supports and reinforces the knife blade. The other two screws are equipped with pressure springs and gaskets. They are mainly used to adjust the pressure of the hot sealing knife. The main reason for the uneven surface of the hot sealing knife is that the middle screw is inclined, not horizontal, or the pressure spring of the upper hot sealing knife is uneven. The solution is to recalibrate the position of the intermediate screw so that it is in a horizontal state. If the upper and lower heat sealing knives are not balanced, it is necessary to adjust the pressure spring to achieve moderate adjustment. When the spring is retreated outward, the heat seal knife will fall down; when the spring of the lower blade is tightened upward, the heat seal knife will move upward.
(3) The uneven pressure of cold-pressed rubber wheels will also cause such sealing faults, and the solution is similar to the first case.
There are two main reasons for the failure of the third seals.
(1) The adjustment on the hot sealing cutter and the cold pressing cutter is completely consistent.
(2) the blade of the heat sealing knife is not smooth enough to refer to the corresponding solution for the second kinds of sealing failure.
2. fuse fuse. The main function of the sealer motor is to drive gearboxes and parts of gears. Sometimes when the sealing machine starts, it will make a "squeak" sound, which can not work properly, and even the fuse on the fire line will break. To troubleshoot the fault, first check whether the power supply is normal, then cut off the power supply, use the resistor to check whether the switch is damaged, in addition to carefully check whether the line and motor short circuit. Usually, when the motor is short circuited, the winding burns or breaks, the fuse will fuse when the sealing machine is started. Another reason for this failure is that the fuse specifications are too small to be enlarged accordingly.
3. The "squeak" sound appeared in the operation of the sealing machine. The "squeak" sound often occurs suddenly, followed by uneven sealing speed, resulting in bad grain at the seal imprint of the packaging bag, affecting the appearance quality of the product. Occasionally, it can work normally, but capricious.
Most of these phenomena are due to mechanical damage or serious wear and poor lubrication. First, follow the sound emitted to find the fault location. Removal of the back guard plate, found that the "squeak" sound is from the gearbox, one by one to remove the fixed screws, found that the gearbox grease has been dry, the gear is bright, which shows that the fault is caused by lack of oil. The same type of oil and grease will be mixed and added to the gearbox, and fastening screw recovery, boot after the "squeak" sound disappeared, seal normal.
In addition, if the high-temperature belt joints loose, seriously worn, and unclean, dirty surface, running process does not synchronize with the traction wheel, sometimes will emit a "squeak" sound. The solution is to replace the same specification of the high temperature band. There is a certain skill to replace high temperature. Firstly, the spring of the pressure wheel is compressed by hand, then one end of the high temperature belt is placed on the rubber wheel, the other end is supported by hand on the other rubber wheel, and the governor is set at low speed. Once started, relying on the motion inertia, the high temperature belt is automatically installed. Sometimes the squeak is also emitted by a DC excited motor. It may be the lack of oil for motor bearings. If this is the case, it should be removed and lubricated, and the sound will be eliminated.
4. Seal temperature out of control This fault is manifested in the thermometer display failure, can not control the temperature, heat seal temperature is not constant, the seal is not burnt, is not firmly sealed, seal deformation, ugly. The main reason for this failure is that the thermometer is broken and must be repaired. In addition, the thermocouple may also be broken, and the induction temperature can not be transmitted to the thermometer normally. Replace the thermocouple with the same type and the same specification. The mechanical reason is that the pressure of the heat seal is not uniform, so long as the pressure spring of the heat seal cutter is adjusted to make the pressure uniform. Meanwhile, the contact surface of the heat sealing knife should be kept clean and free from dirt. Another reason is that the thermal sealing quality of the composite material itself is not good, the thermal sealing coefficient changes, resulting in the temperature difference.
5. Sealing machine running and stopping we have encountered in the production of sealing machine running and stopping, speed inconsistent fault, the back of the sealing machine face plate was removed, found that the motor shaft rod connection and gearbox connection has been shedding, relaxation phenomenon. The problem is solved by re fastening the screws to make it all the same. In addition, the main motor is run by carbon brush contact, if the carbon brush is seriously worn, and slip ring incomplete contact, or poor friction, will also cause the sealing machine to stop and go, replaced with the same type of new carbon brush can solve the problem.
6. Bubbles and irregular marks on the seal are also common failures. Although they do not cause leakage of the packaging, they affect the aesthetic feeling of the packaging and destroy the image of the goods. The reasons for this failure are mainly two points. (1) The equipment has been used for a long time, and dirt such as dust and plastic scraps are attached to the high-temperature zone, resulting in the high-temperature zone is not smooth and uneven, making the sealing heat uneven, after the cold-pressed wheel pressure bubble. The high temperature band can be removed after cleaning or re replacing. The high temperature zone is generally 1.5cm wide and has a thickness of about 22 m. If it sticks to the dirt, it can not be washed away, so it has to be scrapped. (2) There are irregular concave and convex marks on the cold-pressed rubber wheels, which are directly reflected on the package, so that there are more obvious marks on the seal. In order to ensure the beautiful appearance of the packaging bags, it is best to replace the cold pressure rubber wheel.
7. Packing machine equipment maintenance should pay attention to the problem (1) should be placed in the sealing machine ventilation, drying place, general room temperature can be maintained at about 25 degrees Celsius. (2) Every 48 hours of operation, the moving parts should be filled with 6# engine oil, mainly in gears, bearings and gearboxes. (3) dust removal should be regularly maintained to keep the machine clean. It is best to unplug the power supply and cover it with cloth. (4) If the running time is too long, the cooling fan should be turned on before shutting down, and then shut down after the temperature drops, because the high temperature zone is easy to damage. (5) the high temperature zone should regularly remove dirt to ensure the sealing quality. (6) severe wear parts should be replaced in time to prolong the service life of the whole machine.