Automatic film sealing machine common problem solving method

- Jan 21, 2019 -

The multi-functional automatic film sealing machine is favored by small and medium-sized food processing enterprises because of its characteristics of sealing, stable performance and good sealing effect. In the aspect of flexible packaging, the machine has also been widely used. When the edge seal, the middle seal and the bottom seal are poor in the plastic film bag, the machine can be used for resealing to achieve the heat seal quality requirement.
The machine has been used for a long time, especially in the case of work and overload, it is prone to some electrical faults and mechanical faults, such as: the seal is not strong, the machine stops and stops, the fuse is blown at the start, and the "beep" is issued during the operation. The temperature can not be controlled, the finished bag is deformed and bent at the sealing, and bubbles or irregular marks appear at the embossing of the sealing knife. Based on the actual experience, this paper analyzes the causes of several kinds of faults, proposes corresponding solutions, and expounds the maintenance of the sealing machine. It is hoped that the enterprises and individuals who use the sealing machine will be helpful.

1. The seal is not strong

Sealing is not one of the common failures of the sealing machine. The sealing is not strong. There are three layers of meaning: 1 The sealing of the bag cannot be sealed; 2 Under the pressure of the sealing knife, although the bag is sealed, it is squeezed or torn slightly. Peeling, the seal will be cracked again; 3 When the peeling test is carried out on the sealing part, half of the sealing is firm and half separated. The quality of the sealing of the bag is still unsatisfactory, because the contents are easily squeezed during storage and transportation. Missed. This situation often occurs when the composite lining is opp and blown pe.

The main causes of the first type of failure are the following.

(1) The heat sealing temperature is not enough

Under normal circumstances, the composite bag with opp as the lining, when the total thickness of the bag is 80-90μm, the heat sealing temperature should reach 170-180 °C; the total thickness of the composite bag with pe as the lining is 85-100μm. When the temperature is controlled, it is controlled at 180 to 200 °C. As long as the total thickness of the bag is increased, the heat sealing temperature must be increased accordingly.

(2) Heat sealing speed is too fast

Sealing is not related to the speed of the sealing machine. If the speed is too fast, the seal will be transferred to the cold pressure for cooling in the future, and naturally it will not meet the heat seal quality requirements.

(3) The pressure of the cold pressure rubber wheel is not suitable

There is one on each of the cold-pressing rubber wheels, and the pressure between them should be moderate. When adjusting the pressure, only the spring should be clamped.

(4) There is a problem with the quality of the heat-sealed film

Sealing is not related to the quality of the heat-sealing film. If the corona treatment of the composite lining is not uniform, the effect is not good, and it appears at the sealing place, and it is certainly impossible to seal. This situation is rare, but once it appears, the product is bound to be scrapped. Therefore, in the color printing and packaging industry, it is the next process of supervision of the next process. Once the quality problem is discovered, the cause must be analyzed and solved in time. If there is moisture or dirt in the seal, it will also cause the seal to be weak. In short, to solve the problem of the first type of sealing is not strong, generally can properly increase the heat sealing temperature, and then reduce the heat sealing speed, while increasing the pressure of the cold pressing rubber wheel.

The main reasons for the failure of the second type of seal are the following.

(1) The heat sealing temperature is not enough

Simply raise the heat seal temperature to solve the problem.

(2) The surface of the heat sealing knife is not flat enough

The heat sealing knife is divided into two upper and lower pieces, and a thermocouple is usually installed therein to sense the temperature transfer. There are three screws on the heat sealing knife. The middle screw acts as a support and reinforcement blade. The other two screws are equipped with pressure springs and washers, which are mainly used to adjust the pressure of the heat sealing knife. The upper and lower blades each have two springs. . The main reason for the unevenness of the heat-sealing knife surface is that the intermediate screw is inclined, not horizontal; or the pressure spring pressure of the upper heat-sealing knife is uneven.

The solution is to recalibrate the position of the intermediate screw so that it is level. If the upper and lower heat-sealing knives are unbalanced, it should be realized by adjusting the pressure springs, and the adjustment can be moderate. When the spring is retracted, 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) Uneven pressure of cold-pressed rubber wheel

Uneven pressure of the cold-pressing rubber wheel will also cause such a seal to be insecure, and the solution is similar to the first case.

There are two main reasons why the third type of seal is not broken.

(1) Uneven pressure of heat sealing knife or uneven pressure of cold pressing knife

The adjustments on the heat seal knife and the cold press knife are identical.

(2) The surface of the heat sealing knife is not flat enough

Refer to the corresponding solution for the second type of seal failure.

2. The fuse is blown

The main motor of the plastic film sealing machine is the first AC motor pure aluminum joint turbine box in China. Its main function is to drive the gearbox and gear transmission of various components. Sometimes when the sealing machine is started, it will make a "beep" sound, it will not work properly, and even the fuse on the fire line will melt.

To eliminate the fault, first check whether the power supply is normal, and then cut off the power supply, use the resistance file to measure whether the switch is damaged, and also carefully check whether the line and the motor are short-circuited. Usually, when the motor is short-circuited, the winding is burnt, or the wire is broken, the fuse is blown when the sealing machine is started. Another reason for this failure is that the fuse size is too small, and the corresponding specifications can be increased to solve the problem.

3. "吱" sound appears during operation

The fault occurs during the operation of the sealing machine. The "beep" sound often occurs suddenly. The next step is that the sealing speed is uneven, which causes the pattern of the seal of the packaging bag to be bad, which affects the appearance quality of the product. Occasionally, it works fine, but it is capricious.

Most of this phenomenon is due to mechanical damage or wear and poor lubrication. The solution is to mix the same type of oil and grease into the gearbox and tighten the screws to recover. After the start, the "beep" sound disappears and the seal is normal.

In addition, if the joint of the high temperature belt is slack, seriously damaged, and is not clean, the surface is dirty, it is not synchronized with the traction wheel during operation, and sometimes a "click" sound is emitted. The solution is to replace the high temperature belt of the same specification. There are certain skills to replace the high temperature. First, compress the pressure wheel spring by hand, then place one end of the high temperature belt on the rubber wheel, and the other end is to hold it against the other rubber wheel, set the governor to low speed, start, lean against The inertia of the motion, the high temperature belt is automatically loaded.

Sometimes the "beep" sound is also emitted by the DC and the motor. It may be that the motor bearing is out of oil. If this is the case, it should be removed and lubricated, and the sound can be eliminated.

4. Sealing temperature is out of control

The fault is manifested by the failure of the thermometer display, the temperature cannot be controlled, the heat seal temperature is not constant, the seal is not burnt, the seal is not strong, the seal is deformed, and it is difficult to see. The main cause of the failure is that the thermometer is broken and must be repaired. In addition, the thermocouple may be broken and the induction temperature cannot be normally transmitted to the thermometer. Replace the thermocouple with the same model and the same specification.

The mechanical reason is that the heat sealing pressure is not uniform, as long as the pressure spring of the heat sealing knife is adjusted to make the pressure uniform. At the same time, the pressure contact surface of the heat sealing knife should be kept clean and free from dirt.

Another reason is that the heat seal quality of the composite material itself is not good, and the heat seal coefficient changes, causing the temperature to be inconsistent.

5. Sealing machine stop and go

In the production, we encountered the failure of the sealing machine to stop and stop and the speed was inconsistent. The panel on the back of the sealing machine was dismantled and it was found that the connection between the shaft of the motor and the gearbox had fallen off and slack. Retighten the screws to make them all match and the problem is solved. In addition, the main motor is operated by the contact of the carbon brush. If the carbon brush is seriously worn, not completely in contact with the slip ring, or the friction is not good, the sealing machine will also stop and stop, and replace with the new carbon of the same model. Brush to solve the problem.

6. Bubbles and irregular marks appear at the seal

This kind of failure is also more common, although it will not cause the package to leak, but it affects the beauty of the packaging and destroys the image of the product.

Summary The main reasons for this failure are the following two points.

(1) The equipment has been used for a long time, and dust and plastic chips are attached to the high temperature belt, which causes the high temperature belt to be not smooth and uneven, so that the sealing is unevenly heated, and bubbles are formed after the cold pressing wheel is pressed. Troubleshoot by cleaning or replacing the high temperature belt. The high temperature belt is generally 1.5cm wide and 22μm thick. If it is not washed after it is sticky, it will be scrapped.

(2) There are irregular irregularities on the cold-pressed rubber wheel, 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 package, it is best to replace the cold pressure rubber wheel.

7. Problems that should be paid attention to during equipment maintenance

(1) The sealing machine should be placed in a ventilated and dry place, and the room temperature should be maintained at around 25 °C.

(2) For every 48 hours of operation of the sealing machine, 6# oil should be added to each moving part, mainly in gears, bearings and gearboxes.

(3) Dust should be removed regularly to keep the whole machine clean. When not in use, it is best to unplug the power supply and cover it with a 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 it will be shut down without cooling, and the high temperature belt is easily damaged.

(5) The high temperature belt should be regularly decontaminated to ensure the quality of the sealing.

(6) Serious wear parts should be replaced in time to extend the life of the machine.