After prolonged use,
wet wipes packaging machines are prone to various electrical and mechanical faults, particularly under continuous operation and overload conditions. These issues include weak sealing, intermittent operation, blown fuses upon startup, squeaking noises, uncontrollable temperature, and deformities in sealed bags, such as bending or bubbling, as well as irregular marks on the sealed areas.
Drawing from practical experience with
wet wipes packaging machines, let's analyze the causes of several common faults, propose corresponding solutions, and discuss maintenance practices for continuous sealing machines, aiming to assist both businesses and individuals utilizing these machines.
1. Weak Sealing:
Insufficient sealing is a prevalent issue with continuous sealing machines, manifested in three ways:
a. Incomplete sealing of the packaging bag.
b. Sealed bag mouths cracking upon slight pressure or peeling.
c. Uneven sealing, resulting in leakage during storage and transportation, especially in composite bags with OPP and blow-molded PE linings.
Main Causes:
(1) Inadequate Heat-sealing Temperature: Insufficient heat-sealing temperature is often the culprit. Proper temperatures are crucial, with OPP-lined composite bags requiring 170-180°C for bags of 80-90 μm thickness, and PE-lined bags needing 180-200°C for 85-100μm thickness.
(2) Excessive Heat-sealing Speed: High speeds can lead to inadequate heat transfer, causing the seal to fail before proper bonding occurs.
(3) Inappropriate Pressure of Cold-pressed Rubber Wheels: The pressure between cold-pressed rubber wheels should be moderate and adjusted carefully.
(4) Heat-sealing Film Quality Issues: Poor quality heat-sealing film, with uneven corona treatment or contamination, can result in weak seals.
Solutions:
Adjust heat-sealing temperature, reduce speed, increase pressure on cold-pressed rubber wheels, and ensure high-quality heat-sealing film to address weak sealing issues. Additionally, cleanliness is crucial to prevent moisture or dirt from compromising seals. Overall, a holistic approach is needed to optimize sealing quality.
The primary causes of the second type of poor sealing failure are as follows:
Inadequate Heat-sealing Temperature: Increasing the heat-sealing temperature appropriately can resolve this issue.
Uneven Blade Surface of Heat-sealing Knife: The heat-sealing knife comprises upper and lower parts, often with a thermoelectric coupling for temperature sensing. There are typically three screws on the heat-sealing knife. The middle screw supports and reinforces the blade, while the other two screws, equipped with pressure springs and gaskets, adjust the pressure. Uneven blade surfaces may result from the middle screw being installed obliquely or the uneven pressing of the upper heat-sealing knife's pressure spring. To address this, recalibrate the middle screw to ensure horizontal alignment. For imbalanced upper and lower heat-sealing knives, adjust the pressure springs moderately. When withdrawing the spring, the heat-sealing knife will descend, while tightening the spring on the lower blade will elevate the heat-sealing knife.
Uneven Pressure of Cold-pressed Rubber Wheel: Similar to the first case, uneven pressure from the cold-pressed rubber wheel can lead to sealing failures.
The main reasons for the third type of poor sealing failure are:
Uneven Pressure of Heat-sealing Knife or Cold-pressing Knife: Adjustment procedures for the heat-sealing knife and the cold-pressing knife are identical.
Uneven Blade Surface of Heat-sealing Knife: Refer to the solution provided for the second type of sealing failure.
2. Fuse Blown:
The primary function of the sealing machine motor is to drive the gearbox and gear transmission of various components. Occasionally, upon starting, the sealing machine may emit a "squeak" sound and fail to operate normally, leading to a blown fuse on the live line. To address this issue, start by checking the power supply for normalcy. Subsequently, disconnect the power supply and use resistance gear to assess whether the switch is damaged. Thoroughly inspect the circuit and motor for any signs of short-circuiting. Typically, a blown fuse immediately upon starting the sealing machine indicates motor short-circuiting, characterized by burnt windings or broken wires. Additionally, inadequate fuse size can also cause this failure, which can be rectified by increasing its size accordingly.
3. "Squeak" Sound During Operation:
This fault arises during the operation of the sealing machine and is often characterized by a sudden "squeak" sound followed by uneven sealing speed and compromised appearance quality. This issue is typically attributed to mechanical damage, severe wear, or insufficient lubrication. Start by pinpointing the fault location based on the sound. Disassemble the back protection plate to reveal the gearbox and identify the source of the "squeak" sound. Upon inspection, if the gearbox lacks sufficient lubrication, evidenced by dried grease and bright gears, the fault is attributed to inadequate oil. Rectify this by replenishing the gearbox with a mixture of the same type of oil and grease. Tighten the screws to restore functionality, and the "squeak" sound should disappear upon restarting the machine, restoring normal sealing operations.
Furthermore, loose, severely worn, or unclean joints of the high-temperature belt, coupled with misalignment with the traction pulley during operation, may also produce a "squeak" sound. To resolve this, replace the high temperature belt with one of the same specification. When replacing the high temperature belt, first compress the spring of the pressure wheel by hand, then install the belt by placing one end on the rubber wheel and holding the other end against the opposite rubber wheel by hand. The inertia of movement should automatically install the high temperature belt. If the "squeak" sound persists and is emitted by the DC parallel excitation motor, it may indicate insufficient oil in the motor bearing. In such cases, remove and lubricate the motor bearing to eliminate the sound.