Common Issues in Automatic Sealing Machines and Their Solutions

Working Principle of Automatic Sealing Machine

Automatic sealing machine is composed of the frame, speed reduction and speed regulation transmission mechanism, sealing and printing mechanism, conveying device, and electrical control system. Its working principle is that when the sealed packaging containing items is placed on the conveyor belt, the sealing part of the bag is automatically sent between the two running sealing belts, which carry it into the heating area. The heat from the heating block is transferred to the sealing part of the bag through the sealing belt, softening the film due to the heat. Then, as it passes through the cooling area, the surface temperature of the film drops appropriately. Subsequently, the printing wheel rolls the sealing part, bonding the upper and lower plastic films and pressing out a mesh pattern (or printing a logo). Then the guided rubber belt and conveyor belt deliver the sealed package out of the machine, completing the sealing operation.

In recent years, with the rapid development of the food, pharmaceutical, and other industries, automatic sealing machines have also ushered in a broad market, with the industry market scale constantly expanding. In the fierce competition, automatic sealing machines are continuously innovating and upgrading, creating more compact structures, more beautiful appearances, and features such as aesthetically pleasing and firm seals, high efficiency, simple operation, and convenient maintenance, bringing economic benefits to users. However, during the use of the equipment, some common faults still cannot be avoided.

Automatic Sealing Machine Faults: Infirm Seals

Infirm seals are one of the common faults of fully automatic sealing machines, mainly caused by three aspects.

• The first reason is that the sealing part of the bag cannot be sealed, which is caused by insufficient heat sealing temperature, too fast heat sealing speed, inappropriate pressure of the cold-pressing rubber wheel, poor quality of the heat sealing film, etc.
  Automatic sealing machine issues are also related to the quality of the heat sealing film. If the composite inner material has uneven corona treatment and poor effect, particularly at the sealing part, it certainly will not seal. This situation is rare, but once it appears, the product will inevitably be scrapped. Therefore, upon discovery of quality problems, timely analysis and resolution are required. If there is moisture or dirt at the sealing part, it will also cause infirm sealing.

  
  To address this fault, the solution mainly involves appropriately increasing the heat sealing temperature, reducing the heat sealing speed, and increasing the pressure of the cold-pressing rubber wheel.

  
  

• The second reason is that under the pressure of the sealing knife, although the bag mouth is sealed, it splits open with slight force or tearing. This issue relates to insufficient heat sealing temperature and the uneven surface of the heat sealing knife. For the former, the problem can be solved by appropriately increasing the heat sealing temperature. The main cause of the latter is misalignment of the middle screw or uneven pressure of the upper heat sealing knife's pressure spring. Corresponding adjustments can easily fix these issues.

  
  

• The third reason is that during the peel test of the sealing part of the automatic sealing machine, the seal shows a half-bonded, half-separated condition. Such packaging bags with imperfect seal quality do not meet standards, as the contents can easily leak during storage and transport due to pressure.

Automatic Sealing Machine Fault: Temperature Gauge Malfunction

This fault is also critical for fully automatic sealing machines. If the temperature gauge fails and cannot control the temperature, it will result in an unstable heat sealing temperature, causing burnt or infirm seals. We recommend that customers check or replace the thermometer, readjust the heat sealing pressure, and replace the heat sealing material.

Automatic Sealing Machine Fault: Intermittent Operation

For unstable operation of the automatic sealing machine, inspect whether the connection between the motor's shaft and the gearbox is loose or detached. If such issues are observed while checking the wear of the motor's carbon brushes, they need to be tightened or replaced.

In addition to understanding and mastering these three common faults and corresponding solutions, users also need to focus on maintenance and care during the downtime of the equipment to ensure the automatic sealing machine equipment maintains a longer lifespan and ensures stable production operation.