Introduction:
After continuous and overload work for flow packing machine, will appear some electrical and mechanical issues need to be figure out through commissioning, such as sealing is not strong, the temperature can not be controlled, package deformation and bending, sealing knife cutting generates bubbles or irregular traces, etc.
Based on my experiences, I would like to analyze some common issues, the reason and commissioning tips, also I will provide some maintenance skills at the end of the articles, make sure you won’t miss it, so let’s get started.
Issue 1: Sealig is not strong
It’s the most common issue for flow packing machines, there also have 3 kinds of subproblems.
A. The bag cannot be sealed;
B. The bag is sealed but the sealing not strong enough
C. During the air-tight test, the half seal is strong, another half not, it is still not qualified, the package is easy to leak during the transportation process. This situation often occurs when the composite lining material is OPP.
There Have 3 main resasons to causes subissue A:
Hot sealing temperature is not enough
If OPP is the lining material of the composite bag when the total thickness is 80 ~ 90μm, the hot sealing temperature should be under 170 ~ 180 ℃;
If PE is the lining material of the composite bag, when the total thickness is 85 ~ 100μm, the hot sealing temperature should be under 180 ~ 200 ℃.
As long as the total thickness increased, the hot sealing temperature must be increased as well.
Hot sealing speed is too fast
If the speed is too fast, it’s only has a very short period for melting the film, if the temperature didn’t reach, the sealing will be not strong enough.
Packing film is not qualified
If the corona treatment of composite lining material is not uniform, the effect will not be good, it happens on the sealing and certainly, it can not be sealed. This situation is rare, however, once it occurs, the product is bound to be scrapped.
Therefore, in the color printing and packaging industry, it is the next process to supervise the previous process, and once find the quality problem, the cause must be analyzed and solved at once.
If there are moisture and dirt at the seal, it will also cause the sealing to not strong enough.
In short, to solve the first sealing problem, generally, we can increase the heat sealing temperature, and then reduce the heat sealing speed, adjust the cutting pressure to change a film to test.
There have 2 main reasons to causes subissue B:
Hot sealing temperature is not enough
The problem can be solved by increasing the heat sealing temperature accordingly.
The surface of the hot sealing knife is not flat enough
The hot sealing knife is divided into two pieces: upper and lower, in which a thermocouple is installed to sense the temperature transfer.
There are three screws on the hot sealing knife, the middle screw plays the role of supporting and reinforcing the knife, the other two screws are equipped with pressure springs and shims, mainly used to adjust the pressure of the hot sealing knife.
The upper and lower blades have two springs. The main reason for the uneven surface of the hot sealing knife is that the middle screw is installed at an angle, not horizontal; or the pressure spring of the upper heat sealing knife is uneven.
The solution is to re-calibrate the position of the middle screw to make it in a horizontal state. If the upper and lower heat sealing knives are not balanced, it is to be achieved by adjusting the pressure spring to be moderate.
When letting the spring backward, the heat sealing knife will fall downward; when applying the spring of the lower blade upward to tighten, the heat sealing knife will move upward.
There have 2 main reasons to causes subissue C:
Uneven pressure of heat saealing knife
The surface of the hot sealing knife is not flat enough refer to the corresponding solution for the subproblem B.
Issue 2: The “squeak” sound during operation
The problem appears in the sealing machine operation process, the “squeak” sound often occurs suddenly, followed by uneven sealing speed, resulting in bad sealing lines, it affects package appearance, it can work well Occasionally, but it is erratic.
Most reasons are mechanical damage or severe wear and tear, as well as poor lubrication. First, follow the sound issued to find the fault site. Then remove the back protection plate, found that the “squeak” sound is from the transmission, one by one to remove the screws, found that the transmission grease has dried solid, gears are bright, which indicates that the cause of the problem is a lack of oil. The same type of oil and grease mixed into the gearbox, and tightened the screws to restore, after the start of the “squeak” sound disappeared, sealing normal.
If the joint of the high-temperature belt slack, serious wear, and not clean, the surface of the dirt, the operation process is not synchronized with the traction wheel, sometimes will also make a “squeak” sound.
The solution is to replace the high-temperature belt with the same specification.
Issue 3: The sealing temperature out of control
The problem is shown as the temperature table display problem, can not control the temperature, heat sealing temperature is not constant, the sealing is burnt, or not strong, sealing deformation looks bad.
The main reason for the problem is that the thermometer has broken, must be repaired; also, the thermocouple may be broken, and can not transfer temperature to the thermometer. Replace the thermocouple with the same type and specifications.
The mechanical reason is the uneven pressure of the hot sealing knife, just adjust the pressure spring of the hot sealing knife to make the pressure consistent.
At the same time, the pressure contact surface of the hot sealing knife should be kept clean and free of dirt. Another reason is that the packing film is unqualified, and the hot sealing coefficient changes, resulting in the inconsistent temperature endured.
Issue 4: the sealing bubbles and irregular traces
Although it does not cause leakage of packaging but affects the beauty of the packaging, The causes of this problem are the main equipment used for a long time, high-temperature belts stick to the dust and plastic chips and other dirt, resulting in the high-temperature belt is not smooth, uneven, making the seal unevenly heated,
The solution is to clean or replace the high-temperature belt can solve the problem.
The maintenance tips for flow packing machine
- The flow packing machine should be placed in a ventilation, dry place
- Waste should be removed regularly to keep the whole machine clean. When not in use, it is best to unplug the power and cover it with a cover cloth.
- High-temperature belts should be regularly decontaminated to ensure the quality of sealing.
- Severe wear parts should be replaced in time to extend the life of the machine.
