Having worked in our packaging machine factory for so many years, I often hear customers feedback a question: "Why is the heat seal effect sometimes good and sometimes bad when changing packaging materials for the same equipment?" In fact, this is mostly because the heat seal pressure is not adjusted properly! Today, let's talk about the "love-hate relationship" between packaging machine heat seal adjustment and material adaptability. Heat seal pressure does not match? The material immediately "gets angry"! Our packaging machine operators all know that heat seal pressure is like "stamping" the material - if the pressure is too small, the seal is not firm and it is easy to leak; if the pressure is too large, it may press through the film or cause the edge to deform. Especially when encountering packaging films of different materials, such as PE, PP, and aluminum foil composite films, the "sense of proportion" of heat seal adjustment is particularly critical. Last month, our factory encountered a typical case: when the customer used the same packaging machine to switch between the production of puffed food and frozen products, the sealing strength was always below standard. The technical team found that the frozen packaging film was 0.1mm thicker than the ordinary PE film, but the heat sealing pressure was still set according to the original parameters. As a result, the pressure distribution was uneven, resulting in partial cracking of the edge. Later, by recalibrating the heat sealing adjustment mechanism of the packaging machine, the pressure value was increased by 15%, and the problem was solved.
Three steps to solve "materials are not compliant" Get to know the details of the materials :
For each batch of new materials entering the workshop, we will first measure the thickness, melting point and temperature resistance. For example, aluminum foil composite film usually requires higher temperature but lower pressure, while single-layer PE film has to increase pressure compensation elasticity.
Dynamic adjustment test machine :
Don't rush to mass production after starting the machine! First use scraps for heat sealing test. Our factory's habit is "three observations": observe whether the sealing pattern is uniform, whether there is stratification in the tear test, and whether the sealing line width is stable.
Equipment Collaborative Optimization:
The heat seal adjustment of the packaging machine cannot only look at the pressure gauge! Temperature, speed and pressure must be "three-pronged". For example, when dealing with high-barrier materials, we will simultaneously reduce the heat seal speed to allow the material to be fully heated, and then with moderate pressure, the sealing strength will be directly improved to a higher level.
Customer on-site practice: One adjustment solves a thousand worries
Last year, I went to a food factory in the northwest to do equipment maintenance. Their packaging machine heat seal always had "shark tooth" burrs. I was amused when I saw it on site - the operator used the same set of heat seal parameters for all materials to save trouble!
I took them to recalibrate on the spot:
First, use a thickness gauge to confirm that the material thickness error does not exceed ±5%
Adjust the temperature of the heating block according to the melting point of the material (for example, the melting point of PP film is about 20℃ higher than that of PE)
Finally, fine-tune the pressure cylinder of the packaging machine's heat seal adjustment mechanism to evenly distribute the pressing force on the sealing line
After adjustment, I tested 50 packages and the seal was as smooth as a knife cut. The customer gave a thumbs up: "We should have taken care of the pressure and temperature together!"
Daily maintenance tips
Want to make the packaging machine's heat seal adjustment more "obedient"? Remember these three points:
Clean the pressing surface every week: debris or colloid residue will make the pressure "false", wipe the heating block with alcohol cotton, the effect will be immediate
Check the cylinder pressure every month: don't wait for the pressure gauge pointer to shake like "Parkinson" before taking action, the air pressure value fluctuates by more than 10% and needs to be repaired
Replace the sealing gasket every quarter: the aging of the silicone pad will cause uneven pressure distribution, which is the invisible killer of wrinkling of the sealing line.
