In liquid packaging production, leakage is almost unavoidable, but frequent occurrences indicate a problem somewhere in the process, not "normal loss." Many factories repeatedly adjust equipment parameters and even question the quality of the equipment when leakage occurs. However, practical experience shows that most problems lie not in the liquid sachet filling machine itself but in mismatched process details.
Truly stable packaging relies not on luck, but on meticulous control of every single detail.
The seal is not secure
Inadequate sealing is the most common problem, but also the easiest to misjudge. Many operators habitually increase the temperature as soon as a leak occurs, believing that "a hotter seal means a stronger seal." However, there is a reasonable range for heat sealing. If the temperature is too low, the heat-sealing layer will not fully fuse, resulting in a "fake seal"; if the temperature is too high, it may damage the material structure, causing the seal to become brittle and more prone to cracking.
More importantly, sealing quality depends not only on temperature but also on whether the pressure is uniform and whether the sealing time is sufficient. If the equipment speed is increased, but the sealing time is not adjusted accordingly, even if the temperature is correct, the seal may not be strong. Therefore, sealing problems are essentially a comprehensive matching of temperature, pressure, and time, not a problem of a single parameter.
Liquid contamination sealing area
Many people inspecting equipment will say, "The sealing area is clean," but in actual production, liquid contamination often occurs in a very short time, such as micro-splashes during filling, liquid rebound, or tiny droplets brought out by bursting air bubbles. These contaminants are difficult to detect with the naked eye but are enough to damage the heat seal.
This problem is especially common with low-viscosity liquids (such as water and alcohol) or easily foaming products (such as shampoos and detergents). Once a very thin liquid film adheres to the sealing area, a "false seal" is formed; it appears sealed on the surface, but cracks easily under slight pressure. Instead of simply strengthening the seal, it's better to control the filling process at its source, such as optimizing the filling nozzle structure, controlling the filling height, or adding anti-drip measures.
Filling method mismatch
Many people focus on the sealing process but overlook its impact on the sealing process itself. In reality, different liquids require different filling control methods. Aqueous liquids are prone to splashing and backflow, necessitating rapid cutting and anti-drip designs; while viscous liquids are prone to stringing, and if not handled properly, can be carried into the sealing area.
If the filling system isn't tailored to the product's characteristics, problems such as dripping, liquid residue, or insufficient backflow can easily occur. These issues ultimately affect the sealing quality. Truly stable production requires the synergy of the filling and sealing processes, rather than optimizing them independently.
Liquid leakage in packaging may appear to be a sealing issue, but it's fundamentally a systemic problem. Defects in any step-sealing parameters, packaging material selection, filling method, equipment status, and operational management-can lead to ultimate failure.
Instead of repeatedly tweaking a single parameter, it's more effective to focus on the overall logic: ensuring every step functions correctly is the key to truly stable production.
