Leakage During Filling? 90% of Factories Trip on These 5 Points

Leakage During Filling? 90% of Factories Trip on These 5 Points

Lao Zhou runs a sauce processing plant in Foshan, Guangdong, exporting chili sauce and oyster sauce. Last year he installed a new liquid packaging machine, and in the first month he ran into one problem after another — leaking seals.

"I thought it was the film at first. Replaced it three times and still leaking. Turns out the sealing temperature was never set right," Lao Zhou said.

Worse still, leakage didn't just affect product quality — it disrupted the entire production rhythm. Every time a leak was found, the line had to stop for cleanup. In a single shift, that meant 7 to 15 stoppages.

"Crunching the numbers, leakage alone was costing us at least $2,000 a month."

Lao Zhou's story is far from unique. Among the 30+ countries ZSYAN has served, leakage and poor sealing account for over 60% of all after-sales support requests for liquid packaging machines.

The good news? Most of these problems aren't caused by machine quality. They stem from wrong machine selection, incorrect parameter settings, or inadequate daily maintenance. In other words, many of these pitfalls can be avoided entirely.

Pitfall 1: Wrong Film Selection — No Machine Can Compensate

Liquid packaging machines are highly dependent on the right film, yet many factories focus only on machine speed during selection and ignore film compatibility.

Three common mistakes:

First, film heat resistance doesn't match sealing temperature. Liquid packaging machines typically seal at 160-200°C. If you use a composite film with insufficient heat resistance, the seal area can deform or fail to seal properly. When filling pressure changes, liquid seeps through the seal.

Second, film thickness is too low. Some factories choose thinner film to cut costs. Thin film has inherently weaker seal strength, and hydraulic冲击 during liquid filling makes seal cracks more likely. We recommend film thickness of no less than 0.08mm for liquid packaging.

Third, film material is incompatible with the product. Oily products (chili sauce, oyster sauce) need oil-resistant film. Watery products (juice, oral liquids) need moisture-barrier film. Choosing the wrong material affects shelf life at best, and ruins entire batches at worst.

How to avoid it: Always ask your supplier to test with your product and your film before purchase. ZSYAN offers free sample testing — send your product, and within 48 hours you'll get a test report with recommended film specs and sealing parameters.

Pitfall 2: Sealing Temperature Set Arbitrarily

This is by far the most common issue. Many factory operators adjust sealing temperature by feel, thinking "close enough is fine."

But liquid filling pressure and viscosity are completely different from solids. Thick sauces need higher temperature and more pressure at the seal. Thin watery liquids are the opposite — too high a temperature actually squeezes liquid out of the seal area.

Lao Zhou's factory is a textbook case. His chili sauce has high viscosity, but the sealing temperature was initially set to the lower end of the standard range. Result: weak seals, leakage during filling. The ZSYAN tech team diagnosed it remotely and raised the temperature by 15°C. Problem solved.

How to avoid it: Optimal sealing parameters vary significantly by product. Each machine ships with a standard parameter table, but you should fine-tune based on your actual product and film. During your first trial run, record three parameter sets (low, standard, high), evaluate seal quality and appearance, then lock in the best value in the program for future reference.

Pitfall 3: Worn Sealing Roller Goes Unnoticed

The sealing roller is one of the most wear-prone components in a liquid packaging machine. Under long-term high-temperature operation, the silicone pad on the sealing roller gradually hardens and develops grooves, leading to uneven sealing pressure.

Many factories don't check the sealing roller until they're dealing with massive leakage — by then, days of production are already lost.

How to avoid it: The sealing roller silicone pad is a consumable. Inspect it every 3,000 operating hours. Replace immediately if you see hardening or grooves. After replacement, you can lower the sealing temperature by 5-10°C, which extends pad life and reduces film deformation from excessive heat.

Pitfall 4: Residue Crystallization at the Filling Nozzle

After filling powdery or semi-fluid products, residue often remains on the filling nozzle. Over time, this residue crystallizes into hard deposits that prevent the sealing roller from closing completely, causing seal failures.

Lao Zhou's factory encountered this issue and couldn't figure out the cause for weeks. It wasn't until they disassembled the sealing roller that they found it clogged with dried sauce.

How to avoid it: Choose a filling nozzle with an auto-wash function. ZSYAN's SY-LN series liquid packaging machine is equipped with an automatic flushing system. Press one button before product changeover or shutdown, and the system cleans itself. Additionally, run the machine empty for 3-5 seconds after each batch to clear residual liquid from the lines.

Pitfall 5: High Workshop Humidity

Many liquid packaging machines sit in workshops without air conditioning. When summer temperatures exceed 35°C and humidity hits 80%, the film absorbs moisture, significantly reducing seal strength — especially noticeable with powdery and granular products.

While liquid packaging is less affected by humidity than powder packaging, high humidity still causes seal-area stickiness for semi-fluid products like sauces, affecting seal integrity.

How to avoid it: If your workshop lacks dehumidification, install a small industrial dehumidifier near the machine and keep humidity below 60%. Store film rolls in a dry environment and use them soon after opening to minimize moisture exposure.

Quick Reference: 5 Pitfalls at a Glance

If You're Dealing with Leakage Right Now, Do These Three Things

1. Check the sealing roller silicone pad. Remove it and inspect for hardening or grooves. Replace if needed. This is the cheapest and most effective first step.

2. Verify your sealing temperature matches your product viscosity. Thick sauces need higher temperature; thin liquids need lower. Refer to the equipment parameter table and adjust within ±10°C as a starting point.

3. Contact the supplier for remote diagnosis. ZSYAN supports 7x24 video diagnosis via WhatsApp. Send equipment parameters and leakage photos, and a technician will respond within 2 hours.

FAQ

Q1: What are the main causes of leakage in liquid packaging machines? The five most common causes are: wrong film selection, incorrect sealing temperature, worn sealing roller silicone pad, nozzle residue crystallization, and high environmental humidity. Film and temperature issues account for over 70% of all leakage cases.

Q2: How do I know if the sealing temperature is set correctly? Start by checking your product viscosity and film heat resistance. For thick sauces, sealing temperature is typically 180-200°C. For thin watery liquids, 160-170°C is sufficient. During trial runs, record three parameter sets (low, medium, high), evaluate seal quality, and lock in the optimal value.

Q3: How often should the sealing roller silicone pad be replaced? Under normal conditions, inspect every 3,000 operating hours. Replace immediately if the pad shows hardening, discoloration, or grooves. Replacement cost is low (typically a few hundred yuan), but avoiding large-scale leakage saves far more.

Q4: What anti-leakage features does the ZSYAN liquid packaging machine have? The SY-LN series includes auto-flush nozzles, high-precision temperature closed-loop control, servo-driven sealing rollers, and real-time film tension monitoring. ZSYAN also offers free sample testing to help you find the optimal film and parameter combination.

Q5: How do I contact after-sales support for leakage issues? ZSYAN provides 7x24 remote video diagnosis. Send equipment parameters and leakage photos via WhatsApp or email. A technician responds within 2 hours. Spare parts ship from our overseas warehouse within 48 hours.