Why Is My Premade Pouch Sealing Uneven? Top 3 Causes and How to Fix Them

1. Three Primary Causes of Sealing Misalignment

1.1 Pouch Magazine Misalignment

When the pouch magazine (the component that holds the empty pouches) is not properly adjusted in terms of height or angle, the pouch may shift during pickup and clamping. This leads to a tilted seal.

Solution: Recalibrate the magazine to ensure both ends maintain equal distance from the bag pick-up unit.

1.2 Misaligned Bag Clamping Plate

If the bag clamping plate is mounted at an angle or is uneven, the pouch position becomes skewed, resulting in a misaligned seal.

Solution: Loosen the locking screws and use a level or angle gauge to precisely re-align the plate.

1.3 Welding Defects in the Stainless Steel Clamping Bracket

This is the most critical and technically demanding cause. The clamping plate is mounted on a bracket usually made of 304 stainless steel. If the welding is poorly executed—causing deformation or residual stress—the entire assembly becomes uneven.

2. Professional Engineering Practices:

Reputable manufacturers follow strict welding protocols to ensure structural accuracy:

• Use positioning jigs before welding to avoid warping

• Begin with tack welding to fix position, followed by full weld only after confirming alignment

• Carefully control welding temperature to minimize stress deformation

• Ensure welders have experience with stainless steel, producing clean, uniform welds without porosity or cracks

3. Common But Risky Workaround by Low-End Factories

To avoid complex stainless steel welding, some manufacturers replace 304 stainless steel with aluminum. While this simplifies the build process, it introduces new risks:

        * The air cylinder must be externally mounted, which compromises compactness

        * In powder-heavy environments (protein powder, pharmaceutical plants), exposed cylinders attract dust and fail  more easily

         * Aluminum has lower strength and corrosion resistance, reducing machine lifespan

        For long-term durability and hygiene in dusty workshops, 304 stainless steel + precision welding remains the         superior option.

4. What to Look for in a High-Quality Premade Pouch Packaging Machine

The performance of a premade pouch packaging machine depends not only on its control system but even more on structural accuracy and welding quality. A misaligned structure will affect sealing precision no matter how advanced the electronics are.

At YASHICUN Packaging Machinery, all clamping assemblies are made using laser cutting, fixture-guided welding, and monitored quality control, ensuring export-level structural alignment and sealing accuracy. These machines are ideal for industries with strict dust control requirements.

If you're facing similar sealing issues with your premade pouch packaging machine, feel free to contact our engineering team for technical assistance and structural analysis.
Precision packaging starts with precision engineering.