Top 10 common zipper bag failures, finally all found!

Zipper bags are prone to failures, which severely affect packaging results. Shunxingyuan Packaging, a professional flexible packaging manufacturer, provides a detailed analysis of the top 10 common zipper bag failures to help customers with zipper bag ordering needs find quality suppliers.

I. Zipper Bag Bending

1. Poor balance between film tension and zipper tape tension.

(1) Tension of the adjusting roller is too weak.

(2) Zipper tape brake is too tight.

(3) Zipper tape slides poorly.

(4) Zipper flat plate groove is too narrow.

(5) Zipper flat plate slides poorly.

(6) Film slides poorly at the inclined plate/M-plate.

2. Zipper heat sealing temperature is too high.

3. Poor tension of the constant tension adjusting roller for the rubber roller under the zipper.

II. Local Poor Heat Sealing of Zipper Tape

1. Foreign matter (polyethylene residue, dust) mixed in at the zipper heat sealing plate.

2. Teflon surface installed on the zipper frame is damaged or has foreign matter.

3. Teflon surface of the zipper flat plate is damaged or has foreign matter.

4. Zipper flat plate has local damage or deformation.

III. Either end of the zipper tape's heat-sealed part is not sealed or has extremely weak heat-seal strength

1. Zipper tape thickness is unsuitable.

2. Zipper heat sealing plate position and tape are not aligned.

IV. Welding of the Zipper Mating Part

1. Zipper heat sealing temperature is too high.

2. Zipper heat sealing position is off, pressing on the mating part.

3. Affected by preheating due to excessively long waiting time.

V. Tension adjusting roller part is fine, but there is a deviation between the zipper frame edge and the pattern

1. Zipper flat plate position is too low, causing friction between the lower film and the lower heat seal, and the cooling plate. Or affected by preheating from the lower heat seal.

2. The lower rubber roller of the zipper does not grip the film well, causing the film to slip.

3. The position of the upper separation roller for the lower rubber roller of the zipper is not set correctly.

4. Tension of the tension adjusting roller is too low.

VI. Insufficient Mating Strength of the Zipper

1. The inherent mating strength of the original zipper tape is too low.

2. The heat-sealed surface on the opening side/inner bag side of the zipper tape is set incorrectly.

3. The zipper heat sealing temperature is set too high, causing deformation of the mating part, especially the concave part opening up.

4. At the zipper flat plate, there is a deviation between the film flow and the angle of the zipper flat plate, causing the edge of the zipper flat plate to rub against the mating part.

5. The rubber roller presses on the mating part.

6. The edge of the rubber roller groove rubs against the mating part.

7. When making two-lane bags, the film (especially OPP/CPP) shrinks due to heat, and the central flat plate used for two-lane bag making on the zipper flat plate rubs against the mating part.

8. The top cooling plate is too wide, pressing on the mating part.

9. The vertical gap of the lower rubber roller's string is too small, causing the zipper mating part to be pressed too tightly.

VII. Excessive Air Accumulation in Spot Heat Sealing

1. Longitudinal heat sealing temperature is set too high.

2. Longitudinal pressure is too high, pressing the heat-sealed edge into the rubber table.

3. Rubber table is worn or uneven.

4. The width of the cooling plate (upper) is too large, not pressing on the top heat sealing part.

5. In the Teflon roll of the longitudinal heat sealing part, coarse-textured Teflon cloth is used, causing air to be drawn in.

VIII. Excessive Air Accumulation in Transverse Heat Sealing

1. When reinforcing block heat sealing, the heat sealing plate does not press the film down sufficiently.

2. The silicone rubber of the pressure table (especially the upstream side) is concave or has an uneven surface.

3. Coarse-textured Teflon cloth is used on the heat sealing plate and the silicone rubber of the table, causing air to be absorbed into the texture.

IX. Core Remainder or Liquid Leakage in the Pressed Zipper Part

1. The gap of the zipper's spot heat seal is too small.

2. The temperature setting of the zipper's spot heat seal is too low.

X. Separation of Aluminum, Ink, etc. at Spot Heat Sealing and Transverse Heat Sealing

1. Separation is caused by different dissolution speeds of PE or CPP in the soluble layer and the expansion speeds of AL or ink.

2. The countermeasure is to reduce the operating speed to ensure sufficient heat sealing time.

3. Do not apply pressure to the reinforcing block heat seal.

4. When strengthening the block heat sealing, adjust the gap and melt it slowly.

5. Round the edges of the block heat sealing plate to prevent the edges of the expanded AL or ink from being cut.

6. Try to use multi-segment block heat sealing.

7. Use a heat sealing plate and a coarse-textured Teflon cloth for the cooling plate, which is absorbed into the mesh of the fiberglass.

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