Common Problems and Solutions for Laminating Machines

Laminating machines can be divided into two categories: wet lamination machines and dry lamination machines. They are special equipment used for laminating paper, cardboard, and mounting. The process involves pressing the rubber roller and heating roller together to create a laminated product.

What should you do when your laminating machine encounters problems? What are the common faults of laminating machines? These are questions that users of laminating machines often ask. Today, I have summarized some common problems and their solutions. Let's take a look!

1. Curling of laminated products

The main reasons for this issue are as follows:

- The printed material is too thin: Avoid laminating thin paper as much as possible.

- Imbalanced tension: Adjust the tension of the film to achieve balance.

- Excessive composite pressure: Reduce the pressure appropriately.

- High temperature: Lower the composite temperature.

- Excessive film tension: Excessive tension on the film causes elongation and deformation. After cutting and releasing external force, the film will return to its original state, causing the product to bend towards the film side. The solution is to adjust the tension tightening screw depth and reduce the braking force.

- Excessive winding tension: Excessive winding tension causes both the film and the printed material to deform, but the degree of deformation is different. After the external force is released, the product will bend towards the paper side, especially for thin paper. The solution is to reduce the friction of the winding tension wheel.

- High humidity: Laminated products with high moisture content will cause deformation towards the paper side after sufficient drying, due to paper dehydration. The solution is to control the workshop humidity.

- Short drying time: If the drying time is too short, the laminated product will not dry sufficiently and will bend. The solution is to extend the drying time.

2. Snowflakes on the product

- Excessive powder spraying on printed materials: Excessive powder spraying cannot be completely dissolved by the adhesive, resulting in large snowflakes on the laminated product. In this case, increase the amount of adhesive or remove the powder on the printed material before lamination.

- Insufficient adhesive amount: Insufficient adhesive amount will cause snowflakes on the entire surface of the printed material. The solution is to increase the coating amount of adhesive.

- Improper pressure on the pressure roller: Excessive pressure on the pressure roller will squeeze out the adhesive on the edge of the printed material, resulting in snowflakes on the edge. Insufficient pressure will also cause snowflakes. The solution is to correctly adjust the pressure of the pressure roller.

- Dry adhesive on the adhesive roller: The area with dry adhesive on the adhesive roller will have a smaller adhesive amount, causing snowflakes on the laminated product. The solution is to clean the adhesive roller.

- Adhesive rings on the pressure roller: Adhesive squeezed out from the edge of the printed material or the film holes will stick to the pressure roller and form dry adhesive rings over time. When laminating subsequent printed materials, small snowflakes will appear in these areas. The solution is to clean the pressure roller in a timely manner.

- Impurities in the adhesive: If there is too much dust in the surrounding environment or if there are dry adhesive skins and film fragments in the adhesive, snowflakes will appear on the laminated product. Therefore, pay special attention to environmental cleanliness. Unused adhesive should be sealed in the adhesive bucket, or filtered before coating.

3. Bubbles on the product

- The ink layer of the printed material is not fully dried: Heat press the material first and then apply adhesive, or postpone the lamination date to allow complete drying.

- The ink layer of the printed material is too thick: It can be appropriately reduced.

4. Wrinkles on the laminated product

The main reasons for wrinkles on the laminated product are an unbalanced transfer roller for the film, inconsistent tension at both ends of the film, wave-like edges, excessive adhesive layer thickness, unevenness of the electric heating roller and rubber roller at both ends, inconsistent pressure, and unequal line speeds. To solve this, adjust the transfer roller to a balanced state, use thinner film, adjust the adhesive amount, improve the drying temperature, adjust the position and technical parameters of the electric heating roller and rubber roller.

5. Insufficient bonding at overlapping areas

This phenomenon mainly occurs in thick paper laminations. When the thick paper is wound, it undergoes a certain degree of bending and deformation, which becomes more evident when the winding radius is smaller. Laminated products that have just passed through the pressure roller and have not entirely dried are often opened at the overlapping areas where the paper is bent, resulting in insufficient bonding in those areas. To improve the laminating product rate, it is advisable to minimize the width of the overlap to ensure that the width of inadequate bonding is within the die-cutting range.

6. Poor adhesion of the product

- Inappropriate selection of adhesive, improper setting of adhesive amount, measurement and ratio: Choose the right adhesive brand and coating amount, and accurately measure and mix the adhesive.

- Poor surface condition of the printed material: Excessive powder spraying, excessive ink layer thickness, ink not fully dried, etc., can cause poor adhesion. Gently wipe away the powder or increase the adhesive coating amount, pressure, or use heat press before lamination, or use adhesive with higher solid content, thicker adhesive coating, or higher drying temperature.

7. Uneven coating

Uneven thickness of plastic film, too low composite pressure, loose film, adhesive solidification causing swelling or deformation of the roller in the adhesive tank, can cause uneven coating. After the problem occurs, quickly identify the cause and take corresponding measures, such as adjusting traction force, increasing composite pressure, replacing film, roller, or adhesive.

8. Product turning black

This mainly occurs on large area printing and hot stamped products. This is due to a chemical reaction between chemically active elements in the adhesive and gold powder. The solution is to use special gold ink or special adhesive, laminate before hot stamping,