Analysis and Discussion on Common Quality Issues in Lamination Process: Key to Enhancing Print Product Quality

Release Date： 2024-06-07 17:27:56 View Count： 1

The lamination process significantly enhances the quality of printed products, rendering them visually appealing, durable, and highly competitive in the market. Currently, our factory extensively applies lamination in the finishing of book covers, product manuals, wine packaging boxes, among other high-end print items. Given its prominence, there is a pressing need to collectively explore and analyze the quality issues that may arise during lamination, as this is pivotal to further refining the lamination technique. Based on my practical experience, I have summarized some common problems encountered during lamination, acknowledging that there may be omissions and welcoming feedback and guidance from fellow professionals.

1.Wrinkling of the Film During Lamination can stem from:

The inherent unevenness or wrinkled nature of BOPP film.

Wave-like edges of the BOPP film.

Imbalance in tension between the roller sets conveying the film.

Excessive glue layer thickness, causing incomplete solvent evaporation and weak adhesion under pressure.

Unequal pressure or different linear speeds at the heat and rubber rollers, causing inconsistent friction.

Overheating of the heat roller leading to wrinkling.

Unequal pressure between the two small rollers (pressure and rubber roller) before the heating roller.

2.Wrinkling of Paper during lamination may result from:

Excessive pressure between the heat and rubber rollers.

High ink coverage after multiple printing passes, causing paper to absorb moisture and become uneven under roller pressure.

Variable humidity in the paper.

High lamination temperature causing paper edge tightness, or "tight edge," where paper edges lose moisture and shrink inward.

Contaminated glue rollers, e.g., with residual glue.

Skewed paper feeding, also leading to wrinkles.

3.Formation of Bubbles during lamination could be due to:

Insufficient drying of the printed material combined with high humidity at the heating roller, creating steam pockets between the film and paper.

Overly hot heating roller causing uneven glue distribution, with some areas inadequately coated or too thin.

Glue residue on the heating roller being pulled apart during the lamination process.

Rapid roller speed resulting in a wet glue layer, which upon lamination, also causes bubbles.

4.Delamination, where the paper separates from the film shortly after lamination, can occur because:

The glue layer is too thin, reducing adhesion strength between the film and paper.

Insufficient pressure between the heat and rubber rollers can also lead to delamination.

5.Paper Curling might be caused by:

Excessive tension when pulling the plastic film, stretching it too much.

Heavy pressure between the heating and rubber rollers, causing the film to stretch more than the paper fibers; upon cooling, the faster shrinkage of the film compared to the paper leads to curling.

In summary, numerous factors influence the quality of laminated products, encompassing aspects of printing, adhesive selection, BOPP film processing, and the lamination technique itself. Addressing both subjective and objective reasons is crucial for achieving optimal and consistent lamination outcomes. It remains a topic worthy of continued exploration and research within the printing industry.

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