What Should Be Done If Air Bubbles Appear On A Wide-format Laminator?

Wide width laminating machines is widely used in advertising printing, sheet metal processing, printing packaging and other industries, mainly for laminating and protective processing of large size materials. In the daily production process, the most common quality fault is the appearance of bubbles in laminated products. The size and distribution of bubbles are not uniform, not only affect the product appearance smoothness, but also lead to problems of warping, decolletage and moisture deformation in the later stage, which directly reduces the product yield rate. The problem of large film bubble is not caused by a single factor, but is divided into four main categories: equipment failure, operation process, material problems and environmental factors. Targeted inspection and rectification can effectively solve the problem. Here's a more detailed look at why and how to treat it.

1, Equipment malfunction causes bubbles and solutions.
The abnormal state of the equipment is the core hardware cause of bubble forming in wide film, which is mainly concentrated in three core parts: rubber roller, pressure and temperature control. First, there's the laminated rubber roller. rubber roller surface wear, aging, uneven, adhere to dirt and impurities, resulting in uneven roller surface pressure distribution. During laminating, the material does not bond well, and residual air in the gap forms bubbles. At the same time, the the deformation rubber roller and the unevenness of the left and right sides will result in uneven stress of the wide material, easy to appear large areas of loose bubbles.
To solve this problem, you need to regularly clean the surface of the rubber roller, use a professional cleaner to remove any remaining glue, dust and impurities, polish and repair minor abrasions, and replace aging and deformed rubber rollers in a timely manner. Secondly, the abnormal laminating pressure is the main cause of large air bubbles, because the overall pressure is too low and the pressure is not uniform from side to side, making it difficult to completely excrete the air between the membrane material and the substrate. To adjust the pressure step by step according to the equipment standard, ensure that the pressure on the left and right sides of the rubber roller is uniform, and the force on the middle and edge of the wide material is uniform. The pressure should be completely adherent and should not wrinkle or blister.
Finally, the temperature control system malfunctioned. If the temperature is too low, will lead to layered adhesive layer melting, resulting in poor sealing, forming bubbles; too high temperature, will lead to membrane material stretching deformation, resulting in layered adhesive bubbles, forming hollow bubbles. The temperature control parameters of the equipment need to be calibrated and temperature adjusted according to the material of the film to ensure accurate temperature control and uniform heating.

2, Improper operation process, resulting in bubbles and solutions.
Improper debugging and non-standard operation operators are the main human-caused factors of frequent bubble problems in production. Broad-spectrum film coating requires extremely high feeding speed and feeding method. If the feed speed is too fast, the bonding speed between the film material and the substrate will be greater than the exhaust speed. If the air isnot expelled in time, a group of bubbles can accumulate and form, fluctuating at a high rate and jamming the material, causing local air to become trapped and forming irregular bubbles.
In daily operations, follow the principle of low speed and smoothness. When debugging a new machine or replacing a production material, the film coating is first tested at a low speed to ensure a smooth, bubble-free exhaust, then adjusted at a constant speed to maintain the feed steady throughout the process. At the same time, if the feed is not aligned, the prestack material is uneven, the substrate wrinkles, offset, will also envelop a large amount of air, creating bubbles. Before operation, the substrate should be laid flat and aligned with the feed reference to ensure that the film material is parallel to and adheres to the substrate and to prevent dislocation and wrinkling during feed. In addition, the finished product shall be inspected in a timely manner after the film coating has been completed. If small bubbles are found, they can be vented and repaired at high temperatures using a special scraper. Large areas area bubbles need to be recoated.

3. Material problems and solutions for bubble formation.
Quality of the film and substrate itself can also cause the bubbles in the film coating to fail. On the laminated film material one hand, poor quality, uneven thickness, uneven the colloidal coating, poor tensile properties and adhesion, easy to produce bonding gaps and bubbles during the laminating process; if the film material is stored for too long, it will become damp and degenerate, adhesive layer failure, may also appear poor adhesion, blistering, decolonizing, etc. To use qualified and compliant film materials, classified storage, moisture and dust, to prevent the use of expired, damaged, inferior quality film materials.
On the other hand, the nonconformity of the substrate surface is also a key factor. Dust, particles, stains, moisture, impurities, moisture on the surface of a wide plate, spray paint, etc., will form bubbles and white spots after lamination. Prior to operation, the substrate surface must be thoroughly cleaned to ensure that the substrate is clean, dry, flat, free of dust, water and oil stains, and that impurities and bubbles are avoided at source. At the same time, it is necessary to prune uneven, damaged and deformed substrates in advance to avoid bubbles due to inadequate adhesion.

4. Environmental factors causing bubbles and preventive measures.
Film film coating processing requires high production environment, high humidity, excessive dust and large temperature difference will cause film bubbles. The air humidity in the workshop is high, and the substrate and membrane have the adsorption effect on water vapor. After coating, they are sealed in a the interlayer and condense into bubbles; dust flies in the workshop and particles cling to the material's surface, creating bubble-like points after coating.
Daily production needs to control workshop environment, keep the site dry and ventilated, maintain humidity within the standard range, reduce cladding or turn on dehumidification equipment in wet and humid weather, clean workshop environment regularly, keep the work area clean and reduce dust adhesion. At the same time, avoid working in the environment with excessive temperature difference to prevent thermal expansion and shrinkage of the film material, prevent abnormal curing of the adhesive layer, and prevent the occurrence of adhesion bubbles.

5, Summary and daily prevention points
In conclusion, there are four main reasons for bubble formation in wide film laminating machines: equipment, process, material and environment. The core solution is "smoothness of exhaust, tight cooperation, material compliance and environmental compliance." In daily production, the equipment should be cleaned and maintained regularly, the pressure and temperature should be adjusted accurately, the operating process of film coating should be regulated, material quality and substrate cleaning should be strictly controlled, and the production environment should be optimized. Pre-treatment of various tasks can greatly reduce bubble faults and improve the flatness, aesthetics and yield of wide-film products.