Plastic film laser welding technology - the versatile application of CO2

There are many CO laser applications in the packaging industry. This is not surprising, as the materials that are best suited for packaging are also those that are best suited to CO2 laser technology in terms of composition and shape.

In previous articles, we have seen CO2 laser applications on materials such as thermoplastic film, wood, and some of its byproducts such as innovative packaging forms such as MDF, paper, and paperboard. The unique wavelength of the CO2 laser makes cutting, perforating, notching, and marking particularly efficient and cost-effective.

CO2 lasers are an efficient and versatile tool for laser welding of thermoplastics, a technology commonly used in the packaging industry. The process exploits the fact that thermoplastics can be easily processed once they have been heat treated. In layman's terms, the welding process involves heating the area where the two thermoplastic pieces are to be joined with a laser beam until the melting point is reached.

The process can be applied to different types of plastics, whether laminated or molded, opaque or transparent. Laser welding has many advantages:

鈻?amp;nbsp;It is a very fast process鈻?amp;nbsp;Like all laser processes, it is extremely precise and easy to control

鈻?amp;nbsp;It leaves no residue or waste

鈻?amp;nbsp;It does not expose the part to thermal or mechanical stress, as the heating area is localized and the process is non-mechanical

鈻?amp;nbsp;It is highly automated and easily integrated with other systems, both digital and analog

These characteristics make it the tool of choice in industries where precision, cleanliness and the absence of thermal or mechanical stress are decisive factors. The production of biomedical devices or electronic devices, the production of parts for the automotive industry, the production of hermetic packaging for the pharmaceutical and food industries are all examples of laser welding applications.

Laser Welding of Plastic Films

In the packaging sector, laser welding is most often used for laminating thermoplastics. The laser of choice for this technology is a CO2 laser.

Direct welding is the type of welding that is best suited for thin materials. Unlike transmission laser welding, which is mainly used for three-dimensional and molded parts, direct welding is carried out directly on the material. This process allows higher production speeds and therefore increases productivity while reducing production costs.

The most commonly used materials in the packaging industry are:

鈻?Nylon

鈻?amp;nbsp;Polyethylene

鈻?amp;nbsp;Polypropylene

鈻?amp;nbsp;Acrylic (PMMA)

The interaction between the laser beam and the material cannot be determined in advance. Many factors come into play: the type of polymer, the presence of additives added to the formulation, the speed at which the laser beam moves over the surface, and the intensity of the laser beam itself.
But in general, the laser's impact is stronger the closer it is to the surface of the material and weaker the deeper it is. Adding carbon to thermoplastics can significantly increase the material's energy absorption capacity, making the laser more efficient.

Laser welding is ideally suited for producing original packaging that adds value to products, as it can process complex shapes in a very localized way.

Plastic film laser welding equipment

Laser systems for laser welding require different components. The most basic are the laser source, the scan head and the software system for programming and controlling the process.

In addition to the above items, the laser welding system should also include equipment for product management, loading and unloading, and powering the laser source.

In short, due to the wide range of uses of laser technology, laser welding is widely used. It can adapt to a fully digitalized process or integrate with a simulated production line. This technology greatly reduces production costs and not only improves productivity but also improves product quality.