Laser welding used a high concentration beam of light on a tiny spot for the area under the laser beams absorbs light and becomes highly energetic. As the powerful laser beams are being used, the electrons in this area are excited to the point of the material melting due to the atoms breaking their bonds with one another. Laser welding can, in turn, be used in joining plastics. The melting of two materials at the seams will fuse them into one joint. It is astonishing ho light can be so powerful to melt metals within seconds. To ensure that there are powerful laser beams, laser welding machines use various parts in amplifying and directing the laser.
Fibre lasers, solid slate lasers and gas lasers are the three standard lasers used in laser welding machines. Usually, the laser beams are supplied to the laser welding equipment using optical fibres. There are multiple fibre welding machines and single fibre welding machines available in the market. The numerous fibre devices have lasers connected to every fibre, with every fibre, the laser strength increases. To concentrate beams to one point before leaving a machine, a collimator lens together with a focusing lens is usually used.
Nowadays, laser plastic welding is replacing the other joining methods like ultrasound welding and glueing in most off the industrial and manufacturing fields. The modern plastic joining processes are very flexible and free of solvents and particles, and it offers high strength connections without damaging or marking the surface. Plastic laser welding is also invaluable when accuracy and precise control is required in protecting the vital interior parts and can be used in successfully welding plastics even when faced with complicated geometries.
Laser welding plastics using laser transmission welding procedure joins two thermoplastic plastics, an absorbing material and a transparent plastic partner. The laser beams penetrate the upper laser treatment surface and melt the lower laser absorbent element, which bonds with the transparent surface. When done correctly, this can create a secure and leak-free weld.
With this kind of overlapping welding, the generated weld on the inside parts of the component releases no particles. It also creates an invisible and optically top-quality weld containing opaque elements. The local heat input with lasers has a little effect on the component; thus, the weld can be formed in the close proximity of electronic devices. Since laser plastic welding creates welds without the requirement for solvents, it reduces the production of industrial wastes and saves cost, making it the perfect green solution for most manufacturers.
There are four core techniques used in laser plastic welding: simultaneous welding, quasi-simultaneous welding, mask welding and contour welding. Contour welding is commonly used for welding large or three-dimensional parts. Contour welding moves lasers in one single pass along welding joints. As for mask welding, the laser welding plastic uses a wide beam which runs over the whole surface being welded, with a shield that guards the areas where welding is not needed. Quasi-simultaneous welding is a technique that uses a small beam that makes several passes over welding joints. Simultaneous welding involves various rays passing simultaneously over welding joints.