Leister sees itself as a process specialist and, as such, develops special optics as well as special welding processes. The contact pressure or physical contact between the components in the welding plane has a major impact on the welding seam quality. In applications where a piece of film is to be welded flat onto a component, the contact pressure must be even across this surface. This is very difficult to achieve with conventional clamping concepts. That is why Leister has developed a hyperbaric chamber in which the film is pressed onto the surface by air pressure. In this way, the film can fill in any cavities, leading to even welding results.
Special optics are another area dealt with by Leister. Our Optics Team has the necessary experience and equipment to carry out complex optical calculations, and to design and produce the optics concerned. Diffractive optical elements (DOE) for shaping beams are just one part of this extensive sphere of activities.
The Development Team and Application department are constantly endeavoring to optimize welding processes. The laser welding of transparent materials poses a particular challenge in this respect. We use the heat conduction technique to weld transparent films. Two transparent films are positioned on top of one another on a laser-absorbing surface. The radiation penetrates both films and heats the surface. This then melts the bottom film thoroughly until the surface of the top film starts to melt as well. The films are then joined together by applying external pressure.