Twenty Years of Laser Plastic Welding
The engineers of the then LaserQuipment AG, a spin-off of Bayerisches Laserzentrum in Nuremberg-Erlangen, laid the groundwork for laser plastic welding. At that time – just like now at LPKF – they developed and produced laser systems for joining injection-molded parts. Production services for laser plastic welding have also been a field of activity since then. Initially received with hesitation in the market, laser-welded plastics are widely used today in medical technology, consumer electronics – and in every recently built car. No one wants to do without compact and lightweight, yet stable, control devices such as parking sensors anymore.
In laser transmission welding, two components are welded together. They differ slightly in their material properties: one of the parts is transparent to the laser wavelength used and the other absorbs the laser energy. The heat that arises locally in the absorbing part during the process is transferred through a slight mechanical pressure applied to the second part, which results in both parts melting at the weld seam – and a reliable joint with the same strength as the parent material. Many different plastics with various geometries can be welded in this way. (Fig. 1)
In the early days of the company, relatively small welding heads for line integration in the automotive industry were the focus of developments (Fig. 2). They were supplemented by complete systems for standalone operation. Various welding methods became dominant for different application fields. For example, cylindrical bodies are joined with radial welding systems, whereas large 3D parts are welded using a special, patented LPKF method. “Hybrid welding” is LPKF’s name for a method using multiaxis robots to enable fast and flexible processes. (Fig. 3) In addition, with LPKF systems, even transparent plastics can be laser-welded.
With the systems, which have been developed and optimized over the years as expertise has been gained, the most diverse of components – large or small, with wide or narrow weld seams, exhibiting simple or complex geometries – can be joined without any problems. Today, extensive automation of the laser machines is just as natural as easy-to-use hardware and software that ensure the traceability of individual production steps are. As a result, the welded products even meet the exacting requirements in the automotive and medical technology industries.
Simon Reiser, on board as Managing Director since 2019, is proud of his employees’ achievements. “There are now over 1,200 LPKF systems for laser plastic welding in use on all continents of the world; more than 3,000 different processes are carried out with these systems. In the automotive industry, nearly every OEM supplier is using LPKF systems.” (Fig. 4)
He also sees many opportunities for the future. “The still-growing plastics market is changing and is still searching for solutions, for example, for the further treatment of recycled plastics or new materials. LPKF is working on innovative solutions for this, too, so that the advantages of laser technology – cleanliness and joining without chemicals or chip formation – over other joining technologies can continue to be used in as many application areas as possible.”