High power diode lasers (HPDL) at the level of ? 6 kW are efficient cladding tools in heavy engineering applications where thick (up to 5 mm) wear and corrosion resistant coating layers are required. Large beam geometry makes possible the overlap of thick 20 mm wide cladding tracks side by side without coating defects. Compact size and closed cooling water circulation enable HPDL cladding process to take place also at a site of new or worn high-value machine parts, which have worn in operation or been damaged already during overseas transportation. Instead of moving parts of several tons’ weight, it would be perhaps more cost efficient to transport HPDL cladding unit.

Laser cladding is a surface treatment technology in which thick, dense and metallurgically adhered metallic layers are deposited on various structural steels with relatively low heat input, high accuracy and reproducibility. Laser cladding processes used in industrial cladding are largely based on the use of CO 2 or Nd:YAG lasers. High power diode lasers (HPDL) with rectangular beam spots are regarded as ideal laser sources for laser cladding processes, due to their compact size, high electrical to optical efficiency, easy operation, and low investment and running costs. In laser cladding of large surface areas, the affectivity of the laser cladding process becomes more important, i.e. high laser powers, wide laser beam spots, and high coating material feedrates are regarded as beneficial. In order to optimise the cladding process for such applications, special attention has to be put on devices used to deliver the coating power to the process. In the present work, various parameters in effective HPDL cladding are described and new approaches to optimised HPDL cladding process are described. The performance of a new HPDL cladding powder delivery nozzle will be presented and discussed. Abstract only; no full-text paper available.

The repair and quick geometrical changes of components and tools are currently the most important applications of laser build-up welding. Advanced laser technology permits the integration of the main process steps into one machining center for a very efficient and flexible manufacturing process. The solution presented in this paper consists of a 3axes CNC milling machine, in which a 3 kW Nd: YAG laser, a coaxial powder nozzle, and a digitizing system are integrated. All functions (data processing, laser process, powder feeding, and milling) are controlled by one CNC controller using specially developed software. In the first step the workpiece needs to be adjusted to the machine table. Then the contour of the damaged surface is determined by either an optical or mechanical digitizing system. Using the resulting data, a software system generates automatically the laser build-up strategy and the CNC programs for the laser and the milling processes. After laser free-forming, a raw piece with an oversize of 0.3 to 0.6 mm is made. From this geometry the end contour is milled with an accuracy of some 10 microns. This way the machine produces a completely finished tool.