Manufacturing with novel high-power diode lasers

Direct applications of high-power diode lasers (HPDLs) like hardening, heat conduction welding of metals, and joining of polymers have already been de monstrated also in the industrial environment. Relatively low intensities i n the range of 10(3) Wcm(-2) are sufficient for these applications. While t he commercial HPDL systems are built on the basis of diode laser bars with 40 W output power, in the meantime a record continuous-wave-output power of 267 W per bar has been demonstrated. The achievable higher output power pe r bar will lead to enhanced applicability of HPDLs and thus to a further st eep increase of their industrial use. Improved packaging technology, multip lexing the emission of single bars and coherent coupling as well as promisi ng new diode laser structures like Z-shaped broad area emitters, is discuss ed. In this paper, emphasis is laid on the potential applicability of comme rcial HPDLs for metal working with elevated intensities up to 10(5) Wcm(-2) , like oxygen cutting and the worldwide first deep-penetration HPDL-weld up to a sheet thickness of 6 mm in stainless steel. These results have been p redicted by proper theoretical modeling. Strong reduction of phase space di mension takes place in convective-diffusive-type free boundary problems typ ical for thermal processing. This property makes it possible to construct a pproximate finite-dimensional dynamical systems being solvable with control led error. Numerical solutions of the full problem are used to investigate the quality of the approximate model. Observable quantities of the technica l processes like signals from monitoring devices are part of the solution a nd solutions to the inverse problem are given.