Applicazioni del laser a diodi nel settore manifatturiero

In the last decade, a growing interest toward the application of diode lasers in several industrial fields has been showed up. Such interest has been driven by the lower and decreasing cost of diode laser sources, their higher operational efficiency and longer last, the smaller laser head dimensions as well as the easy connectivity of the laser beam with optical fibres, which simplify the ‘mobility’ of the power source. The development and widespread diffusion of high power diode lasers (HPDLs) has been always related to a parallel pulse in the scientific and technical literature. Several lectures, in which the suitability of the HPDLs in surface treatments, welding, machining of advanced materials and sintering process has been tested, are currently available. Such studies have permitted to go in depth in several aspects concerning basic knowledge as well as applicative issues, allowing the testing of diode laser sources in several fields, which, typically, found their solutions in conventional manufacturing systems and/or in standard laser sources (CO2 e Nd:YAG, mostly). Nonetheless, many problems are still very far to be solved, when tasks like process standardization and/or improvement of end-products performance are considered. Get laser processes, in which surface finishing and morphology of end-products are better, beam absorption improved, treatments more consistent and repeatable, still represent a relevant issue. This is, therefore, the context in which the present work moves to analyze a widespread gamma of potential application of HPDLs: more uniform hardening of low-medium carbon content steel, delaquering and deoxidizing, recycling of CD-R, aesthetic welding of silver alloys. Design of experiment (DOE) technique has always been used. Such technique permitted to better understand the leading phenomena, which rule the interactions laser beam-materials in widespread operational ranges, the physical modelling of the available experimental data. This way, the identification of the best settings of process parameters and the related process windows are easily deducible, thus guaranteeing the maximization of the end-products performance and, concurrently, the reduction of operative time and costs. In particular, from the experimental analysis, diode laser sources can be emphasized as viable systems to: 1. allow hardening of low-medium carbon content steel components, hence guaranteeing the uniformity of the treatment and minimizing operative time and costs; 2. allow, on wide operational ranges, the surface decontamination of different substrates from organic and/or inorganic contaminants (i.e., paints and oxides), whatever their chemical composition, colour and morphology; 3. allow the recycling of polymeric substrates, without inducing any damages or alterations of recovered materials; 4. allow the execution of aesthetic welding even on precious metals with low absorption coefficient and susceptible of remarkable oxidation phenomena.