Analyse des Laserstrahlabtragens für den wirtschaftlichen Einsatz im Werkzeug- und Formenbau (Volume 3) (English shop)

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In an increasingly globalised competitive environment, German companies in the tool and mould making sector in particular depend on sustainably strengthening their strategic positioning as technology leaders. The highly demanding manufacture of tool moulds is conventionally carried out by means of process chains in which die-sinking EDM and milling are used in more than 75 % of cases. A promising alternative to this is wear-free laser ablation. The enormous potential of this optical technology makes it possible to pursue targeted and interdisciplinary machine development within the field of tension of often contradictory requirements and to tailor it to potential fields of application in tool and mould making. To this end, a weighted map of target parameters comprising the categories process quality, process throughput time and process costs was developed within the scope of the present work by means of an empirical survey. Following an approach based on the SIX SIGMA methodology and its phases of definition, measurement, analysis and optimisation, laser systems based on Q-switched Nd:YAG and Nd:vanadate laser beam sources in the ns pulse duration range were investigated with regard to the above-mentioned target parameters.

In examining the target parameter of process quality, the critical randomly induced process deviations in particular were investigated in numerical and analytical models, differentiated according to spatial plane. On this basis, scenarios for a process-capable application were developed, characterised among other things by stable pulse crater shapes and diameters.

The process throughput time was investigated on the basis of experimental cavities as well as an industrial case study. While the main processing time depends among other factors on the ablation volume, the ancillary time is an influencing variable that depends strongly on the cavity geometry. With a pulse repetition frequency of f = 100 kHz, increased by a factor of 2 to 3 compared with the state of the art, 75 % of the component spectrum investigated can be manufactured in a shorter main processing time than is possible with die-sinking EDM. The process cost analysis revealed cost advantages of laser ablation particularly in the case of high preparation or tooling costs for the conventional processes as well as high annual utilisation times and short machining times for laser ablation.

In a concluding methodology supported by Quality Function Deployment, the technical characteristics for a holistic optimisation of laser ablation were identified, as were the conflicts arising between target parameters.