NEWS
HIGH-POWER FIBRE LASER WEAKENS ROCK IN GEOTHERMAL DRILLING
A high-power fibre laser has been successfully tested in field trials for weakening hard rock, in order to improve the efficiency and cost of geothermal drilling. Drilling is used to access geothermal heat – a clean and sustainable energy source. Scientists from the Fraunhofer
Institute for Production Technology IPT have joined forces with partners of the research project ‘LaserJetDrilling’, to develop a method for laser-assisted mechanical drilling of hard rock – a technique that could not only increase the rate of penetration of geothermal drilling, but also help preserve the cutting edge of the drill bit by weakening, and even fracturing, the rock immediately before drilling commences. The scientists developed the
technique by initially setting up a test rig with an ytterbium fibre laser from IPG Photonics with an output power of up to 30kW, which they then used to weaken sandstone, granite and quartzite – all of which are hard rocks with a strength of more than 150 megapascals – by up to 80 per cent. A water-jet was
used to guide the laser beam to the rock face – similar to how an optical fibre is able to guide a laser – which also prevents contamination and damage to the sensitive laser optics, and facilitates the removal of the rock debris by the drilling tool. In the next step, engineers used the laser on the drilling rig in a specially
developed drill string and, in collaboration with the International Geothermal Centre Bochum, tested the new tool under realistic conditions in field trials, which also proved to be a success. In future research projects, the
partners intend to further enhance the distribution of the laser power
and add digital sensors to the hybrid tool, in order to obtain feedback from the drilling process, and be able to react to changes in material along the drilling path. The flexible adjustment of the output power of the laser make it a particularly efficient tool for assisting drilling processes.
Horizon 2020 project to make ultrafast laser processing a hundred times faster
A new €4.7 million Horizon 2020 project aims to make material processing with ultrafast lasers up to a hundred times faster during the next three years. The resulting technology will not only
enable significant progress in the tool making industry, but also open up new perspectives for the application of ultrafast lasers for the texturing and functionalisation of large surfaces. The ‘MultiFlex’ project consortium,
consisting of partners Fraunhofer ILT, Amplitude Systèmes, Lasea, AA Opto-Electronic and RWTH Aachen University, is planning what it says is the next step in the development of ultrafast laser processing technology. Together, they intend to develop a
powerful 1kW laser source that can deliver up to 1mJ pulse energy, either at a regular
6 LASER SYSTEMS EUROPE ISSUE 42 • SPRING 2019
1MHz repetition rate or in a burst mode with less than 20ns pulse separation. This source will then be combined with a special optical system that delivers a pattern of more than 60 switchable beamlets – each beamlet can be turned on and off separately. A fast scanner will then be used to direct the resulting pattern onto a workpiece. The complex system will be complemented by an industry-grade control unit. The partners intend to deliver a prototype
of the new system, which they estimate will improve productivity by approximately 100-fold, compared to current standard ultrafast laser processing systems. This could enable significant progress to be made in the tool-making industry, while also opening up new perspectives for the texturing and functionalisation of large surfaces using ultrafast lasers.
@lasersystemsmag |
www.lasersystemseurope.com
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