Lasers are used in a variety of applications in the field of material removal, with a range of machines suited to each process distributed by Raymax Applications in Australia.
Laser systems offer two general processes for material removal. One widely used process occurs during manufacturing for the production of new products that require micromachining. The other refers to a removal of surface congestion or contamination in a large industrial environment. For either process, the team at Raymax are able to provide expert advice, installation and on-going support.
Precision material removal in the production of medical products can be carried out with an excimer laser produced by the OPTEC/LASEA Group, a Belgium-based company that works with some of the largest medical manufacturers in Europe. OPTEC excimer lasers are used to manufacture components for electrophysiology (EP) because they can strip or ablate wire as thin as a human hair. Nitinol wire, an amalgam of nickel and titanium that is highly elastic with excellent shape memory, is initially manufactured with a transparent plastic coating.
A suitable laser is used in the micro-machining process to cut away the insulative coverage without damaging the nitinol wire. In procedures for cariology or neurology, the recipient organ is accessed using a nitinol guidewire via the vascular system to insert a catheter to clear the blockage and then insert a stent. Stents are also made with nitinol wire after the ablation or material removal process.
A second micro-machining material removal application using high-precision lasers is laser ablation of thin layers. This is particularly useful with semiconductor devices that continue to ‘shrink’ in size. Through the combination of the latest generation of femtosecond lasers and ultraprecise scanners with a high dynamic range, excellent quality and rapid ablation are achieved with no spatter.
LASEA lasers can ablate material over a narrow thickness and in a highly localised ad selective way. Called ‘decoating’, it occurs by vaporising or subliming a layer without damaging the underlying layer. Controlling the energy is critical to this process, so as not to damage the substrate at all, and where thicknesses vary, to optimise the energy per pulse to lessen the impact. This process improves the quality and the rate of production in fields such as solar cell production, OLEDs and microelectronics.
Precision material removal can be applied to other sectors including vehicle manufacturing by ablating the metal layer covering windscreens to access electronic sensors; and in the jewellery sector – lasers can ablate the thin layer on a watch face ready for chemical etching, and even create internal or external patterns or designs on containers used in the cosmetic industry by ablating the glass.
An industrial application that has recently been tested and confirmed is the use of blue diode lasers for the removal of biofouling on ship hulls and other metal sub-sea structures. This new use of a blue diode laser has only become possible due to advances in conversion efficiency and optical output power developed by the German laser company Laserline. Commenced in 2019 and funded by the German government, the research project FoulLas – ‘Fouling removal of maritime surfaces using laser radiation underwater’ – was undertaken on the North Sea island of Helgoland, to find a more environmentally-friendly process than the toxic effects of biocide coatings applied to ship hulls. A solution is timely, as restrictions on the use of biocide coatings have increased.
Operators of ships and offshore facilities are doing all they can to get rid of these unwanted organisms or to ensure they do not settle in the first place. Currently used as a preventive measure, biocidal antifouling coatings have been applied either to prevent the growth of vegetation or to destroy the cell structures of adhering organisms. However, due to their toxic effect on other aquatic organisms, only a few biocides have been approved, and even these will completely be banned in the foreseeable future.
One biocide-free alternative is in silicone-based antifouling coatings that create a particularly smooth surface structure. An alternative removal method is mechanical cleaning by diving teams, which is expensive and time-consuming. Mechanical cleaning by diving crews releases numerous marine organisms, which then migrate unwantedly into the local ecosystems; as a result, mechanical ship cleaning has been banned in many ports. Experience shows that these measures have only had limited success, coatings appear to simply delay colonisation. Organisms colonise quickly and in large quantities, so that even when coatings are used, a considerable amount of new biofouling growth occurs within a very short time. Additionally, marine organisms have developed highly effective strategies for adhering to surfaces – their attachment is almost as robust as industrial adhesive bindings.
To find a better removal solution for this unwanted material and prevent further growth of aquatic organisms, the FoulLas research team applied an effective process using the more powerful diode laser sources of the blue spectral range developed by Laserline. With more than 2kW of blue laser power, an underwater irradiation technique was used to damage the cell structures of marine organisms that had settled on a ships’ hull. Once damaged, the marine growth matter is washed away by the current, resulting in a far more eco-sensitive process.
Today it is possible to apply lasers for material removal across a range of manufacturing processes and in product maintenance. Precision material removal using micro-processing has already been adopted by both the medical sector and the electronics industry. The high power of blue diode lasers has been proven an indispensable tool for maintenance of sub-sea structures and the hulls of ships. These examples show just how effective laser systems can be in everyday usage for material removal.