LASER CLEANING
Handheld laser cleaning devices are a popular choice in industry for delivering the beam to the workpiece g
housings, or for cleaning copper wires, hairpins and busbars for contacting. In the aerospace and maritime industries, where the use of chemical solvents is restricted, the large panels and propellers of aircraft and ships can be stripped of paint, vegetation or algae during regular maintenance using lasers. In the oil and gas industry, pipelines can be affected by various kinds of build-ups that must be dealt with to ensure uninterrupted operation. Here, laser cleaning could be performed remotely by automated robots. The technology poses a particular advantage here due to its lack of consumables; only power would need to be supplied to the robots over the long distances involved. In the electronics industry,
typical applications include cleaning the contact areas of plugs and pads, as well as the removal of insulation layers in cables. In addition, before chips are soldered, the component pins must be completely de- oxidised to ensure optimal electrical contact. In the medical industry,
lasers can be used to clean steam steriliser systems,
which themselves are used to clean medical tools at high temperatures. In cleaning the tools, contamination can embed itself into the internal surfaces of the steriliser, staining them and promoting corrosion. Lasers offer a quick and efficient way of removing such embedded contaminants. In the pharmaceutical
industry lasers can be used to
“To ensure user safety during laser cleaning, a suitable fume extraction system must be positioned next to the process”
clean objects such as reactor vessels, agitators, extrusion screws, air treatment systems, storage tanks, tools, moulds, presses, rolls and conveyors. Laser cleaning also plays an
increasing role in restoration, being used to carefully treat stone buildings, statues, monuments and bridges, and also valuable artworks, which can be marred by air pollution, dust or soot particles.
62 LASER SYSTEMS EUROPE THE 2023 GUIDE TO LASER SYSTEMS
What types of laser are used for cleaning? Nanosecond-pulsed fibre lasers operating in the near-infrared wavelength are most commonly used for laser cleaning. Being able to deliver the beam down an optical fibre enables a wide range of integration possibilities from handheld systems to remote, robot- controlled solutions. The short pulse duration minimises the heat-impact on the underlying substrate being cleaned, while the repetition rate and power can be increased to achieve faster processing speeds. Laser systems offering powers from tens of watts to multiple kilowatts are now available, with handheld systems going all the way up to 3kW in power. Less frequently used for cleaning are direct-diode lasers, excimer lasers, CO2
lasers, continuous-
wave lasers and ultrafast lasers. While the majority of cleaning
lasers operate at the standard 1,064nm wavelength of fibre lasers, recently UK firm Woodrow Scientific has been exploring 1,550nm (widely used in autonomous vehicle lidar systems) to develop what it says are ‘retina-safe’ handheld cleaning systems. These devices, which Woodrow
engineers are optimistic will be commercially available by the end of 2023, will have dramatically reduced nominal ocular hazard distances (NOHDs) compared to their 1,064nm counterparts. This means they could potentially be used in an open, occupied space without a safety barrier – only the user will be required to wear safety goggles, according to Woodrow Scientific. To ensure the safety of those in the vicinity of the system, the firm plans to deploy a ‘virtual safety barrier’, enforced for example, using a lidar system that detects when someone steps within the NOHD (approximately 2m) and causes the cleaning laser to shut down. These new ‘retina- safe’ systems have already been proven to effectively remove paint, carbon, oil and grease, as well as clean weld-seams and injection moulds. l
For the latest laser application and technology updates in the field of laser cleaning, visit:
www.lasersystemseurope.com/ applications/cleaning
@LASERSYSTEMSMAG |
WWW.LASERSYSTEMSEUROPE.COM
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