Composite materials such as carbon fibre reinforced plastics (CFRP) are ideal for lightweight construction and are used in automotive and aircraft construction, among other things. To simplify the processing of CFRP and sandwich materials, scientists at the LZH, together with INVENT GmbH and KMS Technology Center GmbH, have developed an innovative process and associated system design.
Simultaneous drilling of small diameters
In the process, a laser beam is split into partial beams using specially designed diffractive optical elements so that it strikes the material at several locations and several holes are created simultaneously. Ideally, this can be done with up to 25 partial beams, so that the drilling time is only a 25th of the original time and thus less than a tenth of a second per hole - a value that cannot be achieved with conventional methods, even for larger holes.
Using this process, the scientists were able to drill holes with a diameter of just 1.2 mm to 0.25 mm. This makes them smaller than holes that can currently be realised using conventional mechanical processes in sandwich and CFRP materials. Thanks to the use of optomechanics manufactured by KMS Technology Center GmbH, the process also enables a high degree of flexibility in terms of hole diameter and hole pattern without the need to change tools.
Sound insulation in lightweight construction as an area of application
Laser micro drilling is of interest to the aviation industry, for example. To reduce noise emissions from aircraft, sound-insulating panelling elements are used to line engines, for example. Such components are often made from CFRP or CFRP sandwich materials and then provided with a large number of small holes over a large area.
Laser micro-drilling is particularly suitable for these so-called acoustic holes, as laser drilling is contactless and therefore force-free and wear-free. This eliminates high costs due to tool wear and quality problems caused by blunt drills. In acoustic tests, the sound absorption properties of the laser-drilled sandwich panels were evaluated as very good by the project partner INVENT GmbH.
About miBoS
The project ‘Micro-drilling of sandwich materials: Development of a laser process’ (miBoS) is funded by the Federal Ministry for Economic Affairs and Climate Protection under the funding code 20T1926C.