System enables efficient laser drilling of rivet holes in CFRP

With a drilling time of less than 10 seconds per hole, the new laser method is now on par with conventional ones.

FIGURE 1. With the laser drilling process developed by LZH, different laminates, even when placed on top of each other, can be drilled quickly and precisely.
FIGURE 1. With the laser drilling process developed by LZH, different laminates, even when placed on top of each other, can be drilled quickly and precisely.
(Photo: CFK Valley e.V.)

Drastically reducing the drilling time per hole for laser-based processes was the outcome of the LaBoKomp project at Laser Zentrum Hannover (LZH; Hannover, Germany). LZH and four partners have developed a laser-based system for drilling rivet holes in composite materials (FIGURE 1), and the LZH scientists tested the laser drilling process and the system on so-called "cargo struts," the C-shaped struts that stabilize the cargo hold floor (FIGURE 2). With a drilling time of less than 10 seconds per hole, the new method is now on par with conventional oneswithout the disadvantage of tool wear or the risk of delamination.FIGURE 2. The laser-based drilling process and the system have been tested on so-called aviation cargo struts.FIGURE 2. The laser-based drilling process and the system have been tested on so-called aviation cargo struts.(Photo: LZH)

The automated process is based on a developed software that enables drilling strategies, which allows parameters to be continuously adjusted during the process. This enables an optimal hole quality that also meets aviation standards. Project partner INVENT GmbH (Braunschweig, Germany) was able to demonstrate that the laser-drilled holes are equivalent to conventional holes. Whole work orders can be programmed by specifying a few variables. The process is continuously monitored by thermography that regulates heat dissipation. 

The system, including a new type of laser from associated partner TRUMPF Laser GmbH (Ditzingen, Germany), was planned and designed in cooperation with KMS Technology Center GmbH (Dresden, Germany), and then put into operation at LZH. The assemblies developed by KMS can be changed flexibly and adapted to different applications. 

The system and the process are suitable for all carbon fiber-reinforced plastic (CFRP) types commonly used in aviation, as well as laminates with glass fiber-reinforced plastic (GFRP) top layers and copper mesh. It is also possible to drill different laminates placed on top of each other. 

The LaBoKomp project, which also involved the company Premium AEROTEC GmbH (Augsburg, Germany), was funded by the Federal Ministry of Education and Research (BMBF) within the scope of the KMU-innovativ: Photonik funding initiative.  

For more information, please visit lzh.de

More in Drilling