Laser equipment has been widely used nowadays, especially metal laser cutting machines , which have a very good performance in processing various metal materials, and can accurately process metal sheet metal into different shapes. The application of this technology to aviation materials has attracted many aviation manufacturing companies.
The rotator parts and transmission of the aeronautical fuselage are forged from large metal billets. The fuselage also contains some forged materials. Most of the fuselage is made of aluminum. Generally, 7000 series zinc-based aluminum alloys are used for processing because the alloy has good static strength and fatigue strength. Although the 7000 series aluminum materials are well suited for aerospace applications, they are not resistant to high temperatures. Rapid heating, such as welding and laser cutting, can cause microcracks. Microcracks cause a reduction in fatigue strength. Welding and laser cutting are two types of processes that produce thermally induced microcracks.
Quality and process control are critical. Any process that brings uncertainties to processing must be controlled or eliminated directly. In the past, laser cutting posed a huge challenge to quality control and consistency between different production batches.
In current laser cutting systems, the limitations of these laser cutting in aerospace applications have been improved. These limitations include problems of reduced fatigue performance and reduced consistency in the manufacturing process. Laser systems now greatly reduce the size of the heat-affected zone (HAZ) and the corresponding micro-cracks. In the laser cutting process, technicians can already control the cutting parameters, and use the calculator software to repeat accurately. These technological advances make people rethink whether laser cutting is suitable for the production of fuselage structures. The fuselage structure is mainly made of 7000 series aluminum materials.
Fatigue fractures usually occur in places where stress is concentrated, such as edges of parts, changes in geometry, or joints. There are many different ways to join fuselage parts made of sheet metal, and most fatigue cracks occur at the joint. If the laser is not used to cut small holes in the joint, the laser is mainly used for edge cutting of parts. For other effects, the most vulnerable connection position can be used to explain the micro-cracks caused by laser cutting compared with the connection, which are not the main damage sites. In this way, we can conclude that if a part is likely to break at the joint, the laser cutting technology will not further damage the fatigue characteristics of the part.
The laser cutting process can process consistent parts faster, and it is more efficient than traditional machining. Laser technology is expected to reduce processing time and production costs. For a long time, in the processing of 7000 series aluminum plates, the advantages of lasers have not been brought into play due to the decline in fatigue performance. Recent innovations in laser systems have led to a re-evaluation of the benefits of laser cutting aluminum for aviation. Preliminary tests have shown the potential of laser technology in fuselage processing. Future fuselage systems and existing designs should not exclude possible applications of lasers in this fuselage system due to past experience. We should keep an open mind to analyze various situations to determine whether laser technology can bring product benefits.