Fiber laser welding of AA 5754 in the double lap-joint configuration: process development, mechanical characterization,
- PDF / 4,162,300 Bytes
- 15 Pages / 595.276 x 790.866 pts Page_size
- 88 Downloads / 217 Views
ORIGINAL ARTICLE
Fiber laser welding of AA 5754 in the double lap-joint configuration: process development, mechanical characterization, and monitoring Matteo Garavaglia 1 & Ali Gökhan Demir 1
&
Stefano Zarini 2 & Brian M. Victor 3 & Barbara Previtali 1
Received: 22 April 2020 / Accepted: 20 September 2020 / Published online: 15 October 2020 # The Author(s) 2020
Abstract Aluminum alloys are widely spread in many industrial sectors due to their desirable characteristics as low density, good formability, high specific strength, and good resistance to corrosion. Autogenous laser welding is a technology that enables the use of these materials in the industrial process due to its high repeatability, reliability, and ease of automatization. In particular, in automotive applications, Al-alloys are welded in lap-joint configurations with more than 2 layers of material. The welding condition should be monitored in order to detect the complete penetration, hence guaranteeing the appropriate weld resistance. The use of non-invasive and coaxial monitoring solutions is highly desirable for the identification of weld defects during the process. This study investigates an autogenous laser welding process and monitoring in the double lap-joint configuration of sheets of AA 5754. First, the process parameters are investigated to identify the geometrical and mechanical characteristics of the resultant welding seams at different process conditions. The employed high-brilliance 3 kW fiber laser provided the possibility of reading the back-reflected light signal from an internal photodiode. The capability of this signal to be used as a non-invasive, coaxial, and remote monitoring system in order to predict the process outcome was tested. In the experiments the back-reflected light intensity could be correlated to the weld seam width at the second interface, as well as the strength of the joint to shear. Finally, the monitoring signal behavior was demonstrated under simulated weld defect conditions. The results show that weld anomalies such as lack of penetration, misalignment, and gap formation can be sensed through the monitoring approach. Keywords Autogenous keyhole welding . Automotive . Body in white . Shear strength . Back reflection
1 Introduction The relevance of aluminum alloys in industrial applications has grown in the last years due to the necessity of lightweight design of mechanical components. In particular, in the automotive sector electric vehicles are gaining importance [1], and aluminum alloys are the first choice as lightweight materials for many components like car bodies and batteries casings [2–5]. Concerning the assembly of aluminum alloy components, laser beam welding has become an established solution
* Ali Gökhan Demir [email protected] 1
Department of Mechanical Engineering, Politecnico di Milano, Via La Masa 1, 20156 Milan, Italy
2
Optoprim S.r.l., Via Carlo Rota 37, 20900 Monza, Italy
3
nLight, Inc., 5408 NE 88th Street, Building E, Vancouver, WA 98665, USA
in the industry. Indeed, the hi
Data Loading...
