A two-dimensional thermal finite element model of laser transmission welding for T joint

Abstract

Recent years have seen wider application of laser transmission welding (LTW) as a means for joining of plastic components. Advantages of LTW arise from it being a contact-free method for delivering precisely controlled energy to the surfaces of the welded components and from flexibility with regard to welding geometry afforded by the laser being under computer control. LTW involves a laser beam passing through a laser-transparent component being absorbed by the laser-absorbent component at the weld interface. Heat generated at the interface melts a thin layer of plastic in both components and thus forms a joint through molecular interdiffusion. To form a strong bond, it is important that the weld interface is exposed to sufficient heat to melt the polymer without degrading it. Delivery of the thermal energy by the laser beam is affected by process parameters, such as laser power, scan speed, beam spot size, and material properties, such as absorptivity, presence of reinforcements, and other additives. Development of a model for this thermal process capable of accurately predicting the extent of the molten zone in space and over time is vital for in-depth understanding of LTW and its optimization. This article presents a two-dimensional (2D) thermal model of LTW solved with the finite element method. A modified T-like joint geometry is modeled for unreinforced nylon 6 specimens. This thermal model addresses heating and cooling stages in a laser welding process. The 2D model is capable of predicting the molten zone depth as well as transient temperature distribution along the weld line. The molten zone predicted by the model was compared to the one observed from the cross sections of unfilled Nylon 6 modified T-joint specimens welded using a 150 W diode laser.

Finite volume model for laser-soot interaction for a laser transmission welding process

“…27 Figure 6 shows temperature distribution as a function of time near the joint interface ͑at y = 4.2 mm͒, where peak temperature of 287°C is predicted. 27 Figure 6 shows temperature distribution as a function of time near the joint interface ͑at y = 4.2 mm͒, where peak temperature of 287°C is predicted.…”

Laser welding: the first and second law analysis

“…In the light of the previous studies (Melyukov et al, 2006;Miyashita et al, 2005;Mayboudi et al, 2006Mayboudi et al, , 2007Sabbaghzadeh et al, 2007;Bardin et al, 2005;Balasubramanian et al, 2008;Pu et al, 2007;Kim et al, 2003;Dahmen et al, 2000;Zhang et al, 2004;Salminen, 2003;Krasnoperov et al, 2004;Longfield et al, 2007;Casalino and Minutolo, 2004), the present study is carried out to examine laser welding efficiency. The first and second laws of thermodynamics are considered when modelling the thermal efficiencies.…”

“…The modelling of the optimum thermal conditions for laser welding joints of small diameter was carried out by Melyukov et al (2006). The finite element model was introduced for laser transmission welding of a lap-joint by Mayboudi et al (2006Mayboudi et al ( , 2007. Laser welding of dissimilar metals and the boundary element method were examined by Miyashita et al (2005).…”

Molten Depth Modeling of Laser Transmission Welding Based on Temperature Distribution of Moving Point Heat Source

“…The prediction of the morphology and geometry of the molten pool in LTW can help to better understanding of the mechanism and optimization of LTW experiments [4]. Extensive research on the temperature distribution and model of the weld during LTW of polymers has been conducted in previous years [5,6]. In 2009, Taha [7] studied the effect of the clamping pressure on the weld geometry and thermal profile.…”