Mechanical Strength of Thermoplastic Polyamide Welded by Nd:YAG Laser

Abstract

Welding is a fundamental process in many industries. It is a fast-changing technology, continuously evolving, with recent developments in laser and robotic welding, virtual reality and machine learning. Focusing on laser welding, there is a significant interest in this technology, as well as an increasing demand for high-strength lightweight structures, replacing metals in some applications. This work presents an experimental study of the mechanical properties of three types of polyamide 6 joints welded by Nd:YAG laser. After welding, tensile tests were carried out in order to evaluate the influence of the joint type and weld passes on joint strength and weld stresses. The results showed that fairly high weld stresses could be achieved, indicating that good-quality welds were achieved.

Laser Welding of Transmitting High-Performance Engineering Thermoplastics

“…The specimens failed within the gauge length ( Figure 4). The average tensile strength was 74.93 MPa, which is similar to the value obtained in [28] and the value reported by the manufacturer [32]. The yield stress also lies within the ranges (45-80 MPa) reported by the manufacturer.…”

“…However, the results from the tensile tests revealed a joint always weaker than the base material. In a previous work, the white and black variants of Ertalon 6 SA were successfully weld [28]. Nevertheless, the joint strength was also inferior than the tensile strength of the base material.…”

“…It has an average maximum power of 300 W and a peak pulse power of 12 kW. It has already been used to carry out other welding studies, from high-strength steels to dissimilar alloys [33,34], as well as to weld the two versions (white and black) of the material herein studied [28]. This machine makes it possible to set parameters such as the laser power, pulse duration, and frequency, percentage of overlapping between beams, and also their diameter.…”

“…Additionally, polyamide can absorb and reflect a considerable portion of laser energy without additives, presenting good optical properties and very good welding characteristics. This material had already been used by the authors in a previous work, where the influence of pulsed laser on the mechanical characteristics of welded PA6 joints was studied [28]. Laser processing of PA has been also employed for additive manufacturing.…”

Mode I Fracture Toughness of Polyamide and Alumide Samples obtained by Selective Laser Sintering Additive Process

“…Commonly, SLS technology uses the energy of a laser beam in addition to an electrical heating source in order to generate a high enough temperature for particle bonding. Due to the large number of process variables that have to be controlled during the process, some variations of shape, size and mechanical properties of the finite product may occur not only in SLS but also in all additive manufacturing (AM) technologies [4][5][6]. The SLS process variables include chamber temperature, laser energy density, layer thickness, beam offset, shrinkage at cooling, part position and orientation, material type and powder degradation [7].…”