Advantages and limitations of laser welding technology for semi-crystalline reinforced plastics

Abstract

Selecting semi-crystalline thermoplastics for welded parts strongly depends on the plastic properties, part design, and processing conditions. Infrared/ laser through-transmission welding (TTLW) requires preferential deposition of energy and subsequent melting and diffusion of the material in the interfacial/weld-plane zone. The thermoplastic properties and composition (reinforcements, fillers, additives, pigments, etc.) may influence energy deposition and need to be characterized for optimum material development. Commercial nylon based thermoplastics cover an array of compositions, which may affect the TTLW process. To provide a guide to plastics selection, we evaluated the effect of specific nylon composition factors, such as fiber-glass, mineral, impact modifier content, and color/pigment version on the Near Infra-Red (NIR) transmission characteristics. We have related these findings to the mechanical performance of nylon welded joints in terms of influence of laser welding technology parameters (laser power, welding speed, laser beam spot diameter, clamp pressure, etc.) and thermoplastic composition.Selecting semi-crystalline thermoplastics for welded parts strongly depends on the plastic properties, part design, and processing conditions. Infrared/ laser through-transmission welding (TTLW) requires preferential deposition of energy and subsequent melting and diffusion of the material in the interfacial/weld-plane zone. The thermoplastic properties and composition (reinforcements, fillers, additives, pigments, etc.) may influence energy deposition and need to be characterized for optimum material development. Commercial nylon based thermoplastics cover an array of compositions, which may affect the TTLW process. To provide a guide to plastics selection, we evaluated the effect of specific nylon composition factors, such as fiber-glass, mineral, impact modifier content, and color/pigment version on the Near Infra-Red (NIR) transmission characteristics. We have related these findings to the mechanical performance of nylon welded joints in terms of influence of laser welding technology parameters (laser...