Laser welding: It's not just for metals anymore

Various welding techniques using diode lasers for joining and welding thermoplastics are presented. Through-transmission infrared welding (TTIR) of thermoplastics is a process whereby laser light in the range from 800 to 1064 nm wavelength passes through a top part and is absorbed by bottom part or a laser absorbent layer between two parts. Spot or contour welding refers to the use of a circular spot of laser energy to transverse a preprogrammed contour path and create a weld or bond. Line welding refers to the use of a laser line for welding with typical weld line dimensions at 1 to 2 mm wide that can vary up to 120 mm in length. Simultaneous line welding utilizes one or more laser lines to produce a weld along a part's contour, and has short cycle time required for completing a weld. Mask welding utilizes the same transmission welding principles as the contour but incorporates the use of a mask to block the transmission of the laser line as the line is scanned over the part.