Introduction

Welding plastics with high-power diode lasers is currently the subject of a great deal of interest in industry and in research institutions. The technique of transmission welding has now been demonstrated using high-power diode lasers. This produces controllable local heating and melting of a low-melting-point thermoplastic at the interface between transmitting and absorbing layers of thermoplastic materials. Diodes offer a number of advantages for this type of process over conventional solid-state or CO2 lasers namely controllability (temporal and spatial), reliability and ease of automation. Using the full-feature, microprocessor-based F-Package System, the Applications Laboratory has developed a technique for welding small diameter, thin-wall plastic tubes. The advantages of the F-Package System are its small size, low capital cost, electrical efficiency and ease of use. Various laser powers are available from these systems, from 500 milliwatts to 2.5 watts depending on the delivery fiber diameter and selected diode laser engine. This is important as the power required depends on the dimensions of the joint and the welding speed.

As with many laser processes, the main objective is to achieve the desired result with minimum heat input to the part. This note gives guidance on processing parameters for thin-wall tube joints on specific problem materials. It details how the minimum heat input was achieved. This practical approach to tube joining is applicable to many different joints and material combinations.