Microwave Welding of HDPE Using Impedance Matching System

Abstract

Microwave welding of HDPE has been demonstrated using multi-mode microwave system. Although the maximumrjoint strength equals the strength of HDPE, the heating time was relatively long, 80 seconds. There are several methods which can reduce the heating time such as using a higher power, more lossy heating composite, or increasing the power transfer efficiency. Increasing the input power for welding of HDPE using a single mode microwave system has also been demonstrated which reduced the heating time to 20 seconds using 60% PANI/HDPE composites and 2400 watts. The maximum joint strength is 97% of the bulk HDPE strength. However, welding of HDPE using 10% PANI/HDPE heating element is impossible. In this study, a new microwave system which provides more stable and narrow band signal for all operating power levels is used. Also, an impedance matching technique is used to improve the energy transfer efficiency which reduces the input power dramatically. It enables reducing the polyaniline concentration in heating elements from 60% to ⁵% with good joint quality. Due to the increase in energy transfer, the welding time is also reduced dramatically.