Microwave welding of HDPE using impedance matching system

Microwave welding of HDPE has been demonstrated using multi-mode microwave system. Although the maximum joint strength equals the strength of HDPE, th e heating time was relatively long, 80 seconds. There are several methods w hich can reduce the heating time such as using a higher power, more lossy h eating composite, or increasing the power transfer efficiency. Increasing t he 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 hea ting element is impossible. In this study, a new microwave system which pro vides more stable and narrow band signal for all operating power levels is used. Also, an impedance matching technique is used to improve the energy t ransfer efficiency which reduces the input power dramatically. It enables r educing the polyaniline concentration in heating elements from 60% to 5% wi th good joint quality. Due to the increase in energy transfer, the welding time is also reduced dramatically.