Friction Stir Welding of High Density Polyethylene

In this report, the progress attained in the Friction Stir Welding (FSW) on polymer
project is depicted, evaluated, and discussed. FSW is a derivative of friction welding
which uses a solid state joining process relying on the conversion of frictional energy
into thermal energy to melt the joint. Two rotational speeds of 1300 rpm and
1400 rpm were used. Other parameters were transverse speed of 10 mm/min, dwell
time of 40 seconds, plunge depth ofl.8 mm, and plunge rate of8 mm/min were kept
constant throughout the project. The effects of FSW on high density polyethylene
(HDPE) were investigated in terms of their tensile and flexural strengths. Due to
very limited studies on FSW techniques on polymeric materials, this project focused
on HDPE. The project started with the construction of proper FSW equipment such
as tooling and clamping device which involved designing and machining. The
preliminary experiments were conducted with several rotation speeds and transverse
rates while other parameters were held constant. Based on the preliminary results,
the transverse rate was kept constant at 10 mmlmin in the finalized experiments.
Tensile and flexural tests were conducted. While the visual welded specimens
showed a promising result, the best tensile strength was 8.9% compared to the
original material. Meanwhile, flexural test was failed due to the root defect. The
condition and location of the welded part examined using optical microscope.