Friction welding is common practice to join different metals
and thermoplastics in automotive manufacturing industries. The
technique involves the plastic displacement and fusion of joint material without
going into melting state usually by applying frictional heat and pressure. Heat
is generated by sliding a spinning work piece against a stationary one which in
turn is used to fuse the joint material while the application of pressure on
lateral sides helps to make a joint firm. There are different frictional welding techniques which are being used to weld a wide range of metals and thermoplastics with different
working principles. Right below, are some of those apparatus and methods that
must be known by future welders.
Frictional Welding Techniques to Weld Metal
How to weld different metals by using friction welding? There
are three techniques viz: Linear Friction Welding, Spin friction Welding and
Friction Surfacing.
1.
Spin Friction Welding Technique
In this technique
work pieces are clamped in two supports, one of which is stationary and the
other one is spinning. The spinning piece is allowed to rotate along with the
mechanically rotated device called flywheel which assists prolonged rotation in later
stage by storing the rotational energy. As the rotating component achieves the required spinning
rate, motor is switched off but the component keeps on spinning due to stored
rotational energy in the flywheel. At that moment both pieces are brought
together with applied pressure until the weld stiffens and spinning action stops.
As flywheel works on the basis of high moment of inertia and that is why this technique is also known as
inertial friction welding technique.
2.
Linear Friction Welding Technique
This technique is same like spin technique excepting the
linear oscillation rather than the use of spinning movement. Under the applied
pressure, moving piece is allowed to oscillate relatively with the stationary
piece in the form of sine wave. The lateral force is acted along the axis of oscillation until the weld sets.
3.
Friction Surfacing Technique
It is another solid state welding technique, in which a rod
with special coating is allowed to rotate on the substrate to deposit a
plasticized weld layer on it. In this process the deposited layer is
homogeneous, having the same composition of consumable rod, because no dilution
of substrate base metal occurs. Moreover this technique is cost effective and
can be applied to eliminate high cost operations.
Friction Welding Techniques to Weld Thermoplastics
Similarly there are some friction welding techniques to weld
thermoplastic materials viz: Linear Vibration Welding and Orbital Welding.
1.
Vibrational Friction Welding Technique
In vibrational welding process, components are brought in
contact under pressure. The components are then allowed to vibrate perpendicular
to pressure applied in such a way that sliding action takes place against each
other. As a result joint is fused with the help of frictional heat along with
the lateral forces.
2.
Orbital Friction Welding Technique
In Orbital Friction Welding, the components are allowed to
rotate in a small size orbit, against each other. After attaining the required
heat, the orbiting faces of components are brought to one axis by applying more
pressure.
Friction Stir Welding
Another type which has a wide range of applications in
welding industry is Friction Stir Welding Process in which a non-consumable
spinning tool is traveled across the joint to produce weld. See more about
Friction Stir welding Process.