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.