For linear friction welding one of the components is laterally reciprocated and axially pressed against the stationary component by applying a pre-set friction force. Friction heats up both workpieces in the joint area. After generating sufficient heat, the oscillation is stopped in the central position and the axial force is increased during the forge phase. The plasticised material is expelled from the joint and a flash is generated. The process operates below the melting point in the solid phase and achieves fine-grained welds of exceptionally high quality.

 



The concept of the LinFric® linear friction welding machines was developed by a group of eight European companies. The experiences of each partner have been successfully implemented, and this resulted in a superior machine concept.

In comparison with conventional linear friction welding machines, the benefits of the LinFric® machines are based on an innovative drive unit. The heart of this is a hydraulic oscillator. This vibrates at frequencies of 25-125 Hz and amplitudes of up to ±3 mm. The maximum forge force is 200 kN (20 t) and therefore a cross sectional area of up to 2000 mm2 can be welded.

The hydraulic oscillator also offers the use of nonsinusoidal vibration curves. These can be optimised for the workpiece geometry and the materials to be welded.




The components are clamped on the vibrating and stationary sides by selfcentring hydraulic clamps. These lead to an economic manufacturing cycle due to the short clamping time. By changing the clamping brackets the LinFric® machines can easily be modified for new workpieces.

 




The LinFric® machines have modern PC based control systems providing quality assessment of the actual weld quality by parameter analysis.