Probability density estimation and local basis function neural networks

Apparatus is provided for welding workpieces in which a first workpiece is secured to a driven shaft and a second workpiece is secured to a freely rotatable shaft. The driven shaft is rotated at a constant speed. The surfaces of the two workpieces to be welded are engaged by an axial force to rotate the second workpiece and accelerate the rotation of the second workpiece to reach the rotational speed of the first workpiece, during which period a weld is completed. Simultaneously, the flash formed at the joint of workpieces during friction welding is removed.