The effect of vibration on surface finish for semisolid and cast components

One of the failings of die casting and semisolid forming processes is that variable surface quality is a common result. This can reduce the competitiveness of these processes because secondary finishing operations are required, i.e. machining, polishing, plating, etc. Dies that are producing poor surface finishes cannot at the present time be substituted as it is not known what changes have to be made to give the necessary improvements. The authors have recently established that die vibration can be used to polish surfaces as they form during solidification [J. Manuf. Sci. Eng., Trans. ASME (2001), in press]. Evidence in the form of experiments performed on a purpose built rig has established that tangential vibration at certain frequencies and amplitudes influences surface finish. Micrographs combined with Talysurf readings show that die vibration can be used to generate surfaces with a quality significantly superior to that of the die.