Influence of the processing time on the finishing of punched micro holes by planetary stirring with natural sand grains

Micro punching is potentially useful for the mass production of micro features. Punched holes have problems with burrs, debris and pullout fragments left by punching. Planetary stirring is proposed for the finishing of micro features such as punched micro holes. Natural sand is used as the abrasive. The specimen is immersed in sand grains in a bowl that is then put under rotational and orbital movement. No fixture is required to prevent the specimen from collision damages during processing. Initial experiments were conducted. Morphology of the holes was studied using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Results showed that debris was removed, burrs were basically cleared and pullout fragments were substantially eroded. Micron- and submicron-sized particles are produced during finishing. Accumulation of such particles at the micro holes can obstruct the finishing process. It is important that the holes are adequately finished before severe accumulation occurs. © IMechE 2013.