Micro-Parts Feeding by a Saw-tooth Surface: Derivation of Feeding Dynamics of Micro-Parts

This paper describes dynamic analysis of micro-parts feeding using a saw-tooth surface. We have proposed a unidirectional feeding using a saw-tooth surface with simple planar and symmetric vibration. Unidirectional feeding is realized by different contact conditions along positive and negative directions. We need to consider not only the inertial force but also the adhesion force when micro-parts are tens or hundreds micrometer in their size. The adhesion forces change according to the contact condition between the micro-parts and the feeder surface. We propose two formulations of contact conditions. The first approach introduces directional friction coefficients. The second approach introduces the identification of adhesion force by estimating the maximum static friction of a micro-part on a fabricated surface. We formulate a dynamics model when the contact condition is defined as directional friction coefficients. Then we identify parameters in the model by conducting feeding experiments with various driving condition of the feeder. We analyze the driving force that changes according to the relative position between the micro-part and the saw-tooth. We derive a dynamics model including the adhesion force. We conduct numerical simulations using the derived model. We then compare the simulation results and feeding experiments with various elevation angles of saw-tooth surface to verify the proposed dynamics model.