There has been an increasing demand for fabricating miniature components in recent years. The application of micro parts in different fields, such as lab-on-chips, micro sensors and actuators, and biomedical implants, resulted in the development of various micro manufacturing methods. Micro mechanical machining is one of the newly developed techniques that has several benefits over conventional micro fabrication methods. Unlike in conventional photolithographic methods, micro mechanical machining can provide the required flexibility to fabricate complex 3D geometries out of different engineering materials utilizing miniature end mills. However, chatter instability is a major challenge in the development and commercialization of the micro milling operation. Chatter is a self-excited vibration that causes rough surface finish and dimensional inaccuracy. Although chatter in macro machining has been studied very well in past decades, the effect of micro milling forces, such as process damping and ploughing on chatter, have not been investigated yet. In order to investigate the chatter in high speed micro milling processes, this research extends current macro milling chatter models with the latest micro milling processes. Several contributions to the chatter investigation in micro milling operation are presented in this research. The effect of process damping to increase the stability at lower rotational speeds is investigated. Also the ploughing forces are considered on the chatter stability model in micro milling. Due to very high rotational speeds in micro milling operation, the dynamics and cutting coefficients are not constant. In order to tackle changing parameters, the robust chatter stability is developed which is based on the edge theorem to suppress chatter vibrations. The experimental tests have been performed to support the proposed model and simulation results.