Study on Stiffness Specification of Miniature Articulated Robot Arm for Machining System of Microfactory

Machining system using miniature robot arm is proposed to apply for microfactory. Feasibility study about stiffness specifications are carried out, and target specification of robot arm elements are indicated based on leading-design-oriented approach. Cutting load of micro end milling is measured by high response/high resolution sensing system. The cutting load conducts a required stiffness of miniature robot arm. Optimum design problem is solved to get required and sufficient condition of sub-module specifications of the robot, which must be achieved to realize the proposing machining system. Results show that the specific load is about 1300 mN for cutting stainless steel, and tough requirement appears on bearing stiffness. High stiffness bearing system made of tungsten carbide is numerically evaluated and shown to achieve sufficient stiffness. Proposed system will achieve less than 4 μm deflection through stainless steel machining.