Experimental Evaluation of Circular Brush Performance Characteristics: Stiffness Response & Contact Zone Geometry

This paper studies the stiffness response and contact zone geometry generated by circular filamentary brushes during orthogonal contact with a flat workpart. The normal and shear stiffness response of the circular filamentary brush while in orthogonal contact with a flat workpart is examined and a strategy for evaluating the planar contact zone geometry generated by the circular brush while in contact with a flat workpiece is identified. With reference to the stiffness response, the experimental set-up used for measuring brush performance characteristics is described. This includes a discussion of the underlying mechanics and signal response characteristics of the experimental apparatus. The stiffness properties and kinetic friction coefficients of the wire brush are determined for a range of rotational speeds and the results compared with a previously developed quasi-static theoretical solution. Finally, the three-dimensional filamentary forces which are developed within the contact zone during brush rotation are examined. In the study of contact zone geometry, relevant parameters which can be used to characterize the contact zone are identified. These parameters are measured for a range of brush operating conditions. The effect of brush width distortion on the contact zone geometry during orthogonal brush-workpart contact is examined. Finally, finite element shape functions are used to evaluate filament tip motion within the contact zone