Ball Tips of Micro/Nano Probing Systems:A Review

To satisfy the measuring demands for the micro components of the industry, micro/nano probing systems with various ball tips have been developed. However, most of them cannot be used to measure the real micro geometrical features high precisely because the parameters of the ball tips are not appropriate. The ball tips with a diameter of less than 100 μm, a sphericity and eccentricity of far less than 1 μm are required urgently. A review on the state-of-the-art of ball tips of micro/nano probing systems is presented. The material characteristics and geometric parameters of now available ball tips are introduced sepa- rately. The existing fabrication methods for the ball tips are demonstrated and summarized. The ball tips＇ future trends, which are smaller diameter, better sphericity and smaller eccentricity, are proposed in view of the practical requirements of high-precision measurement for micro geometrical features. Some challenges have to be faced in future, such as the promotion and high-precision measurement for the small ball tip＇s sphericity and eccentricity. Fusion method without the gravity effect when the molten ball tip solidifying is a more suitable way to fabricate a small diameter ball tip together with a shaft.

On-Line Measurement Method for Diameter and Roundness Error of Balls

This paper presents an on-line measurement method for the diameter and roundness error of balls.An easy-installation rotary scanning system,which integrates the principles of the diameter and the roundness measurements,is constructed.The rotary scanning system consists of a rotary stage,a linear stage,and two sensors with a什at probe.Two sensors are initially installed on the linear stage and contact each other.The outputs of two sensors are reset to zero at first.The ball is then mounted on the rotary stage and positioned between two flat probes.The variations of the diameter and the roundness error of the ball at each angular position can be directly recorded by two sensors when the ball is rotated by the rotary stage.Substituting the outputs of two sensors into the proposed mathematical models,the diameter and roundness error can be evaluated.The effects of the alignment error induced by the spindle error of the rotary stage and the titling error and the eccentric error of the ball on the measurement accuracy can be self-separated in the proposed on-line measurement method.A series of experiments are carried out to verify the effectiveness and the capability of the proposed on-line measurement method and the designed rotary scanning system.The designed system is easy to construct both in the laboratory environment and the factory field.