Design and Construction of a Low-Force Stylus Probe for On-machine Tool Cutting Edge Measurement

A new on-machine profiler employing a cantilever beam was proposed and developed to measure the sharp micro-cutting edges of precision cutting tools with low measuring force of 0.1 mN. The proposed profiler consists of a probe unit and a positioning unit. The probe unit employs a stylus mounted on the free end of a hollow triangular cantilever beam and a laser displacement sensor to detect the deflection of the cantilever beam. The positioning unit consists of two single-axis DC servo motor stages for precise positioning of the probe unit. The cantilever is designed with the assistance of the finite element method. In order to demonstrate the feasibility of the proposed measurement system, experiments are conducted and the measurement result for a micro-cutting edge is compared with that by a commercial profiler. Furthermore, a method to compensate for the measurement error caused by the lateral displacement of the cantilever beam is proposed. The compensated measurement results show good agreement within ± 2 μm with those obtained by the commercial profiler.