Analytical design and finite element analysis of a microgripper for characterizing a single microcapsule

Abstract

The typical technique of hardness testing of pharmaceutical microcapsules uses pressure transducer-based bulky devices by averaging mechanism. This not only produces non-precise results but also causes wastage of costly core material present in the microcapsules. To overcome these issues a miniaturized version of the device using a micro electromechanical system (MEMS)-based microgripper has been proposed, which can mechanically characterize a single microcapsule of sizes ranging from 5 µm to 20 µm with a maximum rupture force of 13.33 mN. The proposed microgripper consists of a hybrid chevron thermal actuator and integrated capacitive force sensor and has been designed using standard silicon-on-insulator multi-user MEMS processes with a device size of 2.5 × 3.2 mm2. The microgripper is efficiently modelled to produce a temperature gradient of about 350 °C from the actuator to the jaws making it able to handle temperature-sensitive samples.