Sequential Exposure Digital Light Processing (sDLP) 3D Printing for Hierarchical Microstructure Tactile Sensors Enabling Ultra High-Sensitivity, Multiaxial Forces Detection and Low Cross-Talk

This paper reports a novel method for fabricating hierarchical microstructure tactile sensors using sequential exposure Digital Light Processing (sDLP) 3D printing. Unlike traditional layer-by-layer 3D printing, this requires only two UV light exposures. Two-step include rapidly printing a flexible TPU resin as a transducer and selectively printing CNT resin active layer, all within minutes. The tactile sensor shows high sensitivity, up to 10.000 kPa⁻¹. It can sustain up to 2500 cycles and operates reliably at frequencies from 0.6Hz to 2Hz, with a response time of 90ms at 0.6kPa. The multiaxial forces tactile sensor can be created to detect bending and horizontal forces, making them suitable for wearable devices in gesture and texture recognition. Our scalable approach can produce a 3x3 sensor array in one step process and performed low crosstalk <0.1%.