Design of an Automatic Machine for Sensor Manufacturing by the GoP Technique

Abstract

As the industry advances toward the Advanced Manufacturing process emerges the need for more autonomous machines in order to get more agile and efficient production. Consequently, it creates the need for the development of cheap, easily manufactured and environmentally friendly sensors. Graphite on Paper (GoP) method for producing sensors is a strong candidate as an alternative to the currently available sensors since they meet all the requirements mentioned above. This technique consists of creating graphite layers onto a paper substrate in order to develop a piezoresistive sensor which shows to be suitable as temperature sensors as well as strain gauges with a wide application range, such as in force and temperature control, robotics, agricultural, biomedical engineering, automation, and control systems. Manual pencil-drawing is the simplest way to exfoliate the carbon on the paper; however, this method generates uneven graphite layers on the substrate leading to unexpected results caused mainly by the high variation of the applied force during the manual exfoliation of the carbon films. Aiming to obtain more uniform graphite layers, a machine was developed to fabricate the sensors using a commercial mechanical pencil to apply the graphite on the substrate. The machine mainframe is built in steel in order to achieve robustness. It has three axes moved by two stepper motors and one direct current motor, the latter used together with a load cell and a microcontroller to control the applied force during the material exfoliation.