Design and Construction of a New Automated Device for Testing the Scratch Resistance of Polymeric Materials

Abstract

This paper aims to design and construct of an automated device for testing the scratch resistance of the polymeric materials by measuring the force required to cause a scratch on the surface of polymeric materials as well as calculating the friction coefficient from the input and output of the device. The device was made of materials available in the local market and some parts were manufactured in local mechanical workshops. The device consists of four main parts were mechanical parts, scratching mechanism parts, electrical and electronic parts and the device operating program. The device designed in this work has the following specifications: normal load (0.1 N - 325 N), sliding speed (1 mm/s - 35 mm/s), tangential force measured by the load cell (0.1 N to 294 N), the samples dimensions (length: 10 - 195 mm, width: 10 - 125 mm, and thickness: 0.25 - 50 mm), maximum scratch length of 195 mm, and the height of the indenter from the platform surface (0.25 mm to 50 mm). Scratch test and calculation of the friction coefficient were performed for samples of pure and reinforced PMMA by Silicon Oxide nanoparticles (SiO2). The results showed an increase in scratch resistance and a decrease in the friction coefficient with increasing the weight ratio of SiO2. Also, the ability of the designed device to measure the tangential force required for scratching accurately and quickly and in simple steps.