An Investigation of Thin Film Coating for Evaluation Friction Coefficient Using Ring Compression Test

This research aims to investigate the types of thin film coating for the evaluation of coefficient of friction using ring compression test. Ring compression test was used to evaluate the coefficient of friction of contact between die coating surface and workpiece material, brass grade C3771. Specimen was machined by CNC to the standard size with ratio of the outer diameter [25.4mm] to inner diameter [12.7mm] and thickness [8.5 mm] is 6:3:2. The dies were made from tool steel grade JIS SKD11 hardened to 60±2HRC then polished die surface at Ra= 0:07 to0:09 microns. Tool surface conditions selected for this research were non-coated, PVD coated DLC, AlCrN, TiCN and TiAlN.The Experiments were carried without lubricant. Experiments were reduced height of the specimen at 50 percent. It was found that Non coated condition had shown lower coefficient of friction than DLC, AlCrN, TiAlN and TiCN due to influence of surface roughness. Furthermore, thin film coated die had shown durable and high resistance scratch of die surface more than non coated die.