Metallic cutting inserts fabrication by means of additive manufacturing with fused filament fabrication technology

Abstract

The present work developed a first approach to the manufacturing of turning inserts using the emerging Additive Manufacturing (AM) technology, specifically employing the fused filament fabrication (FFF) process, based on the extrusion of material and deposition layer by layer. Traditionally, this type of cutting tools were manufactured by powder metallurgy and machining processes, but in this instance Additive Manufacturing processes allowed the customisation of the geometries and eliminated the need of dies to manufacture these tools, leading to economic savings. The study analysed, from different perspectives, the viability of these interchangeable inserts as cutting tools. These approaches included qualitative studies of chip formation and cutting-edge wear as well as thermal and roughness analysis of specimens tested under different conditions. The behaviour of H13 Tool Steel cutting inserts on cylindrical specimens of EN AW-2030 aluminium alloy was compared with commercial carbide inserts, being observed that the chip types produced were extremely similar between those obtained by commercial and those from Additive Manufacturing, particularly in dry conditions. The qualitative study of insert wear showed that AM inserts presented overall larger contribution of built-up edge (BUE) and plastic deformation of the tip, with greater incidence at cutting speeds of Vc = 60 m/min and feed rate of fz = 0.1 mm/r. Regarding thermal analysis, the AM inserts revealed a slightly more abrasive behaviour, resulting in a temperature increase throughout the machining process of approximately 70 °C, with no significant influence from the increase in cutting speed. The study of the surface finish offered average roughness results (Ra) of 0.58 µm for commercial inserts, 1.78 µm in AM inserts with dry tests and 2.06 µm in this same type of insert but tested with lubrication. These variations in average roughness were not significant.