Machinability of 3D printed peek reinforced with short carbon fiber

Abstract

The new manufacturing technologies are advancing and developing rapidly, gradually causing some conventional processes used until now to become obsolete or relegated to second place. One of the challenges of emerging manufacturing processes is sustainability, decreasing raw materials and recycling used components. Additive manufacturing is among these new technologies, allowing the fabrication of complex geometries and the reduction of waste by producing parts close to their commissioning (i.e., net-shape or near-net-shape manufacturing) and the recycling of used components to develop raw material. One of the most widely used thermoplastic materials in manufacturing is polyether ether ketone (PEEK), mainly due to its good mechanical properties. The use of fibers as a means of reinforcement in polymeric materials has witnessed a significant surge in recent times to enhance mechanical properties. Recycling these fibers from other components after service life, giving a second life to these materials, would have a high impact in terms of sustainability. CFRPs have been widely used in different sectors in the last decades, providing a source of carbon fibers suitable for use as polymer reinforcement in additive manufacturing. Processing operations are often necessary to reach dimensional and joining (e.g., assembly) specifications. Despite its widespread use in the industry requiring certain postprocessing operations, just a few publications analyze the machinability of PEEK polymer. The addition of carbon fiber reinforcement influences the machinability of the polymer. This study uses orthogonal cutting tests to focus on the machinability of 3D printed PEEK with and without short carbon fiber reinforcement through orthogonal cutting tests. The additive process procedure is analyzed in terms of printing orientations. The effect of machining parameters (cutting speed and the depth of cut) on the force generation, the superficial damage, and the temperature reached in the samples are also analyzed and related with the addition of reinforcement.