Dimensional Accuracy of Extrusion-Based 3D Printing

The so-called Screw Extrusion Additive Manufacturing (SEAM) is a new technology for printing polymer materials developed by the Fraunhofer Institute for Machine Tools and Forming Technology (IWU). The SEAM technology provides a very high material output of up to 7 kg/h and the motion kinematics allow very high speeds of up to 1 m/s. The nozzle head enables the generation of variable strand widths between 1 and 3.5 mm, thus allowing overhangs of up to 65 degrees without support structure. In comparison to conventional additive manufacturing processes larger series applications are expected [1]. The aim of the paper is to examine the quality of printed components. The effects of various printing parameters like melting temperature, layer height, screw speed and material moisture are investigated on the dimensional stability of demonstration components. For this purpose, 150 mm high components made of polyamide 6 with 40% carbon-fibre reinforcement and a strand width of 2.5 mm were manufactured with parameter changes and measured regarding to their dimensional accuracy.