Influence of raster angle on tensile properties of FDM additively manufactured plates made from carbon reinforced PET-G material

Abstract

Tensile properties of thin plate specimens made from short carbon fiber reinforced PET-G material are experimentally evaluated for various raster angles (printing directions). In additive manufacturing (AM), raster angle is recognized as one of the key printing parameters which strongly influences the strength and stiffness of the final part. The relatively high average value of ultimate tensile strength was obtained for specimens printed with the 0° raster angle, compared to the value obtained for specimens printed with the 90° raster angle - 52.2 MPa and 25.4 MPa, respectively. Similarly, noticeably higher average value of modulus of elasticity was obtained for specimens printed with the 0° raster angle, compared to the value obtained for specimens printed with the 90° raster angle - 4752 MPa and 1569 MPa, respectively. Scanning electron microscopy (SEM) was used for analysis of specimens’ fracture surfaces. SEM images revealed considerable volume fraction of voids (porosity). Тhe porosity, together with weak bonding between two adjacent rasters, could be one of key factors for poor tensile properties of samples printed with rasters perpendicular to direction of load application (90° raster angle).

Keywords

• additive manufacturing
• raster angle
• strength
• stiffness
• carbon fibers