Complexity is not for free: the impact of component complexity on additive manufacturing build time

‘Complexity for free’ has often been claimed as one of the main advantages of additive manufacturing. Several authors have promoted the idea that additive manufacturing allows the fabrication of complex geometries without any increase in the cost of production. Many examples have proven how additive manufacturing can fabricate complex and intricate geometries. However, little attention has been given to the impact that shape complexity has on building time and/or material consumption. This paper explores the effect of shape complexity on part cost in Fused Deposition Modelling and challenges the mainstream assumption that additive manufacturing technologies provide ‘Complexity for free’. A small scale experiment is presented where different shape complexities were produced and their building time and material consumption analysed. The case for the experiment was a load cell holder for a scientific instrument. Four shape types of the holder namely ‘X’, ‘G1’, ‘G2’ and ‘G3’ were compared. The results show how shape complexity increases both building time and material consumption and therefore have a negative impact on part cost. These findings also highlight the need for a revision of the idea of ‘complexity for free’ and in-depth discussion around the concepts of ‘simple’, ‘basic’ and ‘optimal’ design for Fused Deposition Modelling. In addition, other design considerations relating to shape complexity are raised.