Inspecting manufacturing precision of 3D printed concrete parts based on geometric dimensioning and tolerancing

The additive manufacture of parts using extrusion-based techniques such as 3D Concrete Printing (3DCP) offers an alternative to traditional moulding processes. The precision to which the desired shape can be produced, however, is limited by the extrusion process and layer thickness, exacerbated by the deformation that occurs in the wet material during manufacture. Quantifying manufacturing precision is a critical part of defining process capability and quality control procedures, but this has yet to be explored for these technologies. To address this, this paper presents the problem of evaluating the geometrical precision of manufactured parts and then proposes an approach based on geometric dimensioning and tolerancing (GD&T), commonly used in manufacturing. This is then applied in a case study in order to demonstrate the application of the technique for understanding and defining process capability, to enable more effective design rules that lead to greater confidence in the viability of part designs, and to provide the reliable performance metrics necessary for process improvement and control. The work concludes that the outlook for such techniques is positive and that the application will be beneficial in the future development of quality control procedures for 3DCP.