A Lean-based Production Approach for Shotcrete 3D Printed Concrete Components

Additive Manufacturing allows for high geometric freedom and the fabrication of non-standard building components. This new-found flexibility results from the fact that no formwork is required with additive manufacturing and thus each part can be different at no additional cost. One drawback however is that the geometric freedom comes at the price of non-verified geometric precision, requiring methods to determine and possibly counteract deviations and ensure building component's quality. Within this paper we present an "Lean-based Production Approach" for an off-site production of concrete components. Therefore, firstly lean construction is introduced and its synergies with additive manufacturing are shown. Shotcrete 3D Printing is used as a case study and illustrates the approach and unveils current potentials and challenges. Our approach is mainly based on an on demand production, bi-directional digital workflows and quality checks. Current methods for geometric and surface quality as well as for predicting production (and process) times for varying components still need to be developed further. We conclude with forecasting a new and more intelligent production system in construction.