Variable Aggregate Impact Printing of Cob

Abstract

In this article, we present Variable Aggregate Impact Printing (VAIP), a novel additive manufacturing methodology for the automated assembly of traditional cob using a six-axis robotic arm and custom tool. This methodology enables the aggregation of discrete particles composed of soft heterogeneous material containing aggregates of multiple sizes. Single-particle experiments were conducted to optimize particle geometry and study the behaviour of individual soft particles under compression. Multiple particle prototypes were produced to understand the behaviour of soft particle aggregation under sequential compression. Variation in individual block size and aggregate content are accommodated due to the tolerances afforded by the malleability of the blocks. A model for the tolerance of soft particle aggregations is developed for particle positioning and orientation in relation to particle deformation. Finally, a large-scale installation was fabricated as a proof-of-concept prototype for the scalability of natural earth-based materials using computational design and robotic manufacturing technologies.