Additive Processes

Construction can be described as a mixture of additive process and assembly of components. A big question is whether the layer by layer additive processes found in Rapid Prototyping and Rapid Manufacturing can inspire processes for larger scale automation useful to construction.

Traditionally, the realisation of a component design was costly because of the involvement of man hours for the production of a few bespoke parts. The development of computer aided modelling has allowed designs to be developed faster, particularly when combined with simulation and modelling software. These computer representations of solid 3D objects can be used to control additive manufacturing machines, producing a physical component. These machines reconstruct the 3D object by sequentially bonding ‘2D’ layers of material. The technology’s impact to existing manufacturing has been in the form of waste reduction when compared to machining processes and the elimination of tooling when compared to moulding or casting processes. A useful by-product of this approach is almost unlimited geometrical freedom and that moving parts can be constructed in a single build, negating the need for assembly. Additive manufacturing processes are seeding a revolution in customised, end-use parts, adding value to parts (Wohlers 2004).

Additive manufacturing technologies have been used for construction applications, but have been largely restricted to concept modelling in architecture (Kalay, Skibniewski 2002). There are two notable exceptions: Pegna (1997) considered a layer deposition method suitable for traditional construction materials; Contour Crafting is the first automated layer manufacturing process that has been demonstrated to have the potential for generating large structures directly from digital data (Khoshnevis 2002).