The idea that 3D printing could be subject to any design rules was seen as heresy in the early days of the additive manufacturing ‘revolution’. An absence of tooling and the ability to create extremely complex forms seemed to suggest that design freedom was only limited by the designer’s imagination. The reality has turned out to be a little different, particularly if cost and waste are an issue, which they should be.
Whilst it is true that many conventional constraints can be ignored, like draft angles and re-entrant features, 3D printing does have inherent limitations that can result in considerable inefficiencies unless they are designed out.
This is made more complicated by the range of technologies that now fall under the banner of 3D printing, and the differences between them. Many processes require support structures to be built to hold up any downward facing surfaces during construction. Others support the parts in a bed of powder as they are built, removing the need for additional structures and allowing the entire build chamber to be used.
Building, removing and finishing support structures uses energy and creates waste. This may not be a big issue if you are making prototypes, but as more production parts are being made with 3D printing, the reduction of waste, and its associated costs, becomes more important.
From a design perspective, the best way to address this apparently high technology problem is to think organically. By thinking of 3D printing as a way of ‘growing’ a part it is possible to make the most of the technologies, particularly metal based processes like DMLS. This approach leads to more natural forms that flow upwards from the base, avoiding downward facing horizontal surfaces (that need supports) and can result in beautiful, lightweight structures, like the one above.
We think 3D printing is new, but bees have been at it for millions of years!