manufacturing free form architecture

1. Manufacturing Free Form Architecture Presented By: Sally Salah Elnaggar

2. Introduction Most architects are missing one of the greatest opportunities of the computer revolution. Cars and aircraft are now entirely designed, analyzed, and tested in a digital environment. Buildings have this same potential. Already in a few research environments, technologies borrowed from industrial design are being put to use in forming scale models and full-scale building components.

3. A New Design and Manufacturing Paradigm Over the past fifteen years, computer-aided design and manufacturing (CAD/CAM) has emerged in fields other than building design and construction. This paradigm has been enabled by more powerful and less expensive computing, sophisticated solid and surface modeling software such as ProEngineer, Alias/WaveFront, and SolidWorks, and software making it possible to assign material properties to digital representations and perform functional and structural analyses of components and assemblies. These digital models can now be directly translated into tangible three-dimensional form.

4. A New Design and Manufacturing Paradigm Foam patterns for casting freeform architectural column components that have been CNC milled from ProEngineer CAD models.

5. Implications for Architecture New means of production have emerged that can enable new aesthetics in post-industrial digital societies. Advantages Of CAD/CAM Technologies: CAD/CAM technologies enable us to avoid traditional manufacturing costs. Design and produce complex freeform components that were previously either impossible or prohibitively expensive. Custom, digitally crafted architectural components can now be directly or indirectly manufactured without expensive reusable tooling. Mass customization is possible because manufacturing efficiencies are no longer compromised by variations in what is being produced.

6. Prototyping Freeform Architecture The Computer-Aided Design and Manufacturing Laboratory at the Harvard Design School is the most extensive facility of its kind in an architecture school. Advanced research into the design and manufacture of freeform architectural components and surface structures includes: creation of prototypes and advanced composites.

7. Harvard's CAD/CAM facilities Harvard's CAD/CAM facilities include several rapid prototyping machines: A large CNC milling machine (3-axis router). A smaller milling machine. Several CNC lasers. Reverse-engineering equipment. A vacuum forming machine. A broad range of traditional equipment and manufacturing tools. The school has licenses for SolidWorks, Surface Works, other solid and surface modelers such as ProEngineer, Alias/WaveFront, and Maya, and Master CAM, a leading CNC machining program.

8. Freeform Metal Frame Structures Architects began exploring the possibility of freeform metal frames at the turn of the last century in the Art Nouveau movement. The scale of their achievements was limited by available casting technology and representational methods. The largest cast Art Nouveau structures are the Paris Metro stations designed by Hector Guimard. The design of larger freeform metal frames requires that components be optimized as hollow tubes. Manufacturing processes developed in other industries that have the capacity to manufacture freeform tubes are categorized as: Processes that would be applicable and economically viable in current professional practice. Processes with emerging professional viability. Emerging additive technologies for directly manufacturing metal components.

9. Ceramic Mold Casting Processes Ceramic mold casting processes are the most practical and accurate methods for making architectural freeform tubes. Ceramic molds are made by investing an expendable pattern with alternate coats of ceramic slurry and dry stucco, and then, when the ceramic shell is thick enough, burning out the pattern in a furnace. These processes are generally referred to as investment casting technologies. Investment casting with CNC-milled expendable foam patterns is the least expensive method. Making freeform architectural tubes from additively formed expendable patterns is likely to become affordable as rapid prototyping technologies mature

11. Prototyping Freeform Tubes With ProEngineer, a six-foot-long freeform tubular column with an integral secondary branching component was designed. Analysis was made using MAGMA Soft, a computer program for predicting the behavior of molten alloys during casting. This analysis indicated the need to change some variations in wall thickness to ensure proper solidification and casting integrity. Making such changes to a solid model is easy with advanced feature-based parametric modelers, because simple editing of the dimensions or equations used to create the model results in automatic recreation and regeneration of the form. The solid model was divided into two interlocking components in order to accommodate locally available casting equipment. Then each of these components was subdivided into interlocking, self-registering pattern halves that were later glued together.

12. The ProEngineer models of the pattern components were exported in the IGES format, commonly used for importing data into CNC milling software such as Surf CAM or Master CAM. G-Code, the digital code that directs the automatic "carving" of the designed shape out of blocks of material, was then created in Surf CAM. The CNC milling machine automatically uses a predetermined variety of different shapes and sizes of bits as it follows the "tool paths" contained in the G-Code. The CNC-milled foam patterns were successfully used to cast the freeform column components in stainless steel. Prototyping Freeform Tubes (Continue)

14. Manufacturing with Solid Freeform Fabrication Prototype column components were also manufactured from patterns made using solid freeform fabrication.

15. Using CAD/CAM in Practice additive technologies to directly manufacture architectural components are still too expensive except for making relatively small parts, such as ornamental elements, light fixture housings, or stair rail components. The more freeform a component's geometry, and the smaller the quantity required, the more cost-effective the use of solid freeform fabrication. As these technologies mature, architects will be able to design large, custom, freeform components that are now impossible or impractical to make. The use of subtractive formation to manufacture both large and small freeform architectural components is now more affordable. The only major limitation is the drafting-centric software commonly used by practicing architects. To take full advantage of the new CAD/CAM paradigm, architects need to use more advanced solid and surface modeling programs.