Rapid Prototyping Using Metal
15 May 2001 - Printing out three-dimensional metal parts on a computer – how on earth does that work? There may not be many home PCs capable of doing so, but it is rapidly becoming very common in mechanical engineering, where a number of different processes are already being used to manufacture prototypes and molds for injection molding plants, nozzles for extruders, and other tools. The terms "rapid prototyping" and "rapid tooling" clearly express the important factor: Speed is of the essence when you want to manufacture new products and introduce them onto the market. The Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research IFAM in Bremen is the first in Europe to employ a process that allows geometrically complex metal workpieces to be printed out directly from the CAD data.
Haiko Pohl of IFAM's Near-Net-Shape Production Technologies Department explains how the ProMetal RTS-300 system works: "After being designed on the computer, the part to be manufactured exists as a set of three-dimensional data. A computer program known as a layer generator dissects the model into a stack of superimposed layers or slices, and then transfers each one to a special kind of printer. Using the same principle as the familiar ink-jet printer, the print head squirts a binding agent onto a thin layer of powdered steel, "gluing" the particles together. The work platform is lowered slightly, a new layer of powdered steel is applied, and the printer "writes" the next slice."
The second step of the process gives the still rather delicate object more strength and density. The surplus metal powder is blown off, heat is applied to remove binding agent from the surface, and then the object is infiltrated: Molten bronze gradually seeps down between the particles of steel, causing the binding agent to vaporize. In the final stage, various standard metalworking techniques are used to give the part its ultimate form. A process that used to take weeks or even months can now be accomplished in only a few days.
This process is just one of many that the twelve institutes making up the Fraunhofer Rapid Prototyping Network will be presenting at this year's uRapid conference, due to take place in Amsterdam from 28 to 30 May. It is expected to attract around 300 international guests: CEOs, heads of R&D, plant and operations managers and other senior management staff.
Contact: Dr.-Ing. Rudolf Meyer, Fraunhofer Rapid Prototyping Network, Tel: +49 3 91/40 90-5 10, Email: info@urapid.de