What is three dimensional printing?

Answer 1

Three Dimensional Printing is a process under development at MIT for the rapid and flexible production of prototype parts, end-use parts, and tools directly from a CAD model. Three Dimensional Printing has unprecedented flexibility. It can create parts of any geometry, and out of any material, including ceramics, metals, polymers and composites. Furthermore, it can exercise local control over the material composition, microstructure, and surface texture. Process Three Dimensional Printing functions by building parts in layers. From a computer (CAD) model of the desired part, a slicing algorithm draws detailed information for every layer. Each layer begins with a thin distribution of powder spread over the surface of a powder bed. Using a technology similar to ink-jet printing, a binder material selectively joins particles where the object is to be formed. A piston that supports the powder bed and the part-in-progress lowers so that the next powder layer can be spread and selectively joined. This layer-by-layer process repeats until the part is completed. Following a heat treatment, unbound powder is removed, leaving the fabricated part. The sequence of operations is depicted below. Process Capabilities The 3DPTM process combines powders and binders with unprecedented geometric flexibility. The support gained from the powder bed means that overhangs, undercuts and internal volumes can be created (as long as there is a hole for the loose powder to escape). 3D Printing can form any material that can be obtained as a powder - which is just about any material. Further, because different materials can be dispensed by different print heads, 3D Printing can exercise control over local material composition. Material can be in a liquid carrier, or it can be applied as molten matter. The proper placement of droplets can be used to create surfaces of controlled texture and to control the internal microstructure of the printed part. The 3DPTM process surpasses conventional powder processing because while the 3DPTM components rival the performance of those made by conventional methods, there are no tooling or geometric limitations with Three Dimensional Printing. Because of its great flexibility in handling a wide range of materials and because of the unique ability to locally tailor the material composition, Three Dimensional Printing offers potential for the direct manufacture of structural components with unique microstructures and capabilities. Three Dimensional Printing is also readily scaled in production rate through the use of multiple nozzle technology which has been commercially developed for printing images on paper. The Impact of Three Dimensional Printing Three Dimensional Printing has led the field of Rapid Prototyping (RP) in the creation of functional parts and tooling directly from a CAD model. It was the first technology to achieve the fabrication of ceramic parts, and pioneered the direct fabrication of ceramic molds for casting. Three Dimensional Printing was a leader in the creation of metal parts directly and in the use of these parts for dies. Our work on ceramic preforms was the first demonstration of a functionally gradient material by RP. Most recently, we have pioneered the fabrication of structural ceramic parts using the 3DPTM process. MIT has licensed the 3DPTM technology to six companies in diverse fields of use. Three Dimensional Printing can substantially reduce the time to market for new products, enhance product quality by improving the coupling between design and manufacturing, and lower product cost by reducing development and tooling costs. Furthermore, the flexibility of the process makes totally new technologies and applications possible and has already generated novel solutions to engineering problems. 3D Printing is at the forefront of the coming revolution in manufacturing brought about by Rapid Prototyping.