Fabrication of three-dimensional shapes with engineering materials is of considerable interest for last three decades. Aerospace companies such as United Technologies in late Nineteen Seventies reported Nickel Super Alloys. In eighties rapid prototyping with photopolymer and laser sintering of polymer and metals started an industry. During the past decade several laboratories all over the world has made tremendous progress in producing parts directly from Computer Aided Design (CAD). Even tool steels are now possible using Closed Loop Direct Materials Deposition (DMD) technique. H13 tool steel is one of the difficult alloys for deposition due to residual stress accumulation from martensitic transformation. However, it is the material of choice for the die and tool industry. DMD offers Copper chill blocks and water-cooling channels as the integral part of the tool. This can reduce cycle time by 10-50 % for some injection molding dies. Difficult components can be repaired relatively easily. Presently the DMD technology and its derivatives are commercialized by many start-up Companies such as POM Group Inc. at Auburn Hills, Michigan. Using the closed loop Direct Metal Deposition, POM group is involved in fabrication, reconfiguration and restoration of tools, dies and components. Bi-Metallic Forging Tools fabricated by DMD exhibited 3 times the life improvement. This technology has the potential for remote manufacturing and may be useful for repairing and reconfiguration of components in the ship with the data electronically transferred from shore.
This process is amenable to produce both macro and microstructure to a designed specification. Using DMD in conjunction with Homogenization design Method and heterogeneous CAD, one can produce components with predetermined performance such as negative co-efficient of thermal expansion, by synthesis of designed microstructure. This paper briefly reviews the past evolution and state of the art of DMD and describes present and future applications.