| FDM (FUSED DEPOSITION MODELING) |
    FDM(Fused Deposition Modeling) methods are usually used to make some prototypes for functional testing purpose instead of demo purpose. FDM(Fused Deposition Modeling) was developed by S. Scott Crump in the late 1980s and was commercialized in 1990. FDM is an additive manufacturing technology commonly used for modeling, prototyping, and production applications. Similar with most other additive manufacturing processes FDM works on an "additive" principle by laying down material in layers. A plastic filament or metal wire is unwound from a coil and supplies material to an extrusion nozzle which can turn on and off the flow. The nozzle is heated to melt the material and can be moved in both horizontal and vertical directions by a numerically controlled mechanism, directly controlled by a CAM (Computer Aided Manufacturing) software package. The model or part is produced by extruding small beads of thermoplastic material to form layers as the material hardens immediately after extrusion from the nozzle. Several materials are available with different trade-offs between strength and temperature properties. As well as ABS (Acrylonitrile Butadiene Styrene) polymer, the FDM technology can also be used with polycarbonate, polycaprolactone, polyphenylsulfones and waxes. A "water-soluble" material can be used for making temporary supports while manufacturing is in progress. FDM systems are capable of producing parts from the largest range of thermoplastic materials, feature detail, surface finish, accuracy. FDM uses production-grade thermoplastics, such as ABS, PPSF (Polyphenylsulfone) ,PC (Polycarbonate), and PC-ABS. Because of the material properties, FDM parts typically withstand functional testing and have high heat resistance. Some companies have sterilized PPSF for medical applications. Highlights of Fused Deposition Modeling * Standard engineering thermoplastics, such as ABS, can be used to produce structurally functional models. * Two build materials can be used, and latticework interiors are an option. * Filament of heated thermoplastic polymer is squeezed out like toothpaste from a tube. * Thermoplastic is cooled rapidly since the platform is maintained at a lower temperature. * Milling step not included and layer deposition is sometimes non-uniform so "plane" can become skewed. * Make rapid progress in past few years and be used widely. Introduction of Fused Deposition Modeling Stratasys of Eden Prairie, MN makes Fused Deposition Modeling (FDM) machines. The FDM process was developed by Scott Crump in 1988. The fundamental process involves heating a filament of thermoplastic polymer and squeezing it out like toothpaste from a tube to form the RP layers. The machines range from fast concept modelers to slower, high-precision machines. The materials include polyester, ABS, elastomers, and investment casting wax. The overall arrangement is illustrated below:  |
