Fused Deposition Modeling (FDM) is a solid-based rapid prototyping method that extrudes material, layer-by-layer, to build a model. The system consists of a build platform, extrusion nozzle, and control system. The build material, production quality thermoplastics, is melted and then extruded through a specially designed head onto a platform to create a two-dimensional cross section of the model. The cross section quickly solidifies, and the platform descends where the next layer is extruded upon the previous layer. This continues until the model is complete, where it is then removed from the build chamber and cleaned for shipping.
Fused deposition modeling, which is often referred to by its initials FDM, is a type of additive fabrication or (sometimes called rapid prototyping / rapid manufacturing (RP or RM)) technology commonly used within engineering design. The technology was developed by S. Scott Crump in the late 1980s and was commercialized in 1990. The FDM technology is marketed commercially by Stratasys, which also holds a trademark on the term.Like most other additive fabrication processes (such as 3D printing and stereolithography) 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 computer-aided design 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 acrylonitrile butadiene styrene (ABS) polymer, the FDM technology can also be used with polycarbonates, polycaprolactone, polyphenylsulfones and waxes. A "water-soluble" material can be used for making temporary supports while manufacturing is in progress. Marketed under the name WaterWorks by Stratasys, this soluble support material is quickly dissolved with specialized mechanical agitation equipment utilizing a precisely heated sodium hydroxide solution.
Most available commercial printers using FDM technology utilize positioning systems employing either stepper motor or servo motors to move the extrusion head.
In 2006, FDM was the best-selling rapid prototyping technology.FDM systems include two different product lines. The "high-end" FDM systems include the FDM 900mc, FDM 400mc, FDM 360mc and FDM 200mc. These systems are the highest performance FDM systems capabale of producing parts from the largest range of thermoplastic materials, feature detail, surface finish, accuracy. FDM uses production-grade thermoplastics, such as ABS, ABSi, polyphenylsulfone (PPSF) and polycarbonate (PC), including 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, however material manufacturer Stratasys does not advertise that PPSF is sterilizable.Stratasys also markets a line of 3D Printers that print 3D models using the same core FDM technology. Called Dimension systems, these 3D Printers don't have the same performance or material options as a "high-end" FDM system, but are much less expensive.