Additive Manufacturing/3D Printing
This technology is what's known as an "additive" manufacturing process. Many people are familiar with Computer Numerical Controlled (CNC) technologies where a blank of some material is loaded to a machine which then uses a number of spinning tool heads to cut out the desired part. Therefore, CNC is known as a subtractive process. With all current Additive Manufacturing technologies, a part is made one horizontal layer at a time. In this way, the technology is able to create geometries that are impossible with CNC or subtractive technologies.
1. This illustration shows the basic layout of the 3D Printing technology. First, the build area has a fresh layer of material spread at a thickness of .004".
The 3D Printing process begins with the feed side filled with the raw material, and the build area empty and positioned at its top position. The model that's to be printed has been loaded to the driving software, and is sent to the machine for build one layer at a time. The machine spreads a thin layer of material over the build side (illustration 1). The gantry then passes back over the build area, printing the layer as it goes (illustration 2).
2. The gantry containing the print heads returns back, printing a layer of the model as it proceeds.
Several flavors of this technology exist today. The following list shows the most popular technologies currently in use.
3DP - 3D Printing. Using a plaster based powder system, this is the only technology available that can print a part in full color.
SLA - Stereolithography. Several material choices are available for SLA. They are all photo sensitive resins that cure under a UV laser beam. Many of the materials are suitable for full function testing.
SLS - Selective Laser Sintering. Here, a laser sinters layers of powder together. This process supports several metal material choices.
FDM - Fused Deposition Modeling. A thread of ABS plastic is fed through a very hot print head, building a part one layer at a time.