Glossary

RAPID PROTOTYPING

3D Printing	A generic term for processes that use ink-jet technology to print material in layers.
3D Systems	A major player in the rapid prototyping arena. Produce SLA and SLS machines as well as some resins through newly acquired RPC.
Accuracy	A measurement of deviation from the CAD data. Accuracy is dependent on the process used to make the rapid prototype.
Add-In	A program that runs within another program enabling additional functions to be preformed without leaving the native environment.
Additive Manufacturing	A term used to describe rapid prototyping. Rapid prototyping differs from other manufacturing methods in that one starts with nothing and continually adds material instead of starting with a work piece and removing material to construct a part.
Build Envelope	Measurement of the machines part size limitations given by the X, Y and Z axes.
CAD	Computer Aided Design.
CAM	Computer Aided Manufacturing.
Concept Model	A rapid prototype used to evaluate designs early in the design process.
Facet	One triangular element used to approximate the surface of a model. A facet is defined as three nodes and an outward normal. It takes thousands of triangles to define a complex model. The facet data is kept in an STL file.
Form and Fit Model	Rapid prototype used to evaluate assembly and basic functional issues.
Free Form Fabrication	A generic term for all rapid prototyping processes.
Functional Model	Rapid prototype made of materials close to final spec materials that initial testing can be performed on.
Fused Deposition Modeling	Process using molten plastics extruded by a nozzle that traces the parts cross sectional geometry layer by layer.
Post Processing	Once a part is completed, each process has certain operations that need to be performed to it to make the part useable. It may include sanding to remove stair stepping, support structure removal, de-powdering, infiltration or painting.
Resolution	The minimum feature size that a process can be expected to reproduce. In the XY plane it can depend on pixels, laser spot size and mechanical precision. In the Z dimension it depends on the layer thickness.
RP	Rapid Prototyping. Rapid Prototyping is an additive process of layering plastic, wood ceramic or paper to create a 3D object.
Selective Laser Sintering	Process using photosensitive powders sintered by a laser that traces the parts cross sectional geometry layer by layer.
Slice	One layer of a prototype. Many slices are built on top of another to create a complete part. Each slice has a thickness varying from approximately .001 in to .010 in. depending on the process used.
Stair Stepping	Visual detractor caused because rapid prototypes are made using a layer by layer method with each layer having a finite thickness. Small steps are created on curved surfaces. Reducing the layer thickness helps minimize stair stepping.
Stereolithography	Process using photosensitive resins cured by a laser that traces the parts cross sectional geometry layer by layer.
STL	The standard file format for all rapid prototyping processes. The extension stands for STereoLithography but the format applies to all major rapid prototyping technologies.
Stratasys	Producer of machines used to create FDM Models.
Support Structure	A feature added to a part in some RP methods in order to maintain accuracy while building especially where overhangs or undercuts are seen. The supports are removed after the build is completed.