Rapid prototyping
From Wikipedia, the free encyclopedia
- Rapid prototyping also describes a software engineering methodology.
Rapid prototyping, is the automatic construction of physical objects using solid freeform fabrication. The first techniques for rapid prototyping became available in the 1980s and were used to produce models and prototype parts. Today, they are used for a much wider range of applications and are even used to manufacture production quality parts in relatively small numbers. Some sculptors use the technology to produce complex shapes for fine art exhibitions.
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[edit] Introduction
Rapid prototyping takes virtual designs from computer aided design (CAD) or animation modeling software, transforms them into cross sections, still virtual, and then creates each cross section in physical space, one after the next until the model is finished. It is a WYSIWYG process where the virtual model and the physical model correspond almost identically.
In additive fabrication, the machine reads in data from a CAD drawing, and lays down successive layers of liquid or powdered material, and in this way builds up the model from a series of cross sections. These layers, which correspond to the virtual cross section from the CAD model, are glued together or fused (often using a laser) automatically to create the final shape. The primary advantage to additive construction is its ability to create almost any geometry (excluding trapped negative volumes).
The standard interface between CAD software and rapid prototyping machines is the STL file format.
The word "rapid" is relative: construction of a model with contemporary machines typically takes 3 to 72 hours, depending on machine type and model size. Used in micro technologies "rapid" is correct, the products made are ready very fast and the machines can build the parts in parallel.
Some solid freeform fabrication techniques use multiple materials in the course of constructing prototypes. In some cases, the material used for the final part has a high melting point for the finished product, while the material used for its support structure has a low melting point. After the model is completed, it is heated to the point where the support material melts away, and leaving functional plastic prototype. Although traditional injection molding is still cheaper for manufacturing plastic products, rapid prototyping may be used to produce finished goods in a single step.
There are currently several projects to improve rapid prototyping technology to the stage where a prototyping machine can manufacture a majority of its own component parts.[1][2] Of these the RepRap Project is probably the most advanced. The idea behind this is that a new machine can be almost entirely manufactured and assembled relatively quite inexpensively from the same polymer filament feed stock that the rapid prototyping machine uses to make prototypes by the owner of an existing one. Such a 'self-replication' technique will considerably reduce the cost of prototyping machines in the future, and hence any objects they are capable of manufacturing.
[edit] Technologies
A large number of competing technologies are available in the marketplace. As all are additive technologies their main differences is found in the way layers are built to create parts. Some are melting or softening material to shape them (SLS, FDM) where others are laying liquid materials thermosets that are cured with different technologies (SLA, MJM). In the case of the LOM, thin layers are cut to shape and glued together.
| Prototyping Technologies | Base Materials |
|---|---|
| Selective laser sintering (SLS) | Thermoplastics metals, or ceramic powders |
| Fused Deposition Modeling (FDM) | Thermoplastics, Eutectic metals. |
| Stereolithography (SLA) | photopolymer |
| Multi Jet Modeling (MJM) | photopolymer |
| Laminated Object Manufacturing (LOM) | Paper |
| Electron Beam Melting (EBM) | Titanium alloys |
| 3D Printing (3DP) | Various materials |
[edit] References
- ^ The Reprap Project. Retrieved on 2007-03-09.
- ^ The Clanking Replicator Project. Retrieved on 2007-03-09.
- Grenda, E. (2006). The Most Important Commercial Rapid Prototyping Technologies at a Glance.
- Wright, Paul K. (2001). 21st Century manufacturing. New Jersey: Prentice-Hall Inc.
[edit] See also
- Solid freeform fabrication: A list of technologies used in rapid prototyping.
- Fabber: A digital fabricating machine.
- 3D printing: Faster, more affordable rapid prototyping
- MeshLab An open source Windows and Linux application for visualizing, processing and converting 3D meshes to or from the STL file format.
