|
Rapid
Manufacturing -- Rapid Prototyping
Introduction
to RP
Rapid prototyping (a.k.a. Desktop
Manufacturing, Solid Free-form Manufacturing
or Solid Free-form Fabrication) consists of
various manufacturing processes by which a
solid physical model of a part is made directly
from 3D computer-aided design (CAD) model
data. This CAD data may be generated by 3D
CAD Modelers, CT and MRI scan data or model
data created by 3D digitizing systems.
To begin the Rapid Prototyping
process, the 3-D data is sliced into thin
(~.005 in.) cross-sectional planes by a
computer. The cross-sections are sent from
the computer to the rapid prototyping machine
which builds the part layer-by layer. The
first layer's geometry is defined by the
shape of the first cross-sectional plane
generated by the computer. It is bonded
to a platform or starting base and additional
layers are bonded on top of the first, shaped
according to their respective cross-sectional
planes. This process is repeated until the
prototype part is complete.
The resulting prototype
provides a "conceptual model" for design
visualization and review by the entire design
team. It may be used by engineers to check
form and fit and perform limited function
tests. It can also be utilzed for soft tooling
for prototypes and as a pattern for hard
tooling.
The various existing rapid
prototyping methods can be categorized by
the material they use: photopolymer, thermoplastic,
and adhesives. Photopolymer systems start
with a liquid resin, which is then solidified
by discriminating exposure to a specific
wavelength of light. Thermoplastic systems
begin with a solid material, which is then
melted and fuses upon cooling. The adhesive
systems use a binder to connect the primary
construction material.
|
