3D modelling and its corporate big brother of Solid
Freeform Fabrication or Rapid Prototyping began in the early 80's as a
way to use machines to make objects faster than a traditional modeler
could. By using Computer Aided Design machines such as pen plotters and
then variable-height plotters, developers soon came up with the means
to have a machine able to carve elements out of foam or wood in
multiple layers or levels, but it was still one half or one side. A CAD
table could produce an object of up to 48"x48" with a depth of up to 4"
- but only 1 sided, so two of them would have to be made for an 8"
object, or many layers for a more detailed or larger object.
The
first Stereo-Lithography system was believed to have been developed at
Xerox labs in the mid 1980's by a team of engineers who were
experimenting with a way to fuse toner into a more solid substrate.
They realised that by using a platform that moved only on the z axis or
up and down with a scanning laser that could traverse across the entire
plate on the x- and y- axis they could harden a layer of waxy toner,
then drop the platform down a tiny fraction, put new toner on, and do
the process again, thus they could slowly build up a form in 3
dimensions.
Xerox was pretty creative in the 70's and 80's - In
1971, a team from Xerox came up with the idea of putting a printhead
assembly and scanning laser into a photocopier and created the first
laser printer.
So, realising that this solid manufacturing process could be
commercialised, they let the word out to manufacturers and developers
who could put the idea to good use.
In 1988, a team led by S.
Scott Crump developed a process called Fused Deposition Modelling. They
went on to form the company Stratasys and produced Rapid Prototyping
machines that used this technology to create physical objects from 3d
models.
Laminated Object Manufacturing or LOM is a process
developed and commercialized by Heliosys, in which many layers of
laminated paper are sealed together after they have been cut into
shape, creating a 3d object consisting of thousands or tens of
thousands of sheets tightly bonded together.
Laser Engineered Net
Shaping or LENS is a recent process developed by Sandia Labs where a
laser is focussed onto a steady stream of metal particles sprayed into
a pool of liquid metal. This process builds up a fully realised object
with no hollow portions or any gaps. The metal is fully dense and the
final part is almost as strong as a milled item. Optomec has licensed
the LENS technology into a Rapid Prototyping machine.
Selective
Laser Sintering or SLS is a process developed by 3D Systems where a
laser strikes a bed of metal or plastic powder, fusing portions of it
into the required shape. The bed is lowered, more powder added, and the
laser passes over it again. This process, which is the original basis
of the LENS process, can be used to create both fully solid or
partially solid metallic or polymer objects in a limited run
environment.
Stereo Lithography uses a laser striking a pool of
photopolymer in a pattern defined by the CAD or STL file data. Once the
laser has finished it's pass, the platform lowers, immersing the object
under the surface of the photopolymer and the laser passes over again,
slowly building up an object under the polymer. BaE uses
Stereolithography to produce prototypes of equipment and parts
extensively.
These methods have a very fine accuracy, ranging
from 0.01mm for laminated Object Modelling down to 0.003mm for
Stereolithography. This enables models and objects to be made to
exacting specifications and allows for items such as jewellery mounts
to be designed and then mass-produced in days rather than weeks.
For
larger objects such as columns, airplane components, car body panels,
statues and the like - a different method can be employed. 3D routers
or cutting machines have also been developed that have a cutting or
routing blade set on a movable head that can travel on all 3 axes and
do very complex carving down to a resolution of around 0.1mm detail,
depending on the cutting or routing heads.
The markets for Rapid
Prototyping and Rapid Manufacturing for hobbyists is growing. The
machinery ranges in price from $3,500 up to over $500,000 for some of
the metal synthesis equipment. This enables hobbyists and people who
need limited run products to get them at a fraction of the cost of
previous methods such as moulded casting or milling and engraving
prototyping.
Just do a search for Rapid Prototyping or Solid
Freeform Fabrication - there are plenty of companies out here ready to
build your 3d object in 3 full dimensions so you can hold it in your
hand.
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