INNOVATIONS FROM THE EDGE - KPIT

I. Introduction
Traditional methods of creating threedimensional
models used methods such as
woodcutting, engraving, and etching. Now a
machine attached to your computer can print in
three Dimensions. Future could be in which we
can have machines that produce physical
prototype of the real world object with some
activities integrated.
After decades of research, now a machine can
print a 3D model of the virtual object. In the same
way that 2D printers provide computer users with
a 2D picture, 3D printers provide 3D CAD users a
3D model. 3D printing is a form of additive
manufacturing technology where a three
dimensional model is built by laying down
successive layers of material. 3D printer offers to
create the model of the product made of several
materials with different properties that help the
designer to model multiple concepts. Following
will provide you the technologies used in 3D
printing, its applications in different fields,
materials used for printing, and future of the 3D
technology.
solidifies the traced pattern and bonds it to the
layer below. SL technology requires a support
structure to prevent elevated platform from
deflecting due to gravity. These support structures
are created automatically while preparing the 3D
CAD models used for SL and removed from finished
product manually.
3D models created by stereo lithography are strong
enough to be machined and can be used in
injection molding, thermoforming, blow molding,
and metal casting processes. Stereo lithography
has many common names such as 3D printing,
optical fabrication, photo-solidification and solid
imaging. Time taken by SL Machines to produce 3D
models varies from hours to days depending on the
complexity of the cross-section patterns of virtual
models. Most SL machines can produce parts with a
maximum size of approximately 50 cm x 50 cm x 60
cm (20" x 20" x 24") [9].
Disadvantage
SL process is expensive as the photo-curable resin
costs anywhere from $80 to $210 per liter. SL
machine costs ranges from about $100000 to more
II. Technologies used in 3D Printing
A large number of competing technologies are
available for 3D printing. Their main difference is
in the way they build layers to create parts. Some
methods use melting or softening material to
produce the layers, while others lay liquid
materials that are cured with different
technologies [6]. These different technologies are
described below.
Stereo Lithography
The first 3D printer was invented by Charles Hull in
1984 and was based on the technique called
stereo lithography. Stereo Lithography (SL) is
defined as a method and apparatus for making
solid objects by successively “printing” thin layers
of the ultraviolet curable “resin” material one on
top of the other. Subsequently on the surface of
each resin layer laser beam trace the cross-section
pattern of the 3D model. Exposure of the UV rays
Figure 1: stereo lithography Process
Source: http://www.photochembgsu.com/
applications/stereolithography.html
Fused Deposition Modeling
Another well know technology used in 3D printing is
Fused Deposition Modeling (FDM), invented by
Stratasys. In this technology, the digital model (CAD
model) is oriented horizontally and sliced in layers of
different thickness. Disposable support structure is
created based on position and geometry of object.
Then the thermoplastics are liquefied and deposited
by temperature controlled extrusion head, which
follows a tool-path defined by the CAD file. During the
build process, extra material called "support" may be
added to part in order to allow
20 TechTalk@KPITCummins, Volume 5, Issue 1, 2012