3D printing refers to methods of printing 3D objects through additive processes that lay down successive layers of material with the help of a computer. Objects of almost any shape can be printed using technologies like stereolithography, fused deposition modeling, and selective laser sintering. 3D printing offers benefits like increased innovation, reduced development costs, improved communication, and new business opportunities across industries like education, medicine, automotive, and more.

2. WHAT IS 3D PRINTING
1.) 3D printing refers to any of the various methods used for
printing a three dimensional object.
2.) Primarily additive processes are used where successive layers
of material are laid down with the help of computer.
3.) Objects of almost any kind or shape may be printed by this
method.
4.) It is a kind of INDUSTRIAL ROBOT.

3. MODELING STL FILE SLICER SOFTWARE
Cura,slic3r
FINISHING PRINTING G CODE FILE

4.  Technology , for printing 3d objects from digital data
,first developed by CHARLES HULL in 1984.
 He named the technique as stereo lithography and obtained
a patient for the same in 1986.
 By the end of 1980 SLS, FDM methods were introduced.
 In 1993 MIT patented another technology named 3 dimensional
printing technique .
 In 2005,z corp. made a product named spectrum z510 which was the
first high definition colour 3d printer.

5. • Granular type formation, have a wide
range of materials.
• Used materials are thermoplastics,
metal powders, ceramic powders.
3D PRINT TECHNIQUES
1. SELECTIVE LASER
SINTERING (SLA)
• Extrusion type, printed materials have
high strength and durability.
• Mainly thermoplastics, rubber metal-clay,
porcelain are used.
2. FUSED DEPOSITION
MODELLING (FDM)
• Light polymerised type, highly complex
objects can be made.
• Photopolymers are used
3.STEREOLITHOGRAPHY
(SLA)
INKJET POWDER PRINTING, ELECTRON BEAM MELTING (EBM), SELECTIVE LASER MELTING
(SLM), PLASTER BASED PRINTING, LAMINATED OBJECT MANUFACTURING (LOM) etc.

6. SELECTIVE LASER SINTERING
1) POWERFUL LASER
AND POWDER MATERIAL.
2) A HIGH POWER LASER
FUSES SMALL PARTICLES
OF PLASTIC, METAL OR
CERAMIC POWDERS.
3) CAN BE USED
FOR WIDE
MATERIAL RANGE.
4) TYPICAL
THICKNESS IS
AROUND 100 μm

7. SINTERING Def- A process of forming solid mass by heating without melting it to the
point of liquefaction.
DENSIFICATION PROCESS-
1) Bulk coupling
2) Powder coupling
≛ it is high power density, short interaction time process.
DENSIFICATION RATE-
1) Process parameters
2) Material properties(assuming constant)
Parameters affecting energy delivered to the surface are- 1) laser power (P)
2) laser beam diameter (d)
3) scan rate (v)
4) scan line spacing (h)
Energy density , Q=πɳP̸4dv
Where, ɳ is coupling efficiency

8. 1.) Sintering temperature, T(s)= T(0) +1/C [ πɳ/4ρ (P/hvw) - ΔH ]
it is a empirical relation.
where, w is layer density , C is specific heat, T(s) is sintering temp ,
T(0) is initial temp, ρ is density and ΔH is latent heat.
2.) The rate of change in void fraction of powder bed is ,
d€/dt = -k€, €(i) ≤ € ≤ €(s)
where k is sintering rate and € is void fraction.
3.) empirically , k ⋉ P/wh
4.) Full densification can not be obtained

9. STEREO-LITHOGRAPHY
stereo lithography
It is additive manufacturing
process with ultraviolet curable
‘resin’ and uv- laser
layer thickness~ .05-.15mm
High speed manufacturing .
Complex objects are made.
But photo curable resin and the
machine is too expensive

10. How SLA works
P-I →
R* (free radical formation)
M + R* →
R-M* (initiation)
nRM* → R-M-M-M-M* (propagation)
RM* +RM* →RM-MR (termination)
WORKING CURVE EQUATION FOR RESIN
From BEER-LAMBERT law, it can be shown that,
C=Dln[E(max)/E(crt))
Where C is cure depth, D is depth of penetration by
laser until irradiance becomes 1/e, E(max) is peak
exposure of laser and E(crt) is critical exposure.

11. A SEMILOG PLOT OF C VS E(max)

12. WHY 3D PRINTING
1.) Increase innovation
2.) Reduce development costs
3.) Improve communications-(like, recently a 3D printer
has been sent to space (by NASA’s MARSHALL SPACE FLIGHT
CENTER in Huntsville, Ala) to help astronauts building
replacement parts or any other important tools )
4.) Win business.
APPLICATIONS
Education and research
1.)Beam trapper for absorbing radar
radiation to camouflage military
aircrafts, ships, buildings .
2.) complex models, cross
sections, architectural
designs can be made for
practical purposes.
A beam trapper made by
swiss researchers from ETH
Zurich Institute

13. IN BIOSCIENCE 1.)Different organ models like nose, kidney,
skin can be made by bio materials for
replacements
2.) Nanoscale bio printing can be used for
replacement parts according to genetics.
IN INDUSTRY
Most of the applications are industrious of 3D printing. Starting
from small machine tools to 3D printed home are made cheaply.
In automobiles, medicines, firearms, art it has huge applications.
3d printed home in china
3D printed car

14. REFERENCES and SOURCES
1.)www.elsevier.com/locate/msea; A. Simchi / Materials Science and
Engineering A 428 (2006) 148–158
2. Jacobs PF (1992) Rapid prototyping & manufacturing, fundamentals of stereo
lithography. Society of Manufacturing Engineers, New York, NY
3. http://www.space.com/23532-3d-printer-space-station-video.html
4. "How Stereo lithography Works". THRE3D.com. Retrieved 4 February 2014