It all starts with making a virtual design of the object you want to create. This virtual design is made in a CAD(Computer Aided Design) file using a 3D modeling program (for the creation of a totally new object) or with the use of a 3D scanner (to copy an existing object). A 3D scanner makes a 3D digital copy of an object. [1

2. Concepts of 3D-printing
By
Romissaa Aly
Assistant lecturer of Oral Medicine,
Periodontology, Diagnosis and Dental
Radiology (Al-Azhar Univerisity)

3. It all starts with making a virtual design of the object you
want to create.
This virtual design is made in a CAD(Computer Aided Design) file
using a 3D modeling program (for the creation of a totally new
object) or with the use of a 3D scanner (to copy an existing object).
A 3D scanner makes a 3D digital copy of an object. [1]

4. 3d scanners use different technologies to generate a 3d
model such as time-of-flight, structured / modulated light,
volumetric scanning and many more. [1]
models will become as easy as taking a picture. Prices of 3d
scanners range from very expensive professional industrial
devices to 30 USD DIY devices anyone can make at home.

5. To prepare a digital file for printing, the 3D modeling
software “slices” the final model into hundreds or thousands of
horizontal layers
When the sliced file is uploaded in a 3D printer, the object can be
created layer by layer.
The 3D printer reads every slice (or 2D image) and creates the
object, blending each layer with hardly any visible sign of
the layers, with as a result the three dimensional object

6. Three-dimensional (3D) printing is one of the most effective
techniques for developing 3D objects by deposition of source
materials, such as polymers or ceramics, in a layered manner.1

7. It is also referred to as rapid prototyping (RP), solid free-
form technology (SFF), or additive manufacturing (AM).2,3
In 1981Dr. Hideo Kodama invented the rapid prototyping
machine that could polymerize resin using ultraviolet (UV)
light and fabricate parts layer-by-layer.4

8. Chuck Hull, the “inventor of 3D printing”, filed the first patent
for stereolithography in 1986.5
He created and commercialized selective laser sintering (SLS)
and the .stl format (the general file type for 3D printing).
SLS, a different type of 3D printer, was first licensed by a
student atthe University of Texas, Carl Deckard, in 1988.6 In
1989, fuseddeposition modeling (FDM) was patented by Scott
Crump.

11. Figure 10. A) 3D bioprinting with bi-phasic support liquid for the manufacturing of thin-
walled, multi-layered hydrogel structures. B) Schematic illustration
of the velocity and shear stress distribution as well as the stress impinged on cells inside a
bioprinter nozzle. Reproduced with permission.[35

12. Laminated Object Manufacturing (LOM)

27. mullite fibrous porous ...

32. the branch of physics that deals with the deformation and
flow of matter, especially the non-Newtonian flow
of liquids and the plastic flow of solids.

35. nozzle. noun. noz·​zle ˈnäz-əl. : a short tube that narrows in the middle or toward
one end and is often used (as on a hose or pipe) to direct or speed up a flow of
fluid

36. Figure 4. Printing heterogeneous valve and
scaled valve constructs

37. Figure 5. Macrostructure of alginate-gelatin scaffolds with concentrations of (A) 1%, (B) 2% and
(C) 4%. Extrusion printing of alginate-gelatin scaffold
is seen in (D). A mechanically robust 2% alginate-gelatin scaffold after crosslinking with calcium
chloride is seen in (E). Dimensions of alginate-gelatin
scaffolds +/− calcium chloride is highlighted in (F). Reproduced with permission.[41] Copyright
2013, The Royal Society of Chemistry

38. Figure 7. Bioink printability assessment under different printing parameter combinations. A)
Evaluation of printability (Pr) under different gelation
states – under-, proper- and over-gelation. B) Optical microscope images at 30 mins. C) Semi-
quantified Pr value construct for gelatin/alginate
bioink with different concentrations under different printing temperatures. Scale bars are 1 mm.

39. ruthenium (Ru) and sodium persulfate (SPS)
Figure 9. 3D plotting of gelatin+methacryloyl+collagen constructs that have been
photopolymerized in UV+l2959 and Vis+Ru/SPS systems. Different
shape fidelity can be seen post-irradiation and post-swelling with the different systems.
Reproduced with permission.[34] Copyright 2016, American
Chemical Society.

41. Electrospinning is a method to produce
ultrafine (in nanometers) fibres by charging
and ejecting a polymer melt or solution
through a spinneret under a high-voltage
electric field and to solidify or coagulate it to
form a filament

42. Figure 5. (a) CAD
model and (b)
original setup of
hybrid 3D
printing/electros
pinning.
Reproduced
with permission
from Fazal et
al.118 Copyright
2021, Elsevier
Science Ltd

45. Figure 7. (A) 1st step: 3D printing of PLA honeycomb-like structures. (B) 2nd step:
Modifying honeycomb walls with zein film via the casting
technique. (C) 3rd step: Electrospinning coaxial nanofibers on one side of 3D-
printed modified structures. Reproduced with permission from dos