Biomedical Engineering Reference
In-Depth Information
29.3 3D Fabrication Technologies and Their Comparison
There are three major 3D fabrication methods in industries:
machining, casting, and layer manufacturing (Table 29.2).
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,
16
Max-
illofacial bone deformities tend to have complex external shapes,
including overhangs and internal structures such as interconnect-
ing pores suitable for blood vessel and cell invasion.
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Machining
is a method to remove excess parts from bulk materials using cut-
ting tools. For example, a sculpture is made by cutting from wood
and stone. Currently, most sophisticated machining in industries is
achieved by the five-axis machining center. Although machining is
good at the reproduction of surface shape and at the custom-made
production, it has di
culties in fabricating overhangs and complex
internalstructuresbecauseofthelimitedaccessibilityofthecutting
toolsto these structures.
Casting is a method to produce objects by pouring molten mate-
rials into a shaped mold and allowing it to cool and solidify. Cast-
ing is used to shape materials, including glass, plastics, metals, and
alloys. Although casting is good at the reproduction of substan-
tially complex shapes, including some overhangs, it is unable to
reproduce complex internal structures. It is suitable for the pro-
duction of the same shape in a large quantity, not for custom-made
production.
Layer manufacturing is also called rapid prototyping or solid
free-formfabrication.
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,
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Inthismethod, virtualdesignscreated by
computer-aided design (CAD) are transformed into a collection of
thin-slice data. The manufacturing machines then read in the data
and lay down thin layers of materials such as liquid, powder, and
sheet, which are sequentially fused to create the final shape. Layer
Table 29.2. Three major 3D fabrication methods and their
characteristics.
Strong points Weak points
1. Machining Custom-made production Overhangs
Internal structures
2. Casting Fairly complexshapes Custom-madeproduction
3. Layermanufacturing Any shape Availableto limited
Custom-made production biomaterials
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