Biomedical Engineering Reference
In-Depth Information
Figure 31.9.
Fabricated 3D porous scaffolds by indirect-SFF method
based on MSTL.
24
attached to a carriage moving in the horizontal
xy
plane. The main
functionoftheliquefierassemblyistoheatandextrudethefilament
materialsthroughanozzledirectlyontothebuildplatformfollowing
apre-programmedpath,whichisbasedonCAM.Ifonelayerisfabri-
cated,themachinemovesdownonestepinthe
z
directiontodeposit
thenextlayer.Thefinalproductscanbeproducedinalayer-by-layer
process.Bychangingthedirectionofmaterialdepositionforconsec-
utivelydepositedlayersandthespacingbetweenthematerialroads,
scaffolds with highly controllable pore geometry and complete pore
interconnectivity can bemanufactured.
In comparison with other SFF techniques, the FDM method does
not require any solvent and offers great ease and flexibility in
the handling and processing of materials. The use of a filament-
modeling material also reduces the time required in the heating
compartment and allows for continuous production without the
need for replacing feedstock. However, one drawback of the FDM
technique is the need for preformed fibers with uniform size and
material properties to feed through the rollers and nozzle. In addi-
tion, its application to biodegradable polymers, excluding PCL, are
rarely reported Therefore, various modified FDM processes were
developed and evaluated to overcome the limitations of the tradi-
tionalFDM process in tissue scaffoldfabrication.
26
-
34
Hutmacher
et al
. investigated the mechanical properties and
responsesofcellsculturedonPCLscaffoldsdesignedandfabricated
using commercialized FDM (Stratasys Inc., Eden Prairie, MN).
29
Two types of PCL scaffolds with an area of 32.0 (length)
×
25.5
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