SAMPE Journal - November/December 2021 - 79

INTRODUCTION
Additive Manufacturing (AM) or Rapid Prototyping (RP), utilizes metals,
ceramics, and composites to produce 3D structures at a low cost and lead time.
RP can be achieved through methods such as Fused Filament Fabrication
(FFF), Digital Light Processing (DLP), Stereolithography (SLA), etc. to produce
small-, mid- and large-scale structures using polymer materials and their
reinforced composites1,2
. Small-scale FFF printing is a standard system
.
commonly used for small prototypes, flexible sensors, and metal printing2-4
The process involves heating a filament through a nozzle and depositing layers
that range between 0.1 mm - 0.8 mm (0.004 inch - 0.028 inch) in height with
nozzle diameters ranging from 0.2 mm - 1.2 mm (0.008 inch - 0.0472inch)
with a build volume up to a 28317 cm3
(1ft3
technique have low volumetric flowrates around 16387mm3
hour) resulting in long build times5
). Structures fabricated using FFF
/hour (1inch3
/
. Several small-scale systems have recently
nasampe.org/events
. Studies have shown that by using multi.
Other applications include embedded sensors,
.
custom mechanical responses, and changing the color of the part3,6
In order to create large articles at a low cost and short time, large scale
systems were introduced to print with nozzles ranging from 2.5 mm - 12.7 mm
(0.1 inch - 0.5 inch) and a layer height range of 1.27 mm - 8.89 mm (0.05 inch
- 0.35 inch). The Big Area Additive Manufacturing (BAAM) system designed
by the collaborative efforts of Oak Ridge National Laboratory (ORNL) and
Cincinnati Inc., is a large thermoplastic extrusion deposition system with a
build volume of 1.5 m × 3.6 m × 2.4 m (5 ft × 12 ft × 8 ft) and a deposition rate up
to 45 kg/hr (100 lb/hr)8
. The BAAM system has been used to manufacture parts
such as large-scale prototypes, molds and dies and large lightweight optimized
core structures9-11
. Large-scale AM is currently limited to printing structures
with a single material which limits the ability to optimize structure weight,
functionality, cost, and layer time.
High performance feedstock materials, such as Polyethersulfone (PESU)
and Polyphenylsulfone (PPSU), have been used for 3D printing of high
temperature molds and dies11
. AM compression molds are currently printed
completely solid, as the pressures in the compression molding process can
exceed 10.3 MPa- 13.8 MPa (1500 psi-2000 psi). The infill material is typically
less critical for the integrity of the structure during the printing process, but
necessary to prevent deformation during the compression process. Infill in
compression molding prevents distortion during the compression process
by filling the structure with a packing material to prevent the load bearing
perimeters from deforming. Traditionally, a single material is utilized in these
infill patterns, where it drives the cost and weight of the manufactured parts
up. Cost and weight of structures can be minimized by utilizing recycled
materials or foams for the infill. The mechanical and thermal properties of the
AM structure are highly dependent on the material, processing conditions,
and infill pattern density and direction5,12-14
. Incorporating multi material
printing to the process will allow for tailoring of these mechanical and thermal
properties6,14
.
NOVEMBER 17, 2021 | 9:00 AM PT
TOPIC: High Speed AFP Processing
of Thermoplastics, by Michael Asadi,
Electroimpact
FEBRUARY 9, 2022*
TOPIC: Resins & Fibers Advances
APRIL 8, 2022*
TOPIC: Joining Technology Across
Markets
JUNE 8, 2022*
TOPIC: Inspection and Testing Applications
Visit events calendar for latest
updates:
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SAMPE JOURNAL
WEBINARS
Save the dates for our upcoming bimonthly
webinars. The topics below will
feature authors presenting their research
from the upcoming SAMPE Journal issues.
used multiple extruders in order to print dual materials. Multi-material
printing allows users to tune the color, cost, weight, and the mechanical
properties throughout the structure6,7
materials within a structure, new mechanical responses can be achieved such
as increased mechanical properties, soft and rigid robotic structures, impact
resistant structures, etc.6,7
*Schedule is subject to change.
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NOVEMBER/DECEMBER 2021
|
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79
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SAMPE Journal - November/December 2021

Table of Contents for the Digital Edition of SAMPE Journal - November/December 2021
