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grippers can easily adapt to objects of a wide variety
of shapes, and make the gripping process efficient
and flexible.
Between prototype construction and mass production
lies the increasingly important field of
low-volume production. Many product requests
are for relatively high but limited piece counts.
For these products, conventional mass production
with its costly molds and large plants is simply too
expensive.
The special strengths of additive manufacturing
technology, therefore, are even more readily
apparent when it comes to smaller piece counts
(Fig. 2). A few examples of products manufactured
in small batches include headlight housing
for high-priced cars, steering components for vehicles
driven from the right side, and housing for
specialty machines. Not least, lightweight construction
for airplanes and cars is a key sector for
additive manufacturing. Lightweight construction
is an undisputed construction principle in the
trans portation industry, for example, where it is
used to reduce fuel consumption and emissions.
In addition to low-volume production, another
field of application is individually modified components.
Examples include not only medical devices
such as hearing aids, implants or surgical instruments,
and drill guides for operations, but
also helmets and shoes for professional sports and
respirator masks. Until AM technology, the high
costs of creating a mold to produce a single component
made such individual parts as these impossible.
Variants are handled exclusively through
software solutions—from the capture and processing
of the individual data, to a single set of construction
data for each part.
The industry has now developed a whole host
of variations of mold-free production: instead of
solid particles, there are processes that run in
liquid beds. Others work with strands that are
stacked to form a part. The individual layer can be
formed by spraying or pressing binding material
or adhesives. All of these methods have one thing
in common: they can execute even the most complex
forms in a single operation. And they are
flex ible. Without high equipment costs, the part
can be modified and optimized by changing the
spatial construction data until it meets customer
and technical requirements precisely.
New functionalities through
custom-tailored plastics
Thermoplastics are ideal for additive manufacturing:
they are easy to pulverize, can be selectively
melted, and their chemical and physical proper-
elements32 evonik science newsletter
D e S i G n i n G w i t H P o l Y M e r S
Figure 2. Additive manufacturing technologies are significantly more economical
for low-volume production than injection molding, which is cost-effective only
for mass production, owing to the high cost of the mold. The minimum piece count
required before injection molding begins offering cost advantages depends, among
other things, on the size and complexity of the part to be produced and the mold
Cost per unit
Injection molding
Figure 3. Comparison of the material properties of a standard polyamide and an ultraflexible
polyamide specially developed for additive manufacturing
mance Polymers Business Line, experts have spent
roughly ten years developing thermoplastics for
additive manufacturing.
Converting from low-volume production to
additive manufacturing increases the demands on
the materials: aircraft construction requires polymers
that can withstand extremely high temperatures,
and are flame resistant. The sports and shoe
industries need soft materials to manufacture
components with high flexibility. For example,
Evonik developed an ultra-flexible polyamide
(PA) that has eight times the flexibility and five
times the tensile strength of the standard material
(Fig. 3). Another development, namely PEEK
powder for laser sintering, stands out for its high
melting point of 340 °C, which makes it suitable
for parts exposed to high temperatures during
operation. Optimized polymers like this enable
new functionalities, while at the same time creating
ways of replacing other materials, such as
met als, with plastics.
ties can be customized. In Evonik’s High Per for- >>>
Additive manufacturing
Number of units
Standard grade New flexible material
E modulus 1,700 MPa 100–250 MPa
(246,500 psi) (14,500–36,200 psi)
Elongation at break 15 % >100 %
Tensile strength 45 MPa 8 MPa
(6,250 psi) (1,160 psi)
Notched impact strength 3.5 KJ/m² No break
Melting point 186 °C 150 °C
(366 °F) (302 °F)
Common refreshing rate 50 % Not necessary
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