New tool gives structural strength to 3D-printed works

Objects created using 3D printing have a common flaw: They
are fragile and often fall apart or lose their shape.

“I have an entire zoo of broken 3D-printed objects in
my office,” says Bedrich Benes, an associate professor of computer
graphics at Purdue University.

The printed fabrications often fail at points of high
stress.

“You can go online, create something using a 3D printer
and pay $300, only to find that it isn’t strong enough to survive shipping and
arrives in more than one piece,” says Radomir Mech, senior research
manager from Adobe’s Advanced Technology Labs.

The 3D printers create shapes layer-by-layer out of various
materials, including metals and plastic polymers. Whereas industry has used 3D
printing in rapid prototyping for about 15 years, recent innovations have made
the technology practical for broader applications, he says.

“Now 3D printing is everywhere,” Benes says.
“Imagine you are a hobbyist and you have a vintage train model. Parts are
no longer being manufactured, but their specifications can be downloaded from
the Internet and you can generate them using a 3D printer.”

The recent rise in 3D printing popularity has been fueled by
a boom in computer graphics and a dramatic reduction of the cost of 3D
printers, Benes says.

Researchers at Purdue University and Adobe’s Advanced
Technology Labs have jointly developed a program that automatically imparts
strength to objects before they are printed.

“It runs a structural analysis, finds the problematic
part, and then automatically picks one of the three possible solutions,”
Benes says.

Findings were detailed in a paper presented during SIGGRAPH
2012. Former Purdue doctoral student Ondrej Stava created the software
application, which automatically strengthens objects either by increasing the
thickness of key structural elements or by adding struts. The tool also uses a
third option, reducing the stress on structural elements by hollowing out
overweight elements.

“We not only make the objects structurally better, but
we also make them much more inexpensive,” Mech says. “We have
demonstrated a weight and cost savings of 80%.”

The new tool automatically identifies “grip
positions” where a person is likely to grasp the object. A
“lightweight structural analysis solver” analyzes the object using a
mesh-based simulation. It requires less computing power than traditional
finite-element modeling tools, which are used in high-precision work such as
designing jet engine turbine blades.

“The 3D printing doesn’t have to be so precise, so we
developed our own structural analysis program that doesn’t pay significant
attention to really high precision,” Benes says.

Future research may focus on better understanding how
structural strength is influenced by the layered nature of 3D-printed objects.
The researchers may also expand their algorithms to include printed models that
have moving parts.

Source: Purdue University

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