New tool gives structural strength to 3D printed works

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

3D printed fabrications often fail at points of high stress

(Just like any other manufactured good)

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

“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 3-D printer.”

Video so you don’t have to read the rest of the article:

Automatically add some structural engineering to your models

Researchers at Purdue 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 said.

Findings were detailed in a paper presented during the SIGGRAPH 2012 conference in August. 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.

Stronger, cheaper and lighter – the engineer’s Holy Grail

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

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 3-D 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 said.

The paper was authored by Stava, now a computer scientist at Adobe, doctoral student Juraj Vanek; Benes; Mech; and Nathan Carr, a principal scientist at Adobe’s Advanced Technology Labs.

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

Paper Details:

ABSTRACT

Stress Relief: Improving Structural Strength of 3-D Printable Objects 

Ondrej Stava¹ Juraj Vanek¹ Bedrich Benes¹ Nathan Carr² Radom?r Mech²

¹ Purdue University ² Adobe Systems Incorporated

The use of cheap 3D printers has rapidly expanded in the past couple of years. It is now possible to produce 3-D-printed objects with exceptionally high fidelity and precision. However, although the quality of 3-D printing has improved, both the time to print and the material costs have remained high. Moreover, there is no guarantee that a printed model is structurally sound. The printed product often does not survive cleaning, transportation, or handling, or it may even collapse under its own weight. We present a system that addresses this issue by providing automatic detection and correction of the problematic cases. The structural problems are detected by combining a lightweight structural analysis solver with 3-D medial axis approximations. After areas with high structural stress are found, the model is corrected by combining three approaches: hollowing, thickening, and strut insertion. Both detection and correction steps are repeated until the problems have been eliminated. Our process is designed to create a model that is visually similar to the original model but possessing greater structural integrity.