Manufacturing Bits: Oct. 1

3D balloon printing
Using an elastomeric or stretchy balloon, the University of Houston and the University of Colorado have developed a new 3D printing method as a means to develop three-dimensional curvy electronic products.

The technology involves the field of 3D printing, sometimes known as additive manufacturing (AM). In 3D printing, the goal is to develop parts layer-by-layer using materials.

The University of Houston and the University of Colorado have put a new twist in 3D printing. This manufacturing technology, called conformal additive stamp printing or CAS, starts off with an inflated balloon that is coated with a sticky substance.

The balloon is then used as a stamping medium. The balloon pushes down on a pre-fabricated electronic device. Then, it prints them on a curvy surface.

The technology has been used to print various curvy products, such as silicon pellets, photodetectors, small antennas, hemispherical solar cells and contact lenses. These devices range anywhere in size from millimeters to centimeters, according to researchers.

The technology solves a major problem. Existing techniques are limited in terms of developing products with curvy designs. Many are limited to 2D capabilities.

“We tested a number of existing techniques to see if they were appropriate for manufacturing curvy electronics,” said Cunjiang Yu, the Bill D. Cook Associate Professor of Mechanical Engineering at the University of Houston. “The answer is no. They all had limitations and problems.”

“Electronic devices are typically manufactured in planar layouts, but many emerging applications, from optoelectronics to wearables, require three-dimensional curvy structures,” according to researchers in the journal Nature Electronics. “However, the fabrication of such structures has proved challenging due, in particular, to the lack of an effective manufacturing technology.”

Printed turbines
H+E-Produktentwicklung and the Fraunhofer Institute for Manufacturing Technology and Advanced Materials have developed a fully functional gas turbine using 3D printing technologies.

With the technology, researchers have developed a demonstrator turbine based on Siemens’ SGT6-8000 H system. This system, which is a scaled model of the original, is a gas turbine for power generation.

The turbine consists of 68 parts, which are made with aluminum, steel and titanium. In comparison, the original system has almost 3,000 individual parts.

The printed system has been produced using a combination of two technologies–Laser Beam Melting (LBM) and Selective Electron Beam Melting (SEBM). The Ti-6Al-4V portion has been made using SEBM, while the turbine stages and other components used LBM.

“SEBM is a powder-based process for the additive manufacturing of 3D parts. The powder bed is selectively melted layer-by-layer by an electron beam under a high vacuum atmosphere,” according to Fraunhofer.
LBM is also powder bed based additive manufacturing process, according to Fraunhofer.

CAD tools
3D printing can be a challenging task using the current design methods and computer-aided design (CAD) tools, according to the Singapore University of Technology and Design (SUTD).

In response, SUTD has developed data-driven methods for use in 3D printing applications. It has developed a next-generation CAD system for AM.

“This CAD-AM system will enable designers to design complex geometric and material structures that exhibit behaviors that are unobtainable with conventional design and manufacturing tools. Designers can rapidly examine design alternatives 10 times more compared to what the current methods allow,” said SUTD Professor David Rosen.