Technology News
IMAGING TECHNOLOGY
3-D Viewing System Displays Virtual Prototypes
 |
|
Actuality's
3-D system allows users to view an image from all angles.
|
A newly developed true 3-D image system may provide design engineers with a more convenient way to view product designs than current methods of 3-D viewing. Developed by Actuality (Reading, MA, USA), the viewing system projects a 3-D display that can be seen without goggles and doesn't need to be rotated on screen to get the full picture.
Actuality president Gregg Favalora says the system offers an alternative to traditional methods of creating a 3-D model. "Many design tasks require deep thought when performed on a traditional computer monitor, since they require building a mental 3-D model from various 2-D images. It may take days of rotating an image on a screen to understand its shape."
Whereas traditional technology flattens 3-D information onto a 2-D screen, the projection system allows an image to be displayed in a viewing dome. Resembling a large crystal ball, the viewing dome allows users to see an image from all angles. The viewing technology may change the future of design engineering, according to Favalora. "Looking at an Actuality display will be equal to looking at a model of a physical object, and will provide an instant and intuitive understanding of your work," he says.
Produced by a high-performance computer, 3-D rasterization algorithms, and interface software, the image has a resolution of approximately 100 million voxels (the smallest distinguishable box-shaped parts of a 3-D image). A high-speed projection system generates the image by illuminating a rotating screen.
"We're creating a virtual prototype in which designers can make the most of their visual information," Favalora says. Using the 3-D imagery, design engineers can gain an understanding of spatial relationships and can verify the fit and function of assemblies without producing a prototype. The transparent imagery enables engineers to verify that parts fit correctly. Applications for the imagery system include conceptual design, modelling, finite element analysis, rapid prototyping, and numerically controlled machining.
Currently in beta testing and scheduled to launch early next year, the imaging system has not gone unnoticed, according to Favalora. Biotechnology companies, and various others, have expressed interest in the new technology. "We've had to turn down so many requests from companies that want to be involved in the beta testing. They are very excited about the technology," says Favalora.
Jamie Graham
PLASTICS
New Smart Plastic Has Good Memory
 |
|
This
shape-memory plastic from mnemoScience reverts to its parent shape in
45 seconds at a temperature of 65°C.
|
For years, nitinol and other alloys that have memory properties have been used in everything from catheter wires to eyeglass frames and orthodontia. But these metals have limitations, including restricted pliability and resource-intensive fabrication. That is why Robert Langer and Andreas Lendlein, two scientists working at the Massachusetts Institute of Technology (Cambridge, MA, USA), set out to create a shape-memory plastic that would be easier to mould and control. And as announced in the January 30, 2001, issue of Proceedings of the National Academy of Sciences, the pair has succeeded in creating a mixture of polymers that reliably remembers its shape when properly combined and treated.
This novel material, composed of oligo-dimethacrylate and n-butyl acrylate, works similarly to existing shape-memory alloys. The plastic is formed in its parent shape and heated to a high temperature, locking in that particular arrangement as the unit's natural structure. Upon cooling, the piece can be moulded into any desired temporary shape that is within the material's mechanical limitations. This structure is retained until the material is subjected to its transition temperature, when it rebounds to its original shape. This process can be repeated an unlimited number of times.
Though the new plastic may work in a similar fashion to its metallic predecessors, it holds several distinct advantages. Programming metal to remember its shape is a time-consuming process that requires temperatures of several hundred degrees Celsius. Shape-memory plastics, on the other hand, can be conditioned in seconds at temperatures around 70°C. Plastics can also be bent to a greater degree and still return to their original shape. The maximum deformation with metal is about 8%; with plastics, it is 300–400%.
Because the material is also biocompatible, shape-memory plastic has numerous potential medical uses. Its use could increase the flexibility of stents, stitches, and catheters. It also could be used to produce the opposite effect in devices that contract as a result of an environmental stimulus. Lendlein and Langer have set up a new company called mnemoScience (Aachen, Germany) to explore various medical applications. Among the nonmedical uses being considered: car bumpers that snap back to their original shape after an accident.
Zachary Turke
Photo Courtesy of The National Academy of Sciences
MATERIALS
Composite Material Heals Itself
 |
|
This
graphic image displays a ruptured capsule with the polymerized healing
agent emerging from it.
|
A team of researchers from the University of Illinois (UI; Champaign, IL, USA) recently developed a synthetic material that can heal itself. The material is modelled after the autonomic healing response of biological systems. Although the mimicry isn't exact, the composite recovers as much as 75% of its strength in fracture tests, according to Scott White, professor of aeronautical and astronautical engineering at UI.
The polymer composite consists of a special catalyst and a healing agent contained in numerous microcapsules embedded in a structural composite mix. When the material is cracked or broken, the microcapsules rupture and release the healing agent into the damaged area through capillary action.
The self-healing process depends on a chemical reaction known as ROMP (ring-opening metathesis polymerization). The reaction meets certain requirements that make the self-healing possible, including a long shelf life, low monomer viscosity and volatility, rapid polymerization at ambient conditions, and low shrinkage following polymerization.
Often structural cracks occur in polymers that are almost impossible to detect or repair, but in the self-healing composite the structural cracks are repaired as soon as they rupture the microcapsules. White says work continues on increasing the material's healing capabilities by developing the smallest capsule possible while still maintaining the composite's structural matrix.
Even in its early development, the composite already shows great potential, according to White. "This technology could increase the lifetime of structural components by as much as two or three times," White says, adding that the material can be used in any application that involves the use of a polymer.
The most obvious medical application for the composite is implantable medical devices, but in the future, the technology could be used in tissue generation to produce skin or capillaries, White says.
Jamie Graham
Copyright ©2001 European Medical Device Manufacturer
