Friday, December 28, 2012

3-D Manufacturing

From DW, an article on customizable "mass" production using 3-D printers, discussing the current status and problems, and possible solutions:
Until now, products printed using 3D have mostly been prototypes. But the technology can also be applied to serial production, and is set to revolutionize industry, the nature of production, and consumption.

... The technology for printing components in 3D form has already been available for several years. Until now, it has mainly been used for manufacturing rare or expensive prototypes for the research and development departments of major companies. But the technology has advanced enough to be put to use elsewhere, and is now increasingly being used in serial production. The big advantage of this technique is that each component can still be different, even as part of a series.

The sky's the limit
All sorts of objects can be printed directly using 3D technology. The most common process involves selective laser melting (SLM).... First a laser beam fuses the contours of the object into an extremely thin layer of plastic and metal powder. Then the machine pushes fresh powder over it, and the laser melts on another layer. Layer for layer, a new component is created.

Other processes exist which do not require powder, and which are even more similar to an ink-jet printer: for example, a print head shooting melted plastic, layer for layer, onto a plate.
Such printers can manufacture more or less anything, as long as a computer model for it exists and the objects aren't larger than the printers themselves. Materials of all sorts can also be printed: plastics, alloys, even glass and ceramics. Metal components produced in this way are just as durable as those that are cast or forged. Furthermore, the manufacturing process creates no waste, as any leftover powder is simply reused.

Computer tomography can even be employed to make 3D images for the digital models. That's one reason why this technology is absolutely booming in the field of medicine. Each year, thousands of individual implants - such as cobalt-chrome knee replacements and titanium hip prostheses - are made using the technology.

In the future, end consumers could design their own models on computers and then send the files to manufacturers via the Internet. The objects would then be printed and sent back to customers. "This means that customers will be much more intensively involved in the product development process," says Meiners.

... But the technology faces one major hurdle: the printing process simply takes too long. It can take hours for a printer to create even the smallest objects, since the layers that compose them are exceedingly thin.

That's why researchers and manufacturers are working to improve the machines - for example, by using more intense lasers that can melt the powder faster. However, this is only possible when the materials can withstand the heat without evaporating. Where that doesn't work, manufacturers aim to use more laser heads simultaneously.

... It would be more efficient, Uckelmann says, if the implants came out of the machine one by one as each is finished, like on a conveyor belt. ... But this only works when the powder is slanted toward the construction platform....

Printing components in this tilted position is then not only faster: "You can also manufacture products that are as long as you want them to be," Uckelmann explains. "Theoretically, I could print out a wing for an Airbus plane, provided I had a machine that was deep enough - that would be no problem."

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