|From: The Ox||5/18/2020 11:44:26 AM|
Bursting your (tiny) bubbles: new research points the way toward pore-free 3-D printing
by Andre Salles, Argonne National Laboratory
What this research team found surprised even them. In a paper published in Nature Communications, the group described the three forces acting upon pores within the melt pool: buoyancy, which should force the gas up and out of the melt area; melt flow drag, which should swirl the gas around within the molten pool; and thermocapillary force, which drives the pores to move along the temperature gradient.
Of these three forces, they discovered that the thermocapillary force in certain area of the molten pool exerts the most influence over where the pores ended up. The drag created by the melting liquid metal is second, which means that the natural tendency of these gas pockets to move upward and out of the melt area was countered.
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|From: Savant||6/25/2020 11:22:02 AM|
|Medical Engineers 3D Print Sensors Directly Onto A Moving Lung|
Video of printing @ link
If you’d finally got your head around the concept of 3D printing, it just got a whole lot weirder. In a groundbreaking feat of medical engineering, a team of scientists from the University of Minnesota have successfully used 3D-printing technologies to apply sensors to a moving lung. Using motion capture technology straight out of Hollywood, the researchers hope their breakthrough could have future applications in monitoring the heart and lung function of patients with illnesses such as Covid-19 where symptoms can be elusive. Their findings are published in the journal Science Advances.
While printing physical objects is old news, this is the first time sensors have been printed directly onto organs that warp in shape as they expand and contract. The invention is part of a new generation of 3D printing technologies and was discovered two years ago by scientists from the University of Minnesota. The same team was responsible for 3D printing directly onto the skin of a moving hand but have now taken their technique further by tracking moving organs like the lungs or heart. The technology successfully printed a functional sensor on the tissue’s surface by mapping the organ as it expanded and contracted.
"We are pushing the boundaries of 3D printing in new ways we never even imagined years ago," said Michael McAlpine, a University of Minnesota mechanical engineering professor and senior researcher on the study, in a statement. "3D printing on a moving object is difficult enough, but it was quite a challenge to find a way to print on a surface that was deforming as it expanded and contracted."
Their creation began by testing on a balloon-like surface to understand the complexities of 3D printing on a changing platform. Using motion capture tracking markers, like those placed on anchors to improve special effects in cinema, the printer could map its printing path, taking into consideration the warping of the printing plane. Once successful with the balloon, they moved onto a porcine lung that was artificially inflated to mimic breathing. The technique successfully printed a hydrogel-based sensor onto the surface of the lung even as it “breathed”. McAlpine said the technique could also possibly be used in the future to 3D-print sensors on a pumping heart. The team hope the same approach can one day be applied to the lungs, heart, and other tissues of living patients to improve patient monitoring and wound treatment.
"The broader idea behind this research, is that this is a big step forward to the goal of combining 3D printing technology with surgical robots," said McAlpine in a statement. "In the future, 3D printing will not be just about printing but instead be part of a larger autonomous robotic system. This could be important for diseases like Covid-19 where health care providers are at risk when treating patients."
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