A route for avoiding defects during additive manufacturing

A route for avoiding defects during additive manufacturing
Artwork showing the boundary and origin of keyhole porosity. On the left side of the figure, the keyhole porosity boundary in the laser power – scan velocity space is sharp and smooth. On the right side, around the porosity boundary, the critical keyhole instability releases acoustic waves (shock waves) in the melt pool. The waves then drive the pore near the keyhole tip to accelerate rapidly away from the keyhole. When the pore is captured by the solidification front, it becomes a detrimental structural defect in the build. Credit: Ye Feng, Cang Zhao at Tsinghua University

Laser powder bed fusion is a dominant additive manufacturing technology that has yet to reach its potential. The problem facing industry is that tiny bubbles or pores sometimes form during the printing process, and these pores create weak spots in finished products.


When a slow-speed, high-power laser is melting metal powder during the 3-D

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Scientists regenerate skin with stem cells to see how DNA defects in kids cause cancer

Scientists regenerate skin with stem cells to see how DNA defects in kids cause cancer
Shown are microscopic images of human epidermis with pluripotent stem cells derived from donated skin cells. The images on the left are epidermis from a healthy control subject, the images at right being from a person with Fanconi anemia. The colorful confocal images (bottom) offer a more superficial view that does not reveal differences between control and FA samples. The black and white electron microscopic images, with 1,000-fold greater magnification, do reveal defects in the FA epidermis. Researchers studying Fanconi anemia-related skin disease and cancer report new data in Cell Stem Cell. Credit: Cincinnati Children’s

Physicians and scientists at Cincinnati Children’s Hospital Medical Center used new stem cell technology to regenerate and study living patient-specific skin in the lab, giving them a precise close up view of how inherited DNA defects cause skin damage and deadly squamous cell carcinoma in children and young adults with Fanconi anemia (FA).

Reporting

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