Measuring UV curing parameters of commercial photopolymers used in AM

A testing methodology was developed to expose photopolymer resins and measure the cured material to determine two key parameters related to the photopolymerization process: Ec (critical energy to initiate polymerization) and Dp (penetration depth of curing light).

Five commercially available resins were evaluated under exposure from 365 nm and 405 nm light at varying power densities and energies. Three different methods for determining the thickness of the cured resin were evaluated. Caliper measurements, stylus profilometry, and confocal laser scanning microscopy showed similar results for hard materials while caliper measurement of a soft, elastomeric material proved inaccurate.

Working curves for the five photopolymers showed unique behavior both within and among the resins as a function of curing light wavelength. Ec and Dp for the five resins showed variations as large as 10x. Variations of this magnitude, if unknown to the user and not controlled for, will clearly affect printed part quality. This points to the need for a standardized approach for determining and disseminating these, and perhaps, other key parameters.

Read more:

https://www.sciencedirect.com/science/article/pii/S2214860417301732

UAVs for 3D Mapping

Lockheed Martin has released a commercial software, named Hydra Fusion Tools, that allows to create a real-world 3D Map of any site. Hydra Fusion runs on commercial computers leveraging state-of-the-art graphical processing units, to render the entire evolving scene in real time, as the UAV flies: The images are geometrically stitched together into an immersive three dimensional world view, showcasing buildings, trees, vehicles, terrain, etc.

“Hydra Fusion Tools’ stand-out feature is its ability to turn big data into actionable intelligence,” says John Molberg, business development manager at Lockheed Martin CDL Systems. “This is true world-leading technology – there is nothing else out there that does this, everything else is just post-processing.”

The system comes in two variants: the baseline Hydra for commercial use, with agriculture and first responder application, and Hydra Tactical, which is specifically for military use.