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Layer-by-Layer: The Evolution of 3-D Printing

IEEE member Charles Hull invented the original process in 1983

4 min read
Photo of IEEE Member Charles Hull with a 3-D printed bust of himself.
Photo: European Patent Office

THE INSTITUTENearly three decades ago, long before machine parts, jewelry, toys, and even artificial organs were being created with 3-D printers, IEEE Member Charles Hull printed a small cup using ultraviolet light and a vat of plastic goop using a process he invented called stereolithography.

The technique involves curing and bonding a liquid photopolymer with ultraviolet (UV) light, then building 3-D structures layer by layer as the plastic hardens. Stereolithography is still used by many of today’s industrial 3-D printers, but the devices are no longer found only in factories. Over the last three decades, these printers have gotten smaller and more affordable. Now, 3-D printers can be found in laboratories, small businesses, and even people’s homes.

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Economics Drives Ray-Gun Resurgence

Laser weapons, cheaper by the shot, should work well against drones and cruise missiles

4 min read
In an artist’s rendering, a truck is shown with five sets of wheels—two sets for the cab, the rest for the trailer—and a box on the top of the trailer, from which a red ray is projected on an angle, upward, ending in the silhouette of an airplane, which is being destroyed

Lockheed Martin's laser packs up to 300 kilowatts—enough to fry a drone or a plane.

Lockheed Martin

The technical challenge of missile defense has been compared with that of hitting a bullet with a bullet. Then there is the still tougher economic challenge of using an expensive interceptor to kill a cheaper target—like hitting a lead bullet with a golden one.

Maybe trouble and money could be saved by shooting down such targets with a laser. Once the system was designed, built, and paid for, the cost per shot would be low. Such considerations led planners at the Pentagon to seek a solution from Lockheed Martin, which has just delivered a 300-kilowatt laser to the U.S. Army. The new weapon combines the output of a large bundle of fiber lasers of varying frequencies to form a single beam of white light. This laser has been undergoing tests in the lab, and it should see its first field trials sometime in 2023. General Atomics, a military contractor in San Diego, is also developing a laser of this power for the Army based on what’s known as the distributed-gain design, which has a single aperture.

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