Patent. Source: Kheng Guan Toh/Shutterstock.com
Patent. Source: Kheng Guan Toh/Shutterstock.com

On January 28th, 2014, Carl Deckard’s patent for Selective Laser Sintering (SLS) technology expired. This expiration opens up the market for SLS 3D printers, which will allow the printers to become more affordable as time goes on.

Part of the description for Deckard’s patent states, “An apparatus for selectively sintering a layer of powder to produce a part made from a plurality of sintered layers. The apparatus includes a computer controlling a laser to direct the laser energy onto the powder to produce a sintered mass. The computer either determines or is programmed with the boundaries of the desired cross-sectional regions of the part. For each cross-section, the aim of the laser beam is scanned over a layer of powder and the beam is switched on to sinter only the powder within the boundaries of the cross-section.

“Powder is applied and successive layers sintered until a completed part is formed. Preferably, the powder dispensing mechanism includes a drum which is moved horizontally across the target area and counter-rotated to smooth and distribute the powder in an even layer across the target area. A downdraft system provides controlled temperature air flow through the target area to moderate powder temperature during sintering.”

Other key patents are set to expire this year, 2015, and 2016, including three SLA patents from 3D systems and six FDM patents from Stratasys. Other patents include “Simultaneous Multiple Layer Curing in Stereolithography” (April 25th, 2014), “Method and Apparatus for Producing a Three-dimensional Object by Stereolithography” (June 5th, 2015, 3D Systems), and “Method and Apparatus for Prototyping a Three-dimensional Object” (December 20th, 2016, Z-Corp).