Powder Distribution for Laser Sintering Systems

Abstract

There is provided improved laser sintering systems that increase the powder density and reduce anomalies of the powder layers that are sintered, that measure the laser power within the build chamber for automatic calibration during a build process, that deposit powder into the build chamber through a chute to minimize dusting, and that scrubs the air and cools the radiant heaters with recirculated scrubbed air. The improvements enable the laser sintering systems to make parts that are of higher and more consistent quality, precision, and strength, while enabling the user of the laser sintering systems to reuse greater proportions of previously used but unsintered powder.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]The present application claims priority pursuant to 35 U.S.C. 119(e) to U.S. Provisional Application, Ser. No. 61 / 793,870, filed Mar. 15, 2013.FIELD OF THE INVENTION[0002]The present invention is related to laser sintering systems, and more particularly, to laser sintering systems apparatus and methods for improving part quality and reduced disposal of used, unsintered powder.BACKGROUND OF THE INVENTION[0003]Laser sintering is one form of additive manufacturing that fabricates three-dimensional objects from digital data. As known in the art, laser sintering heats layers of powder, typically a polymer or a metal, with a laser to cause the powder particles to fuse to one another in predetermined patterns to define the cross-sectional layers of the object being fabricated. Such techniques are disclosed in U.S. Pat. Nos. 4,863,538; 5,155,321; 5,252,264; 5,352,405; 6,815,636; 7,569,174; and 7,807,947, the disclosures of which are incorporated b...

AI Technical Summary

Benefits of technology

The present invention provides methods and devices to improve the quality of parts produced by laser sintering. The invention addresses issues such as surface roughness and reduced strength of parts caused by unfavourable surface features. The invention uses a two-pass approach to apply a powder layer with improved uniformity and density. A chute device is used to minimize the distance powder needs to fall, reducing the amount of dust created. A roller heater is positioned to evenly heat the roller surface and prevent temperature gradients that lead to uneven powder surfaces. An air scrubber is used to clean the air within the build chamber and recirculate it back into the chamber to cool the heaters without creating significant turbulence. The invention results in improved part quality and reduced waste material.

Problems solved by technology

The build chamber of a laser sintering system is typically very hot and includes fumes and dust that can adversely affect surfaces.

The roller may be rotated so that the roller heater evenly heats the surface of the roller to prevent temperature gradients on the roller surface which can lead to undesirable adhesion of powder to some, but not all, surfaces of the roller which results in powder being slung behind the roller which further results in uneven powder surfaces that ultimately result in rough surfaces or other imperfections in the final part.

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