Laser sintering powder recycle system

Abstract

A method and apparatus for forming three-dimensional objects by laser sintering that includes the use of dense phase pneumatic conveying to internally recycle overflow powder, and to thoroughly blend overflow, recovered and virgin powder to provide a consistent powder feed mix to a laser sintering machine. Overflow powder from the laser sintering machine is recovered and recycled back into the laser sintering machine for reuse. The approach results in a compact and reliable powder recycle system with complete blending and minimum attrition to the handled powder.

Description

BACKGROUND OF THE INVENTION [0001] This invention is in the field of freeform fabrication, and is more specifically directed to the fabrication of three-dimensional objects by selective laser sintering. [0002] The field of freeform fabrication of parts has, in recent years, made significant improvements in providing high strength, high density parts for use in the design and pilot production of many useful articles. Freeform fabrication generally refers to the manufacture of articles directly from computer-aided-design (CAD) databases in an automated fashion, rather than by conventional machining of prototype articles according to engineering drawings. As a result, the time required to produce prototype parts from engineering designs has been reduced from several weeks to a matter of a few hours. [0003] By way of background, an example of a freeform fabrication technology is the selective laser sintering process practiced in systems available from 3D Systems, Inc., in which articles...

AI Technical Summary

Benefits of technology

[0016] It is an advantage of the present invention that the powder recycle system achieves excellent blending of fresh or virgin powder with overflow and recovered powder to reduce powder loss and achieve consistent and uniform powder quality for use in a laser sintering system.

[0017] It is another advantage of the present invention that part artifacts from poor powder blending are reduced in parts produced in a laser sintering machine utilizing the powder recycle system.

[0018] It is still another advantage of the present invention that a low cost, automated powder handling system for a laser sintering machine is provided.

[0019] It is yet another advantage of the present invention that more uniform virgin powder and recovered powder are obtained.

[0020] It is a further advantage of the present invention that a compact, reliable powder handling system is provided that recycles for reuse overflow powder within a laser sintering machine.

[0021] It is still a further advantage of the present invention that powder stratification among virgin or fresh, recovered and overflow powder in blended powder within the powder recycle system is eliminated or minimized.

Problems solved by technology

These systems tend to take up a large amount of floor space and can be expensive because they have to handle large amounts of powder and use mechanical conveying systems such as spiral conveyors to move powder around.

The use of mechanical spiral conveyors can lead to powder attrition issues with some powders.

These systems also can have poor blending of different quality powders, leading to artifacts in the parts produced.

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