Counterflow gas flow delivery structure for apparatus for the layer-by-layer formation of three-dimensional objects

Abstract

A structure for delivering a flow of gas across a window or aperture of an imaging or measurement device within an apparatus for the manufacture of three-dimensional objects by layer-by-layer consolidation of particulate matter, the structure comprising: a hollow body having an upper aperture for mounting in correspondence with the window/aperture of said device, a gas flow intake region below the upper aperture, and a lower aperture; wherein the gas flow intake region is provided on opposing sides of the hollow body when viewed in cross-section along a longitudinal axis that runs from the upper aperture to the lower aperture, and comprises one or more channels configured to allow, in use, a flow of intake gas to enter the hollow body from the opposing sides of the hollow body with a flow component that predominantly lies in a plane parallel to the plane of the upper aperture, and to come into confluence within the hollow body; and wherein the hollow body is symmetrically shaped about the longitudinal axis so as to redirect the confluent flow of intake gas to form a substantially axial flow of gas along the longitudinal axis, and a backflow of gas near the internal wall of the hollow body, wherein the upper aperture is substantially shielded from the backflow by the intake flow, and wherein the velocity of the backflow is relatively low in comparison to the velocity of the intake flow. Also provided is an apparatus for the manufacture of three-dimensional objects by layer-by-layer consolidation of particulate matter, incorporating such a structure, and a method of delivering a flow of gas using such a structure.