US-12623400-B2 - Counterflow gas flow delivery structure for apparatus for the layer-by-layer formation of three-dimensional objects

US12623400B2US 12623400 B2US12623400 B2US 12623400B2US-12623400-B2

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.

Inventors

Gianluca Dorini
Anders HARTMANN
Marcel GARRIDO BARRABES

Assignees

STRATASYS POWDER PRODUCTION LTD.

Dates

Publication Date: 20260512
Application Date: 20201223
Priority Date: 20191230

Claims (7)

1 . 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 or aperture of said device, a lower aperture, a primary gas flow intake region and a secondary gas flow intake region, each arranged along at least part of a perimeter line of the hollow body and provided below the upper aperture and 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, wherein the primary gas flow intake region 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; wherein the one or more channels are each configured as an elongate through-hole extending in a direction of elongation along the perimeter line of the hollow body and being bounded by two side walls, wherein one of the two side walls is arranged at an acute angle to the perpendicular to the longitudinal axis such that the flow component enters the hollow body at an acute angle to a perpendicular to the longitudinal axis to create a circulating flow of gas into the hollow body; wherein the secondary gas flow intake region is provided on opposing sides of the hollow body when viewed in cross-section along the longitudinal axis, and comprises one or more secondary channels configured to allow, in use, a secondary flow of intake gas to enter the hollow body with a secondary flow component that is predominantly parallel to the internal wall of the hollow body, and wherein the secondary channels are arranged such that, in use, the secondary flow of gas flows in a rotational sense opposite to that of the primary flow of gas; 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 velocity of the backflow is relatively low in comparison to the velocity of the intake flow such that the upper aperture is substantially shielded from the backflow by the intake flow.
2 . The structure of claim 1 , wherein the elongate through-hole extends substantially perpendicular to the longitudinal axis of, and through the wall of, the hollow body.
3 . The structure of claim 1 , wherein the elongate through-hole includes side edges that are angled away from the perpendicular to the internal wall surface of the hollow body so that, in use, the flow component that predominantly lies in a plane parallel to the plane of the upper aperture is created.
4 . The structure of claim 1 , wherein the elongate through-hole is bounded by a lower edge and an upper edge connecting the two side walls, and one of the edges is angled away from the perpendicular to the internal wall surface of the hollow body so that, in use, the flow component that predominantly lies in a plane parallel to the plane of the upper aperture is created.
5 . The structure of claim 1 , wherein the elongate through-hole narrows in its cross-sectional area from the outer wall of the hollow body towards the internal wall of the hollow body.
6 . The structure of claim 1 , wherein, in use, the intake flow creates a continuous curtain of high velocity circulating gas parallel to and underneath the upper aperture, or angled down from the plane of the upper aperture, with respect to the velocity of the backflow of gas.
7 . The structure of claim 1 , wherein all of the channels are configured as elongate through-holes, and wherein the side walls between adjacent channels form a vane, each vane being arranged at an acute angle to the perpendicular to the longitudinal axis, such that the channels extend along the majority of the perimeter line of the hollow body and are separated by the vanes.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a National Stage Entry of International Application No. PCT/GB2020/053359, filed Dec. 23, 2020, which is based on and claims the benefit of foreign priority under 35 U.S.C. § 119 to GB Application No. 1919422.4, filed Dec. 30, 2019. This entire contents of the above-referenced applications are expressly incorporated herein by reference. The present disclosure relates to 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 (3D) objects by layer-by-layer consolidation of particulate matter, and to apparatus for the layer-by-layer formation of 3D objects comprising such a structure. The structure may be particularly suitable for use in powder bed applications that require infrared radiation. BACKGROUND Applications such as laser sintering, or so-called “print and sinter” techniques such as high speed sintering, for forming three-dimensional objects from particulate material are receiving increased interest as they are moving towards faster throughput times and become industrially viable. In these 3D manufacturing processes, the object is formed layer-by-layer from particulate material that is spread in successive layers across a build surface. Each layer of particulate matter is fused, or sintered, over defined regions to form a cross section of the three-dimensional object. These applications use infrared lamps to preheat the layer and/or to sinter the defined regions. For example, print and sinter applications use a high power infrared lamp to sinter areas of particulate material, such as polymer powder, that have been printed with radiation absorptive material (RAM). The 3D manufacturing process creates a hot dusty environment within the apparatus, that can compromise the ability to reliably measure properties of the process, such as build bed surface temperature, by depositing contaminants such as dust and fumes on sensitive components of measurement or imaging devices that are exposed to said environment within the apparatus. SUMMARY Aspects of the invention are set out in the appended independent claims, while particular embodiments of the invention are set out in the appended dependent claims. The following disclosure describes, in a first aspect, 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 is predominantly 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. According to a second aspect of the disclosure there is provided an apparatus for the manufacture of three-dimensional objects by layer-by-layer consolidation of particulate matter, the apparatus including: a build bed in which said objects are formed in use; an imaging or measurement device directed towards the surface of the build bed, said device having a window or aperture; and a structure in accordance with the first aspect, mounted in correspondence with the window/aperture of said device, for delivering a flow of gas across the window/aperture of said device. According to a third aspect of the disclosure there is provided a method of delivering a flow of gas across the window/aperture of the imaging or measurement device of the apparatus of the second aspect, the method comprising: supplying a flow of intake gas through the gas flow intake region of said structure, from opposing sides of the hollow body, and thence into the hollow body of said structure, the flow of intake gas having a flow component that is predominantly parallel to the plane of the upper aperture of said structure, and coming into confluence within the hollow body; and redirecting the confluent flow of intake gas to form a predominantly axial flo