Extraction system for apparatus for the layer-by-layer formation of three-dimensional objects, and associated methods and controller

Abstract

An apparatus for the layer-by-layer formation of three-dimensional objects, the apparatus comprising a gas extraction system and an enclosed working space from which gas is to be extracted, wherein the working space is enclosed by side walls, a ceiling and a working surface, and comprises a working space inlet for allowing gas to enter into the working space, a working space outlet for allowing gas to exit the working space, and a build bed surface in which a layer of the object is formed; wherein the gas extraction system comprises: a primary conduit comprising at least a first primary inlet, at least a first interfacing inlet, and a primary outlet; and at least a first secondary conduit comprising a respective first secondary inlet and a respective first secondary outlet, the first secondary inlet being in fluidic communication with the working space for extracting gas from the working space, and the first secondary outlet being in fluidic communication with the first interfacing inlet; wherein the or each primary inlet is open to an environment external to the working space, and wherein the primary outlet is connectable to an external extraction source so as to suction gas from the primary conduit; and wherein the gas extraction system further comprises one or more flow control devices for controlling the flow of gas from the working space into the first secondary conduit, and thence into the primary outlet of the primary conduit. Methods for operating the apparatus, and a controller for controlling the apparatus and carrying out the methods, are also provided.