The present disclosure generally relates to additive manufacturing systems and methods on a large-scale format. One aspect involves a build unit that can be moved around in three dimensions by a positioning system, building separate portions of a large object. The build unit has an energy directing device that directs, e.g., laser or e-beam irradiation onto a powder layer. In the case of laser irradiation, the build volume may have a gasflow device that provides laminar gas flow to a laminar flow zone above the layer of powder. This allows for efficient removal of the smoke, condensates, and other impurities produced by irradiating the powder (the “gas plume”) without excessively disturbing the powder layer. The build unit may also have a recoater that allows it to selectively deposit particular quantities of powder in specific locations over a work surface to build large, high quality, high precision objects.

A gas concentration meter includes a first gas concentration detection sensor capable of detecting at least a gas concentration in a first concentration range, a second gas concentration detection sensor capable of detecting at least a gas concentration in a second concentration range, and a control unit. An upper limit value of the second concentration range is lower than an upper limit value of the first concentration range, and a lower limit value of the second concentration range is lower than a lower limit value of the first concentration range. The control unit is configured to output either the lower limit value of the first concentration range or the upper limit value of the second concentration range as an indication value when an output signal of the first gas concentration detection sensor corresponds to a gas concentration lower than the lower limit value of the first concentration range.

A gas concentration meter includes a first gas concentration detection sensor capable of detecting at least a gas concentration in a first concentration range, a second gas concentration detection sensor capable of detecting at least a gas concentration in a second concentration range, and a control unit. An upper limit value of the second concentration range is lower than an upper limit value of the first concentration range, and a lower limit value of the second concentration range is lower than a lower limit value of the first concentration range. The control unit is configured to output either the lower limit value of the first concentration range or the upper limit value of the second concentration range as an indication value when an output signal of the first gas concentration detection sensor corresponds to a gas concentration lower than the lower limit value of the first concentration range.

The invention relates to a control method for controlling a multi-beam apparatus having one or more beam sources for producing a plurality of beams of a system for manufacturing a three-dimensional workpiece by means of an additive layer construction method, in which method a material that can be solidified in order to manufacture the three-dimensional workpiece is applied in layers to a surface of a carrier and the material that can be solidified is solidified by the plurality of beams in a respective layer at points of incidence of the plurality of beams on the material that can be solidified, wherein the points of incidence of the beams for solidifying selective regions of the layers of the material that can be solidified in order to manufacture the three-dimensional workpiece are each controlled substantially against a gas flow direction of a gas flow over the surface of the carrier; wherein the control method comprises (a) dividing the material to be solidified in the respective layer into at least two sections, wherein two of the at least two sections extend in the gas flow direction of the gas flow prevailing over the two of the at least two sections in succession at least in part, (b) dividing at least one of the two of the at least two sections into at least two surface pieces, (c) assigning each of the surface pieces to exactly one specific beam, which solidifies the material to be solidified in the assigned surface piece, (d) controlling the points of incidence of the beams such that, at at least one point in time during an exposure of the material to be solidified, the material to be solidified is solidified in at least two surface pieces, and a network consisting of straight lines extending between each center point of the points of incidence to every other center point of the points of incidence, at no point in time during the exposure, in which all center points of the points of incidence are located outside of a predetermined distance from each other, has a straight line parallel to the gas flow direction of the gas flow prevailing over the two of the at least two sections.

We describe an apparatus for producing a three-dimensional workpiece, the apparatus comprising: a process chamber for receiving a material from which the three-dimensional workpiece is producible using an additive layer manufacturing technique, wherein the process chamber comprises a translucent window; an irradiation device for irradiating, through the translucent window, the material for producing the three-dimensional workpiece; and an enclosure arranged between the translucent window of the process chamber and the irradiation device, wherein at least a part of the enclosure is translucent for an irradiation beam stemming from the irradiation device to travel from the irradiation device through the enclosure to the material for producing the three-dimensional workpiece, wherein the enclosure comprises an inlet and an outlet, and wherein the apparatus is configured to control a flow of a fluid through the enclosure via the inlet and the outlet.

An additive manufacturing apparatus of the disclosure includes: a supply port that supplies an inert gas to a chamber; a supply nozzle which is attached to the supply port and releases two layers of airflow having different speeds toward the window; and a discharge port that discharges the inert gas from the chamber. The supply nozzle has: a first nozzle member having an inlet surface connected to the supply port; a net-like member which has a plurality of through holes and is attached in a manner of covering a portion of a lower part of an outlet surface of the first nozzle member; and a second nozzle member that is attached to the upper side of the outlet surface of the first nozzle member.

Disclosed is a system for depowdering a workpiece formed from a reactive powder by an additive manufacturing process. The system includes a powder removal enclosure, an inert gas source, a sealed ultrasonic transducer, an oxygen sensor, and a controller coupled to the sealed ultrasonic transducer and the oxygen sensor. The controller is configured to perform a plurality of operations including monitoring the oxygen sensor to observe an oxygen level within the powder removal enclosure as an inert gas from the inert gas source displaces a gas environment within the powder removal enclosure, and applying electrical power to the sealed ultrasonic transducer within the powder removal enclosure to ultrasonically remove a residual amount of the reactive powder from the workpiece based on determining that the oxygen level within the powder removal enclosure is below a minimum oxygen level threshold.

Disclosed is a system for depowdering a workpiece formed from a reactive powder by an additive manufacturing process. The system includes a powder removal enclosure, an inert gas source, a sealed ultrasonic transducer, an oxygen sensor, and a controller coupled to the sealed ultrasonic transducer and the oxygen sensor. The controller is configured to perform a plurality of operations including monitoring the oxygen sensor to observe an oxygen level within the powder removal enclosure as an inert gas from the inert gas source displaces a gas environment within the powder removal enclosure, and applying electrical power to the sealed ultrasonic transducer within the powder removal enclosure to ultrasonically remove a residual amount of the reactive powder from the workpiece based on determining that the oxygen level within the powder removal enclosure is below a minimum oxygen level threshold.

A module for an additive manufacturing apparatus including more than one optical train, each optical train providing a route for a laser beam to pass through the module and including steering optics for steering the laser beam towards the material to be consolidated as part of a layer-by-layer additive manufacturing process. The module is configured to deliver laser beams from the more than one optical trains through a single window in a build chamber of the additive manufacturing apparatus.

A module for an additive manufacturing apparatus including more than one optical train, each optical train providing a route for a laser beam to pass through the module and including steering optics for steering the laser beam towards the material to be consolidated as part of a layer-by-layer additive manufacturing process. The module is configured to deliver laser beams from the more than one optical trains through a single window in a build chamber of the additive manufacturing apparatus.