The invention discloses a method for preparing an anticorrosive surface layer of a metal material in a marine environment by laser, which belongs to the technical field of laser processing. First, the laser cladding method is used to prepare a cladding surface layer on the surface of the metal material that is not easy to undergo chemical substitution reaction with the chlorides (NaCl, MgCl.sub.2 , CaCl.sub.2 etc.) in the seawater. Then, on the surface of the cladding surface layer, ultrafast laser processing is used to form a surface layer with a wetting angle (and water) greater than 90 degrees and with hydrophobic characteristics.

Aspects of the disclosure include air flow systems configured to regulate air flow when laser welding to improve laser weld quality. An exemplary air flow system can include a primary inlet coupled to an air source and one or more secondary inlets coupled to the primary inlet. At least one of the one or more secondary inlets can include an internal valve. Each internal valve is actuatable between a fully open state, a fully closed state, and an intermediate state. The air flow system can further include an outlet coupled to each of the one or more secondary inlets downstream of the internal valve and a controller configured to adjust a position of each internal valve. The controller is configured to adjust the position of each internal valve based on an air flow mapping to increase an average air flow velocity along a laser beam of a welding laser.

A device including a chamber and a nozzle detachably connected to the chamber, the nozzle defining an aperture, a target carousel disposed within the chamber, a first laser configured to generate a first beam directed toward the target carousel to perform in-situ ablation to form a laser plume, a gas flow system configured to supply gas into the chamber, such that the gas interacts with the laser plume and causes condensation and formation of nanoparticles, and a second laser configured to generate a second beam directed through the interior of the chamber, through the aperture of the nozzle, and toward a substrate disposed outside the device, the second laser beam configured to sinter and crystalize on the substrate the nanoparticles exiting the nozzle.

Selective laser solidification apparatus is described that includes a powder bed onto which a powder layer can be deposited and a gas flow unit for passing a flow of gas over the powder bed along a predefined gas flow direction. A laser scanning unit is provided for scanning a laser beam over the powder layer to selectively solidify at least part of the powder layer to form a required pattern. The required pattern is formed from a plurality of stripes or stripe segments that are formed by advancing the laser beam along the stripe or stripe segment in a stripe formation direction. The stripe formation direction is arranged so that it always at least partially opposes the predefined gas flow direction. A corresponding method is also described.

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 laser processing system herein includes a laser oscillator, a laser optical path that guides laser beam from a laser beam emission port of the laser oscillator to a workpiece, an impure gas absorbent for absorbing impure gases that influence the propagation of the laser beam, and a shutter that exposes the impure gas absorbent in the laser optical path.

A laser processing apparatus includes: a scan moving unit which moves one or both of a workpiece and a laser beam; a laser beam irradiation unit which irradiates the workpiece with the laser beam; and a gas discharge unit which discharges at least a first gas to an irradiation area irradiated with the laser beam in the workpiece. The gas discharge unit has a rectifying surface at a position facing the workpiece during laser beam irradiation. The rectifying surface is provided with a first gas discharge port through which the first gas is discharged; and one or both of a second gas discharge port and a gas front-back suction port. The second gas discharge port discharges a second gas to the workpiece during laser beam irradiation on both outer sides of the first gas discharge port at least in the scanning direction.

A laser build-up method according to an embodiment includes the processes of: forming an annular counter sunk groove 15 in an edge of an opening of a port on a side of a combustion chamber; and irradiating a laser beam 30 while a metallic powder 26 is being supplied to the counter sunk groove 15 and successively forming a cladding layer 16 for a valve seat, in which: the cladding layer 16 is formed while a seal gas 24 is being sprayed onto a melt pool 31, the cladding layer 16 includes a starting end part 17a, a part formed just after the starting end part is formed 18a, an intermediate part 18b, a part formed just before a terminating end part is formed 18c, and a terminating end part 17b, which are formed in this order.

A flow control device for an additive manufacturing system is provided. The flow control device includes a gas supply configured to discharge a gas, a first flow modifier configured to modify at least one flow characteristic of a first portion of the gas, and a second flow modifier configured to cooperate with the first flow modifier to modify the at least on flow characteristic of the first portion of the gas. The second flow modifier is further configured to modify at least one flow characteristic of a second portion of the gas, and the first flow modifier and the second flow modifier are configured to cooperate to direct at least a portion of the first portion and the second portion of the gas towards a melt pool in a plurality of particles.

A method for machine processing, in particular for machine welding processing of workpieces, in particular of plate-like workpieces, tubes and/or profiles, by means of a thermal processing beam, in particular by means of a processing beam is described, wherein the processing of the workpiece is carried out with a relative movement between the processing beam and the workpiece, wherein a process gas is fed to a processing zone in a settable quantity of process gas per unit of time. After a stored stabilization time, in which the processing of a workpiece is continued with a relative movement between the processing beam and the workpiece, a quantity of process gas per unit of time is automatically reduced. Further a control apparatus of a setting device for process gas feed according to such a method is described.