Abstract: The invention relates to a 3D printer. The 3D printer includes a first feeder containing a metallic powder first print material, a second feeder containing a metallic powder second print material, delivery means that sprays the print materials, a holder holding a substrate, and a controller. As the print materials are sprayed from the delivery means the controller, which is computerized, adjusts the relative disposition of the delivery means and substrate, and the controller controls the first and second feeders to each feed their print material to the delivery means, so that the print materials form a 3D article on the substrate wherein different parts of the 3D article have different characteristics due to the different print materials or proportions thereof being used for different portions of the 3D article.

Abstract: Apparatus for forming a 3D object from powder, comprising: a) delivery means adapted to emit a flow of powder at sufficiently high velocity to enable it to form the 3D object; b) positioning means adapted adjust the position of the delivery means; and c) control means adapted to control: i) movement of the positioning means; and ii) the velocity of the flow of powder.

Abstract: An apparatus for producing a three-dimensional object by spray deposition including a powder conveyance line A arranged to channel a flow of spray material entrained in a carrier gas to a nozzle (a first flow). The apparatus also has a process line B arranged to channel a flow of gas to the nozzle (a second flow). The apparatus also has a spray nozzle. The apparatus is such that pressure and temperature parameters of the first flow are controlled in real time, but for the second flow these parameters are not controlled in real time. The two flows merge to cause spray material to be propelled from the nozzle to a substrate to create a three-dimensional object.

Abstract: A method of 3D printing an item, includes printing part of the item in three dimensions on a substrate, reorienting the part with respect to holding means that holds the part or substrate, and printing a further part of the item in three dimensions on the first mentioned part.