Abstract: Additive layer manufacturing apparatus utilizing a housing, which bounds a vacuum chamber and has a window for monitoring a region of the chamber in which additive layer manufacturing is to be carried out, and an electron beam column for generating an electron beam and transmitting the beam through the chamber to the region for action on successive layers of fusible powder material, particularly metallic material, to produce an article therefrom. In order to combat the problem of deposition on the window of metal material escaping from the layer as gaseous phase constituents with a boiling point below the melting point of the material, an optical element is arranged in the chamber to intercept such liberated gaseous phase constituents, which in a vacuum environment in the chamber travel along an optical path between the region and the window, and optical element heating means substantially preventing condensation of the intercepted constituents.

Abstract: A computer-implemented method of generating scan instructions for forming a product using additive layer manufacture as a series of layers is provided.

Abstract: A method of additive layer manufacture includes the steps of successively depositing layers of fusible powder material in overlying relationship and introducing energy, such as by an electron beam, into each deposited layer to selectively melt material in the layer so as to fuse the melted material together and to already fused material of a layer thereunder in order to produce a three-dimensional solid article in successive cross-sectional layers. In order to monitor layer quality, structured light defining a fringe pattern is projected onto each deposited layer before and/or after melting of material in that layer and the fringe pattern on each layer is imaged from a perspective different from that of the projection so as to reveal disturbance of the pattern by topographical features of the layer.

Abstract: A method of charge mitigation in additive layer manufacturing is provided, which uses a charged particle beam (103) to fuse metal powder (122) within a metal powder bed (123) to form a product layer-by-layer, the method comprising using a charged particle beam optical system to form a charged particle beam, to steer the charged particle beam to be incident on a powder bed of metal powder and to scan over the powder bed to fuse powder into a desired layer shape. While steering the charged particle beam, the method comprises using a neutralising particle source (160) to generate neutralising particles of an opposite charge to the charged particles in the vicinity of the charged particle beam such that the neutralising particles are attracted to the charged particles of powder in the powder bed. An additive layer manufacturing apparatus (100) is also provided.

Abstract: A method of additive layer manufacture includes the steps of successively depositing layers of fusible powder material in overlying relationship and introducing energy, such as by an electron beam, into each deposited layer to selectively melt material in the layer so as to fuse the melted material together and to already fused material of a layer thereunder in order to produce a three dimensional solid article in successive cross-sectional layers. In order to monitor layer quality, structured light defining a fringe pattern is projected onto each deposited layer before and/or after melting of material in that layer and the fringe pattern on each layer is imaged from a perspective different from that of the projection so as to reveal disturbance of the pattern by topographical features of the layer.

Abstract: Additive layer manufacturing apparatus utilizing a housing, which bounds a vacuum chamber and has a window for monitoring a region of the chamber in which additive layer manufacturing is to be carried out, and an electron beam column for generating an electron beam and transmitting the beam through the chamber to the region for action on successive layers of fusible powder material, particularly metallic material, to produce an article therefrom. In order to combat the problem of deposition on the window of metal material escaping from the layer as gaseous phase constituents with a boiling point below the melting point of the material, an optical element is arranged in the chamber to intercept such liberated gaseous phase constituents, which in a vacuum environment in the chamber travel along an optical path between the region and the window, and optical element heating means substantially preventing condensation of the intercepted constituents.

Abstract: A computer-implemented method of generating scan instructions for forming a product using additive layer manufacture as a series of layers is provided.

Abstract: A method of charge mitigation in additive layer manufacturing is provided, which uses a charged particle beam (103) to fuse metal powder (122) within a metal powder bed (123) to form a product layer-by-layer, the method comprising using a charged particle beam optical system to form a charged particle beam, to steer the charged particle beam to be incident on a powder bed of metal powder and to scan over the powder bed to fuse powder into a desired layer shape. While steering the charged particle beam, the method comprises using a neutralising particle source (160) to generate neutralising particles of an opposite charge to the charged particles in the vicinity of the charged particle beam such that the neutralising particles are attracted to the charged particles of powder in the powder bed. An additive layer manufacturing apparatus (100) is also provided.