Examples of methods for predicting porosity are described herein. In some examples, a method includes predicting a height map. In some examples, the height map is of material for metal printing. In some examples, the method includes predicting a porosity of a precursor object. In some examples, predicting the porosity of the precursor object is based on the predicted height map.

A three-dimensional (3D) metal object manufacturing apparatus has a plurality of thermally insulative members that float in a volume of heat transfer lubricating fluid in which a X-Y translation mechanism moves to position a platform opposite an ejector. The apparatus also includes a housing having an internal volume in which the platform and X-Y translation mechanism are located. The heat transfer lubricating fluid can be a molten salt, such as a molten fluoride, chloride, or nitrate molten salt. The thermally insulative members can be spheres made of zirconium oxide or zirconium dioxide. The thermally insulative layer formed by the members floating in the fluid protects the X-Y mechanism while the housing helps keep the surface temperature of the object being formed on the platform in an optimal range for bonding of melted metal drops ejected from the ejector to a surface of a metal object being formed on the platform.

A three-dimensional (3D) metal object manufacturing apparatus has a plurality of thermally insulative members that float in a volume of heat transfer lubricating fluid in which a X-Y translation mechanism moves to position a platform opposite an ejector. The apparatus also includes a housing having an internal volume in which the platform and X-Y translation mechanism are located. The heat transfer lubricating fluid can be a molten salt, such as a molten fluoride, chloride, or nitrate molten salt. The thermally insulative members can be spheres made of zirconium oxide or zirconium dioxide. The thermally insulative layer formed by the members floating in the fluid protects the X-Y mechanism while the housing helps keep the surface temperature of the object being formed on the platform in an optimal range for bonding of melted metal drops ejected from the ejector to a surface of a metal object being formed on the platform.

A printing apparatus for printing a three-dimensional object comprising an operative surface, at least one supply hopper for depositing layers of powder onto the operative surface and an energy source for emitting at least one energy beam onto the layers of powder. The supply hopper and energy source are configured such that when a topmost layer of powder is being deposited onto an underlying layer of powder on the operative surface, the direction travelled by the supply hopper when depositing the topmost layer is different to the direction travelled by the supply hopper when depositing the underlying layer, and at least one energy beam is emitted onto the topmost layer and at least one further energy beam is emitted onto the underlying layer, simultaneously, to melt, fuse or sinter the topmost and underlying layers.

A printing apparatus for printing a three-dimensional object comprising an operative surface, at least one supply hopper for depositing layers of powder onto the operative surface and an energy source for emitting at least one energy beam onto the layers of powder. The supply hopper and energy source are configured such that when a topmost layer of powder is being deposited onto an underlying layer of powder on the operative surface, the direction travelled by the supply hopper when depositing the topmost layer is different to the direction travelled by the supply hopper when depositing the underlying layer, and at least one energy beam is emitted onto the topmost layer and at least one further energy beam is emitted onto the underlying layer, simultaneously, to melt, fuse or sinter the topmost and underlying layers.

A 3D printer includes a nozzle configured to jet a drop of liquid metal therethrough. The 3D printer also includes a light source configured to illuminate the drop with a pulse of light. A duration of the pulse of light is from about 0.0001 seconds to about 0.1 seconds. The 3D printer also includes a camera configured to capture an image, video, or both of the drop. The 3D printer also includes a computing system configured to detect the drop in the image, the video, or both. The computing system is also configured to characterize the drop after the drop is detected. Characterizing the drop includes determining a size of the drop, a location of the drop, or both in the image, the video, or both.

A 3D printer includes a nozzle configured to jet a drop of liquid metal therethrough. The 3D printer also includes a light source configured to illuminate the drop with a pulse of light. A duration of the pulse of light is from about 0.0001 seconds to about 0.1 seconds. The 3D printer also includes a camera configured to capture an image, video, or both of the drop. The 3D printer also includes a computing system configured to detect the drop in the image, the video, or both. The computing system is also configured to characterize the drop after the drop is detected. Characterizing the drop includes determining a size of the drop, a location of the drop, or both in the image, the video, or both.

A method includes illuminating a drop with a pulse of light from a light source. A duration of the pulse of light is from about 0.0001 seconds to about 0.1 seconds. The method also includes capturing an image, video, or both of the drop. The method also includes detecting the drop in the image, the video, or both. The method also includes characterizing the drop after the drop is detected. Characterizing the drop includes determining a size of the drop, a location of the drop, or both in the image, the video, or both.

A method includes illuminating a drop with a pulse of light from a light source. A duration of the pulse of light is from about 0.0001 seconds to about 0.1 seconds. The method also includes capturing an image, video, or both of the drop. The method also includes detecting the drop in the image, the video, or both. The method also includes characterizing the drop after the drop is detected. Characterizing the drop includes determining a size of the drop, a location of the drop, or both in the image, the video, or both.

A method for manufacturing a part by additive manufacturing, the part to be manufactured including at least one portion to be held forming an angle of less than 45° with respect to a building direction of the part to be manufactured, the portion to be held having a first lateral surface and a second lateral surface opposite each other, the method comprising the steps of: providing a digital model of the part to be manufactured, adding to the digital model at least one holding element positioned on one side of the portion to be held, so as to be in contact with said first lateral surface or said second lateral surface.