An additive manufacturing apparatus includes a powder layer forming portion, an energy beam source, and a contact detection sensor including a plate-like probe. The powder layer forming portion is configured to form a powder layer in a predetermined region. The energy beam source is configured to radiate an energy beam to the powder layer formed by the powder layer forming portion to fuse or sinter the powder layer so that a solidified layer is formed. Presence or absence of a projection portion on a surface of the solidified layer is detected by using the contact detection sensor.

A powder spreading apparatus includes a hopper having a first end, a second end opposite from the first end, a front wall, a rear wall opposite from the front wall, and a floor. The front wall, the rear wall, the first end, the second end, and the floor define an interior. An impeller is disposed within the interior of the hopper. The impeller includes a plurality of circumferentially spaced flutes and is configured to rotate about an impeller axis that extends from the first end of the hopper to the second end of the hopper to deposit powder onto a print area. A spreader rod is coupled to the hopper and extends along a spreader rod axis parallel to the impeller axis. The spreader rod is configured to rotate about the spreader rod axis to smooth the powder as it is deposited onto the print area.

A powder spreading apparatus includes a hopper having a first end, a second end opposite from the first end, a front wall, a rear wall opposite from the front wall, and a floor. The front wall, the rear wall, the first end, the second end, and the floor define an interior. An impeller is disposed within the interior of the hopper. The impeller includes a plurality of circumferentially spaced flutes and is configured to rotate about an impeller axis that extends from the first end of the hopper to the second end of the hopper to deposit powder onto a print area. A spreader rod is coupled to the hopper and extends along a spreader rod axis parallel to the impeller axis. The spreader rod is configured to rotate about the spreader rod axis to smooth the powder as it is deposited onto the print area.

A three-dimensional fabrication apparatus includes a flattening member and a rotation drive unit. The flattening member moves on layers of a fabrication material to flatten an upper surface of the layers of the fabrication material. The rotation drive unit rotates the flattening member and determines a circumferential position of the flattening member.

A three-dimensional fabrication apparatus includes a flattening member and a rotation drive unit. The flattening member moves on layers of a fabrication material to flatten an upper surface of the layers of the fabrication material. The rotation drive unit rotates the flattening member and determines a circumferential position of the flattening member.

An example of a method, for three-dimensional (3D) printing, includes applying a build material and patterning at least a portion of the build material. The patterning includes selectively applying a wetting amount of a binder fluid on the at least the portion of the build material and subsequently selectively applying a remaining amount of the binder fluid on the at least the portion of the build material. An area density in grams per meter square meter (gsm) of the wetting amount ranges from about 2 times less to about 30 times less than area density in gsm of the remaining amount.

This method describes techniques to create 3D parts by dispensing a liquid polymer or slurry in evenly delivered layers, which are exposed to light from a visual display screen before the print platform upon which it is being built is moved one-layer thickness away and the process is repeated. The process of dispensing the photosensitive material is via a pumped system through a metering device that discharges and levels the material. Multiple dispensing devices can be arranged in sequence to deliver different materials, either multiple photosensitive dispensing heads or alternative mechanisms such as robocasting, fused deposition modelling or inkjet in addition to a photosensitive deposition head.

This method describes techniques to create 3D parts by dispensing a liquid polymer or slurry in evenly delivered layers, which are exposed to light from a visual display screen before the print platform upon which it is being built is moved one-layer thickness away and the process is repeated. The process of dispensing the photosensitive material is via a pumped system through a metering device that discharges and levels the material. Multiple dispensing devices can be arranged in sequence to deliver different materials, either multiple photosensitive dispensing heads or alternative mechanisms such as robocasting, fused deposition modelling or inkjet in addition to a photosensitive deposition head.

A method of conditioning layers of build material powder for metal additive manufacturing including depositing an amount of build material powder on a work surface, the amount of build material powder having a lower surface separated from an upper surface by a height. A roller is traversed across the work surface in a first direction while rotating the roller in a direction opposed to the first direction. During the step of traversing the roller, a lower surface of the roller extends below the upper surface of the amount of build material powder by a distance. The roller has a surface conditioning configured to, in conjunction with a controlled speed of the rotation of the roller, provide a powder density in a compacted layer within a predetermined powder density range.

A method of conditioning layers of build material powder for metal additive manufacturing including depositing an amount of build material powder on a work surface, the amount of build material powder having a lower surface separated from an upper surface by a height. A roller is traversed across the work surface in a first direction while rotating the roller in a direction opposed to the first direction. During the step of traversing the roller, a lower surface of the roller extends below the upper surface of the amount of build material powder by a distance. The roller has a surface conditioning configured to, in conjunction with a controlled speed of the rotation of the roller, provide a powder density in a compacted layer within a predetermined powder density range.