Abstract: In an example of a method for three-dimensional printing, a first amount of a binding agent is selectively applied, based on a 3D object model, to individual build material layers of a particulate build material including metal particles to forming an intermediate structure. The binding agent and/or a void-formation agent is selectively applied, based on the 3D object model, to at least one interior layer of the individual build material layers so that a total amount of the binding agent, the void-formation agent, or both the binding agent and the void-formation agent in the at least one of the individual build material layers is greater than the first amount. This patterns an area that is to contain voids. The intermediate structure is heated to form a 3D structure including a void-containing breakable connection.

Abstract: A method comprising dividing a build model comprising an object model arranged within a virtual volume into cross-sectional layers along a vertical axis. The layers represent layers of an additive manufacturing process. A set of base layers is identified with each of the base layers comprising a flat bottom surface of the object model. A base characteristic is assigned to the set of base layers. A set of bulk layers is identified which excludes the set of base layers. A bulk characteristic is assigned to the set of bulk layers. An additive manufacturing apparatus is instructed to build a build cake according to the build model, layers and assigned characteristics, so a fluid agent is deposited at a first rate for the set of bulk layers having the bulk characteristic and a second rate, slower than the first rate, for the set of base layers having the base characteristic.

Abstract: According to one example, there is provided a 3D printing build unit comprising a build chamber, a build platform, and a heating element controllable to heat a portion of the contents of the build chamber to a temperature at or above a curing temperature whilst maintaining upper layers of the build chamber at or below a printing temperature.

Abstract: An example three-dimensional printing method is described, comprising selectively depositing droplets of a liquid agent on a layer of build material, by depositing liquid agent on the layer of build material from a first distance above the layer, for example on a first part of the layer, and depositing liquid agent on the layer of build material from a second distance above the layer, for example on a second part of the layer. An example 3D printer is also described.

Abstract: In an example of a method for three-dimensional printing, a first amount of a binding agent is selectively applied, based on a 3D object model, to individual build material layers of a particulate build material including metal particles to forming an intermediate structure. The binding agent and/or a void-formation agent is selectively applied, based on the 3D object model, to at least one interior layer of the individual build material layers so that a total amount of the binding agent, the void-formation agent, or both the binding agent and the void-formation agent in the at least one of the individual build material layers is greater than the first amount. This patterns an area that is to contain voids. The intermediate structure is heated to form a 3D structure including a void-containing breakable connection.

Abstract: In an example implementation, a method of 3D printing includes receiving a 2D data slice derived from a 3D object model, where the 2D data slice defines an object area of a layer of build material that is to receive a liquid functional agent and be fused as a layer of a part. The method includes determining that the 2D data slice distinguishes first and second tolerance zones within the object area. The method includes controlling a printhead to print a liquid functional agent onto the layer of build material according to a first droplet ejection spacing when printing in the first tolerance zone, and controlling the printhead to print a liquid functional agent onto the layer of build material according to a second droplet ejection spacing when printing in the second tolerance zone.

Abstract: In an example implementation, a method of adjusting frame length in an inkjet web press includes measuring a time T1 between a first sensor sensing a first mark and a second sensor sensing a second mark, and measuring a time T2 between the second sensor sensing the second mark and the first sensor sensing a next first mark. The method includes adjusting a gap between printed frames when T1 does not equal T2.

Abstract: In an example implementation, a method of adjusting frame length in an inkjet web press includes measuring a time T1 between a first sensor sensing a first mark and a second sensor sensing a second mark, and measuring a time T2 between the second sensor sensing the second mark and the first sensor sensing a next first mark. The method includes adjusting a gap between printed frames when T1 does not equal T2.

Abstract: In an example implementation, a method of adjusting frame length in an inkjet web press includes measuring a time T1 between a first sensor sensing a first mark and a second sensor sensing a second mark, and measuring a time T2 between the second sensor sensing the second mark and the first sensor sensing a next first mark. The method includes adjusting a gap between printed frames when T1 does not equal T2.

Abstract: In an example implementation, a method of adjusting frame length in an inkjet web press includes measuring a time T1 between a first sensor sensing a first mark and a second sensor sensing a second mark, and measuring a time T2 between the second sensor sensing the second mark and the first sensor sensing a next first mark. The method includes adjusting a gap between printed frames when T1 does not equal T2.