Abstract: According to one example there is provided a build material measurement module to determine build material characteristics from a build material to be analyzed.

Abstract: An electromagnetic filtering system comprising an electromagnetic radiation source, a filter chamber to filter the radiation and a filter chamber control system to selectively modify the contents of the filter chamber in order to modify the wavelengths of the radiation that pass through the filter chamber. There is also provided a method of controlling an electromagnetic filtering system that comprises a controllable filter chamber capable of being controlled so as to selectively be filled with a filter material, the method comprising —determining filtering characteristics to be provided by the filtering system, —determining whether the filter chamber should be filled with the filter material, and —controlling the filter chamber to be filled as determined.

Abstract: A method of fabricating a three dimensional object is provided. A build layer comprising an area of solidified build material and an area of non-solidified build material is formed. The build layer is formed by depositing a layer of non-solidified build material and treating the build material to form the area of solidified build material. The method also involves determining an edge profile for the build layer. Determining the edge profile involves measuring a variation in height of the build layer across a transition between the area of solidified build material and the area of non-solidified build material.

Abstract: A method of aligning an agent distributor in an apparatus for generating a three-dimensional object comprises selectively depositing an agent on a layer of build material to form a predetermined alignment pattern (211, 212, 311, 312), and detecting the alignment pattern (211, 212, 311, 312) from a height profile in a surface of the build material, and performing an alignment operation using the detected alignment pattern (211, 212, 311, 312). An alignment pattern (211, 212, 311, 312) may comprise, for example, a series of triangles which are scanned to determine misalignment.

Abstract: In some examples, a carriage for a printing system includes a printhead, a conduit to carry a cooling airflow to the printhead, a return chamber to receive a heated exhaust airflow produced from heating of the cooling airflow by the printhead, and a seal between the printhead and the return chamber to prevent the heated airflow from flowing to a location below the printhead.

Abstract: Methods and devices for setting a printing distance in a 3D printing system are disclosed. In one example the method comprises forming a layer of build material below a printing plane and relatively displacing the formed layer of build material with respect to the printing plane until the distance between the formed layer of build material and the printing plane is a desired printing distance.

Abstract: In an example, a method includes forming a layer of build material and selectively applying fusing agent on to the layer based on a predetermined pattern. Energy may be applied to the layer of build material, and at least one temperature of the layer may be measured. A temperature distribution over the layer of build material may be determined, the temperature distribution indicating, for each of a plurality of locations on the layer of build material, whether fusing agent is present at that location. At least one characteristic derived from the temperature distribution may be compared to a predetermined characteristic. When the compared characteristics differ, an operational characteristic of an additive manufacturing apparatus may be adjusted.

Abstract: Printing stations to receive build units are disclosed. The printing stations may comprise a first wall comprising two fixed receiving ports to engage with two fixed mounting elements of the build units, respectively, and a second wall comprising a third fixed receiving port to engage with a third fixed mounting element of the build units, and a calibration receiving port to be coupled to a fourth fixed mounting element when the build unit is inserted into the printing station.

Abstract: In some examples, a printing system includes a printhead that is relatively moveable with respect to a print platform, and an airflow generator assembly to generate a first cooling airflow towards the printhead responsive to the printhead being at in a first inactive region on a first side of the print platform, and generate a second cooling airflow towards the printhead responsive to the printhead being in a second inactive region on a second, different side of the print platform.

Abstract: In one example, an elevator for a roll of print media includes rotatable shafts oriented parallel to one another and translatable supports to support a roll of print media. Each support is operatively connected to the shafts such that rotating the shafts in a first direction raises the supports and rotating the shafts in a second direction opposite the first direction lowers the supports.

Abstract: In one example, an elevator for a roll of print media includes rotatable shafts oriented parallel to one another and translatable supports to support a roll of print media. Each support is operatively connected to the shafts such that rotating the shafts in a first direction raises the supports and rotating the shafts in a second direction opposite the first direction lowers the supports.

Abstract: An electromagnetic filtering system comprising an electromagnetic radiation source, a filter chamber to filter the radiation and a filter chamber control system to selectively modify the contents of the filter chamber in order to modify the wavelengths of the radiation that pass through the filter chamber. There is also provided a method of controlling an electromagnetic filtering system that comprises a controllable filter chamber capable of being controlled so as to selectively be filled with a filter material, the method comprising —determining filtering characteristics to be provided by the filtering system, —determining whether the filter chamber should be filled with the filter material, and —controlling the filter chamber to be filled as determined.

Abstract: In one example of the disclosure, a system for limitation of energy wavelengths applied during 3D printing includes an energy source to provide energy to a target zone during a 3D printing operation. The system includes a filter chamber through which the energy is to pass before arriving at the target zone. The system includes a filter chamber control component to selectively modify the contents of the filter chamber to limit the wavelengths of energy that can pass through the filter chamber based upon type of the target zone.

Abstract: A printer comprises a printing assembly for printing an image on a print media in a print zone; a cutting assembly for cutting the print media along a contour in a cut zone; wherein the print zone and the cut zone are distinct from one another, one of the zones being downstream of the respective other zone in a print media advance direction; a control unit controlling the printhead assembly and the cutting assembly to perform printing and cutting operations during a single print media feed. A method of printing, using said printer, comprises feeding the print media through the cut zone and through the print zone, in any order; and simultaneously printing an image and cutting a contour while the print media is being fed through the cut zone and through the print zone.

Abstract: A method is described in which a pattern is printed using a nozzle for depositing a first agent to a layer of build material, the layer of build material is cured, and the presence of a difference in height between at the edge of the first pattern is checked and an anomaly is detected if said difference is not present.

Abstract: According to one example there is provided a 3D printing system (300) comprising a build material measurement module (310) to determine a level of contraction of a solidified portion of a layer of build material. The system further comprises a controller (312) to determine if the determined level of contraction is within an acceptable range, and to modify one or multiple operating parameters of the printing system such that solidified portions of a subsequently processed layer of build material have a level of contraction within an acceptable range.

Abstract: According to one example there is provided a build material measurement module to determine build material characteristics from a build material to be analyzed.

Abstract: In one example, a print head drop detector (202) is described. The print head drop detector (202) comprises a sampling volume and a fan (208) to cause an airflow though the sampling volume (206). Detection apparatus to detect the presence of non-gaseous material within the sampling volume is also provided.

Abstract: A method of fabricating a three dimensional object is provided. A build layer comprising an area of solidified build material and an area of non-solidified build material is formed. The build layer is formed by depositing a layer of non-solidified build material and treating the build material to form the area of solidified build material. The method also involves determining an edge profile for the build layer. Determining the edge profile involves measuring a variation in height of the build layer across a transition between the area of solidified build material and the area of non-solidified build material.

Abstract: According to one example there is provided an accessory for a printing system. The accessory comprises a cylindrical core on which a web of media may be wound, and a flexible sheet having a first end attached to the core and a second free end opposite the first end having a media connector attached thereto, the media connector to connect a free end of a web of media thereto.