A three-dimensional printing system includes a print bed and a shelf insertion mechanism for inserting a shelf of one or a plurality of auxiliary shelves into a print volume between the print bed and a printer head. A printer assembly is configured to deposit layers of material within the print volume to form one or more objects on a support platform, the support platform including the print bed or an auxiliary shelf that is inserted into the print volume by the shelf insertion mechanism. A controller is configured to control the shelf insertion mechanism to insert an auxiliary shelf between the print bed and a printer head of the system after formation of the objects on that support platform by the printer assembly is complete.

A method is provided of sintering a green object body to form a manufactured object. The method comprises providing a green object body. The green object body comprises granular construction material bound together by a binder. The method comprises providing a green support body for supporting the green object body. The green support body comprises granular construction material bound together by a binder. The method comprises supporting the green object body with the green support body. The method comprises sintering the green support body together with the green object body supported by the green support body. A method of manufacturing an object, a method of processing object data, a data carrier carrying program instructions and an object data processor are also provided.

In an example implementation, a method of printing a multi-structured three-dimensional (3D) object includes forming a layer of sinterable material. The method includes processing a first portion of the sinterable material using first set of processing parameters and processing a second portion of the sinterable material using a second set of processing parameters. The processed first and second portions form, respectively, parts of a first and second structure of a multi-structured 3D object.

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.

Adjustment of a halftoning threshold can, in an example implementation, include assigning a relative energy value, relative to a reference energy value, to a location of a build area and adjusting a halftoning threshold based on the relative energy value.

In a three-dimensional shaped object manufacturing device, when a unit is moved in a forward direction, powder is supplied from a first supply portion, a powder layer is formed by a first layer forming portion, a liquid is discharged to a shaping region from a head, and a shaping table is moved in a direction separating from the unit after discharging the liquid is ended and before a second layer forming portion faces the shaping region, and when the unit is moved in a backward direction, the powder is supplied from a second supply portion, the powder layer is formed by the second layer forming portion, the liquid is discharged to the shaping region from the head, and the shaping table is moved in the direction separating from the unit after discharging the liquid to the shaping region is ended and before the first layer forming portion faces the shaping region.

In one example, a 3D printing system includes a support structure generator to identify a breakaway support to temporarily support part of the object, to design a wedge shaped groove between a portion of the object and the support, the groove ending at a line along which the support intersects the object, and to generate a digital object model that includes the support and the groove. The system also includes a 3D printer to print the object, support and groove based on the object model.

In one example, a 3D printing system includes a support structure generator to identify a breakaway support to temporarily support part of the object, to design a wedge shaped groove between a portion of the object and the support, the groove ending at a line along which the support intersects the object, and to generate a digital object model that includes the support and the groove. The system also includes a 3D printer to print the object, support and groove based on the object model.

In a three-dimensional shaped object manufacturing device, when a unit is moved in a forward direction, powder is supplied from a first supply portion, a powder layer is formed by a first layer forming portion, a liquid is discharged to a shaping region from a head, and a shaping table is moved in a direction separating from the unit after discharging the liquid is ended and before a second layer forming portion faces the shaping region, and when the unit is moved in a backward direction, the powder is supplied from a second supply portion, the powder layer is formed by the second layer forming portion, the liquid is discharged to the shaping region from the head, and the shaping table is moved in the direction separating from the unit after discharging the liquid to the shaping region is ended and before the first layer forming portion faces the shaping region.

An apparatus for the manufacture of an object, the apparatus having a print bed, a stencil, a heater arranged to heat the stencil, and a squeegee. The stencil comprises one or more apertures and is positionable over the print bed. The squeegee is movable to spread a printing material across the stencil and to thereby force printing material through the stencil aperture(s). One or both of the stencil and the print bed is movable to adjust the spacing between the stencil and the print bed.