Abstract: A method of operating an apparatus for the layerwise manufacture of 3D objects. The method includes two or more operational cycles of a warm up phase, starting from ambient, followed by a build phase and a cooling phase. The warm up phase and the build phase each include a layer cycle of: (a) dosing build material to the work surface; (b) distributing a portion of the dosed amount over a build area; (c) heating the dosed amount; and (d) monitoring a temperature of the build material to determine a thermal state. The build phase includes melting layer-specific regions. These steps are repeated until the warm up and build phases are completed. A property of the subsequent warm up phases is determined such that the duration of a subsequent warm up phase is shorter than the duration of a preceding warm up phase.

Abstract: A method of operating an apparatus for the layerwise manufacture of 3D objects. The method includes a warm up phase followed by a build phase. The phases each include a cycle of (a) dosing an amount of build material from a dosing device; (b) pushing a portion of the dosed amount across a build area into a receiving chamber; (c) heating the dosed amount at one or both of (a) and (b); repeating (a) to (c) until each phase is complete. During the build phase, at step (b) a layer is formed over the build area and, at step (c), build material within a layer-specific region is selectively melted. Over a given duration of time, an aggregate volume of build material pushed into the receiving chamber during the warm up phase is larger than an aggregate volume of build material pushed into the receiving chamber during the build phase.