A powder processing machine comprising: a work bed; a powder deposition device operable to deposit layers of a powder in the work bed; at least one energy beam device operable to emit an energy beam with a variable beam power and scan the energy beam in a path across the powder in the work bed with a variable beam scan rate to melt and fuse regions of the powder to produce fused powder; at least one sensor comprising a temperature sensor operable to detect temperature in the work bed by location in the work bed during scanning of the energy beam and produce signals representative of the temperature and locations; and a controller in communication with the temperature sensor to receive the signals, the controller configured to identify one or more temperature excursions that are associated with defects in which ejected material coming off of the powder leaves one or more craters in the fused powder and responsively adjust at least one of the beam power or the beam scan rate at the locations corresponding to the craters, characterised in that the controller is adapted to detect the temperature excursions during scanning of a first layer of the powder by detecting a temperature anomaly that violates a temperature threshold, thereby indicating the presence of craters in the fused powder produced from the first layer of the powder, wherein on the fused powder produced from a first layer of the powder there is subsequently deposited a second layer of the powder that is of uniform thickness except that there is a greater thickness of the second layer of the powder in the craters, and the controller is adapted to increase energy input of the energy beam into the second layer of the powder at the locations corresponding to the craters in order to fuse the greater thickness of the second layer of the powder in the crater by increasing beam power of the energy beam, decreasing the scan rate of the energy beam, or both, in order to fuse the greater thickness of the second layer of the powder in the craters. a work bed; a powder deposition device operable to deposit layers of a powder in the work bed; at least one energy beam device operable to emit an energy beam with a variable beam power and scan the energy beam in a path across the powder in the work bed with a variable beam scan rate to melt and fuse regions of the powder to produce fused powder; at least one sensor comprising a temperature sensor operable to detect temperature in the work bed by location in the work bed during scanning of the energy beam and produce signals representative of the temperature and locations; and a controller in communication with the temperature sensor to receive the signals, the controller configured to identify one or more temperature excursions that are associated with defects in which ejected material coming off of the powder leaves one or more craters in the fused powder and responsively adjust at least one of the beam power or the beam scan rate at the locations corresponding to the craters, characterised in that the controller is adapted to detect the temperature excursions during scanning of a first layer of the powder by detecting a temperature anomaly that violates a temperature threshold, thereby indicating the presence of craters in the fused powder produced from the first layer of the powder, wherein on the fused powder produced from a first layer of the powder there is subsequently deposited a second layer of the powder that is of uniform thickness except that there is a greater thickness of the second layer of the powder in the craters, and the controller is adapted to increase energy input of the energy beam into the second layer of the powder at the locations corresponding to the craters in order to fuse the greater thickness of the second layer of the powder in the crater by increasing beam power of the energy beam, decreasing the scan rate of the energy beam, or both, in order to fuse the greater thickness of the second layer of the powder in the craters.