3d printer with advantageous irradiation device, and method

A 3D printer comprising:

• an irradiation assembly including an array of multiple irradiation units;
• a controller;
• a build field;
• a recoater for applying a particulate material to the build field;
• and
• a print head for selectively applying a liquid to the build field, wherein the print head selectively applies an IR absorbor;
• wherein the controller controls the array of multiple irradiation units, each of which is individually controllable with regard to its temperature, or a subset of irradiation units being combined to a group, each group of irradiation units being controllable with regard to its temperature;
• and
• wherein a target temperature on the build field is adjustable by a target temperature setting of each irradiation unit or/and each group of irradiation units in the irradiation assembly;
• wherein the irradiation assembly includes:
• i) a thermographic camera and/or an infrared pyrometer directed at the build field;
• and
• ii) a thermocouple or resistance thermometer;
• wherein the printer is for a high-speed sintering process.