Abstract: Examples relate to methods of printing a 3D printed tamper evident security structure for protecting a feature; the method comprising repeatedly: depositing a layer of build material; doping one or more than one region of the layer of build material using a dopant to influence a respective electrical attribute of one or more than one region associated with a graph of the structure; and agglomerating one or more than one selected portion of the layer of the build material, including the one or more than one doped region of the layer of build material, to form progressively the graph with a predetermined measurable electrical characteristic.

Abstract: Examples relate to methods of printing a 3D printed tamper evident security structure for protecting a feature; the method comprising repeatedly: depositing a layer of build material; doping one or more than one region of the layer of build material using a dopant to influence a respective electrical attribute of one or more than one region associated with a graph of the structure; and agglomerating one or more than one selected portion of the layer of the build material, including the one or more than one doped region of the layer of build material, to form progressively the graph with a predetermined measurable electrical characteristic.

Abstract: Examples relate to methods of printing a 3D printed tamper evident security structure for protecting a feature; the method comprising repeatedly: depositing a layer of build material; doping one or more than one region of the layer of build material using a dopant to influence a respective electrical attribute of one or more than one region associated with a graph of the structure; and agglomerating one or more than one selected portion of the layer of the build material, including the one or more than one doped region of the layer of build material, to form progressively the graph with a predetermined measurable electrical characteristic.

Abstract: Examples relate to back electromotive force controllers for influencing movement of a carriage of a device in an unpowered state; the carriage being moveable by a motor responsive to a motor driver; the controller comprising: braking circuitry to couple power associated with a back electromotive force generated by displacement of the motor, due to carriage movement, to power the motor driver to urge the motor in a contrary direction to the displacement.

Abstract: Method and devices for calibrating heat sensors are provided. The heat sensors may measure, from a distance, temperatures of build materials arranged on build platforms. Using the heat sensors, remote temperature measurements of regions may be acquired from a distance. Using temperature sensors integrated in the build platforms, local temperature measurements of regions of the build platforms may be acquired. The local temperature measurements may be compared with the remote temperature measurements to calculate differences. Correction factors associated with the calculated differences may then be applied when acquiring temperature measurements using the heat sensors.

Abstract: Examples relate to back electromotive force controllers for influencing movement of a carriage of a device in an unpowered state; the carriage being moveable by a motor responsive to a motor driver; the controller comprising: braking circuitry to couple power associated with a back electromotive force generated by displacement of the motor, due to carriage movement. to power the motor driver to urge the motor in a contrary direction to the displacement.

Abstract: Examples of the present disclosure relate to a method of cooling objects produced by an additive manufacturing process. The method comprises obtaining a volume of build material output from the additive manufacturing process. The volume of build material comprises unsolidified build material. The volume of build material comprises a plurality of objects and a separating element between the plurality of objects, the objects and the separating element having been produced by sequentially depositing layers of build material and the separating element having been produced based on at least one of the plurality of objects. The method comprises applying gas to the volume of build material to cool the plurality of objects, wherein the separating element provides a barrier between the plurality of objects during the applying of the gas to the volume of build material.