Abstract: An additive manufacturing apparatus for manufacture of aluminum parts layer-by-layer, the apparatus comprising an eddy current sensor for in-process measuring of contour and defects of manufactured layers with a defect resolution of at least 0.25 mm. Preferably, the eddy current sensor is embodied as a differential mode line sensor with dual use of sensor coils. Preferably, the array of the line sensor comprises a zig-zag-arrangement of sensor coils with a cross section of 0.15 mm2 maximal and with a core with an initial magnetic permeability of at least 5000, preferably a permalloy or metal glass coil core.

Abstract: An additive manufacturing apparatus for manufacture of aluminum parts layer-by-layer, the apparatus comprising an eddy current sensor for in-process measuring of contour and defects of manufactured layers with a defect resolution of at least 0.25 mm. Preferably, the eddy current sensor is embodied as a differential mode line sensor with dual use of sensor coils. Preferably, the array of the line sensor comprises a zig-zag-arrangement of sensor coils with a cross section of 0.15 mm2 maximal and with a core with an initial magnetic permeability of at least 5000, preferably a permalloy or metal glass coil core.

Abstract: Provided is an aircraft having a spherical body which generates buoyancy or which may generate buoyancy when filled with gas, wherein the aircraft further comprises four actuation units arranged on the surface of the body for movement of the aircraft in a translation and/or rotation through air, and at least one camera arranged on or in the surface of the body. Further provided is a method for providing optical information to a person in the environment of a flying aircraft, a method for providing optical information about an object and/or surveying of an object, a method for transmission of acoustic information and a method for observing or tracking an object.