Apparatus for producing three-dimensional multilayer model, method for producing three-dimensional multilayer model, and flaw detector

An apparatus for producing a three-dimensional multilayer object which produces a three-dimensional multilayer object by partially applying energy to a conductive powder and thereby melting or sintering and curing the conductive powder, the apparatus comprising:

• a holding unit holding the conductive powder, and holding the cured three-dimensional multilayer object;
• a regulation unit leveling an upper surface of the conductive powder held by the holding unit;
• an energy application unit being controlled by a control unit to apply applying energy to the conductive powder held by the holding unit;
• a probe disposed spaced apart from a surface layer portion of the cured three-dimensional multilayer object and detecting a flaw in the surface layer portion;
• and
• a probe moving mechanism being controlled by the control unit to relatively move the probe with respect to the surface layer portion,
• wherein the probe has a plurality of coil units attached to the regulation unit
• wherein each of the coil units includes an excitation coil generating an eddy current in the surface layer portion, and a pair of detection coils disposed side by side inside the excitation coil such that a change in a magnetic field of the surface layer portion is detected,
• wherein the pair of detection coils include a portion overlapping along a first direction, and a portion not overlapping along the first direction.