Disclosed are a method and apparatus of estimating a depth of a molten pool formed during a 3D printing process, and a 3D printing system. A surface temperature of the molten pool is measure by taking a thermal image of a laminated printing object during the 3D printing process with a thermal imaging camera. The measured surface temperature is compared with a melting point of the base material to determine a surface boundary of the molten pool. The maximum lengths in x-axis and y-axis directions of a surface region of the molten pool defined by the surface boundary of the molten pool are determined as a length and a width of the surface of the molten pool, respectively. A maximum depth in the z-axis direction of the molten pool is determined in real time based on the length and width of the surface region of the molten pool.

The disclosure includes a temperature measuring device and a temperature measuring method for measuring the temperature of molten metals. The temperature measuring device includes a temperature sensing element, a support tube, a connecting tube and an exhaust structure. The temperature sensing element is a cermet tube with a closed end and an open end, and can sense the temperature of a molten metal and emit stable thermal radiation energy based on the blackbody cavity principle when being extended into the molten metal. The open end of the cermet tube is fixedly connected to one end of the support tube, the cermet tube is communicated with the support tube, and the other end of the support tube is fixedly connected with the connecting tube. The exhaust structure is used to discharge the smoke inside the cermet tube and the support tube.

An additive manufacturing apparatus includes a laser and a detection system. The laser emits a laser beam to heat a powder bed to form a melt pool, and the melt pool emits light proportional to a temperature of the melt pool. The detection system includes a spectral disperser and one of a) two or more on-axis sensors or b) a line scanner. The two or more on-axis sensors or the line scanner are/is located along an axis of the emitted light, the detection system receives the emitted light from the melt pool, and an intensity of the emitted light detected by the a) two or more on-axis sensors or the b) line scanner is compared with a blackbody spectral map at a particular wavelength of the emitted light to determine a temperature of the melt pool.

Devices, systems, and methods for calibrating for an electron beam additive manufacturing system. The electron beam manufacturing system includes electron beam guns. A calibration system includes an optical pyrometer. The optical pyrometer captures thermal radiation emitted from raw material. An analysis component is communicatively coupled to the optical pyrometer. The analysis component is programmed to determine calibration parameters from information from the optical pyrometer and a phase transition temperature.

A method for optically determining the temperature of a molten metal with a measuring device, including calibrating a replacement measuring chain by a measuring chain as a system-internal measuring standard. The measuring device includes an optical waveguide, to guide electromagnetic radiation emitted from the metal or from the tip of the optical waveguide to an optical detector, at least one replacement optical waveguide, an optical detector for determining the temperature of the metal from an analysis of the electromagnetic radiation, a measuring chain, in which the optical waveguide is the measurement recorder, and at least one replacement measuring chain, in which a replacement optical waveguide is the measurement recorder. A reeling device includes a conveying device for successive reeling of the optical waveguide from a stock and of the replacement optical waveguide from a replacement stock, a receiving device for a stock and at least one replacement stock.

A method, device and apparatus are provided for measuring the temperature of a melt, particularly of a molten metal, with an optical fiber, fed into the melt through a disposable guiding tube. The optical fiber and an immersion end of the tube are immersed into the melt and have feeding speeds which are independent from each other. An elastic plug is arranged within the tube or at an end of the tube opposite the immersion end. The optical fiber is fed through the elastic plug, and the elastic plug reduces a gap between the optical fiber and the tube, which has a larger inner diameter than the outer diameter of the optical fiber. The apparatus includes a fiber coil and a feeding mechanism for feeding the optical fiber and the tube, including at least two independent feeding motors, one for feeding the optical fiber and one for feeding the tube.

A device for measuring a temperature of a molten metal bath, comprising: an optical cored wire; a tube, wherein the optical cored wire is at least partly arranged in the tube, wherein the tube has an outer diameter in the range of 4 mm to 8 mm, and a wall-thickness in the range of 0.2 mm to 0.5 mm; and a plurality of separating elements comprising more than two separating elements arranged in the tube spaced apart from each other, and forming at least one compartment between two of the more than two separating elements.

The invention also relates to a system and method for measuring a temperature of a molten metal bath.

An additive manufacturing system includes a work region having a layer of metallic powder distributed across at least a portion of the work region. The system further includes a power source, a scanning and focusing system and a processor. The processor is configured to control the power source to emit a beam of energy at a power level and to manipulate the beam of energy across the work region in a plurality of build tracks to form a part from the fused metallic powder. The processor further determines a cooling rate at a termination of each of the plurality of build tracks and controls the power level of the power source in response to the determined cooling rate.

An oxide layer thickness measurement device according to the present invention stores, for each of layer thickness measurement sub-ranges constituting a layer thickness measurement range, layer thickness conversion information representing a correlation between a layer thickness and an emitting light luminance where a ratio of a change in the emitting light luminance to a change in the layer thickness in the layer thickness measurement sub-range falls within a set extent. The device includes a plurality of emitting light luminance measurement parts for measuring emitting light luminances of a surface of a steel sheet at respective measurement wavelengths different from each other. Calculated in connection with each of the emitting light luminances of the surface of the steel sheet measured by the emitting light luminance measurement parts are the layer thickness corresponding to the measured emitting light luminance and a ratio at the layer thickness by using the layer thickness conversion information corresponding to each of the emitting light luminance measurement parts. The calculated layer thickness is extracted as a candidate value for an actual thickness layer when the calculated ratio is within the set extent assigned for the layer thickness conversion information.

An oxide layer thickness measurement device according to the present invention stores, for each of layer thickness measurement sub-ranges constituting a layer thickness measurement range, layer thickness conversion information representing a correlation between a layer thickness and an emitting light luminance where a ratio of a change in the emitting light luminance to a change in the layer thickness in the layer thickness measurement sub-range falls within a set extent. The device includes a plurality of emitting light luminance measurement parts for measuring emitting light luminances of a surface of a steel sheet at respective measurement wavelengths different from each other. Calculated in connection with each of the emitting light luminances of the surface of the steel sheet measured by the emitting light luminance measurement parts are the layer thickness corresponding to the measured emitting light luminance and a ratio at the layer thickness by using the layer thickness conversion information corresponding to each of the emitting light luminance measurement parts. The calculated layer thickness is extracted as a candidate value for an actual thickness layer when the calculated ratio is within the set extent assigned for the layer thickness conversion information.