In situ and real time quality control in additive manufacturing process

A method for in situ and real time quality control of an additive manufacturing process in an ion beam, electron beam, microwave, or laser sintering or melting setup, using an ion beam, electron beam, microwave, or laser source and an ion beam, electron beam, microwave, or laser focusing device controlled by ion beam, electron beam, microwave, or laser electronics for focusing the ion beam, electron beam, microwave, or laser beam on a process surface of a sintering or melting body in an ion beam, electron beam, microwave, or laser irradiation focused spot with controllable ion beam electron beam, microwave, or laser parameters during the running additive manufacturing process, the method comprising:

• real time detection of acoustic waves emitted through the process zone and induced by the sintering or melting pulses by using at least one optical fiber sensor in form of fibers with Bragg grating, fibre interferometers or Fabry-Perot structures, wherein the at least one optical fiber sensor is arranged separated from the sample and source alongside a process axis between the ion beam, electron beam, microwave, or laser source and the ion beam, electron beam, microwave, or laser irradiation focused spot, and the at least one optical fiber sensor respectively a fiber axis is tilted in an angle of range 0° to 90° relative to the process axis,
• transfer of the measured sensor signals via at least one signal line to a processing unit,
• digitizing measured sensor signals and subsequent analysis of the digitized sensor signals in the processing unit by an algorithmic framework providing extraction and classification of measured acoustic emission features for quality control of the sintering or melting process,
• determination of improved future additive manufacturing parameters, before
• transfer of the improved additive manufacturing parameters via a feedback loop from the processing unit to the ion and electron beams, microwave or laser electronics for application of the improved additive manufacturing parameters in the upcoming ion beam, electron beam, microwave, or laser sintering or melting step,
• wherein the correlation of acoustic emission with additive manufacturing quality is done by wavelet packet decomposition (WPD) as extraction technique as part of the algorithmic framework.