Meteorology

Operating system

Political science

Politics

Computer science

Digital signal processing

Process (computing)

Acoustics

In situ

SIGNAL (programming language)

Quantum mechanics

Computer hardware

Signal processing

Composite material

Power (physics)

Acoustic emission

Representation (politics)

Repeatability

Chemistry

Materials science

Programming language

Reliability (semiconductor)

Chromatography

Physics

Materials & Design

Additive Manufacturing (AM), or 3D printing, processes depend on a user-defined set of optimized process parameters to create a component. Monitoring and control of AM processes in real-time can help achieve process stability and repeatability to produce high quality parts. By applying in-situ monitoring methods to the AM process, defects in the printed parts can be detected. In this review, application of both imaging and acoustic methods for the detection of sub-surface and internal defects is discussed. Imaging methods consist of visual and thermal monitoring techniques, such as optical cameras, infrared (IR) cameras, and X-ray imaging. Many studies have been conducted that prove the reliability of imaging methods in monitoring the printing process and build area, as well as detecting defects. Acoustic methods rely on acoustic sensing technologies and signal processing methods to acquire and analyze acoustic signals, respectively. Raw acoustic emission signals can correlate to particular defect mechanisms ...

In-situ monitoring of sub-surface and internal defects in additive manufacturing: A review