Investigating Non-destructive Tests Used in the Inspection of Parts Produced by Additive Manufacturing (AM) Method,

Additive manufacturing (AM) is based on the deposition of materials with high precision to make a final part or component using different methods. This process is considered one of the main developments in the fourth industrial revolution and is still growing. There are many different types of additive manufacturing methods, and today, the use of efficient inspection methods is required to ensure a certain level of quality and detect defects and discontinuities in the industry. Today, in industry, non-destructive testing (NDT) is widely used, especially in additive manufacturing, to ensure efficient quality control and predictive maintenance without changing the properties and initial state of materials. Each non-destructive testing method is based on different physical principles and the correct selection and use of each test depends on the application, manufacturing process, type of material and possible discontinuities and many other things. The most common defects created in AM parts in terms of appearance include porosity, entrapped impurity, cracks, and material defects, which are mainly caused by changes in manufacturing parameters, injection parameters, and initial material properties. In this article, the performance of non-destructive tests was investigated to inspect the parts produced by the additive manufacturing method. These tests include visual inspection, liquid penetrant testing, magnetic particle testing, eddy current testing, ultrasonic testing, XCT, acoustic emission testing and thermography test. The application of each of the mentioned NDT methods in additive manufacturing and their suitability for detecting the defects of parts manufactured by AM method were investigated. Also, the sensitivity, advantages and disadvantages of each method were evaluated and the types of defects and the ability to detect these defects by NDT methods were mentioned. Considering that there are 7 categories of production methods in additive manufacturing, in this research, the application of each NDT test for different categories of AM process was discussed and the challenges in each were mentioned.