METHODS OF QUALITY CONTROL FOR AEROSPACE PARTS, PRODUCED WITH 3D-PRINTING OUT OF COMPOSITE-REINFORCED POLYMERS

Abstract

One of the features of parts, made from polymer composite materials, is that the part and material are both formed at once, when the part is being made. Complexity of interaction processes between matrix and reinforcing fiber makes it difficult to achieve prognosed characteristics of part due to possible imperfections of manufacturing processes and technology. Therefore, an important part of parts life cycle is quality control. Quality control can be destructive or non-destructive, the latter giving more information and insight on defects of the part itself and, possibly, at flaws in manufacturing technology. With the increase in popularity of use of additive manufacturing technologies, especially – FDM 3d-printing, in aerospace industry, there’s a need to improve the performance of parts. Benefits of FDM 3d-printing is the absence of need for specialized forming equipment and tools, especially for forming the parts with complex, topologically-optimized geometry and structure. One of the ways to improve printed parts performance and its physical properties is to use continuous fiber reinforcement. Because of need to control the state and position of the fiber in the part, quality control is also an important part of this type of additive manufacturing. Existing popular methods of quality control, used in polymer composite materials part manufacturing were reviewed. Also, the features and limitations, imposed by structure of printed parts and printing technology were reviewed as well, the differences of them and polymer composite parts made in traditional forming ways, were noted too. The destructive testing methods reviewed are tensile stress testing, bend testing and impact stress testing. The non-destructive quality control methods reviewed are visual, acoustic, radiological and ultrasound. Also, recommendations on their use on FDM 3d-printed parts were formed. As a result, visual and ultrasound methods were accepted as non-destructive methods of quality control, with need to perform destructive tests on sample parts as well. Also, as a promising method, thermography was proposed, yet because of the limitation of using it with high-temperature polymers, its utility is also limited.