Three-dimensional printing of high-performance continuous fiber-reinforced thermoplastic composites: Causes and elimination of process-induced defects

Continuous fiber composite three-dimensional (3D) printing technology enables the production of lightweight, complex 3D composite parts with functional integration and other significant advantages. However, in high-end applications, scenarios such as aerospace and energy delivery the performance stability of materials in long-term service environments is critical. The poor performance and instability of the existing 3D printing of fiber composite materials, particularly fiber-reinforced thermoplastic materials, caused by the various defects introduced in the printing process, has become the main challenge. This paper focuses on high-performance continuous fiber-reinforced thermoplastic composites. It reviews various defects in the printing process and discusses their mechanisms, effects on properties and possible elimination measures. Printing defects are categorized into two types based on their primary components: polymer defects and fiber-related defects. This paper also discusses two types of defects: defects in turning zones and defects on surfaces, which are classified based on their location. In addition, this paper summarizes the existing defect elimination methods and research progress. It also suggests the direction of future development, emphasizing that understanding the mechanisms and addressing irremovable defects are crucial for advancing high-performance 3D printing technology.