Improvement of reinforcement technique of parts with composite fiber in FDM 3D-printing

The use of parts produced via FDM 3D-printing is getting more and more popular withing aerospace field. Parts, made with such additive manufacturing methods, can be used for prototyping, as manufacturing implements or used directly as an end product. One of the means of improving the functional parameters of parts is reinforcing parts with composite fibers or other similar additives. There are some popular and widespread types of composite fiber reinforcement, used during 3D-printing, such as using filament with fiber filling, use of a second printing head to deposit reinforcing fibers where needed or use of in-situ mixing and impregnation printing head. Most of existing methods have several drawbacks, such as inability to precisely and discretely reinforce only the needed areas of parts and layers or not keeping the reinforcing fibers continuous and intact. Therefore, the objective of work is to develop a new way of reinforcing parts with continuous composite fiber during FDM 3D-printing process. Tasks include developing the technique of reinforcement and the technological equipment to be used on, in or with commercially available 3D-printers or ones popular among amateurs. Work was done with use of such materials as PLA plastic, coPET (PET-G) plastic and basalt fiber. During the work, a way of reinforcing parts with continuous fibers was developed. It involves using externally laid strands of fiber, applied between layers of parts in the process of printing. Strands are laid down as a set, kept at intervals and arrangement as designed, with spacing and attitudes maintained by technological equipment, installed on the 3D-printer. After each layer of fibers is laid, it’s printer over by the next layer of plastic, and after every layer of fibers, the set of strands is turned 180 degrees before next layer of plastic is printed over. No cutting of fibers is done to keep them continuous. Also, a piece of technological equipment was designed, to be installed onto printing bed of a 3D-printer and facilitate the laying of composite fibers in the way mentioned above.