Recently, the American Advanced Composites Manufacturing Innovation Agency (IACMI) announced that the first phase of the project, led by DuPont, Fibrtec and Purdue University, has developed a new continuous fiber reinforced thermoplastic composite production process, fabrics. The formability is significantly improved compared to conventional fabrics. This is of great significance to the second phase of research, which can effectively reduce the production cost of carbon fiber composite structures, making it more suitable for mass production in automotive, aerospace and other fields.
The goal of the project is to reduce the manufacturing cost of carbon fiber reinforced polymer matrix composites by using relatively inexpensive carbon fiber/polymer tow prepregs and near net shape forming processes such as automated fiber placement. The key points of this new process breakthrough include three aspects: First, a flexible coated tow developed by Fibrtec, FibrflexTM, which is a partially impregnated carbon fiber/polyamide composite. The material tow, ie the carbon fiber is not completely wetted by the polyamide, resulting in a tow material that is softer than the fully impregnated polyamide; the second is DuPont's Rapid Fabric Forming (RFF) technology and DuPont's proprietary polyamide resin. The RFF process enables ultra-fast production of fabrics with different directions of tow, without the need to lift the tow during processing; the third is the support of Purdue University in modeling and characterization, related experiments, modeling and simulation results show that this The combination of new molding processes and materials technology is a potential method for producing lower cost continuous fiber reinforced polymer thermoplastics. Compared to traditional methods, the new technology developed by the project is expected to reduce carbon fiber material waste by 30%.
There are currently two mainstream continuous fiber reinforced polymer thermoplastic molding processes, but due to obvious defects, it has limited its use in the automotive and aerospace industries. One method is to weave a fabric from a dried carbon fiber tow, layer the fabric with a thermoplastic resin film, and then heat and compress it into a composite. This method is slow, and the carbon fiber is easily broken during the weaving process to produce a bundle of conductive short fibers, so it is necessary to ensure electrical isolation between the knitting machine and related equipment. The second mainstream process involves impregnating and flattening carbon fiber tows with a thermoplastic resin to make a low void, fully cured composite tape which is then woven or placed and positioned to form a fabric which is then rapidly cured into the final composite part. The main problem with this method is the treatment of the unidirectional composite strip, which is rigid and brittle so that it breaks at room temperature and bends to a tight radius, resulting in a slow and costly manufacturing process from strip to fabric.
In the second phase of the project, advanced carbon fiber composites will be further developed to more fully study the forms of these new carbon fiber thermoplastic prepregs, and to verify whether these materials are suitable for mass production, including reducing manufacturing costs and increasing design freedom. Meet special performance requirements, etc. In addition, as one of the earliest projects implemented by IACMI, the project is also a model for accelerating innovation through public-private collaboration.
