Development of rCF Thermoplastic Non-woven Prepreg for Automotive Class A Body Panels via Compression Molding
- BASF Corporation, Wyandotte, MI (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- IACMI The Composites Institute, Knoxville, TN (United States)
One of IACMI’s stated goals is the recycling of composites into useful products. To achieve this, the institute plans to demonstrate recycling technologies at a sufficient scale to justify the investment risk for private industry commercialization. Success will mean the reduction of regulatory disposal risks, encouraging additional investment and will allow for the opening of new composite markets. This is a particular concern as failure to achieve this could mean the loss of US global competitiveness in the composites marketplace as US manufacturers become unable to meet increasing regulatory burdens surrounding composite waste disposal nor are able to compete with emerging, inexpensive recycled composites from Europe and Asia. IACMI is uniquely positioned to conquer this fundamental risk for industry by demonstrating economical recycling technologies which reduce environmental impact while creating circularity in manufacturing and producing new recycled composite intermediates and products. The core IACMI team has come to view the recycling problem along three dimensions, with the first leg of identifying of composite waste types and characterizing that waste to determine appropriate methods of recycling. Along the second leg is the science behind the materials used in advanced composites and how different recycling methods alter these materials innate mechanical performance. Along the third leg is the building of relationships with key industrial partners to procure composite waste streams and build new markets for recycled composite products. In making carbon fiber economics circular, this project was explicitly concerned with developing the materials and process to manufacture a reclaimed carbon fiber (rCF) - polyamide (PA) composite automotive body panel with a painted Class A surface comparable to the incumbent steel technology. Additional project targets included cycle time for molding the part, mechanical performance and thickness tolerances. The approach to meet these targets and showcase technical feasibility was a combination of material formulation, composite layup, processing conditions and paint application. The composite preform consisted of a comingled non-woven mat of reclaimed carbon fiber and polyamide fiber. Through compression molding, the polyamide fiber melts, forming the composite panel. To meet the cycle time target and achieve a high-quality surface finish, a rapid heating and cooling tool from RocTool was designed and built for the project. This tool was installed at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility. However, due to startup challenges and troubleshooting, much of the development work for the project occurred at RocTool’s development facility in Charlotte, NC. The key technical challenge was to mitigate differences in thermal expansion between the carbon fiber and polyamide resin. The temperature changes that the molded part experiences during forming and paint curing causes the surface topology to change. Some of this surface topology can be smoothed by the paint system, but to approach the Class A designation, the polyamide resin, composite stack, and molding protocol must all be optimized to produce a smooth part directly from the tool, then the paint system can further improve the surface finish. Class A was defined based on steel benchmark panels and measured shortwave and longwave values from a BYK Wavescan® tool. The target values for this study to achieve Class A were below 20 and 10 for the shortwave and longwave values, respectively. A rCF/PA composite was demonstrated to meet these benchmark values, and a pathway has also been identified to provide further improvement in surface quality and processability in the future. The mechanical performance of the composite panels was characterized and compared with benchmark panels where cycle time and surface quality were not the target. Molded parts using the RocTool compression molding tool exhibited slightly lower mechanical performance but still exceeded the target values. Furthermore, these parts also were produced within the targeted cycle time and had a high-quality surface finish. Additional characterization showed that these parts could be produced at a repeatable thickness within the allowable tolerance and it was identified that any significant variation in the molded parts came from variability in the incoming material. The feasibility of creating a carbon fiber composite with an automotive Class A surface, suitable for high volume manufacturing, was established in this project. Areas for further optimization have been identified and would be tested in future work. A future study would focus on developing this technology further from a demonstration plaque tool to a real application to be defined with an automotive OEM.
- Research Organization:
- IACMI - The Composites Institute
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing Office
- DOE Contract Number:
- EE0006926
- OSTI ID:
- 1608657
- Report Number(s):
- IACMI/R0001-2020/6.5; IACMI/R0001-2020/6.5
- Country of Publication:
- United States
- Language:
- English
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