An Automated Conversion Process
Many industries still hand cut, stack and assemble layers of carbon fiber, making them subject to misalignment, wrinkles, missing layers and fiber crimping. Start-up company Seriforge is automating the process of converting unidirectional carbon fibers into advanced composite preforms that can be mass produced, a dream for the high-volume automotive industry and others.
San Francisco-based Seriforge uses CAD technology to design a composite laminate based on customer requirements and then proprietary software to fully automate how the dry carbon fiber layers are cut, stacked, assembled and stitched together to form a 3D preform that is ready for insertion into a tool for infusion. The result is high-volume production capability – from 10,000 to 20,000 near net shape preforms per line/per month depending on the part complexity.
Automating the process simplifies future part revisions. Once a design change is entered into the part’s CAD file, the downstream processes are also updated. “Our CAD system and production equipment are integrated from start to finish,” says Marco Zvanik, vice president of business development for Seriforge. “A change made at the starting point of the design automatically alters the entire process.” Automating production also enables documentation of the manufacturing process, creating a record for historical analysis.
Seriforge offers Z-axis reinforcement of unidirectional and woven continuous carbon fiber preforms. For parts requiring a high fiber-to-resin ratio and designed for maximum performance, Seriforge stitches the stack with a continuous fiber tow with no tension on the fiber stitch and no chain or lock stitch, which can cause distortion of the X and Y layers of the unidirectional fibers, reducing the performance of the finished laminate.
The Z stitching is only used where needed, such as areas with a significant load pattern or a cutout in the part that poses the risk for delamination. “Our same design software develops the laminate schedule for the part based on what the loading requirements are and where the load paths are,” says Zvanik.
The resulting near net shape preforms are cost neutral or lower in cost than those made by hand lay-up or other standard prepreg fabrication methods, says Zvanik. Seriforge’s current customers are primarily in the oil and gas and recreational markets, although the company has several automotive projects underway. The company moved into a new manufacturing facility in 2017, and its first production line kicked into gear in June 2018. Seriforge is currently building a second production line and plans to add a third by the end of this year.