![]() ![]() “Replacing machined metal parts is an excellent application for FMC,” Akiyama adds. While raw material prices will likely be higher for FMC than aluminum, short molding cycles, light parts and near-net shape designs reduce material usage and secondary finishing, which should help make FMC parts roughly cost-comparable to aluminum parts. Since then, Gemini has led FMC design and process development to ensure isotropic properties aren’t lost during processing. It also made Gemini an ideal acquisition target for Mitsubishi. Fortunately, Gemini Composites, which had been developing low-flow molding for structural CF-SMC, proved a perfect fit for FMC. Further testing indicated that if FMC was allowed to flow during compression molding like traditional SMC, it not only would lose isotropic fiber alignment, but excessive flow would produce defects and property loss. The main challenge, as mentioned above, was how to mold it without losing those isotropic properties. Low-flow, not low-pressureĭevelopment soon accelerated thanks to opportunities to use FMC in primary body structures. “We developed proprietary equipment and a process to break bundles up further and achieve the type of fiber distribution we believed would give us both excellent properties and good moldability.” Because FMC doesn’t rely on flow in the tool to help mix material, impregnation and compounding steps have to be carefully controlled to ensure very low variation in mechanical properties. “Split-tow carbon fiber does break up into smaller bundles during chopping, but those bundles weren’t small enough to provide the level of property enhancement we sought,” continues Akiyama. The goal was to produce a true isotropic composite with chopped fibers in complex shapes that offered mechanical performance closer to prepreg. Initially, the team’s focus was on increasing the performance of Mitsubishi’s own 3K and 15K chopped carbon fiber SMC (CF-SMC) rather than developing a new material. ![]() Interestingly, technologies that would prove key to FMC development began as separate research projects around 2015. Together, these factors enable FMC to replace lightweight metals in structural applications at significantly lower weight.” Foundational research It involves an advanced material, an optimized molding process and dedicated design. FMC technology really consists of three factors. “What we wanted to create was a high-performance, chopped carbon fiber material that could be used in a much wider variety of applications and formed on commonly available equipment. “While there are many different continuous carbon fiber composites, they have limited application,” explains Koichi Akiyama, president, Gemini Composites and one of the developers of FMC. Cure occurs in 40-120 seconds at 130-150☌.ĬW Trending: A New Video Series From CompositesWorld By splitting larger tows into finer bundles, it’s possible to achieve materials with better and more uniform mechanical performance at lower cost than starting with aerospace-grade tows. It combines industrial-grade carbon fiber tows, which are chopped and split into smaller bundles, then impregnated with vinyl ester (VE) or epoxy matrices. Highly moldable, isotropic and better performingįMC edges closer to prepreg performance while retaining more of SMC’s processability and affordability. Called forged molding compound (FMC), the material is an advanced SMC reinforced with chopped carbon fiber and developed for structural applications with fairly complex designs using a compression molding variant. (Tokyo, Japan) with engineering support from Gemini Composites LLC (Seattle, Wash., U.S.), which Mitsubishi acquired in 2017. With new kinds of SMC come new application opportunities, as with a new product developed by Mitsubishi Chemical Corp. However, as compounders extend technology to more novel resins, reinforcement types and formats, SMC is being reinvented. Sheet molding compound (SMC) is a workhorse composite - in the form of a tough, thermosetting, B-staged, compression moldable sheet-form molding compound - used commercially since the early 1960s. Photo credit, all images: Mitsubishi Chemical Corp. ![]() Using FMC in conventional high-flow compression molding (lower image cross-flow direction) destroys the isotropic properties and can lead to property loss. A key element of Mitsubishi’s new forged molding compound (FMC) carbon fiber-reinforced SMC is the use of low-flow (but not low-pressure) compression molding, which helps preserve isotropic fiber orientation/distribution in the material to yield parts with high complexity and high mechanical properties for use in structural applications (upper image cross-flow direction). ![]()
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