The markets: Sports and recreation (2019)

The sporting goods market was a boon to the advanced composites market in the final decade of the 20^th century. Carbon fiber fishing rods were introduced to great fanfare — and sales. Golf shafts and tennis rackets weren’t to be left out, and driven by the growing popularity of cycling races like the Tour de France, carbon fiber bicycles went from pro racing to bike trail and street and saw numerous innovations in the 1990s and 2000s, in materials and fabrication methods.

Today, composites are found in products used in seven of the 10 most popular outdoor sports and recreational activities. Glass- and carbon-reinforced composites (alone or in hybrids with other fibers) continue to replace wood and metal in skis, fishing rods, bowling balls, tennis rackets, spars/shafts for kayak paddles, windsurfing masts and boards, hockey sticks, kites and bicycle handlebars, as well as in niche applications, such as fairings for recumbent bikes.

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Market Research firm Lucintel (Irving, TX, US) estimates that the global sporting goods industry, at retail, is worth US$5 trillion and brings in US$110 billion/yr in the US alone. Although carbon fiber has a strong position in this segment, Lucintel maintains that use of carbon fiber in the worldwide sporting goods market could see its lowest growth rate in the near term, but is still expected to reach US$3 billion in 2018, up from US$1.8 billion in 2013. Notably, the sporting goods segment in China, which is projected by Lucintel to reach US$408 million by 2018, will consume more carbon fiber (51% of the total) than China’s aerospace and industrial segments combined. 

Bicycles continue to be the highest-profile market for composites use — or lack of composites use. That is, composites use in bikes is valuable in that it enables significant weight savings, so the less material used, the better. The challenge the bicycle manufacturing industry faces, as reported in CW in the story on bicycle design and manufacturing integrity, is the lack of strictly enforced standards for the design and fabrication of carbon fiber composite bike frames. The lack of standards and oversight can and has led to substandard product quality, resulting in injury or death due to failure of composite structures. No legally binding structural safety standards yet exist that address common rider load and environmental conditions (braking, impact loads, fatigue, vibration, material aging or degradation, material abrasion and wear) for high-performance composite bikes. Further, the existing ASTM D-30 test methods are not yet recognized by ASTM’s F-08 Bicycle Committee. That said, the International Organization for Standardization (ISO, Zurich, Switzerland) published its ISO 4210 standard for bicycles in 2014 and 2015 in nine sections. ISO 4210 was “developed in response to demand throughout the world, and the aim has been to ensure that bicycles manufactured in compliance with this International Standard will be as safe as is practically possible [editor’s italics]. The scope has been limited to safety considerations and has specifically avoided standardization of components,” according to ISO.

Recently, there has been significant activity in the watersports market, particularly in the area of stand-up paddleboard fins. CW covered several applications where concern for customer-specific performance demands and growing watersports participants’ respect for the health of their environment have come together in inventive composite designs. A standout was surfing equipment manufacturer Future Fins (Huntington Beach, CA, US) ownership team, which felt such a responsibility to protect the environment that they took aim at a new fin product that would reduce landfill waste and be as Earth-friendly as possible.

Toward that end, they collaborated with Green Dot Bioplastics (Cottonwood Falls, KS, US) to introduce a fin formed from bio-composites and bio-plastics but with adequate stiffness for a fin designed for stand-up paddleboards (SUPs). Future Fins came to Green Dot for an environmentally friendly material with the natural aesthetics of wood that also met the performance requirements of the engineering-grade plastics normally used for fins. One of Green Dot’s trademarked Terratek wood-plastic composites, a blend of reclaimed wood fibers with recycled polypropylene (PP) plastic, was the right solution. Terratek WC100300, which blends pine wood fiber and PP at 30% wood fiber by weight (although loading can be as high as 60%, depending on customer specs), fit the bill. With a density of 1.02 g/cm³, it delivers a tensile modulus of 399,000 psi, yet has the look and feel of wood. The injection molded RWC (reclaimed wood composite) Keel fin reportedly performs at the same level, or better than, many of the fiber-reinforced composite fins that Future Fins manufactures for SUPs, in terms of flex (stiffness), rake and flow (drag) characteristics, but is ~35% lighter than standard products of engineered plastic. The point? Manufacturers are discovering that sustainable materials and extreme high-performance are not incompatible goals.

A growing trend toward customization, and high-end manufacturers’ desires to cater to the unique needs and desires of individual athletes, has opened the door to 3D printing. Krone Ltd. (Dallas, TX, US), for example, is employing the process in the manufacture of its top-end golf clubs. Faced with exacting limits of club size and weight, and increasing individual expectations on the part of golfers not only in terms of driver performance (ball distance, loft, speed and spin) but also nuances such as “feel” and balance, company founder Mark Kronenberg approached for guidance the CRP Group (Modena, Italy), which had long experience with 3D printing in Formula 1 racing. CRP Group companies include CRP Technology, which produces additive manufacturing materials and technology, and CRP Meccanica, with high-precision CNC machining experience. 

The three companies worked together to develop the KD-1, a composite driver club head consisting of an additively manufactured body, using selective laser sintering (SLS) and employing Windform SP, a sinterable carbon fiber/polyamide powder; a Ti6A14V titanium strike face, CNC-machined from billet material, followed by sandblasting and cleaning; and a brass weight, also CNC-machined and sandblasted. Printable in hours, the hollow body’s lattice geometry optimizes its stiffness, while the carbon/polyamide exhibits high ductility and impact absorption. The machined titanium face fits over and is adhesively bonded to the body. Four Helicoil inserts in the body, opposite the face, accept fasteners that attach a brass weight. According to Krone, the AM process coupled with CNC reduces the touch labor otherwise required for conventional composite driver heads made with prepreg, and produces parts with tighter tolerances than those made from cast and forged metals, without time- and labor-intensive secondary operations.