Exel Composites and Diversified Structural Composites: Synergies in wind energy

In May 2018, Exel Composites announced a further significant step in its growth strategy with the acquisition of Diversified Structural Composites (DSC), marking its expansion into the substantial US market. As an experienced technical pultruder, particularly known for high-level carbon fibre applications, DSC strengthens and extends both Exel's technological know-how and its product portfolio. In the first part of this article, we introduced DSC and outlined projects in the aerospace and oil sectors which showcase its carbon fibre technologies.

Here we focus on the company’s expertise in the wind energy sector and present an overview of its glass fibre activities.

Unparalleled expertise in wind energy

Wind energy, where both Exel and DSC have been trusted suppliers for many years, is one of the markets promising significant opportunities following the acquisition. To capture more power from the wind turbine blade manufacturers have been developing longer, slimmer blade concepts. To enable these designs manufacturers have started to convert the main load-carrying element of the blade – the spar cap – from glass fibre composite to carbon. While infusion is the dominant technology in spar production at present, pultruded carbon spar caps offer higher quality parts with superior mechanical properties. Pultruded parts, supplied prefabricated and ready to install, can also reduce blade production time, leading to important cost savings. DSC has been actively developing carbon fibre spar caps for turbine blades since the mid-2000s. The company is currently supplying product to one company, and is involved in multiple development programmes with a number of other customers, David Lewis, DSC's Director of Technology & Business Development, reports. Exel's complementary offering for wind energy includes blade reinforcements and laminates, spar caps, blade root joints, cable management systems, service platform structures and ladders, generator insulation components.

"The highly competitive wind energy market places many demands on suppliers in terms of cost and service level, which smaller organisations cannot satisfy," states Exel Composites' SVP Sales and Marketing, Kari Loukola, who will transition to the newly-created role of SVP Exel Composites Americas and President of DSC in July 2018.

"The union of Exel and DSC provides wind energy customers an unparalleled combination of materials and process expertise, coupled with cost effective, global production capabilities."

Endless possibilities

SC's carbon pultrusion capabilities have been further proven in diverse applications ranging from guitar stiffeners, sporting goods and external bone fixation devices used in the medical and veterinary sectors, to large components for the paper and printing industry, engineered vibration damping devices, and components for satellites and UAVs. In addition, the company is currently working with a number of Tier 1 and Tier 2 automotive companies to develop body-in-white structural components.

"We've also developed an advanced pultrusion process which enables the high speed production of carbon and glass ‘micro rods’ down to 0.25 mm in diameter," Lewis notes.

"This process runs multiple times the speed of traditional pultrusion lines and requires no internal mould releases."

Because of this, and the ability to manufacture such small profiles, these products can be used as spot reinforcements, co-moulded into other composites with superior bonding capability, and can be used to make lightweight and flexible structures or rigid trusses for the hobby sector all the way to the aerospace industry. Loukola reports that a large number of Exel's clients are using carbon fibre to help speed up their manufacturing processes.

"The possibilities are endless when you have machines with fast moving parts," Loukola explains.

"Carbon fibre profiles help everything from manufacturing robots to textile machines function more efficiently. Many machines have a single part that can make a machine go faster. Printing machines, for example, have a critical frequency, which means that if you achieve a certain speed the parts start to vibrate at their own frequency. If you can replace that part with carbon fibre you can go faster and print more in less time."

Beyond carbon

Offering good tensile strength and higher elongation than E-glass or carbon fibre, S-glass is utilised in parts that need fatigue performance, such as springs and components that require damage tolerance. DSC processes large volumes of high performance S-glass each year for numerous customers, which enables it to offer low lead times on order deliveries. DSC also employs E-glass fibre for projects in various markets.

In the infrastructure sector, the company has supplied substantial volumes of sheet piling, a tongue and groove retaining wall system often used to prevent erosion in marine locations, as well as large panels for use as sound barriers on highways manufactured using fire retardant polyester resin. Drive shafts for trolling motors used by fishing boats, and complex shapes with low wall thickness for the window and door market are examples of further products. A clear advantage in the consumer market is DSC's ability to produce a near-Class A surface finish without the use of expensive paint or coatings.

or applications where high stiffness is required but weight is not critical, DSC can manufacture hybrid glass/carbon rods. The carbon fibre is employed in the outer area of the rod and glass fibre on the interior, so that the required stiffness is achieved with minimal use of expensive carbon. The company also provides a number of value added services including secondary finishing operations such as machining, thermoplastic coating, assembly and painting.

A global team

With the acquisition of a Chinese composites manufacturer in 2017 and DSC this year, Exel Composites is now the only pultrusion company with significant presence on all three major continents and is well its way to creating a truly global footprint. This expanded geographic presence together with DSC's complementary technological strengths and market focus open up new opportunities for the Exel group.

We are delighted to welcome Diversified Structural Composites to the Exel group and are excited about the opportunities this brings,” states Loukola.

“The combined product portfolios of Exel and DSC will enhance our attractiveness and provide cross-selling opportunities to existing and new customers. Our complementary strengths will improve our competitiveness and enable synergies for the ultimate benefit of our customers."