What’s best, pultrusion or pull-winding?

Louise Davis

From window and door manufacturers to the professional tree surgeon, weighing up material options usually comes down to cost — but there are a variety of factors to consider before making a purchase. Considering the pros and cons of the materials you choose can even come down to the process in which they are made. Here, Robert Glass from Exel Composites outlines some options.  

Tree pruning telescoping poles can be made from a variety of materials, from aluminium to fibreglass and plastic, and each has its own advantages. But for anyone who uses tools, safety is always a top priority.

When thinking about safety, there is a huge argument for fibreglass in equipment like telescopic pruners. Lightweight and strong, fibreglass is non-conductive, presenting a distinct advantage in areas with high quantities of overhead cables compared to its aluminium counterpart.  

Due to the frequency of use and the force often exerted on the poles, the handles of tree pruning tools are prone to bend or snap. Strong fibreglass tubes, however, are resistant to corrosion and repeated hitting against tree branches, and they can last a lifetime, saving money in the long run.

What are the benefits of composites?

For many manufacturers, the benefits of composite materials are still being discovered. Combining the strength of glass or carbon fibre with the adaptability of a resin system that can be tailor made and cost-efficient to suit your exact technical requirements and needs is certainly appealing to many manufacturers. At Exel Composites, we specialise in two types of continuous manufacturing processes — pultrusion and pull-winding.

The earliest pultrusion patent dates back to the mid-1940s, but it was American plastics pioneer, W Brandt Goldsworthy, who is widely credited with inventing the process in 1959. Pultrusion technology perhaps gives the most flexibility in terms of profile design and the structural possibilities are near unlimited.

The process almost does exactly what it says on the label. Rolls of fibres and optional matting are simultaneously guided and pulled together before being saturated with resin. The fibres are then pulled through a heated die, which cures the composite before the profiles are cut to the desired length at the end of the line.

Pull-winding is very similar to pultrusion with the exception that fibres are wound around a profile before it enters the heated die. The advantage is in the fibre alignment possibilities in both the crosswise and longitudinal directions that enable us to provide a wider range of solutions, and even thinner profile walls, such as those used for tubing.

These manufacturing technologies are important solutions to help provide solutions for manufacturers who are looking to reduce weight, improve performances and efficiencies, and even reduce lifetime costs.

Technologies like pultrusion and pull winding give manufacturers the ability to produce some of the largest and most complex profiles on the market.

The use of composite materials is increasing — from window and door frames to tool handles to automotive stiffeners. The many advantages of pultruded composite materials are clear and can be applied in a number of areas including transport, building, construction and infrastructure industries as well as helping lower the costs of wind energy.

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