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Composite profile design can be tailored to suit a broad range of applications

The look and feel of a composite tube can be customized to meet a range of requirements. From a solid color smooth surface to custom designed cross-winding patterns, there are many options available for consideration. Here Lauri Turunen, product business owner for tubes, tool handles, and telescopes at Exel Composites, discusses how pultrusion and pull-winding help enable a broad range of composite tube aesthetic customizations.

With composite tubes made using pull-winding and pultrusion there are many tube aesthetic design possibilities which can be achieved. These range from the surface tactility with solid colors to using combinations of reinforcing fibers to create a custom cross-wound pattern that can be unique to your specific composite.

Because pultrusion and pull-winding are continuous processes, they are designed to incorporate the desired aesthetic in-line, during the creation of the composite. This is important for consistent quality and repeatability of the desired aesthetic. Many different aesthetics are produced using a combination of fibers, veils, mats, fabrics, and cross-windings. Even wood-imitations are possible by using patterned foils into the manufacturing process.

The surface aesthetic design is considered when developing new composite products. Often the surface aesthetic will be part of the mechanical requirements solution, where the entire construction of the composite is determined.

Veil: A non-mechanical, thin, lightweight layer of fiber, typically fiberglass, which produces a highly resin-rich surface. This is the standard surface finish for composites manufactured by Exel, smooth to the touch and brightly pigmented due to the resin-rich surface.

Mat: Chopped strand or continuous strand mats – a non-woven mat made of strands of fibers with a random orientation. Mats add to the structural design of the composite and also provide a resin-rich surface for strong pigmentation. The fibers in the mat add a tactile surface feel to the finished composite.

Fabrics: With different weave patterns available, reinforcing fabrics contribute to the mechanical structure of the composite while the weave pattern contributes to the aesthetic.Weave patterns (such as a twill) can have fibers oriented to ± 0/90 degrees or ±45 degrees, relative to the tube axial direction.

Cross-windings: Perhaps the most highly-aesthetic example, cross-windings are produced using a variety of reinforcing fibers wrapped around the tube, crossing over each other to produce unique patterns. The cross-wound fibers provide transverse stiffness and strength to the composite.

Functional coatings: A layer of thermoplastic can be extruded on top of the tube surface during the pultrusion/pull-winding process. The coating can provide many functions, from a high-friction surface to an alternative to resin pigmentation or even additional UV-protection.

Post-manufacturing options: These consist of traditional painting of the composite or more advanced surface treatments, such as grinding the composite surface to produce a matte finish. When considering your next composite solution be sure to ask about the range of aesthetic possibilities your composites supplier can provide. If you are looking for something unique and are not yet sure what you would like, contact Exel Composites to start a discussion.

Manufacturing Update