Claude Maack explores the challenges and opportunities for an innovative endless filament winding process
Since the first implementations in the 1800s of carbon fibres in arc lamps, incandescent light bulbs (bamboo slivers) and textiles, the use of fibres has widely expanded and developed further to become one of the finest options to design heavy duty parts and structures subjected to high tensile loads, thermal conductivity, and less weight.
Nowadays, different endless fibres made of various materials with miscellaneous material properties are being made available for industrial applications and in industrial quantities. Fibres made of natural and non-natural materials demonstrate exceptional mechanical and thermal properties that can be used to tailor new components and structures according to specific lightweight structural needs.
More and more new automated production methods using endless fibres are coming to market. The current automatised techniques such as the 3D printing, robotic filament approach, where fibres are mixed with a binder, shows a revolutionary change in how to design new thermo-mechanical components and structures.
This fabrication technique is usually used for manufacturing open or closed end structures. This offers the possibility of having continuous filament through the structure and the possibility of continuous manufacturing without wasting the materials, as there is almost no off-cut.
The 3D printing methods have the disadvantage of having, in most of cases, limits in shape, orientation and needing too much production time. On the other hand, an industrial robotic/CNC approach, where the process is sizeable and designed according to the parts to be produced makes good sense. Such an approach allows the manufacture of high technological parts using endless fibres with special features, including: ultralight, high geometric flexibility; optimised bionic shape; and reduction of complexity. Force and tension can be optimised (fibre strength/direction according to load) and there can be definable/adjustable strength and stiffness. This approach offers multi-axial load capacity (tension/compression, bending, torsion). It is also material optimised and resources friendly.
Some designers, engineers and manufacturers are already developing new components and structures using the endless fibres instead of metal/plastic approach for some applications. Parts with endless fibres that have already been produced include lightweight brackets and sandwich panels.
What are the Challenges?
As in any materials and manufacturing process, technical and industrial challenges appear. Engineers and manufacturers must analyse the possibilities versus the product risk that new materials and technology demonstrates. The main challenge that appears to determine the intense use of endless fibres is to understand and know the manufacturing process from the start to the end. A well automated and calibrated manufacturing process will enable a continuous and repeatable quality of the manufactured products.
As the use of endless fibre material is considerably lower as the traditional way to manufacture parts, this approach brings significant added value for the coming future where resources are getting more and more rare and costly. Moreover, a well-established supply chain of the endless fibre material is a must. It is important to select a reliable and industrial endless fibre material and manufacturer with industrial capacities.
Considering that, in the near future, it will be possible to manufacture 3D structural parts using natural fibres combined with natural bio-based binders, which are 100% repairable (self-healing), recyclable and sustainable, the potential of endless fibres as main structural material is clear.
Sustainability is a mega-trend that will influence our behaviour for the next decades, as humanity starts to understand that things must change. The challenges are huge. Lightweight is the smallest common denominator for all mobility topics (street, water, air or even in space). Half of weight leads to half of energy, independent of what kind it is, needed for acceleration.
Technology with Vast Potential
xFK in 3D is a process technology that will contribute considerably to this topic. OEMs have referred to it as a “gamechanging technology”. The reasons for this are obvious. It delivers from 50 to 70% of weight savings at the same stiffness. Integration of functions leads to a reduction in complexity. Complex 3D structures of large size (dimensions of a car or even bigger) are possible. A simulation-driven digital process chain means topologic optimisation. Studying patterns found in nature, by thinking in ropes, leads to a bionic design. CAD-FEA-CAM is a fully automated robotised winding process. Finally, this approach offers high flexibility for using any fibres in combination of any binder.
By adding the use of natural fibres today and in the near future, bio-based resins for circular economy aspects, by repairing structures and recycling the materials in an intelligent way, this process will be a breakthrough for sustainable systems.
The added value versus the relative quality of xFK in 3D solutions is compelling. OEMs and other industry experts confirm that this technology will be unavoidable.
Claude Maack is managing director of Gradel