SEER: Smart self monitoring composite tool
A “Smart” Self-monitoring composite tool for aerospace composite manufacturing using Silicon photonic multi-sEnsors Embedded using through-thickness Reinforcement techniques.
The SEER project will address these challenges by designing and building composite tools with embedded photonic integrated circuits (PICs) in a way that minimises alteration of the tooling structure and processes.
Photonic devices offer the advantages of being small, cheap, and able to provide a fast response. Our approach relies on the use of standard photonic structures and tool manufacturing processes, which will be adapted and optimised for our purpose and combined into a unique solution. Such smart self-monitoring composite tooling will be able to measure temperature, pressure, and refractive index, which is directly correlated with the state of the material, and, therefore, provide a real-time process control with unprecedented reliability.
The performance advantages offered by composites over traditional materials, specifically lightweight, high strength, and high stiffness, has led to their growing adoption in several industrial sectors. They are ideal materials for those applications requiring highly advanced technologies, such as aircraft and automotive parts, but also for construction and infrastructure elements. The aerospace industry has undergone a transformation from a metal-driven world to a composite-dominated new standard. The automotive industry has also been increasingly using composites for their cost and weight reduction and recyclability advantages.
The major drivers for growth in the composite market are represented by the increasing demand for lightweight materials in the aerospace and automotive industries. In order to respond to this demand, we need to focus on two aspects:
- Efficient and controlled curing cycles to reduce costs and speed up production;
- The adoption of composite tools (moulds) for their lower (10 times less than metal tools), ease of movement, ease of construction, and lower price, compared to standard metal tools.
Currently, most manufacturers use standard filling and curing cycles with high safety factors to determine the cure duration. Long curing times lower the productivity and can imply a risk of products not fully being cured. We can optimise filling and curing cycles and, thus, increase productivity, by applying process monitoring. Different techniques are already available in the market, like thermocouples and dielectric sensors. However, these electric solutions suffer in terms of operating capabilities and integration within assemblies incorporating electrically conductive tooling and reinforcement such as carbon.
Furthermore, the shifting from metal to composite tools, due to their above-mentioned advantages, has been suggesting the deployment of sensors as an integral part of the tool itself. However, this integration can be challenging and can alter the structural integrity of composite tools, resulting in the production of composite parts of lower quality. This is mainly due to the size or material of sensors, for which drilling is required in order to be mounted in the tool. Therefore, there is a need for sensing devices to be small and flexible - and strong enough to be embedded through the thickness of the composite tools.