New generation of manufacturing technologies: liquid print of composite matrices

Composite industry exhibits a wide spectrum of efficient manufacturing methods spanning from cheap and robust liquid moulding processes to high quality expensive autoclaving. All the available methods have one feature in common: the continuously reinforced components, no matter how big or small, are produced in one curing/consolidation shot. Thus to achieve good dimensional tolerances and internal composite quality, a heavy tooling must be used: autoclaves, hot presses, double sided RTM moulds and other equipment that can provide high levels of applied pressure over large area.

Considerable efforts are required to design and monitor these manufacturing processes. It is difficult to introduce any correction once the process has started or to detect and mitigate the defect occurrence when it runs. All possible scenarios of the material formation have to therefore be considered in advance and any possible quality issues must be addressed prior to the material consolidation. There is also a very limited instrument pallete available to adjust the process as the overall manufacturing parameters do not determine the formation of local geometrical features directly. This makes these processes expensive and risky particularly for new applications and reinforcement systems.

This project introduces a new additive manufacturing concept which negates the need for heavy manufacturing equipment. The process is implemented through local deposition of liquid resin by means of a series of high precision injections through the thickness of a textile preform followed by local consolidation. In other words, the process is realised as 3D print of matrix into the reinforcement which maintains the liquid resin in the required position. The locality of the process guarantees its flexibility and sophisticated control over the geometry and properties. The current project looks at (a) optimisation of injection and consolidation process aimed at competitive rates of print, and (b) understanding effects of manufacturing parameters on the composite properties. In other words, this study offers new flexible high-quality composite manufacturing method tailored to the needs of property enhancement and the management of complex failure processes.

Success of the proposed project has several aspects of impact. The major ambition is to introduce a new paradigm in composite design and manufacturing. The multi-scale manufacturing philosophy will make one more step in achieving a full potential of composites.

A number of attractive features guarantee a fast pick up of the technology by industry once proven competitive in terms of print rates and composite properties: (a) the locality of the process allows early stage detection and in-situ mitigation against forming defect, (b) the high efficiency and the compactness of the tooling gives obvious advantages compared to conventional technologies, (c) compatibility with conventional liquid moulding ensures that the local print can be used to enhance the properties locally, stabilise textile preforms, control the flow in liquid moulding processes. All these possibilities are beyond the capacity of any of the current manufacturing method.

These benefits are relevant for the entire spectrum of composite industries but the highest potential for the fast technology pick-up have the applications where high-quality multi-functional well-controlled materials are needed, e.g. the aerospace components. Apart from clear industrial benefits there is an important fundamental aspect of this project.

Understanding the role of locally enhanced material systems is critical for efficient design and properties such as toughness, stiffness, and damage resistance. Exploring opportunities by using the new tools for the new purposes maximises both the academic and industrial impact. In addition, expanding the limits makes textile composites more attractive to end users hence it serves as a catalyst for spreading these materials as well as taking a full advantage of these composites in existent applications. The current project provides an opportunity for material researchers to increase fundamental knowledge on this subject.