New generation of manufacturing technologies: liquid print of composite matrices

复合材料工业展示了一系列高效的制造方法，从廉价而坚固的液体模塑工艺到高质量、昂贵的高压蒸汽灭菌法。所有可用的方法都有一个共同的特点：连续增强的部件，无论大小，都是在一次固化/固结中生产出来的。因此，为了获得良好的尺寸公差和内部复合材料质量，必须使用重型工具：高压灭菌器、热压机、双面RTM模具和其他设备，这些设备可以在大范围内提供高水平的施加压力。设计和监控这些制造工艺需要付出相当大的努力。一旦过程开始，就很难引入任何纠正，也很难在过程运行时检测和减少缺陷的发生。因此，必须事先考虑材料形成的所有可能情况，并且必须在材料合并之前解决任何可能的质量问题。由于整体制造参数不直接决定局部几何特征的形成，因此可用于调整工艺的仪表盘也非常有限。这使得这些工艺昂贵且有风险，特别是对于新的应用和加固系统。该项目引入了新的添加剂制造概念，消除了对重型制造设备的需求。这一过程是通过局部沉积液体树脂来实现的，方法是通过一系列高精度的注射穿过纺织预制件的厚度，然后局部固结。换句话说，该过程被实现为将基质3D打印到增强体中，从而将液体树脂保持在所需的位置。工艺的局部性保证了其对几何形状和性能的灵活性和复杂的控制。目前的项目着眼于(A)针对具有竞争力的印刷率的注射和固结工艺的优化，以及(B)了解制造参数对复合材料性能的影响。换言之，本研究提供了新的柔性高质量复合材料制造方法，以满足性能提高和复杂失效过程管理的需要。

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.