New generation of manufacturing technologies: liquid print of composite matrices

复合材料工业展示了广泛的高效制造方法，从廉价和强大的液体成型工艺到高质量昂贵的高压灭菌。所有可用的方法都有一个共同的特点：连续增强构件，无论大小，都是在一次固化/固结中产生的。因此，为了实现良好的尺寸公差和内部复合质量，必须使用重型工具：高压灭菌器，热压机，双面RTM模具和其他可以在大面积上提供高水平施加压力的设备。设计和监控这些制造过程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，或者在过程运行时检测和减轻缺陷的发生。因此，必须提前考虑材料形成的所有可能情况，并且必须在材料固化之前解决任何可能的质量问题。由于整体制造参数不能直接决定局部几何特征的形成，因此用于调整工艺的仪器托盘也非常有限。这使得这些过程昂贵且有风险，特别是对于新的应用和加固系统。该项目引入了一种新的增材制造概念，消除了对重型制造设备的需求。该工艺是通过通过纺织品预成型的厚度进行一系列高精度注射来实现液体树脂的局部沉积，然后进行局部固结。换句话说，这一过程是通过3D打印的方式实现的，将基质打印到增强物中，使液体树脂保持在所需的位置。该过程的局域性保证了其灵活性和对几何形状和属性的复杂控制。目前的项目着眼于(a)优化注射和固化工艺，以提高打印效率，以及(b)了解制造参数对复合材料性能的影响。换句话说，这项研究提供了新的柔性高质量复合材料制造方法，以满足性能增强和复杂失效过程管理的需求。

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.