Computer Controlled Rotational Moulding of liquid polymers for the manufacturing of elastomeric prosthetic interface liners.

接口衬垫在假肢使用者的舒适和健康方面发挥着重要作用。它们安装在残肢上，并位于肢体和承窝之间（承窝是包裹肢体并将用户连接到假肢的外壳。衬垫是由柔性缓冲材料制成的保护性覆盖物。（通常是硅树脂、聚氨酯或共聚物）戴在残肢上，它可以减少皮肤和接受腔之间的移动和摩擦。衬板设计具有特定的特性，可与不同的悬架系统配合使用。 目前的制造方法利用腔体模制技术，其中未聚合的液体树脂在固定体积的腔体中重力进料或压力注射。成熟的内衬制造商提供了一个相当大的内衬范围与不同的尺寸，以适应西部截肢人群的多样性。在液体材料固化之后，模具被分离并且产品从腔中移除。该工艺具有高质量的一致性，但模具的制造复杂且昂贵，因此提高了产品成本。此外，当需要一种以上的材料特性时，例如硬区域和软区域，需要多个腔。 一种令人兴奋的创新制造技术是液体滚塑工艺，旨在使用通常用于制造界面衬里的标准注塑聚合物牌号。在该过程中，将2组分聚合物注入到围绕两个轴旋转的单个模具中。双轴滚塑具有生产中空制品的优点。以前，固有的困难在于生产具有均匀厚度的物体，因为两个主轴的速度是固定的，并且不能独立地变化以考虑材料特性（例如其密度和粘度）的变化。随着计算机的出现，现在可以精确地控制物体的厚度。这是通过创建一个智能软件来实现的，该软件考虑聚合物的粘度和密度随时间的变化，并使用平板取出理论来计算每个轴的新速度。本项目的重点是室温硫化（RTV）硅橡胶系统生产内衬的滚塑工艺参数与聚合物材料性能之间的关系。此外，单旋转模具方法将提供，除了现成的产品，真正个性化的能力，用于制造定制的多材料/行为衬里。

Interface Liners play an important role in the comfort and health for prosthetic leg users. They fit over the residual limb and go between the limb and the socket (the socket is the shell that encases the limb and connects the user to the prosthesis. The liner is a protective cover made of a flexible, cushioning material. (typically silicone, polyurethane or co-polymer) Worn over the residual limb, it reduces movement and chafing between the skin and the socket. Liners are designed with specific characteristics to work with different suspension systems. Current manufacturing methods utilise a cavity moulding technique where liquid not polymerised resin is gravity fed or pressure injected in a fixed volume cavity. The established liner manufacturers offer a considerable liner range with different sizes to accommodate for the diversity within the western amputee population. After curing of the liquid material, the moulds are separated and the product removed from the cavity. This process has a high quality consistency but the manufacturing of moulds is complex and expensive and therefore driving up the product costs. In addition, multiple cavities are needed when more than one material behaviour is required such as hard and soft areas. An exciting and innovative manufacturing technique is the liquid rotational moulding process aiming at using standard injection-moulding polymer grades normally used in the manufacturing of interface liners. In this process, the 2 component polymer is injected into a single mould rotating around two axes. Rotational moulding in two axes has the advantage of producing hollow products. Previously, the inherent difficulty was in the production of objects with uniform thickness since the speed of the two primary axes are fixed and cannot be varied independently to take into account the changes in material properties such as its density and viscosity. With the advent of computers, it is now possible to control the thickness of the object accurately. This is made possible by creating an intelligent software which takes in the viscosity and density time variation of the polymer and using the flat plate withdrawal theory, computes the new speed for each axis. The relationship between rotational moulding parameters and polymeric material properties for a room temperature vulcanisation (RTV) silicone rubber system to produce liners is the focus of this project. In addition, the single rotational mould approach will deliver, beside, off the shelf products a truly personalised capability for the manufacturing of bespoke multi material/behavioural liners.