GRAiL

加法制造AM用于为更广泛的市场(APPA)建立各种材料(特别是塑料和金属)的物理模型、原型、图案和生产件。数字格式的组件被绘制成薄的水平切片，并使用各种技术(如选择性激光烧结(SLS)、还原光聚合法、材料挤压和粉床融合)逐层添加材料来构建组件。SLS是在1984年开发的，它利用激光将金属或聚合物粉末熔化到彼此上(APPA)，自专利到期以来，这些机器的价格和供应大幅下降，进一步刺激了需求。最初，聚合物SLS系统使用熔点范围较宽的无定形聚合物(ABS)，但如今几乎所有聚合物SLS系统都使用熔点较高的结晶聚合物(通常为尼龙PA12)，粉末被熔化。不幸的是，SLS聚合物的性能与传统挤出材料相比有所降低。纤维状填料可以提高韧性，但尼龙必须复合，然后进行冷冻球磨，在粉末上产生角状表面，这限制了其流动特性。快速粉末拥有一种专利工艺，可以在沉淀的球形粉末上涂覆各种填充材料(包括纳米填料)，特别是石墨烯，这是聚合物纳米复合材料理想的填料，可以改善其机械性能。我们建议证明生产一系列具有良好流动特性的PA12石墨烯纳米复合粉末的概念，这些粉末在SLS机器中熔化或烧结时具有与挤出PA12相当的性能，使SLS能够生产成品部件。

Additive Manufacturing AM is used to build physical models, prototypes, patterns, andproduction parts in a wide variety of materials (in particular plastic, and metals) for a widerange of markets (AppA). Components in digital format are rendered into thin horizontalsections and using various techniques (e.g. Selective Laser Sintering (SLS), VatPhotopolymerisation, Material Extrusion and Powder Bed Fusion) material is added layer bylayer to build the component. SLS which utilises lasers to melt layers of metal or polymerpowder on to each other (AppA) was developed in 1984 and since the patents expired and theprice and availability of these machines has dropped dramatically, further stimulatingdemand. Initially, polymer SLS systems used amorphous polymers (ABS) with a broadmelting range but today almost all polymer SLS systems use crystalline polymers with a sharpmelting point (typically Nylon PA12) and the powder is melted. Unfortunately SLS polymerproperties are diminished compared to conventional extruded material.Fibrous fillers can improve toughness but the nylon has to be compounded and then cryogroundor milled producing angular surfaces on the powder which restrict its flowcharacteristics. Rapid Powders has a proprietary process whereby precipitated sphericalpowders can be coated with a wide range of filler materials (including nano-fillers) and inparticular Graphene which is a desirable filler for polymer nanocomposites and improves theirmechanical properties. We propose to prove the concept of the production of a range of PA12graphene nanocomposite powders with good flow characteristics that when melted or sinteredin a SLS machine have improved properties comparable to extruded PA12 enabling the SLSproduction of finished components.