Disentangled UHMWPE composites for warp-free SLS parts

拟议项目的目标是在SLS中制备和使用定制的聚合物复合颗粒，从而生成具有扩展性能的SLS部件，特别是旨在克服当前有限的层间粘附力。用于生产功能粉末的原位聚合技术和用于生成SLS部件的模拟支持的工艺优化的组合是实现所得部件的改进的机械和尺寸稳定性的方法。在第一种方法中，将制备和烧结具有解缠结的UHMWPE的单壁CNT纳米复合材料粉末。这将导致基于UHMWPE的部件;由于其出色的机械和化学稳定性，选择后者作为部件的材料。预计在烧结过程中缠结的形成将导致颗粒之间更高的粘附力，这也是由起始复合物的较低粘度给出的。将通过热成像仪记录的数据建立数值模拟并进行验证和调整。然后，通过模拟评估的温度分布将与材料特定的结晶行为相关联。基于这种相关性，通过调整成型后的温度可以避免不均匀结晶和翘曲。随后，将确定SLS部件的材料性能，并与参考材料（如通常模塑的UHMWPE纳米复合材料）进行比较。因此，将建立关于材料特性和工艺参数的反馈和优化回路。

The proposed project targets the preparation and use of tailor-made polymer composite particles in SLS, allowing to generate SLS parts with extended properties, in particular with the aim to overcome the current limited interlayer adhesion. The combination of in-situ polymerization techniques for the production of functional powders and simulation supported process optimization for generating SLS parts is the approach to reach improved mechanical and dimensional stability of the resulting parts. In a first approach, single-walled CNT nanocomposites powders with disentangled UHMWPE will be prepared and sintered. This would lead to parts based on UHMWPE; latter was chosen as material for the parts on account of the outstanding mechanical and chemical stability. It is expected that the formation of entanglement in the sintering process will lead to a much higher adhesion between the particles, also given by the lower viscosity of the starting composite.A numerical simulation will be established validated and adapted by data recorded from a thermal camera. Then the temperature distribution assessed by the simulation will be correlated to the material-specific crystallization behavior. Based on this correlation inhomogeneous crystallization and thus warpage will be avoided by means of post-build temperature adjustments.Subsequently, the material properties of SLS parts will be determined, compared against reference materials like commonly molded UHMWPE nanocomposites. A feedback and optimization loop will be thus established regarding material properties and process parameter.