An advanced modelling approach for micro EDM wear analysis

在更广泛的材料上进行微米和纳米加工的能力，包括真正的3D形式的结构化，对于开发创新的新应用变得越来越重要，以便在许多高价值制造领域，包括生物技术（例如生物传感器，微流体）和光电子学，灵活和经济高效地制造由不同材料制成的多功能产品。微尺度电火花加工工艺（微细电火花）带来了独特的结构化能力，这对于开发用于生产微米和纳米产品的成本效益加工链至关重要。微细电火花加工的一个主要吸引力是它能够在任何导电材料上加工几乎任何深度的3D结构，而不管材料的硬度和耐磨性如何，这使得它特别适用于生产高性能的微注射工具刀片。然而，与大多数微加工技术一样，微细电火花加工技术仍然相对缺乏成熟度，仍然需要进行密集的研发工作，以充分发挥其潜力并提高整体的微制造能力，这是本提案的最终目的。更具体地说，精确地表示在微观尺度上的电火花加工的物理行为的分析模型仍有待开发，防止准确的预加工预测。特别是在模具成形微细电火花加工过程中，用于加工工件的电极上存在的微特征将经历严重的磨损，导致难以预测电极形状变形。本提案中提出的一个想法是模具成形微细电火花加工可以成为用于生产复杂微3D形状的高成本效益的制造工艺，只要能够精确地模拟电极形状变形的磨损效应。因此，可以在设计阶段通过向电极添加小心放置的额外体积来补偿变形。磨损建模和模拟方法的主要问题是，迄今为止，很难预测的参数（冲洗，材料性能变化在微观尺度上，弹坑形状等）的强有力的假设，必须作出，部分是由于在计量和实验装置等领域的技术限制。该提案将建立在计量学，材料科学和微制造的最新进展的基础上，以开发一种先进的实验装置，为模具下沉微细电火花加工提供更可预测，稳定和可测量的环境，从而验证一种新的，更准确的建模和仿真方法。一个特别的重点将是对非晶和超细晶粒金属的加工。

Capabilities for micro and nano processing on a wider range of materials, including the structuring of true 3D-forms, are becoming increasingly important for the development of innovative new applications in order to enable flexible and cost-efficient manufacturing of multifunctional products made of different materials in many high value manufacturing sectors, including biotechnology (e.g. biosensors, micro fluidics) and optoelectronics. The micro scale Electro-Discharge Machining process (micro EDM) brings unique structuring capabilities that can be crucial for the development of cost effective processing chains for the production of micro and nano products. One major attraction of micro EDM is its ability to machine almost any deep 3D structure on any conductive material, regardless of material hardness and wear resistance, making it, for instance, particularly useful for producing high performance micro injection tool inserts. However, like most micro machining technologies, micro EDM still suffers from a relative lack of maturity and intensive R&D work is still required to fully realise its potential and to enhance micro manufacturing capabilities as a whole, which is the ultimate purpose of this proposal. More specifically, analytical models representing accurately the physical behaviour of EDM at the micro scale remain to be developed, preventing accurate pre-machining prediction. In particular, during a die sinking micro EDM process, the micro features present on the electrodes used to machine a work-piece will undergo severe wear, resulting in difficult to predict electrode shape deformations.One idea put forward in this proposal is that die sinking micro EDM could become a highly cost effective manufacturing process for the production of complex micro 3D shapes, providing that one could model accurately the wear effect on electrode shape deformation. Deformation could thus be compensated for at the design stage by adding carefully placed extra volume to the electrodes. The main issue with the wear modelling and simulation approaches developed so far is that strong assumptions on difficult to predict parameters (flushing, material properties variations at the micro scale, crater shapes etc) have had to be made, due partly to technological limitations in areas such as metrology and experimental setup. This proposal will build on combined recent advances in metrology, material science and micro manufacturing in order to develop an advanced experimental set up, allowing a more predictable, stable and measurable environment for die sinking micro EDM and to consequently validate a new, more accurate modelling and simulation approach for micro EDM wear. A special focus will be on the machining of amorphous and ultrafine grained metals.