An advanced modelling approach for micro EDM wear analysis

在更广泛的材料上进行微和纳米加工的能力，包括构建真正的3D形式，对于开发创新的新应用正变得越来越重要，以便在许多高价值制造部门，包括生物技术(例如，生物传感器、微流体)和光电子产品中，能够灵活和低成本地制造由不同材料制成的多功能产品。微尺度电火花加工(Micro EDM)带来了独特的结构能力，这对于开发成本效益高的微米和纳米产品加工链至关重要。微细电火花加工的一大吸引力在于，它能够在任何导电材料上加工几乎任何深3D结构，而不考虑材料的硬度和耐磨性，例如，这使得它特别适用于生产高性能的微注射工具插件。然而，与大多数微加工技术一样，微细电火花加工仍存在相对不成熟的问题，仍需进行密集的研发工作，以充分发挥其潜力，提升整体微制造能力，这是本提案的最终目的。更具体地说，在微观尺度上准确地表示电火花加工的物理行为的分析模型仍有待开发，这阻碍了准确的加工前预测。特别是在微细电火花加工过程中，用于加工工件的电极上的微观特征会受到严重磨损，导致电极形状变形难以预测。本文提出的一个想法是，如果能够准确地模拟磨损对电极形状变形的影响，那么微细电火花加工可以成为一种高性价比的制造工艺，用于生产复杂的微三维形状。因此，可以在设计阶段通过向电极添加精心放置的额外体积来补偿变形。迄今为止开发的磨损建模和模拟方法的主要问题是，必须对难以预测的参数(冲洗、材料特性在微尺度上的变化、弹坑形状等)做出强有力的假设，部分原因是计量和实验设置等领域的技术限制。这项提议将建立在计量学、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，为芯片下沉微细电火花加工提供更可预测、更稳定和更可测量的环境，从而验证一种新的、更准确的微细电火花加工磨损建模和模拟方法。将特别关注非晶态和超细晶金属的加工。

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.