Abstract

Fabrication of high aspect ratio (HAR) complex micro features on high strength temperature resistant (HSTR) alloys is challenging by any conventional or non-conventional machining methods. In this study blind, HAR and complex micro features have been fabricated by micro electrochemical milling (MEM) on HSTR Cobalt alloy (Haynes-188) introducing a new strategic approach with novel flushing technique which could get rid of the need of pulsed DC power supply. Multiphysics simulation of the rotating micro-tool at different rpm and its impact on effective sludge removal has been analyzed and verified experimentally. In this study, most influencing parameters of MEM like voltage, feed rate, rpm of tool and milling layer depth have been selected to investigate their effects on the machining responses like width overcut, machined depth and surface roughness on Haynes-188 alloy. Comparison has also been made with constant and pulsed DC power source to know the influence of these process parameters on the MEM responses. Finally, several linear and non-linear blind, HAR (AR > 11) and intricate micro features have been fabricated successfully on cobalt alloy at the most suitable parametric combination, i.e., 7.5 V of machining voltage, feed rate of 0.3 mm/min, and tool rotation of 750RPM with 0.5 M of NaNO₃ electrolyte.

摘要

在高强度耐高温 (HSTR) 合金上制造高纵横比 (HAR) 复杂微特征是任何传统或非常规加工方法的挑战。在这项研究中，通过微电化学铣削 (MEM) 在 HSTR 钴合金 (Haynes-188) 上制造了盲、HAR 和复杂的微特征，引入了一种新的战略方法，采用新颖的冲洗技术，可以摆脱对脉冲直流电源的需求. 对不同转速下旋转微型工具的多物理场模拟及其对有效污泥去除的影响进行了分析和实验验证。在这项研究中，选择了电压、进给率、刀具转速和铣削层深度等 MEM 的大部分影响参数来研究它们对加工响应的影响，如宽度过切、Haynes-188 合金的加工深度和表面粗糙度。还与恒定和脉冲直流电源进行了比较，以了解这些工艺参数对 MEM 响应的影响。最后，在钴合金上以最合适的参数组合成功制造了几个线性和非线性盲、HAR（AR > 11）和复杂的微观特征，即加工电压为 7.5 V，进给速率为 0.3 mm/min，和工具旋转 750RPM 与 0.5 M 的 NaNO₃电解质。