OPTIMIZATION OF ELECTRO-CHEMICAL MACHINING PROCESS PARAMETERS USING GENETIC ALGORITHMS

ECM and ECM-based processes (derived and hybrid processes) are one of the most widely used advanced machining processes (AMPs) to make complicated shapes of varying sizes in the products made of electrically conducting but difficult-to-machine materials such as superalloys, Ti-alloys, alloy steel, tool steel, stainless steel, etc. These materials are extensively used in aerospace, automobile, space, nuclear, defense, cutting tools, dies and mold making applications. ECM offers some unique advantages over other conventional and advanced machining processes but its use incurs relatively higher initial investment cost, operating cost, tooling cost, and maintenance cost. Use of optimum ECM process parameters can significantly reduce the ECM operating, tooling, and maintenance cost and will produce components of higher accuracy which is very important in some critical areas such as aerospace, space, defense, nuclear applications. Therefore, choice of optimum process parameters is essential to ensure the most cost-effective, efficient, and economic utilization of ECM process potentials. This paper describes optimization of three most important ECM process parameters namely tool feed rate, electrolyte flow velocity, and applied voltage with an objective to minimize geometrical inaccuracy subjected to temperature, choking, and passivity constraints using real-coded genetic algorithms. Comparison of the obtained optimization results with the results of past work in this direction shows an improvement in terms of geometrical accuracy.     

新型磺化聚芳醚酮的合成与性能

用浓硫酸磺化对苯二酚型聚芳醚酮（PAEK-H）制备了磺化聚芳醚酮（SPAEK-H）,采用核磁共振、红外光谱和热失重对SPAEK－H的结构进行了表征,结果表明,采用直接磺化法成功地将磺酸基团引入到了PAEK-H分子链中。对其离子交换容量和磺化度进行了计算,并对SPAEK—H进行了力学性能测试,表明SPAEK-H具有较高的离子交换容量,具备一定的力学性能,较商用的Nation膜拉伸强度和弹性模量都有所提升。