Facing the requirements of wafer scribing, this paper proposes a megasonic-assisted laser processing method to address the issues of ablation products and low depth-to-width ratio in laser scribing. Through theoretical analysis of laser ablation and megasonic vibration, it is shown that megasonic waves can remove the liquid-phase material and molten debris generated during ablation from the processing area, thereby reducing the accumulation of ablation products and improving the depth-to-width ratio. Subsequently, a three-factor two-response experiment was designed using the response surface methodology. Experimental results demonstrate that the introduction of megasonic waves significantly improves the surface morphology of the wafer. After grooving, the area of ablation products on the wafer surface is reduced by 80 μm2, representing a decrease of approximately 25
The recast layers, discharge craters and micro-cracks on the micro-shaft surface fabricated by wire electrical discharge grinding (WEDG) can negatively affect mechanical properties and fatigue life in particular as micro tools. An online polishing method using fluid magnetic abrasives (FMA) is proposed to improve the micro-shaft surface quality. A polishing device is designed that uses two permanent magnets to apply an external magnetic field and changes FMA container thickness to adjust magnetic field strength in the processing area. The FMA polishing device is integrated into a micro-EDM machine tool with a WEDG function, and the micro-shaft can be polished online by moving the set trajectory in the FMA. A single-factor experiment was employed on tungsten material micro-shafts fabricated by WEDG to explore the polishing ability. The effects of micro-shaft diameter, magnetic field strength, polishing time, spindle speed, abrasive particle size, and motion trajectory were analyzed. After FMA polishing, the surface roughness Ra could be reduced from 0.1 μm to below 0.05 μm generally, and the minimum could be reduced to 0.019 μm. Results show that the surface material removal was uniform and obvious. The tungsten micro-shafts had almost no deformation compared to before polishing, while the brass micro-shafts deformated obviously. After FMA polishing, the recast layer was significantly removed and the micro-shaft surface quality was improved, which was discovered by observing the surface topography. It proves that the online polishing of micro-shafts by FMA is feasible and valuable.
为实现复杂结构金属零件高精度制造成形,系统研究了激光立体成形各工艺参数对熔道截面形貌尺寸的影响规律.结果表明,激光立体成形熔道形貌尺寸与工艺参数有重要关系.沉积层截面面积、高度和宽度随着激光功率、送粉速率和基板温度的增大而增大,随着扫描速度的增大而减小,随着离焦量的增大呈现先增大后减少的趋势;重熔层截面面积、高度和宽度随着激光功率和基板温度的增大而增大,与扫描速度、送粉速率和离焦量等因素关系不大.
超快激光作为一种先进加工手段,因具有高柔性、高峰值功率密度、热影响小等特点可满足任意材料的精密加工,在航空航天、电子信息、新能源等领域的金属材料精密制孔中具有显著优势,故针对金属材料的超快激光冲击制孔、铣削制孔、螺旋制孔、环切制孔以及复合工艺制孔等工艺进行综述,总结了各制孔工艺的优势和面临的挑战.
针对目前掩膜电解加工深度溶解能力受限问题,以微凹坑阵列为研究对象,提出了基于流体动压效应的扫描阴极掩膜电解加工新方法.利用高流速电解液冲刷微凹坑表面堆积的电解产物,提高深度溶解能力,并且借助扫描阴极射流产生的流体动压效应使掩膜与工件表面动态贴合,从而简化工艺装置设计.基于加工试验,探讨了不同平底阴极结构和加工参数耦合作用对微凹坑尺寸变化的影响,最终实现直径259.8μm、深度44.1μm和直径418.1μm、深度102.7μm微凹坑阵列的加工,论证了扫描阴极掩膜电解加工方法具有提高深度溶解的能力.
