超窄脉冲微细电解铣削加工机理和成型预测建模

采用超窄脉冲电源,利用简单圆柱工具电极在数控系统控制下,实现三维微细电解铣削加工.本文探索了低浓度Na Cl O3溶液、超窄脉冲的微细电解铣削加工机理,进行微细电解铣削加工成型预测建模,并进行基于超窄脉冲微细电解铣削加工试验.     

Surface Micromachining of Bulk Acoustic Wave Filters

The most common typical bulk acoustic wave (BAW) filters are fabricated using bulk micromachining technology, but they have several disadvantages. This paper describes a new structure for front end passband BAW filters manufactured using surface micromachining. Porous silicon is used as a thick sacrificial layer. The structure reduces the influence of the support film on the filter to improve the VLSI compatibility as well as the filter quality. The cross-talk between resonators with different frequencies can be dramatically reduced by using resonators with a self-supporting structure.     

快速消除维持电压微细电化学加工脉冲电源

以绝缘栅型场效应管(MOSFET)作为开关元件的独立式单路微细电化学加工脉冲电源在脉间存在维持电压,使得微细电化学加工的散蚀增加,导致工件的形状精度降低.在分析维持电压存在特性的基础上,通过分析实验中采集到的波形,对脉冲电源进行改进,设计了双路控制的MOSFET开关电路,并根据MOSFET的开关特性,采用合理的电路参数.对比实验表明,改进后的电源快速消除了脉间维持电压,从而有效地降低了加工过程中的平均电压值,进而使加工表面痕迹的形貌得到了很大的改善,提高了加工的尺寸精度和表面质量.     

高速单颗磨粒磨削机理的研究

进行了单颗磨粒高速磨削45钢、20Cr钢和典型难磨材料钛合金TC4和GH4169高温合金的试验·试验结果表明,对于45钢和20Cr钢,高速条件下单颗磨粒磨削的比磨削能显著低于比熔化能·发现了国外一些学者提出的钢铁材料的最低比磨削能约束于材料比熔化能假设的例外·高速磨削四种材料均表现出尺寸效应·采用高速磨削,对改善磨粒的切削状态,降低比磨削能是非常有利的·在磨削钛合金TC4和高温合金GH4169时,易发生金属粘附·锆刚玉磨削钛合金TC4比磨削高温合金GH4169的粘附严重·高速下金属粘附作用减轻·     

A new micro programmable blazed grating (μPBG) and its application to multispectral imaging

A new micro programmable blazed grating (μPBG) was designed, fabricated and characterized using the two-layer polysilicon surface micromachining process. The μPBG presented is simple in structure and has the capability of continuous spectral tuning for a wide wavelength range. To maximize the operational blazed angle, dimple structure was adopted as the key component for grating slats, and its height was close to the air gap. By the measurements, the developed μPBG sample can reach a maximum blazed angle of...