石油测井仪器筒体内孔加工技术

石油测井仪器筒体内孔的加工属于难加工材料的超细长深孔加工 ,加工精度要求较高 ,难度很大 ,效率很低。针对筒体的加工特点 ,进行了深孔加工方法的研究 ,设计了深孔钻削、深孔镗削和深孔珩磨加工工艺 ,对现有深孔钻和深孔珩磨工具的结构做了改进 ,优化切削参数。对传统的深孔加工方法改进后 ,可以明显地减小切削力 ,减小钻削过程中的振动 ,提高钻头耐用度、钻孔效率和钻孔精度 ,可以较准确地控制油石压力 ,防止珩磨头“抱死” ,使该筒体的加工质量和加工效率大大提高     

Shoe Last Machining Using Virtual Digitising

Shoe lasts are the moulds used in the footwear industry in order to mount the shoe. Most of the machines used in the sector to make lasts are simply mechanical copiers. CAD/CAM systems have just arrived in the shoe last market but their accuracy and efficiency is no better than traditional machines, and so it is difficult to persuade the industry to adopt new systems. A tool-path generation algorithm that takes advantage of traditional copier systems that do not fulfil the CNC standards is presented in this paper. The tool path is computed from a "virtually digitised" model of the last surface. The algorithm is then analysed in terms of computing cost and accuracy, and refined by applying a series of optimisations. Some computer architectures are proposed in order to reduce the computation time. The proposed algorithm has been successfully implemented in a commercial CAD/CAM system specialised for shoe-last making. Finally, some illustrative examples are given.     

Tool path generation for free form surfaces using Bézier curves/surfaces

Presented in this paper is a tool path generation method for multi-axis machining of free-form surfaces using Bézier curves and surfaces. The tool path generation includes two core steps. First is the forward-step function that determines the maximum distance, called forward step, between two cutter contact (CC) points with a given tolerance. The second component is the side step function which determines the maximum distance, called side step, between two adjacent tool paths with a given scallop height. Using the Bézier curves and surfaces, we generate cutter contact (CC) points for free-form surfaces and cutter location (CL) data files for post processing. Several parts are machined using a multi-axis milling machine. As part of the validation process, the tool paths generated from Bézier curves and surfaces are analyzed to compare the machined part and the desired part.     

基于OpenGL技术的数控车床虚拟仿真系统研究

当数控代码庞大、加工的轴形状复杂时,如何实时、逼真地仿真切削过程成为实现数控加工过程三维仿真系统的难点。本文介绍了利用OpenGL技术和面向对象的思想实现数控车床三维虚拟仿真的方法。重点分析了三维虚拟对象的绘制,面向对象的数据存储方式和面向对象的过程实现方法。基于该方法,开发了实用的数控车床三维仿真系统,实验结果验证了该方法的可行性与高效性。     

用三坐标数控铣床加工空间曲面时的圆弧插值算法

论述了在三坐标数控铣床上采用球头铣刀铣削空间复杂形面时圆弧插值的计算方法.把刀具中心等距曲线轨迹的计算归结为计算零件轮廓上点的坐标,确定了加工空间等距曲线时插值点的计算流程图.利用圆弧插值算法推导出了坐标增量计算公式,此公式可应用到数控装置修正刀具的半径,从而提高零件廓形的加工精度.此算法也可应用到端铣刀加工时圆弧插值的计算.     

Microfabrication of DC microarcjets with UV lasers

Microfabrication of a microarcjet with Fifth-harmonic generation Nd:YAG pulses (wavelength 213 nm) and its plasma acceleration characteristics was investigated. The microarcjet with a rectangular exit of 0.44 mm in height was machined in a 1.2 mm thick quartz plate. For electrodes, Au films of 100 nm in thickness were coated on a divergent part of the nozzle for anode and an inner wall surface for cathode. In operational tests, a stable discharge was observed for mass flow of 1.0 mg/s, discharge current of 6 mA, discharge voltage of 600 V, or 3.6 W input power. With the 3.6 W input power, plasma speed of 1441 m/s and an energy efficiency of 7% were obtained.     

数控加工零件工时估算的神经网络方法研究

为了快速合理地估算数控加工零件工时，提出了零件相似检索规则和算法，该算法应用神经网络获取典型零件的工时规律，并按此预测当前零件的加工工时。经实验表明这种算法可以快速有效地得到数控加工零件的工时估算值，为工厂技改实施、投资咨询及产品设计提供了辅助决策支持。     

多功能智能化在线检测技术的研究

介绍一种性能可靠、操作方便的多功能智能化在线监测仪及检测技术的研究.该仪器和检测技术可用于大型复杂零件或者薄壁弱刚度零件表面加工精度和刀具破损的智能监控.     

非晶态As2S8半导体薄膜波导的热处理效应

研究了非晶态As2S8半导体薄膜在热作用下的结构变化效应.采用棱镜耦合技术、喇曼光谱测试技术,确认了As2S8薄膜经热处理后,薄膜密度增高和折射率增大的现象.实验表明,淀积态非晶As2S8半导体薄膜经紫外光饱和照射后,再经退火处理,当光折变在退火温度不低于160℃时,出现不完全可逆现象,可逆程度跟退火温度有关.实验显示,退火态非晶As2S8半导体薄膜在玻璃转化温度130℃时退火处理,光折变存在完全可逆现象.光传输实验显示,热处理后的非晶态As2S8半导体薄膜波导,其传输损耗减小了约4dB/cm.     

Electrical Discharge Machining of Ti6Al4V in Hydroxyapatite Powder Mixed Dielectric Liquid

Hydroxyapatite (HA) powder suspension in deionized water was used as a dielectric liquid during electrical discharge machining (EDM) of Ti6Al4V work material. The machined surfaces were evaluated by scanning electron microscopy (SEM), energy dispersive spectroscopy, and optical microscopy. The powder particles in the dielectric liquid extensively migrated and formed an HA-rich layer on the work material surface under specific machining conditions. The result was attributed to the generation of secondary discharges due to altered discharge conditions. The particles divided the primary discharge channel into several secondary ones. When the main discharge channel subdivided into several sub-discharges with comparable energy densities, the particles in the discharge region got stuck among them. Then, they moved toward the melted cavities and penetrated the surface at the end of the discharge duration. The results suggest the process as a practical alternative for producing biocompatible interfaces or coatings for medical applications.