关键词： Electric discharge machining  

摘要： Electric Discharge Machining (EDM) removes metal with sparks. A shaped graphite or copper electrode is used to make a cavity that is the mirror image of the electrode, without direct contact with the workpiece. Sparks travel through a dielectric fluid, typically a light oil, at a controlled distance. EDM can machine cavities with thin walls and fine features, achieve difficult part geometry, produce burr-free parts, and is insensitive to workpiece *** values of these parameters significantly affect such machining outputs as material removal rate and electrodes wear. In this paper, the mathematical relationships between input and output parameters of EDM are established using regression method and the best set of models is chosen. Genetic Algorithm is then used to optimally determine input parameters levels in order to obtain any desired set of outputs. Numerical simulation of process in ANSYS software an for gaining the thermal profile, the effect of parameter variation on temperature field and process optimization are done. The numerical results show the time-dependant distributions of arc pressure, current density, and heat transfer at the workpiece surface are different from presumed Gaussian distributions in previous models.

关键词： EDM   EDM-C3   EWR   Micro-crack   MRR   Tungsten carbide  

摘要： Tungsten carbide (WC-Co) composites are mainly used to produce moulds and dies because of their high hardness and high wear resistance at high temperatures. However, conventional machining techniques, such as turning and milling, cannot be easily performed on tungsten carbide composite materials. Therefore, this study considers the effect of a copper-graphite electrode (EDM-C3) material on tungsten carbide workpieces during the electrical discharge machining process. The experiment found that the important parameters for this process are the discharge current, the on time, the off time, the opencircuit voltage and the electrode polarity. The negative polarity of the EDM-C3 electrode was also found to significantly improve the material removal rate (MRR), the electrode wear ratio (EWR), the surface roughness (Ra) and the micro-crack density better than a positive polarity electrode. The results show that the optimum electrode parameters for the process with negative polarity are an open-circuit voltage of 90 V, a current of 12 A, an of 25 μs and an off time of 200 μs. The effectiveness of the process is evaluated by the surface roughness, as determined by scanning electron microscopy (SEM). Moreover, the MRR increases with the discharge current intensity, and the micro-crack density was determined. © EuroJournals Publishing, Inc. 2012.

摘要： Hydrogenated amorphous silicon films subjected to KrF excimer laser irradiation with a profiled beam in air leads to the formation of microstructures. The main objective of this research was to perform a comprehensive study in understanding this material in three different aspects: thermal, electrical, and optical properties by experiment, SEM analysis and modelling. For the thermal interactions, analysis was carried out to investigate factors relating to the formation of the microstructures in a range of applied laser fluences from 93.8 to 443.8 mJ/cm2. The tallest microstructures were formed with average height from 1 to 3 m at laser fluence of 312.5 mJ/cm2. Investigation also include the effect of different applied laser fluence, different scanning schemes, the effect of the presence of 300 nm metal layer, and irradiation environment. Thermal modelling using COMSOL simulation software was used to simulate heat transfer during laser- material interaction and the results suggest a fair agreement with experimental findings. SEM and TEM reveal that the material formed was an oxynitride with embedded particles of crystalline silicon. In the electrical part, conductivity and field emission were the main tools to help elucidate the internal structure. Arrhenius plots acquired from conductivity measurements demonstrates a decrease in activation energy from 0.8957 eV from original sample to 0.3955 and 0.1727 eV for HE and LE sample respectively. Analysis also showed an agreement with Meyer Neldel rule for both samples. Observation made on the ratio of dark current to photogenerated current revealed the decrease from 59600 in original sample to 1.77 and 1.40 for HE and LE samples respectively. For the field emission properties, IE plots from samples were analysed using 170 m fixed gap structure, and lowest emission thresholds were achieved at 3 and 2.4 V/ m for HE and LE samples respectively. The results were fitted to a model of conducting particles in an insulating matri

关键词： 叶片   冲压成形   线切割加工   激光切割加工   电火花加工   抛光  

摘要： 为了提高精密络筒机的导纱性能,作者根据多年的实践经验,针对络筒机导纱机构中叶片的加工难点,先后采用不同的加工方法,对叶片进行工艺试验及分析对比,从中找到最适合络筒机叶片中、小批量生产和今后大批量生产需求的最佳工艺方案。

关键词： 激光加工   光纤   激光技术   激光切割机   加工行业   深圳市   设计者   集成商  

摘要： 作为国内第一台光纤激光切割机的设计者——深圳市大族激光科技股份有限公司（以下简称“大族激光”），是激光加工行业的领军企业，也是亚洲第一、令世界瞩目的纵向集成商，在激光加工领域占据着举足轻重的地位。大族激光在掌握先进技术和工艺的同时，引导着激光技术发展和产业发展潮流。

关键词： 特种加工   实验教学模式   教学改革  

摘要： 特种加工课程是培养机械制造和机电控制复合型人才所必需的一门高新技术专业课，特种加工工艺是直接利用各种能量，如电能．光能，化学能、电化学能、声能,热能及机械能等进行加工的方法，集数控，控制、传感等高新技术为一体，实践教学在讲授中占有重要地位。本文从实验教学方式,教学内容和教学手段等方面对现有特种加工实验教学进行改革，取得了明显效果。

关键词： 激光加工   纺织服装   金   应用   上市企业   中小功率   工业技术   裁剪设备  

摘要： 作为专业为全球用户提供中小功率激光加工解决方案的上市企业，武汉金运激光股份有限公司（以下简称金运激光）在近年的表现十分抢眼。今年3月底，金运激光携新开发的激光裁剪设备在第十三届中国（东莞）国际纺织制衣工业技术展上做了重点展示。

关键词： 中国机床工具工业协会特种加工机床分会   电火花成形机床   数控技术   50型   产品   E型   北京市   研究所  

摘要： 2011年11月25日，中国机床工具工业协会特种加工机床分会年会在云南召开，大会公布了2011年度中国机床工具工业协会特种加工机床分会审批的“达标认定产品”和“达标认定优等产品”。北京市电加工研究所及所属北京迪蒙数控技术有限责任公司研制生产的“AA50型、B30E型”精密数控电火花成形机床被审批为“达标认定优等产品”。翟力军书记代表公司领取了奖牌和证书。

关键词： 中国机床工具工业协会特种加工机床分会   电火花成形机床   产品   数控   E型  

摘要： 2011年11月25日,中国机床工具工业协会特种加工机床分会年会在云南召开,大会颁发了2011年度中国机床工具工业协会特种加工机床分会审批的＂达标认定产品＂和＂达标认定优等产品＂。

关键词： CCD传感器   细微电火花加工机床   实时传感  

摘要： CCD传感器实时检测系统是一套基于光电检测技术的质量监测仪器,可用于实时观测和测量被加工工件,特别适合安装应用于微细电火花加工机床。此系统利用CCD(Charge-Couple Device)传感器对工件进行非接触式测量,提高了微细电火花加工机床的工作效率和质量。此文对这一系统进行讨论,分析了其特点和优越性。