关键词： 飞秒激光   SiC   烧蚀阈值   材料去除机理  

摘要： 超短脉冲激光微加工技术以其独特的优势,尤其是对硬脆难加工类宽带隙材料的精密处理,而使其成为微结构加工中的研究热点。利用飞秒激光微加工系统对宽带隙材料SiC的烧蚀特性进行理论和试验研究。应用扫描电子显微镜、原子力显微镜和光学显微镜等检测技术对样品的烧蚀形貌进行检测,以分析烧蚀区域的形貌特征及微结构质量。依据烧蚀孔径和入射脉冲激光能量之间的函数关系,得出SiC材料的烧蚀阈值为0.31J/cm2,并估算出光束的束腰半径为32μm。研究脉冲数目、重复频率和入射激光功率等对加工微结构形貌的影响规律,根据试验参数加工出形状规则的微孔结构,并对微结构的烧蚀形貌及材料的去除机理进行分析,为实现微结构的精密加工提供了重要的指导。

关键词： 特种加工   教学改革   实习   实验   CAI课件  

摘要： 教学的目的是为了让学生掌握和应用所学知识,特种加工方法因为有别于传统加工,学生在掌握和理解上有一定的难度,更难以在设计中运用。通过对教学方法进行改革,提出三步教学,极大提高了学生对特种加工的认识和掌握,能够将其运用到具体的设计中,达到了教学的目的,也符合CDIO的教学理念。

关键词： PC机   单片机   激光加工机   硬件接口   软件流程  

摘要： 用单片机作激光加工机控制核心,采用PC机为上位机,实现了多功能激光加工机的计算机控制系统,该系统可广泛应舶于线切割、模具加工等机械的控制,具有图形和文字编辑功能完善,加工精度高、运行可靠等特点。

关键词： electrical discharge machining   ultrasonic vibration   assisting electrode   silicon nitride insulating ceramic  

摘要： The authors have previously performed numerous experiments on the machining of insulating materials using the assisting electrode method. However, the machining performance was inferior to that of the electrically conductive materials. To overcome this inferiority, for this research, an ultrasonic vibration system was combined with electrical discharge machining (USEDM) and applied with the assisting electrode method. Rotational machining was also added. A cylindrical copper tungsten bar was used as the electrode material for machining the sintered Si3N4 insulating ceramic. The effects of the electrode polarities, the effects of the amplitude on machining performance, the generation of a conductive layer and the discharge waveforms were investigated. The results were then compared to the conventional electrical discharge machining (normal EDM). The finishing process was performed by combining the ultrasonic vibration and various abrasive suspensions to remove the conductive layers and the craters. The results show that the material removal rate improved by a factor of approximately two over the normal EDM, and the surface roughness increased when the ultrasonic vibration was applied. The conductive layers and the craters were removed by the ultrasonic vibration using an abrasive (US-I-abrasive) method. The surface roughness of the workpiece was greatly improved by using the proposed method. [doi:10.2320/matertrans.M2010194]

关键词： 特种加工  

ISBN: (纸本)9787111316336

关键词： EDM   Fuzzy rule base   Machining parameters   Stainless steel  

摘要： Electrical discharge machining (EDM) is widely used process in the production of mould / dies, aerospace, automobile and electronics industries where intricate complex shapes need to be machined in very hard materials. The selection of the AISI 304 stainless steel was made taking into account its use in almost all industrial applications for approximately 50% of the world's stainless steel production and consumption. In this paper an attempt has been made to develop the mathematical model for predicting die-sinking electrical discharge machining of AISI 304 stainless steel characteristics such as the metal removal rate (MRR), the tool wear rate (TWR), the surface roughness (Ra value) and the hardness(HRB) using fuzzy mathematical method. The process parameters taken into consideration were the current (I), the open-circuit voltage (V), the servo (SV) and the dutycycle (η). A fuzzy rule base characterizing the relationship between input and output parameters was built through experiments. The design of experiments technique has been used to conduct the experiments, which in turn reduced the number of experiments. The prediction of the metal removal rate, the tool wear rate, the surface roughness and the hardness was achieved under the condition of given input parameters by rule-based fuzzy reasoning. The predicted results were analyzed through experimental verification. The model predicted values and measured values were fairly close to each other. A regression analysis of experimental and predicted outputs was performed to investigate the model. It was found that the R² values are 0.978, 0.91, 0.992 and 0.979 for the metal removal rate, the tool wear rate, the surface roughness and the hardness, respectively. © 2010, INSInet Publication.

关键词： 模具  

ISBN: (纸本)9787564038304

关键词： 电火花   特种加工   难加工材料  

摘要： 电火花加工技术在制造业中占有很重要地位,是实现难加工材料、复杂零件精密加工的有效方法。本文重点介绍了电火花小孔磨削、电火花加工螺纹、电火花表面强化和刻字及深小孔电火花加工的原理、特点及应用。

关键词： 型腔模   混粉电火花加工   工艺方法  

摘要： 混粉电火花加工是一种改善电火花加工表面粗糙度与加工效率的先进工艺方法,近几年在像手机外壳模具、遥控器外壳模具等型腔模的电火花精加工中发挥着越来越重要的作用。通过对型腔模混粉电火花加工应用技术的探讨,对模具制造企业吸收与消化当前先进的电火花加工工艺具有实际的应用价值。

关键词： 气膜孔   电火花加工   参数   设备  

摘要： 高压涡轮叶片是航空发动机的关键零件,其气膜孔的加工一直是困扰发动机研制的难题。采用先进的电火花小孔加工方法加工某型发动机高压涡轮叶片的气膜孔,针对加工难点制定有效措施,进行了大量现场试验,与激光加工相比,产品品质和生产效率明显提高,零件合格率达到80.7%,有效降低了研制成本,大大缩短了研制周期。