定电流短路引弧的逆变式空气等离子切割机

本文在分析试验的基础上，采用复合隔离型逆变电路和非高频起弧割炬，配以相应的内拖外特性控制方式和电路设计法，研制成功了低干扰高可靠性的逆变式空气等离子切割机。实验表明，该机具有可靠性高，切割质量好，操作简便等特点，为空气等离子切割工艺提供了一种新型的优良设备。     

截齿等离子束表面冶金铁基耐磨涂层研究

采用等离子束表面冶金技术，在采煤机截齿磨损严重的部位制备了与基材呈冶金结合的铁基复合涂层。利用光学显微镜、扫描电镜、X衍射仪和显微硬度计等手段分析了冶金涂层组织，测试了涂层的显微硬度和磨损性能。结果表明：涂层主要由γ-（Fe，Ni）和（Cr，Fe）7（C，B）3相组成，在固溶强化、弥散强化和细晶体强化共同作用下，冶金涂层具有较高的显微硬度和较好的耐磨性能。     

发电机组转子轴系机电耦联扭振的二重共振研究

找到发电机与直流电动机的气隙磁场能量表达式,应用拉格朗日—麦克思韦方程建立了机组轴系机电耦联的非线性扭振方程组,分别得到了发电机及直流电动机的电磁刚度,从理论和实验研究中发现了新的零阶固有频率,利用多尺度法对非线性扭振方程组进行了求解,得到了二重共振的规律,利用实验室的发电机组模型进行了实验研究,所取得的实验曲线和相应的理论曲线,不论在定性和定量上均有很好的吻合。     

A global cutter positioning method for multi-axis machining of sculptured surfaces

Traditional cutter positioning methods have defects of global errors and incomplete optimization. Because of using local differential geometry and focusing on the cutting contact point, these defects cannot be avoided and will deteriorate accuracy in precision machining. The authors presented the conception of actual cutting edge of a toroidal mill which was extended from cutting contact point, and pointed out its importance in programming. Instantaneous cutter position error (ICPE) was also investigated. A new global method based on the ICPE curve was presented. Taking the relationship between surface and cutter into consideration thoroughly, this global method shows many advantages which have been verified by simulation and cutting tests.     

具有梯度结构的涂层硬质合金刀片

研究了Co和Ti(CN)含量对梯度硬质合金的力学性能、梯度结构的影响.测试了梯度硬质合金刀片的切削性能.结果表明:随着合金钴含量的增多,合金梯度层厚度增厚,梯度结构越明显;合金的强度提高,磁饱和提高,磁力、硬度和密度减小.随着合金Ti(CN)含量的增多,合金梯度层厚度有变薄的趋势;随合金的硬度提高,合金的强度和密度减小.切削试验表明:具有梯度结构涂层硬质合金刀片的切削性能比无梯度结构涂层硬质合金刀片的切削性能优良.达到同一磨损高度hB=0.15 mm时,前者的切削寿命较后者提高了近一倍.同时随着合金钴含量的增多,硬质合金刀片的切削性能提高.     

Wear and cutting performance of diamond composite material-a comparison with tungsten carbide

A series of wear and rock cutting tests were undertaken to assess the wear and cutting performance of a thermally stable diamond composite (TSDC). The wear tests were conducted on a newly designed wear testing rig in which a rotating aluminium oxide grinding wheel is turned (also known as machined) by the testing tool element.The rock cutting tests were performed on a linear rock-cutting planer. The thrust and cutting forces acting on the tool were measured during these tests. A tungsten carbide element was also studied for comparative purposes. The wear coefficients of both materials were used to evaluate wear performance while cutting performance was assessed by tool wear and the rates of increase in forces with cutting distance.     

折边模折边浮块线切割加工工艺

分析了折边模折边浮块线切割加工工艺思路 ,介绍了减少变形的措施和加工中的技术要点     

基于DSP的数字化控制逆变式空气等离子切割电源研究

采用数字信号处理器DSP56F805,建立了逆变式空气等离子切割电源数字化控制系统.利用霍尔电流传感器检测电源输出电流,通过采样与A/D变换、数字滤波和PID控制实现了稳定的恒电流输出特性,并通过大林算法克服了数字PWM控制以及功率变换电路输出本身的延迟效应.此外,电源系统还采用Boost电路进行有源功率因数校正,输入EMI滤波电路滤除高频干扰,从而有效地提高了电源系统的功率因数和工作稳定性,以及数字化控制系统的抗高频干扰能力.实验结果表明,该数字化控制逆变式空气等离子切割电源切割过程稳定,切割质量良好.     

高精度铝带材纵剪机

介绍了高精度铝带材纵剪机的类型及最新技术，并对影响剪切质量的关键因素、张力控制形式等进行了综合分析。     

Optimizing the use of dry cutting in rough turning steel operations

The main objective of using cutting fluids in machining operations is the reduction of temperature in the cutting region to increase tool life. However, the advantages offered by cutting fluids have been strongly debated because of their negative effects on the economic aspect, the environment and the health of workers using them. A trend to solve these problems is cutting without fluid, a method named dry cutting, which has been made possible due to technological innovations. This work aims to seek conditions in which dry cutting is satisfactory compared with the flood of fluid (called here wet cutting) usually used. Aiming at this goal, several experiments were carried out varying parameters such as cutting speed, feed, depth of cut and tool material in rough turning of ABNT 1045 steel in dry and wet cutting. The analysis of the results showed that wet turning is, as expected, better for tool life. The second conclusion is that dry cutting cannot be used with large depth of cut. But the main conclusion is that, if the tool material is changed to a more wear resistant one, dry cutting can be used with results very similar to those obtained with a flood of fluid.