用于磨削法离线清除焊管内毛刺的磨管机

介绍了一种焊管内毛刺磨管机的结构和工作原理,其主要用于对内毛刺超标的HFW焊管进行离线处理,适用于φ219～610 mm焊管.实际应用表明,该磨管机具有稳定性高、适应范围广、生产效率高等特点,是比较理想的焊管内毛刺离线清除设备.     

变量柱塞泵、马达、整体式多路阀零件的去毛刺、光整设备和工具

针对工程机械的变量柱塞泵、马达、整体式多路阀的零件进行了研究,对行业最薄弱的工艺环节即去毛刺、光整工艺进行了分析.为避免重蹈日本20世纪70年代的覆辙,系统地提出了去毛刺、光整设备和工具应用的可行性方案,填补了行业的空白,并把去毛刺、光整技术提高到21世纪机械制造业的战略高度,为决策层和企业的投资提供了依据.     

Development of a micro-drilling burr-control chart for PCB drilling

A drilling burr-control chart (DBCC), based on experimental results, is a tool for the prediction and control of drilling burrs for a large range of drilling parameters. A micro-drilling burr-control chart (M-DBCC) was developed for a standard double-sided copper-clad laminated (CCL) printed circuit board (PCB) with laminated fiber-reinforced plastic (FRP) substrate. This chart will assist in the selection of favorable drilling parameters for predicting and achieving preferred types of burrs. Burr classification was carried out according to the burr geometric characteristics, burr formation mechanisms, burr height, and drill bit breakage while drilling. The design of experiment (DOE) technique based on the Taguchi method was used to find the most significant drilling parameter affecting burr height. The results show that the drill diameter makes a statistically significant contribution to burr-height variation.     

微铣加工关键技术研究现状与发展

微铣削加工技术在精密三维微小零件制造中的应用,引发了微细制造领域的重大技术变革,其区别于MEMS技术和超精密加工技术,是利用传统铣削加工方式并针对微米和中间尺度微小零件进行高效率、高精度微细制造的有效途径,具有加工材料的多样性和能实现三维曲面加工的独特优势.论文通过综合国内外大量文献,对微铣床设备研发、微铣削表面形貌、表面粗糙度与微毛刺及微铣刀具磨损等进行讨论,指出微铣削加工相关技术研究存在的不足并对该领域的发展提出自己的观点.     

Dynamics of physicochemical and biological parameters during the co‐composting of chestnut burr/leaf litter with solid poultry manure

Dynamic parameters of the transformation of chestnut burr/leaf litter with solid poultry manure (ratio 1:3) into a fertiliser using a co‐composting process are reported in this work. Determinations of temperature, granulometric composition, pH, electrical conductivity, organic matter content, nitrogen content and available potassium and phosphorus as well as biological germination tests on ryegrass (Lolium perenne), barley (Hordeum vulgare) and wheat (Triticum aestivum) seeds were performed. The loss of organic matter was only 6.27% (w/w dry weight) and the available potassium changed from 2820 to 3265 mg kg^?1 in the co‐compost studied. Germination tests showed that the co‐compost was mature in 103 days. © 2001 Society of Chemical Industry     

Edge burr development when using a cemented carbide micro-drill: Formation and control mechanisms

To explore the mechanism of formation and methods of control of edge burr in the grinding and forming of cemented carbide micro-drill, the morphology, material composition, and the edge structure of the generated area of the edge burrs are studied. Through indentation and scratch experiments, the critical grinding depth (h_c) of grinding machining is calculated to be 0.793–1.052 μm. The grinding experiments have verified the effects of the actual grinding depth h₀ of different single abrasive particles on the edge burr and the effectiveness of the method of controlling the burr by increasing the cutting angle of the abrasive particles. The experimental results show that edge burrs are mainly concentrated on the cutting edge close to the outer cylinder of the micro-drill. When the actual grinding depth h₀ of a single abrasive particle is less than the critical grinding depth h_c, workpiece material is mainly subjected to plastic deformation removal, the length L of the edge burr along the edge direction is 10–20 μm, the width W of the burr perpendicular to the edge direction is 1–3 μm. The formation of edge burrs is mainly related to the actual grinding depth and the abrasive grain cutting angle γ of abrasive grains. With the increase of h₀, the length L of the edge burr decreases, and the width W thereto first increases, then decreases. Increasing the cutting angle of abrasive particles can control the edge burr. By changing the grinding direction of the grinding wheel, the cutting angle of the abrasive particles can be changed from an acute angle to an obtuse angle, thereby eliminating the edge burr without affecting the performance of micro-drilling.     

QFN封装芯片切割分离技术及工艺应用

总结当前QFN封装芯片切割分离方式的优缺点,从QFN封装器件材料特性出发,提出一种砂轮切割技术,并通过QFN芯片切割实验,探索能有效抑制铜材料特有毛刺发生的工艺条件。     

手机电池外壳注塑模常见不良情况分析

介绍了手机电池外壳注塑模几种常见不良情况分析,从模具的影响及产品本身的要求分析问题并提出修改意见,对同类产品的生产中具有一定的借鉴作用.     

一类数字信号N级采样滤波整形电路研究

提出一类数字信号N级采样滤波整形电路,该电路包括N级信号采样电路、采样信号状态比较电路、输出判决电路三部分。该电路在信号采样输出时,通过信号前后间的关系来判断信号的输出结果,避免了毛刺噪声被当作有用信号输出。该方案对信号传输过程中的毛刺噪声,特别是抖动频繁的毛刺噪声具有较好的滤波效果,可广泛应用于数字电路系统、PLD等系统设计中。