Detection of dressing time using the grinding force signal based on the discrete wavelet decomposition

This paper describes the use of the grinding force signal to show the mechanical noise reduction and to detect the dressing time based on the discrete wavelet decomposition. As a result of de-noising, the wavelet de-noising method was more effective than the FFT filtering technique. From the approximation coefficients of the higher order wavelet transform, the grinding force signal obtained by a tool dynamometer was clear so it was possible to successfully detect the dressing time. A measured result by the surface roughness and the ground surface photograph coincided with the detection result.     

絮凝剂净化黄铜矿选矿尾矿回水的工业生产实践

在常规pH值条件下,使用定量絮凝剂APAM+助凝剂净化黄铜矿选矿尾矿回水,在工业应用中取得了良好效果,提高尾矿回水利用率20%~35%。使用净化后的尾矿回水浮选对精矿品位有明显提高,精矿金品位合格率提高2.55%,精矿铜品位合格率提高2.23%。既减轻了环保安全压力,又保证了生产指标,同时也提高了尾矿回水利用率,缓解了选矿厂季节性水资源短缺的问题。     

金刚石砂轮金属结合剂的气中单脉冲电火花放电去除机理

针对金属结合剂金刚石砂轮修锐困难的问题,提出采用气中电火花接触放电修锐的方法。为有效地实现微细金刚石砂轮的修锐,建立单脉冲电火花放电去除加工的试验系统,研究金属结合剂的气中和液中电火花放电去除机理。在试验研究中,主要分析无负荷电压和放电极性对脉冲放电电流、脉冲放电间隙、脉冲放电去除量、电极磨耗比等的影响。结果表明,正极性不易发生短路现象,而且气中的脉冲放电间隙小于液中的 ,适应于微细金刚石砂轮的修锐。此外,在气中放电中存在由绝缘破坏引起的火花放电向附有电弧柱的电弧放电转变的临界无负荷电压,且电火花放电的去除量可以明显小于电弧放电的去除量,但是当无负荷电压小于某一定值时电极消耗比会快速增加。修锐的试验结果显示,利用气中单脉冲电火花放电去除加工条件可以实现金属结合剂微细金刚石砂轮的修锐,产生较好的砂轮出刃形貌,改善磨削表面质量。     

齿轮形超硬修磨轮的设计与制作技术

论述了齿轮形超硬修磨轮的制造工艺 ,提出了基体轮的设计原则 ,分析了主要工序的技术要求 ,研制出了高质量的齿轮形超硬修磨轮 ,并用于对齿轮加工刀具和砂轮的修形上 ,为硬齿面齿轮多种高效精加工方法的应用提供了保证。     

3D graphical evaluation of micron-scale protrusion topography of diamond grinding wheel

A new graphical evaluation of micron-scale wheel protrusion topography is proposed by using 3D coordinate data derived from contact measuring of 180 diamond grinding wheel. The objective is to quantify 3D distribution of grain protrusion height, gain rake angle and grain relief angle on wheel working surface in dressing. First adaptive measuring was conducted on the base of topographical curvature to identify grain cutting edge in 3D space, second grain protrusion mode was established by polar coordinate transfer so as to ascertain datum plane of grain protrusion, then linear approximation graphics was conducted to display wheel protrusion topography, finally distributions of gain rake angle and grain relief angle were investigated with reference to grain protrusion height. Analytical results show that higher outer grains have more and shaper cutting edges, but lower layer grains retain approximately original crystal forms. In wheel protrusion topography, grain protrusion heights, grain rake angles and grain relief angles are dispersedly distributed in the range 0–28 μm, −45.0° to −89.1° and 1.2–73.1°, respectively, which can be increased by dressing. It is concluded that 3D grain protrusion attitudes distributed on wheel working surface can be quantified by 3D graphical evaluation method.     

司家营铁矿选别流程的演变及技术改造

叙述了司家营铁矿自2007年10月投产以来多项重大选矿工艺改造。氧化矿选别系统：新建浮选厂房并增加新型浮选设备,过滤设备扩容、改型,中强磁前弱磁设备提高场强,增加强磁设备,重选增加扫选和重精控制筛分,三段磨矿“二对一”改造,循环水净化处理,沉降池改造,浮选药剂制度优化等。原生矿选别系统：磁选柱尾矿返回位置优化,增加尾矿回收系统,增加污水池,改造给排水系统,实现工业废水零排放。系统改造后提高了选矿技术水平以及精矿产量与质量,社会效益和经济效益显著。同时,提出了氧化矿选别系统降低尾矿品位,提高金属回收率的研究方向;原生矿系统磨前预选提高入选品位,以达到增产减排的目标。     

会东铅锌矿选厂生产工艺的若干问题探讨

会东铅锌矿选矿厂的扩建工程,经半年多的建设,现已正常运行３年。本文仅对工艺设计及试生产中暴露出的一些问题进行初步分析总结。     

陶瓷喷涂层精密镜面磨削技术的研究

１陶瓷喷涂层的结构与特性喷涂层在结构上不同于致密的金属材料。在喷涂过程中,被加热至熔化或接近熔化的粉末材料,或者被加热熔化并雾化的丝材颗粒,在高压气流的带动下撞击到基材表面上,产生变形、流散并冷凝成盘状,镶嵌、咬接和填塞到基材表面上。随后喷来的粒子以...     

摩托车发动机铸铝件毛坯的一次性机械清理工艺

从生产实际要求出发,详细介绍了铸件绕冒口机械冲切清理设备与结构布局,模具与工装的设计,并对工艺要点进行了分析。使有证明一次性机械去除代替手工式具有很多优势。     

The mechanism investigation of ultrasonic roller dressing vitrified bonded CBN grinding wheel

To clarify the ultrasonic roller dressing mechanism of the vitrified bonded cubic boron nitride grinding wheel (V-CBN), the collision number model between the diamond dresser and CBN grits was established based on the geometric and kinematics analysis. The influence of each dressing parameter on the collision number was analyzed and discussed. The grinding experiment was performed on the bearing raceway with the dressed V-CBN grinding wheel, results obtained discovered that there was an inverse relationship between the collision number and the surface roughness and runout of the workpiece. Additionally, compared with conventional dressing, ultrasonic dressing has the advantage in improving the surface quality because it can produce more collision numbers and raise grit retention. In words, the collision number can be used to predict the dressing effect, which provides a reference for formulating an appropriate dressing process for V-CBN to improve the workpiece surface quality and production efficiency.