梅山选矿厂磨矿过程控制研究与应用

以梅山选矿磨矿生产过程为背景,研究了选矿生产中磨矿过程的自动控制技术,在充分研究磨矿过程自动控制及工艺特点的基础上,提出了基于现场总线的监督控制与数据采集系统方案,采用现场控制级、过程监控级和生产管理级三层榘构,系统具有开放、可靠、经济的特点.     

家具漆底擦色及修色剂的研制及应用

介绍了家具漆用底擦色及修色剂的主要组成,并结合家具厂的实际应用,对其配方进行优选,最终使其产品与本厂PU系列家具漆配合使用,达到国内出口家具的涂装要求。本文仅对影响产品研制的主要因素进行了讨论。     

GRINDING OF SILICON AND GLASS USING A NEW DRESSING DEVICE AND AN IMPROVED COOLANT SYSTEM

Ductile mode machining of brittle materials such as ceramics is recognized as an emerging technology with important applications. Ductile machining is possible if the depth of cut is less than the critical depth of cut of the machined material. By using a new device for dressing a resin-bonded diamond wheel and an improved coolant system proposed here, ductile mode grinding of silicon and glass was achieved using an inexpensive, conventional surface-grinding machine. The low-cost dressing device also ensured minimum disruption to the grinding operation and a higher level of safety. A flooding supply of coolant at the grinding zone provided better cooling performance and lubrication. A relationship appeared to exist between the surface finish and the lightness values of ground silicon surfaces.     

提高国内某铜钼矿选矿指标的试验

根据某铜钼矿矿石性质和钼回收率不高、钼精品位低的实际,采用石灰调整矿浆pH值,混合使用Z-200#、丁黄药和煤油为捕收剂,硫化钠为铜的抑制剂,水玻璃为铜钼分离的分散剂,可以实现铜钼的高效浮选回收并能提高钼精矿质量。在实验室条件试验的基础上,依照现场生产流程进行了实验室小型闭路试验,可获得铜精矿品位22.48%、回收率92.41%,钼精矿品位48.32%、回收率91.12%,钼精矿含铜降至0.89%。     

基于数值建模的砂轮形貌仿真与测量

建立球形磨粒在空间随机运动的数学模型,提出创建三维砂轮数值模型的方法。提取仿真砂轮的表层磨粒以生成虚拟砂轮形貌,依据振动模型确定的磨粒中心坐标,将球形磨粒转化为不规则六面体进行统计分析。以单点金刚石笔为修整工具,建立修整模型并将其引入砂轮形貌生成过程之中。利用激光传感器测量实际砂轮形貌的磨粒分布规律,并将试验统计数据与同特征的仿真结果相比较,分析两结果之间的区别和联系。通过计算磨粒突出高度、磨粒间距等评价参数,讨论砂轮形貌修整前后的差异,测量和仿真的结果表明：在初始砂轮形貌中,磨粒突出高度呈正态分布,修整后则近似均匀分布,大部分磨粒间距分布在0.2～0.6 mm,为进一步探讨砂轮形貌对磨削工件的影响提供了依据。     

The role of specific energy in micro-grinding of titanium alloy

This paper is concerned with understanding the role of specific energy in micro-grinding of conventional and additively manufactured Ti6Al4V. The effects of grinding and dressing parameters, cooling-lubrication conditions, and the directions of material build-up are studied. It is demonstrated that the minimum specific energy in single grain tests is independent of the material-fabrication method. The lowest measured specific energy obtained is 11.5 J/mm³ for both workpiece materials. The direction of material build-up influenced the process only when grinding with low aggressiveness, where 20% higher specific energy was observed. Similar specific energies were obtained for oil-lubricated and dry conditions, indicating that lubrication had minimal effect. The effects of the diamond concentration in the wheel and the dressing parameters were also investigated. Comparable specific energies were observed for wheels with C150 and C200 concentrations. The specific energy was found being predominantly influenced by dressing. Coarse dressing conditions produced 18% lower specific energy and, therefore, a more efficient micro-grinding process.     

医用棉纱布的羧甲基化改性

采用两步加碱水媒法,并通过浸轧的方式对医用棉纱布进行羧甲基化改性,制备高吸水性医用敷料。考察了烧碱浓度、烧碱与氯乙酸的配比对样品的取代度、吸水性、透气性和力学性能的影响,确定了最佳工艺条件。结果表明：随着第一步烧碱浓度和第二步烧碱与氯乙酸的摩尔比的增加,羧甲基化医用棉纱布的取代度和吸水性均呈现明显的上升趋势。当第一步加碱的烧碱浓度为20%,烧碱与氯乙酸的摩尔比为2.7：1时,样品的拉伸断裂强力及伸长率上升到最大值,羧甲基化医用棉纱布表现出良好的柔韧性,同时也具有较好的透气性。此时,样品的取代度为0.17,吸水率达到170.98%,纱布表面形成了均匀有效的水凝胶保护层。     

Simulation of elliptical patterns based on grinding with wheel dressed by elliptical tool

Dressing is a sharpening operation aimed to produce a specific groove shape on the active surface of the wheel. The preparation of grinding tools in special way is the most important enabling factor in the grinding process. It greatly influences the subsequent geometry of the workpiece. As the groove shape of the wheel surface determines the shape of the surface patterns, therefore, it is essential to produce desired groove on the wheel cutting surface before grinding. Therefore, an elliptical groove surface pattern model is proposed based on grinding with dressed wheel. An elliptical tip tool is used for the dressing process to make grooves on the wheel instead of sharp tip tool or rounded tip tool in the previous work. The dressing tool passes helically over the surface of the grinding wheel for making grooves. After that, the grooved wheel passes over the flat surface to generate elliptical patterns. The results showed the three-dimensional geometry of the surface patterns with elliptical groove which are uniformly distributed on the workpiece. An experiment is carried out for the verification of the simulation results and it is revealed that the simulation results agreed well with the experiment.     

异型螺杆数控磨床的研制

进行异型螺杆磨削时，除了要求机床实现螺旋运动之外，还需要适时进行砂轮截形的计算，并按所计算截形进行砂轮的修整。针对这个要求，研制了异型螺杆数控磨床，实现对异型螺杆整个磨削过程的自动化。     

MODELING OF DRESSING FORCES DURING ROTARY DIAMOND CUP DRESSING OF VITRIFIED CBN GRINDING WHEELS

This paper presents a mathematical model of dressing of vitrified CBN grinding wheels by a diamond cup dresser. It predicts the dressing forces during rotary diamond cup dressing of vitrified CBN grinding wheels. This model is based on the fracture of abrasive grits, the fracture of the bond and the contact forces between dresser and grinding wheel. It considers the kinematical influences and in particular speed ratio and overlap factor during the dressing process. A Weibull distribution is used to predict the probability of bond fracture and also the collision number between the diamond grits of a rotating dresser and the CBN grits. This model is validated by experimental results. The theoretical modeling values agree reasonably well with the experimental results. On the basis of this model the effect of different cup dressing parameters on dressing forces is theoretically discussed with the aim of establishing appropriate dressing process configurations. Furthermore the presented model provides a basis for further prediction of wheel topography and the grinding process.