油缸断裂故障分析及改进措施

油缸是巷道修复机运行的重要执行元件,设备复合动作均通过调节油缸来实现,斗杆油缸动作最频繁,其推拉力直接决定设备挖掘力,因此斗杆油缸也是故障率最高的部件。该文对一起典型的油缸断裂故障进行了分析,从设计计算、产品质量及使用工况三个方面进行分析,根据分析结果得出故障原因,失效模式属于脆性断裂,随后针对故障原因制定改进措施,为巷道修复机油缸及臂架的设计、制造及故障分析提供了借鉴。     

自动扶梯的安全人机工程学分析及改进

介绍了自动扶梯和安全人机工程学的基本内容,用人机工程学的方法对自动扶梯梯级、扶手、斜度等主要设计进行分析,并进行改进,使之适应特殊人群的使用,并对扶手设计和制动设计进行防逆转、防踩踏改进设计,使自动扶梯所在的"人—机—环境"系统安全、经济、高效地运作。     

基于变压法的变压器真空干燥设备的监控系统设计

根据某变压器企业新改进的变压法真空干燥工艺进行了监控系统设计,使用组态软件技术使复杂的自动化工业现场软件开发变得更加简单,并且对今后系统的改进与扩展也留有接口。上位机PC、下位机PLC和现场设备通过通信接口线路及程序进行协调工作,实现整个干燥过程的智能监控和正常运行。运行结果表明,整个工艺及监控系统的改进使真空干燥过程由原来3天时间变成现在1天时间完成,提高了生产效率和产品质量,具有一定的社会价值。     

拉丝机凸轮式收卷机润滑系统的改进与设计

本文介绍了浙江产SJ-2200型塑料扁丝拉丝机S-STL-Ⅱ480凸轮收卷机润滑系统的改进与设计,与原润滑系统相比,新装置结构简单,注油方便,省去了油泵,节油显著。经过一年的试用,运行稳定可靠,是一项节能降耗的有效措施。     

供应链环境下制造商产品质量改进决策模型

产品质量是影响消费者购买行为的一个重要因素,针对产品质量影响顾客需求问题,建立了制造商处于领导地位的二级供应链决策模型,研究了固定质量改进成本如何影响供应链环境下制造商的决策及利润,以及在不同固定改进成本情况下制造商如何改进产品质量。结果表明,当固定改进成本较少时,制造商可以主动改进产品质量以获取更高的利润;当固定改进成本较高时,制造商可以通过收入共享契约和零售商合作一起改进产品质量以获取更高的利润;当固定改进费用成本太高时,制造商没有动力去改进产品质量,其费用需要得到部分补贴后才有可能去改进产品质量。     

安装拆卸美国贝尔浩印片机小卡簧专用工具的设计

美国贝尔浩６１２４印片机面板上共有８只卡簧,其中画底片供收各１只,声底片供收各１只,正向印片正片供收各１只,反向印片正片供收各１只。其作用是装卸胶片时,卡住压片柄。生产线一个班如果印图１图２小本一般８０本左右,其正片卡簧共被使用１６０次;画底片１６本...     

摩擦收卷中柔幅材料力学建模及张力控制策略研究

对柔幅材料在某新型高速摩擦收卷机收卷状态下力学行为进行研究,以张力为核心,将收卷状态下处于不同位段的幅材张力区分为工作张力和上卷张力两类,分别建立其力学模型,并提出对应的张力控制策略。为合理设计收卷机的结构,提高张力控制精度提供理论依据。     

锌空电池生产线控制系统设计及伺服控制算法

 搭建了以ARM9为控制核心的锌空电池生产线控制系统的硬件平台,并对其软件系统进行设计．针对系统中伺服电机的控制设计了一种有效的控制算法,实现了收卷、放卷速度的高精度匹配,提高了产品质量．实践表明,该系统能较好地完成实时控制任务,实现对速度、张力的精确控制．     

基于“勒洛”三角形的扑克牌改良设计研究

目的 针对当前传统长方形扑克牌收牌效率低、持握体验欠佳以及造型单一等问题,结合人机工程学进行以用户为中心的改良设计研究。方法 对国内市面上主流的长方形扑克牌进行个案分析,对用户使用过程中的行为进行梳理,并结合用户体验设计方法和人机工程学,利用“勒洛”三角形的等宽曲线特性以及稳定性,对该类扑克牌进行造型改良设计。结论 对用户使用扑克牌的全过程进行系统的用户研究,设计出一款便于用户抓握及操作的“勒洛”形扑克牌,该设计不仅丰富了传统扑克牌的造型设计,而且通过控制变量的相关实验,在实际的使用过程中,验证了改进后的扑克牌在收牌效率和抓握体验等方面有所提高,实验结果证明了该设计可以改善用户的使用体验。     

EJⅡ-1型静重式力标准机一种常见故障的分析与改进

EJⅡ-1型静重式力标准机作为一种测力标准设备,因具有诸多优点而在国家力值量值传递中起到重要作用,但其长期使用后会出现重复性降低的问题。本文通过对EJⅡ-1型静重式力标准机设计思路的研究,分析了重复性降低问题产生的原因,并提出了一种改进方案,以恢复设备的计量性能。     

MAGNETIC BEARING SPINDLES FOR ENHANCING TOOL PATH ACCURACY

Thin rib machining of electronic components or airframe structures can benefit from high speed machining for burr free cutting, improved surface quality and increased metal removal rate. It is suggested that the use of a magnetic bearing spindle can not only successfully provide the benefits of high speed machining but, more importantly, minimize tool path errors. In this paper the various sources of tool path error are discussed as functions of machine tool positioning errors and cutting force errors which are characterized as static, dynamic and stochastic. The operation of high speed magnetic bearing spindles is described and a control scheme whereby the spindle may be translated and tilted for minimizing tool path errors is discussed. This overall research activity is a cooperative effort between the University of Maryland, Cincinnati Milacron, Magnetic Bearings, Inc., The Uestinghouse Corporation, and The National Bureau of Standards.     

Results of studies of the stress-strain state of the material of spindles in torsion by means of inductance transducers

It is established from the results of experimental studies that a reliable estimate of the stress-strain state of spindles made of magnetic and nonmagnetic materials can be arrived at any stage of the loading process through the use of an inductance transducer.     

Quality improvement practices and the effect on manufacturing firm performance: Evidence from Mexico and the USA

A comparison of organizations in Mexico and the USA demonstrates that, for these two countries, different quality improvement approaches are related to actual quality and financial performance. For 345 firms multiple quality improvement variables are correlated with seven quality measures, four financial measures, and one operating performance measure. Results suggest that in both countries an increase in employee involvement leads to improved quality-a decrease in internal failure costs, the percentage of items defective, and costs of quality. In Mexico an increase in employee knowledge about quality improvement and customer focus also leads to improved quality (as measured above). In the USA, but not in Mexico, the quality improvement approach relates to financial performance. An increase in senior executive leadership and an increased emphasis upon both design and conformance in the USA leads to an improved return on assets and increased net profit. In each country similar distributions from respondents regarding individual items that improve quality can be found, yet statistical modelling demonstrates country-specific models best explain quality improvement/performance relationships. This suggests culture-specific quality improvement models are necessary to better understand how quality may be improved globally.     

The phenomenon of all-elements-sleeping-beauties in scientific literature

The phenomenon of all-elements-sleeping-beauties in science is revealed by four special cases. The ??sleeping beauties?? prick their fingers on the ??spindles?? so that they fall into sleep then are awakened by their ??princes??. The authors speculate that the phenomenon could happen in scientific literatures with high quality.     

高频变流诱发的电主轴高次谐波振动及其抑制方法

高速电主轴已在超高速磨削中获得成功应用,但由高频变流诱发的高次谐波机电耦合振动严重影响磨削系统的稳定性和磨削质量,而其动力学机理尚不明确.利用传统的砂轮转子机械模型尚不能定量解释高频变流诱发高次谐波机电耦合振动的原因.在传统砂轮转子机械模型的基础上建立了"逆变器-电主轴-砂轮-磨削载荷"系统的机电耦合数学模型.利用该模型研究了启动、升速及突变磨削载荷等条件下磨削系统的几类典型非平稳过渡过程,并在超高速平面磨床上进行了试验研究.揭示了功率开关高频变流诱发超高速磨削系统机电耦合振动的物理机理,提出了通过优化逆变器工作参数抑制机电耦合振动的具体策略.     

Process planning for reliable high-speed machining of moulds

A method of generating NC programs for the high-speed milling of moulds is investigated. Forging dies and injection moulds, whether plastic or aluminium, have a complex surface geometry. In addition they are made of steels of hardness as much as 30 or even 50 HRC. Since 1995, high-speed machining has been much adopted by the die-making industry, which with this technology can reduce its use of Sinking Electrodischarge Machining (SEDM). EDM, in general, calls for longer machining times. The use of high-speed machining makes it necessary to redefine the preliminary stages of the process. In addition, it affects the methodology employed in the generation of NC programs, which requires the use of high-level CAM software. The aim is to generate error-free programs that make use of optimum cutting strategies in the interest of productivity and surface quality. The final result is a more reliable manufacturing process. There are two risks in the use of high-speed milling on hardened steels. One of these is tool breakage, which may be very costly and may furthermore entail marks on the workpiece. The other is collisions between the tool and the workpiece or fixtures, the result of which may be damage to the ceramic bearings in the spindles. In order to minimize these risks it is necessary that new control and optimization steps be included in the CAM methodology. There are three things that the firm adopting high-speed methods should do. It should redefine its process engineering, it should systematize access by its CAM programmers to high-speed knowhow, and it should take up the use of process simulation tools. In the latter case, it will be very advantageous to use tools for the estimation of cutting forces. The new work methods proposed in this article have made it possible to introduce high speed milling (HSM) into the die industry. Examples are given of how the technique has been applied with CAM programming re-engineered as here proposed, with an explanation of the novel features and the results.     

Hematite solid and hollow spindles: Selective synthesis and application in gas sensor and photocatalysis

Hematite solid spindles and hollow spindles have been selectively synthesized by a template-free, economical hydrothermal method, using FeCl₃·6H₂O as the starting materials and NaOH as the homogeneous precipitant. XRD analyses indicated that the products consisted of α-Fe₂O₃. SEM and TEM measurements showed that the morphologies of products were in the shape of solid spindles and hollow spindles, respectively. A possible formation process based on the nucleation-oriented aggregation-recrystallization mechanism is proposed. Moreover, the as-prepared hollow spindle-like α-Fe₂O₃ exhibits a good response and reversibility to some organic gas, such as 2-propanol and acetone. Compared with other hematite nanostructures, the porous hollow hematite spindles show outstanding performance in gas sensing due to their large surface area and porous hollow structure. Because of the unique porous hollow structures of the samples, the photocatalytic property of the spindle-like α-Fe₂O₃ was also investigated.     

超精密飞刀切削加工表面中频微波纹产生机理

超精密飞刀切削是一种重要的超精密加工手段,安装大飞刀盘的超精密铣床能够加工大口径超精密光学元件,加工表面具有很高的面形精度和很低的表面粗糙度值.但是加工表面普遍存在中频微波纹（空间周期从100μm到300μm,幅值低于0.1μm）,极大影响了光学元件的使用.超精密铣床的主轴旋转精度对加工工件影响很大,尤其是主轴轴线偏转会使安装在大飞刀盘外缘处的刀具产生很大位移.为此,建立了适用于空气静压轴承支撑的立式主轴角位移欧拉动力学方程,推导出方程解析解,得出主轴运动规律及其对表面中频微波纹的影响,并设计实验进行验证.最终给出了抑制中频微波纹的工程措施.     

高速电主轴多场耦合动力学特性研究

建立了一种新型的高速电主轴多场耦合动力学模型,讨论了轴承模型、热态模型、芯轴动力学模型和电机电磁模型之间的耦合关系,提出热膨胀、轴承内圈离心膨胀、轴承内外圈接触膨胀、电磁不平衡拉力载荷和离心力载荷5种耦合因素,并且设计出多场耦合动力学模型的计算流程,分析耦合因素对高速电主轴系统运行状态的影响。以2ZDG60型高速电主轴为研究对象,计算结果表明：考虑耦合因素与不考虑耦合因素相比较,轴承动态支承刚度、轴承损耗功率以及芯轴动力学行为差别较大;实验结果表明：考虑耦合因素时的高速电主轴温升分布和芯轴固有特性与实验结果的吻合度较高。     

CdS hierarchical spindles: Structural defects and properties

Hydrothermal process has been successfully applied to synthesize CdS hierarchical spindles. The compositions and morphologies of the as-produced CdS were investigated through X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. It is found that the hexagonal wurtzite-structured CdS spindles are endowed with hierarchical morphologies with the branches nearly perpendicular to the trunks. Some of the structural defects are also detected by TEM. Furthermore, the absorption and emission spectral properties were studied using UV-Vis spectrometer and photoluminescence spectrometer, respectively. It is speculated that the red shift of absorption edge and the enhanced deep-level (DL) emission are all related to the structural defects of the as-prepared CdS hierarchical spindles.