直线式箱体全自动无氟发泡线充注机械手的设计

介绍了直线式全自动箱体发泡线充注机械手的结构及其驱动系统,该系统可直接应用在新箱体发泡线的制造上,又可用在老箱体发泡线的改造上,因此具有极大的推广价值和显著的经济效益.     

铜线替代金线在晶体管封装中的压焊工艺研究

通过比较铜线与金线的性能,论述了铜线压焊的特点、设备的改造、铜线产品质量检验与常见不良产品等,在晶体管产量较大时,使用铜线压焊能有效地降低生产成本,因而在通用民品中有着非常广阔的应用前景.     

金亿机械有限公司:玉米收获机创造新纪录

11月18日,山东金亿机械制造有限公司在美丽的海滨城市日照举办了山东省玉米机械化发展与推广研讨会暨2008年商务年会.原计划600多人参加的会议却来了900多人,这在金亿公司是史无前例的,让公司领导及员工忙得不亦乐乎.金亿公司董事长马金英满面春风对记者说:"人气旺盛,一是得益于党的政策好,二是今年金亿公司拥有喜人的表现,小麦机产销1600台,市场占有率由去年的5%提升为15%,玉米机销售1200台,占行业内同类机型首位.同时,金亿产品也是获得政府补贴最多的产品."     

SIMATIC IT助力制造

西门子中国有限公司的业务结构涉及的行业和领域主要包括:信息通讯、自动化与控制、医疗、照明、能源、交通、金融和房地产等.西门子MES属于西门子自动化与驱动集团,这个业务集团是西门子最古老的集团之一,在中国的业务也发展非常好,产品覆盖各行业客户的自动化需求.自动化与驱动集团分为七个部门,MES隶属于其中的自动化与系统部.整个集团全球有近10万种产品,每个月约有18种新产品问世.自动化与驱动集团将其年销售额的约9%用于研发投资,尤其在工业软件方面很多人都认为自动化是一个硬件设备,但随着现在软件的发展,西门子也提供大量的软件开发.     

为推动国内实验室离心机行业升级而努力——专访上海安亭科学仪器厂董事长陆永泉先生

我国的实验室离心机产业近年来在研发生产方面取得了进步,但由于大部分企业的规模较小等原因,整体上与国外产品尚有一定差距。《中国仪器仪表》杂志记者专访了上海安亭科学仪器有限公司董事长陆永泉先生,陆先生评述了实验室离心机行业现状并提出了提高产品水平的措施,为推动国内实验室离心机行业升级提供了很好的建议。     

"数字化组织"迈出智能化敏捷制造第一步

PTC这支在船舶领域雄立多年的老牌劲旅,早在1992年就开始涉足船舶业,并取得了不错的成绩,1998年收购CV公司后更加强了其在船舶业的发展势头.目前在中国,军船市场一直占主导地位,民船虽然近几年才开始兴起,但市场表现也不俗.2007年我国的船舶业迎来了前所未有的井喷时期,也为PTC船舶业绩的提升带来了发展良机,而这一切早已洋溢在了PTC中国船舶业销售总监王慧杰的脸上.     

颅骨解剖机械设备的研制

本文针对目前法医解剖人体颅骨用设备存在的问题,探讨研究一种科学实用的颅骨解剖专用设备,用以提高解剖人员的工作效率,提高解剖质量,改善工作环境.     

防雨、防暴晒、夜晚能自动收缩的智能晾衣架设计

智能晾衣架的机械部分是在普通拉杆式晾衣架两支撑杆的端部各安装一个滑轮,再穿入钢丝绳.钢丝绳与最前外面的晾衣杆固定连接.钢丝绳的另一端连接到与直流电动机相连的转轴上,通过电动机的正反转达到晾衣架的伸缩效果.其控制部分的电路CPU采用89C2051单片机.利用温度、雨水、光敏等传感器,达到下雨时自动收回,雨后自动伸展;气温高于设定值时自动收回,低于设定值时自动伸展;夜晚自动收回,白天自动伸展的功能.     

船舶螺旋桨的偏振和抗冲击稳定性研究

船舶螺旋桨的偏振对螺旋桨叶片的寿命和船体尾部的振动情况有着重要的影响,为了减少螺旋桨偏振、提高其抗冲击稳定性,运用理论分析和实验室模拟测试手段,研究了螺旋桨偏振发生的频段,提出了防范措施,具有广阔的推广应用前景.     

基于WTK冷冻缸产品设计及加工虚拟现实软件的开发

在虚拟环境中利用数字化产品模型来代替实物模型进行仿真、分析,实现产品设计和制造过程的集成,已成为目前产品开发技术的重要发展方向.文中应用SolidWorks实现产品零配件和虚拟车床、夹具的实体造型,在VC 6.0开发平台上采用与World Tool Kit软件相结合的方法,同时利用与实体造型连接的技术实现虚拟设计和运动视景仿真并虚拟加工过程.     

The stabilization of the position of the body of walking machinesLa stabilisation de la position du corps d'une machine marchante

This paper shows that in the task of the maintenance of constant orientation of the body of a walking robot the determination of the actual position of the body, i.e. absolute altitudes of its points and remoteness from the supporting surface, is the most complicated problem. Two possible systems of measurement and stabilization of the position by the height of the body of the walking mechanism are compared, i.e. a system of adaptation automatically adjusting the length of the supporting leg to the roughness of the terrain, and the system of the maintenance of constant remoteness of the body from the terrain. The inefficiency of a solitary application of any described system is revealed and the possibility of an accumulation of errors of the position of the body by the walking on the soft terrain is shown. Possible approaches for raising the quality of stabilization of the body by the walking are evaluated.     

Posterior regeneration following fission in the holothurian Cladolabes schmeltzii (Dendrochirotida: Holothuroidea)

The regeneration of the posterior portion of the body after fission was studied in the holothurian Cladolabes schmeltzii using electron microscopy methods. Following fission, the aquapharyngeal complex, gonad and anterior portion of the first descending part of the intestine remain in the anterior fragment of the body. The entire regeneration process is divided into five stages. In the first three stages, the digestive system and damaged ends of the longitudinal muscle bands regenerate. The intestine is formed through the rearrangement and growth of the remaining portion of the first descending part of the intestine. The gut anlage grows down the mesentery and joins the regenerating cloaca. The cloaca is formed from two sources: its posterior portion appears as a result of immersion of the epidermis, while the anterior portion develops from the terminal segment of the growing intestine. Regeneration of muscles progresses in the typical manner for echinoderms: through immersion and myogenic transformation of the coelomic epithelium. Respiratory trees appear in animals when the growth of the external part of the body has begun (fourth stage). They are formed as an outgrowth of the dorsal wall of the anterior portion of the cloaca. It was concluded that regeneration of the posterior portion of the body in the holothurian C. schmeltzii following fission is realized through morphallactic rearrangements of the remaining parts of organs. The main mechanism through which the digestive, respiratory, and contractile systems are formed is epithelial morphogenesis. Microsc. Res. Tech. 78:540–552, 2015. © 2015 Wiley Periodicals, Inc.     

The vibration behavior of impeller blades in the five-axis CNC flank milling process

Today, in most cases, impellers of centrifugal compressors are produced by flank milling on five-axis CNC milling machines. The complex three-dimensional geometry of the very thin blades consists of ruled surfaces. The flank milling process allows a fast production of the impellers and the surface of the blades is of high quality. The limited strength of the very thin blades and also the thin outer radial part of the disk lead to a high sensitivity to static and especially dynamic forces that are caused by the instationary flow in the impeller. The dynamic forces of rotating stall and surge are the most dangerous excitations of the bladed disk. Coupled vibrations may occur and damage the impeller. The highest static load is caused by the centrifugal forces. Therefore, most of the high-loaded impellers are manufactured from aluminum alloy or titanium because of the low density of this light metals and the relatively high strength. Most of the interests and the investigations in the last years are paid to the vibration behavior and the dynamic loads of the impeller during operation. But sometimes, the highest stress may occur during the production process and damage the impeller or weaken the strength and so cause later problems. Especially, excitations from the dynamic forces during the flank milling process have to be taken under consideration. The vibration behavior of the impeller is very complex and is affected by the vibration behavior of the cutter and the milling machine. In this paper, the change of the vibration behavior of centrifugal compressor impeller blades during the manufacturing process is investigated. During the finishing of the thin blades, the blade thickness is continuously changing and also the strength and the corresponding eigenfrequencies of the blade. The dynamic forces acting on the blades are caused by the cutter, the milling machine, and the cutting process. The quantity of the forces and the frequency of the excitation are determined by the rotational speed of the cutter, the feed, the number of edges, and the chip thickness. The results described in this paper give useful information about the change of the vibration behavior of the centrifugal impeller blades during the flank milling process and possible interaction with the cutter and the machine.     

Numerical study on the dynamics of an electrical discharge generated vapor bubble in EDM with different shapes of the tool and the workpiece

In this paper, the effect of the shapes of the tool and the workpiece on the dynamic behavior of an electrical discharge generated vapor bubble in the process of EDM (Electrical Discharge Machining) is investigated. The boundary integral equation method is employed for numerical simulation of the problem. Results show that in the case of the concave tool and workpiece the lifetime of the electrical discharge generated vapor bubble is longer than the case of the flat tool and workpiece. By increasing the concavity of the shapes of the tool and the workpiece, the lifetime of the bubble increases. Results also show that in the case of the convex tool and workpiece, the lifetime of the electrical discharge generated vapor bubble is shorter than the lifetime of the bubble in the case of the flat tool and workpiece. In this case also, by increasing the convexity of the shapes of the tool and the workpiece, the lifetime of the bubble decreases. Numerical results show that in the case of the concave tool and workpiece the rate of pressure drop on the surface of the workpiece is higher than the rate of pressure drop on the workpiece in the cases of the flat and convex tool and workpiece. The high rate of pressure drop on the surface of the workpiece leads to the ejection of more molten material from the crater and consequently leads to more material removal rate.     

A parametric study on the deformation of gas diffusion layer in PEM fuel cell

A well-designed proton exchange membrane (PEM) fuel cell requires a robust design of cell components. Therefore, the understanding of the deformation mechanism of each component is essential for a successful design. This study deals with the induced deformation of gas diffusion layer (GDL) due to the deformation of the membrane during fuel cell operation. A parametric study with six cases is constructed and the corresponding responses of a stress variation, distribution of contact pressure and a channel intrusion are selected to assess the effect of design parameters on the deformation of the GDL. The variation in the thickness of the GDL is considered as a parameter of the study in addition to the material model of the membrane. The variation in stress levels in the GDL induced due to the cyclically deformed membrane is calculated with different material models of the membrane. Through-plane stiffness of the GDL represented by the thickness of the GDL affects the three responses of the model considered. However, the material model of the membrane influences the planned responses selectively. An observation of contact loss at the interface is a strong indication of the importance of through-plane stiffness of the GDL on the deformation between the GDL and the membrane. In order to come up with a way that improves the cell’s performance, we numerically show that the manipulation of through-plane stiffness of the GDL is needed by employing an appropriate thickness of the GDL. The results from this study assist in understanding the interrelation between the GDL and the membrane for the deformation of the GDL.

     

螺杆泵腔室内流场的数值模拟研究

在SolidWorks软件中建立了螺杆泵定子与转子模型,并成功地进行装配,运用Fluent提供的UDF功能建立描述螺杆泵转子运动的动网格;运用Fluent求解器对螺杆泵腔室内的非定常流动进行数值模拟,得到流场的速度分布、压力分布和应力场;分析流体粘度、转子转速以及螺杆泵偏心距对流场的影响。计算结果表明:当转子要离开定子的两端面时,泵内流场总会出现十分明显的涡流;粘度仅影响速度、压力和应力数值的大小,而对分布规律的影响不大;转子转速对速度分布影响比较大,流场速度随转子转速的增大而增大;此外,偏心距对流场有较大的影响,且偏心距越大流场参数变化幅度越大,这表明偏心距对螺杆泵的稳定性影响很大。     

弹性波在一维掺杂声子晶体中的多缺陷模特征

推导出弹性波在一维掺杂声子晶体中的转移矩阵,研究了弹性波在一维掺杂声子晶体中的缺陷模特征。得出:弹性波在一维掺杂声子晶体中会出现多个缺陷模。缺陷模的数目随杂质厚度的增加而增加,缺陷模的半高宽随缺陷模数目的增加而减小。缺陷模的数目也随杂质声阻抗的增加而发生变化,各缺陷模的位置随杂质声阻抗的增加向禁带中心移动。这些特性可以作为设计多通道弹性波滤波器的理论依据。     

基于柔性动力学的辊道窑烧结过程匣钵运动特性分析

盛装锂电正极材料的匣钵在辊道窑烧结过程中极易出现异常横向运动,为此基于柔性动力学分析辊道柔性对传动过程匣钵运动特性的影响。首先,基于柔性动力学建立匣钵-辊道传动动力学简化模型,分析辊棒弹性变形及传送时匣钵运动特性,并通过实验验证了模型的有效性;其次,建立相应的匣钵-辊道刚体动力学模型,通过对比分析刚性和柔性两种辊棒传送条件下匣钵运动特性的变化以及不同辊棒挠度下匣钵横向运动的变化,揭示辊道柔性对匣钵运动特性的影响。在此基础上,对原有辊棒进行了改进并开展实验验证改进方案的效果。结果表明:由于弹性变形的影响,匣钵在前行的同时,匣钵之间间隙出现了明显向外扩张趋势,而当辊棒呈现刚性时匣钵则几乎无外扩现象;辊棒挠度对横向运动有重要影响,在辊棒挠度从0到2 mm区间变化时,其匣钵扩展间隙随挠度增加而呈增大趋势,而当辊棒挠度超过2 mm后,匣钵扩展间隙随挠度增加反而呈减小趋势。改进实验效果表明,适当增大辊棒刚度可显著减轻匣钵异常横向运动现象。     

高速动车组减振器载荷特征研究

减振器的主要功能是提供阻尼力以衰减和抑制车辆系统振动,对高速动车组动力性能有十分重要的影响。既有研究主要将减振器处理为阻尼力以研究车辆系统动力性能,极少从动力学和结构可靠性角度关注减振器自身承受的载荷。制作某型高速动车组转向架抗蛇行减振器、轴箱减振器、二系横向和垂向减振器测力元件,在大同-西安高速线路上测试并获得该型动车组运行过程中四种减振器载荷引起的应变信号。对测试数据进行处理和分析,获得高速动车组运行工况下四种减振器载荷的时间历程,分析减振器载荷的时域和频域特征。采用雨流计数法统计减振器载荷峰谷值和频次,获得不同速度等级下载荷分布。结果表明,高速动车组抗蛇行减振器载荷最大、二系横向减振器载荷最小。轴箱减振器相对速度最大、二系横向减振器相对速度最小。减振器载荷总体上呈正态分布,而且一般有列车运行速度越高减振器载荷越大。列车正线行驶时曲线半径对轴箱减振器、二系垂向减振器以及二系横向减振器载荷影响不明显,列车速度和线路小半径曲线对抗蛇行减振器载荷影响明显。     

Invariant system for measuring the flow rate of wet gas on Coriolis flowmeters

One of the important tasks of modern flow measurement is to measure the flow rate and the amount of wet gas. This task becomes especially important when there is a need to obtain information about the amount of dry gas at the production facilities. The paper presents the principle of operation and structure of the invariant wet gas measurement system. The work of the invariant flow measurement system is based on the application of the principle of multichanneling and the method of partial flow measurement. Coriolis flowmeters are used as the main elements of the system. The proposed measurement system does not imply the use for gases with abundant droplet moisture. The authors propose a method of verification of the measurement system, which is currently limited by the measurement error of moisture in the gas equal to 5%. The article also provides information on the results of the test of the system.