恒力液压机测控系统设计

恒力液压机能实现加载力、位移或其速率的恒定。测控系统以小型PLC为控制核心,位移测量采用光栅尺,并采用PLC中断程序进行4倍频处理以提高测量精度,压力测量采用带有通讯功能的高性能调理转换模块代替性能有限的PLC的A/D模块,显著提高了测量分辨率和精度。自编的PID算法充分发挥了PLC的性能,提高了闭环控制精度。液压机的参数设定、显示由触摸屏完成,而长期的数据保存、输出由上位机实现。试验结果表明,测控系统达到了设计要求。     

模具制造的测量技术

为保证模具在装配后达到所需的加工精度和正常运转,必须对每只零件规定加工精度,其中包括尺寸精度、形位精度及表面粗糙度等。对加工完毕的模具零件进行测量是确认各零件是否达到精度要求的主要手段。1 模具零件的一般测量方法(1)模具零件的测量时机通常,在模具零件加工完毕后由检验人员对模具零件进行测量。但在这时发现模具零件不符合要求则为时过晚,重新加工模具零件就会拖延整副模具的生产计划。所以,旨在保证模具零件达到精度要求的测量应在加工过程中进行,加工完毕后的测量只能作出合格品或废     

比例电磁铁电感的测量

设计比例电磁铁电感测量系统,该系统由高速数据采集卡和数字功放等组成,根据满电流下的暂态过程测量出比例电磁铁电感。经实际测量验证,在规定温度下测量精度达到±10μH,测量精度高,测量可靠,操作便捷,满足比例电磁铁电感的测量要求。     

基于图像的尺寸测量应用研究

零件尺寸测量是生产中一个十分常见而重要的项目。利用摄像机等硬件和图像处理算法等程序共同构成图像尺寸测量系统,在这个平台上完成尺寸测量工作。通过标定试验,得到像素当量为0.1198 mm/pixel,测量范围为0.1198～42.169 mm。通过试验数据分析,测量精确度达到＆#177;0.09 mm。仪器在试验室环境下工作正常,达到设计要求。     

应用感应同步器数字显装置车削阀体级位

B 690液压牛头刨床的换向阀、操纵阀、变级阀和制动阀等的阀体级位加工工序系在一台专用C630车床上用搪刀进行的,由于测量困难等原因,精度很难保证,废品率很高,产量也上不去,是个老大难问题。图1为操纵阀和换向阀的结构,每个级位都有精度要求。级位的位置精度和液压动作的准确性、平稳性、油路内泄漏、功耗发热等密切有关,以前要求的精度是±0.1毫     

激光干涉仪在PCB数控机床精度检测中的应用研究

激光干涉仪已成为PCB数控机床中测量定位与重复定位精度的标准仪器。针对测量数据不稳定的问题,分析激光干涉仪测量原理,得出测量距离与波长和脉冲数之间的关系;对生产现场环境模块数据进行测量,环境模块变化量对波长总的补偿量为0.23μm,与实际误差相比,波长变化导致的误差几乎可以忽略,通过测量得出测量精度不稳定的主要原因是横梁X轴连接杆的变形。针对该原因进行了结构的重新设计,实现了精度补偿及测量的稳定。     

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 文章研究了应用积分器系统对软磁合金磁性测量的方法。分析了积分漂移，积分时间常数等主要因素对积分误差的影响，设计出测量精度达到10-9C电量的电子积分器以达到对软磁合金磁性测量的要求。研究了应用0.01H的标准互感对积分系统标定的方法，并完成了软磁合金1J85材料的标准样品进行饱和磁感应强度Bs的测量比对实验，系统测量精度达到1.8%，满足测量要求。     

一种提高直线度误差测量精度的方法

随着科学技术的发展，一些精密零件的形状精度要求越来越高，以致于难以找到相应的测量仪器对其进行测量。若采用本文介绍的方法，对精密零件利用现有仪器进行测量，把系统误差从测量数据中分离开，可获得精确的测量结果。     

数控齿形／导程测量仪

日本大阪精密机械株式会社推出的CLP-35WIN型数控齿形／导程测量仪主要用于对传动装置及其它机械装置所用齿轮的齿形误差、齿向误差和齿距误差（含偏心）进行全自动、高精度快速测量。该仪器也可用于检测齿轮滚刀、剃齿刀、插齿刀等切齿刀具的相应精度参数，还能对蜗轮精度进行测量分析。仪器配备的测量数据管理图形软件可成为齿轮加工质量管理的有力工具。     

类磁栅液压缸位移高精度测量技术研究

针对类磁栅液压缸集成位移传感器无法直接进行高精度位移测量的现状,研究了传感器信号处理的相关技术。通过对传感器响应信号的数学模型分析,设计了专用的直流分量滤除、脉冲干扰滤除与高次谐波分析等预处理方法。在此基础上,为进一步提高细分精度,引入了支持向量机对测量精度进行提升,并最终实现了信号的350细分。测量结果可满足传感器高精度测量的要求,达到了预期效果。     

五轴并联机床刀具末端运动位姿自适应控制技术

高精尖领域对精密小零件的加工精度要求越来越高，五轴并联机床作为主要机械加工设备，严格控制机床刀具的运动位姿对于保证成品零件的加工精度具有极其重要的作用。在此背景下，研究一种五轴并联机床刀具末端运动位姿自适应控制技术。在五轴并联机床前方布置两个CCD 摄像头作为视觉系统，拍摄关于刀具末端的左右两张图像；在图像预处理、特征点提取与匹配等环节的基础上，求解位姿参数，包括位置三维坐标以及3个姿态数据。以刀具末端运动实际位姿为输入，利用神经网络获取与刀具末端紧密相连的五轴关节角度补偿量。利用PID控制器，通过补偿量计算位姿控制量不断纠正位姿误差，靠近理想位姿。结果表明：应用所提控制方法，与理想位姿之间的平均误差均更小，且平均误差的波动最小，三维位置坐标波动仅在-0.02~0.015、-0.01~0.02、-0.02~0.02 mm之间；横滚角、俯仰角以及方位角波动仅在-0.02°~0.03°、-0.01°~0.04°、-0.02°~0.01°之间，由此说明所提控制方法的精度更高，控制稳定性更高。     

复合梯度楔形表面上液滴自输运特性的数值研究

目的 提高表面液滴的自输运速率。方法 在表面引入润湿梯度和楔形形状,基于VOF模型(流体体积模型)对表面液滴运动进行数值研究,并建立一种适用于润湿梯度和楔形图案联合的模型,分析润湿梯度和楔形角度对液滴位移的影响。结果 润湿梯度越大,液滴受不平衡的表面张力越大,液滴移动速度越快。润湿梯度为15 (°)/mm表面上液滴的平均速度比10、5 (°)/mm润湿梯度的表面分别快42.3%和130%。楔角越大,加速阶段的液滴移动速度越快,但会越早失去驱动力而停止移动,而楔角越小,液滴移动位移越大。液滴在40°楔角表面最先停止运动,在20°楔角表面位移比30°和40°楔角表面分别远10.3%和32.3%。联合润湿梯度和楔形图案后,15 (°)/mm表面上的液滴在20°、30°、40°和20°楔角表面上的液滴在15、10 (°)/mm下均能运动到计算模型出口,且15 (°)/mm、40°楔角表面液滴的平均速度达到292 mm/s,比单一梯度表面增长37.7%,比单一楔形图案表面(20°)增长175.5%。结论 通过调节润湿梯度和楔形角度,可有效控制液滴移动速度。联合润湿梯度和楔形图案的复合梯度楔形表面能同时减小润湿性范围瓶颈和楔形形状制约,提高表面液滴的移动速度和距离。研究结果将有助于设计高效的液滴输运功能表面,并可将其扩展到冷凝装置、微流体装置和药物检测等领域。     

选区激光熔化成形点阵结构的各向异性对力学性能的影响

选区激光熔化技术（selective laser melting, SLM）成形的金属点阵结构由于具有结构设计自由度大、轻量化、缓冲吸能等优势,在航空航天等领域具有广泛的工程应用前景,然而对其力学性能的研究不够充分。本研究设计了不同方向的体心立方（body-centered cubic, BCC）和金刚石（Dia）两种晶胞点阵结构,基于SLM技术成形了AlSi10Mg点阵结构,并对成形试样进行了压缩试验,结合有限元分析（finite element analysis, FEA）研究了点阵结构的各向异性对其压缩响应和吸能特性的影响。结果表明,两种点阵结构均存在明显的各向异性。在相对密度基本一致的情况下,点阵结构方向从0°到45°,随着角度的增大,屈服强度明显增大,BCC点阵结构的各向异性对其压缩屈服强度的影响更加明显,Dia点阵结构的屈服强度明显高于BCC点阵结构。不同方向点阵结构的比吸能(specific energy absorption, SEA)存在明显差异,点阵结构方向从0°到45°,随着角度的增大,SEA明显增大,Dia点阵结构的SEA明显高于BCC点阵结构。不同方向点阵结构的碰撞载荷效率(crash load efficiency, CLE)存在明显差异,BCC点阵结构在0°方向取得最大值1.07,并随着点阵结构角度的增大逐渐减小,Dia点阵结构CLE随着点阵结构角度的增大而增大,并在45°方向上取得最大值1.01。     

Boundary energies of Σ11 [110] asymmetric tilt boundaries in Cu determined from the shape of boundary silica particles

The boundary energies of Σ11 [110] asymmetric tilt boundaries with a misorientation angle of θ=50.5° in Cu have been experimentally determined by a silica particle observation method for various inclination angles between φ=0 and 90°. This method has no drawbacks that are inevitable in boundary grooving and tri-junction methods. In the boundary energy vs inclination angle diagram, three deep cusps exist at φ=10, 64.8 and 90° whereas a shallow cusp appears at φ=35.3°. Such inclination angle dependence of the boundary energy has been utilized to analyze the faceting of the boundary. The observations on the faceting reported for Σ11 [110] tilt boundaries in face-centered cubic (f.c.c.) metals have been quantitatively accounted for by the present analysis.     

Phase-field simulation of secondary dendrite growth in directional solidification of binary alloys

Phase field method was used to simulate the effect of grains orientation angle θ_(11) and azimuth θ_A of non-preferentially growing dendrites on the secondary dendrites of preferentially growing dendrites. In the simulation process, two single-factor influence experiments were designed for columnar crystal structures. The simulation results showed that, when θ_(11) 45o and θ_A 45o, as θ_(11) was enlarged, the growth direction of the secondary dendrites on the preferentially growing dendrites at the converging grain boundary(GB) presented an increasing inclination to that of preferentially growing dendrites; with increasing θ_A, the growth direction of the secondary dendrites on the preferentially growing dendrites at the converging GB exhibited greater deflection,and the secondary dendrites grew with branches; the secondary dendrites on the preferentially growing dendrites at diverging GBs grew along a direction vertical to the growth direction of the preferentially growing dendrites.When θ_A = 45o and θ_(11) = 45o, the secondary dendrites grew in a direction vertical to the growth direction of preferentially growing dendrites. The morphologies of the dendrites obtained through simulation can also be found in metallographs of practical solidification experiments. This implies that the effect of a grain's orientation angle and azimuth of non-preferentially growing dendrites on the secondary dendrites of preferentially growing dendrites does exist and frequently appears in the practical solidification process.     

3003铝合金X射线法表面残余应力的检测

采用X射线衍射法测量铝合金3003基体材料表面残余应力中用到的衍射角.试验中,将等强度梁加载后表面产生的应力假设为“表面残余应力”,用传统电测法和X射线法分别测量加载后铝合金3003等强度梁的应力值.以电测值为参照,考察X射线法在衍射角为142°和156°时的应力测量值,并对其进行对比分析.试验表明,衍射角为142°时的测量结果存在非测量不当引起的测量非线性点.因此,X射线测铝合金3003宏观表面残余应力的最佳衍射角为156°.     

Parametric study of gas−liquid two-phase flow field in horizontal stirred tank

Based on Fluent software, the gas?liquid two-phase flow in the horizontal stirred tank was simulated with SST k?ω turbulence model, Eulerian?Eulerian two-fluid model, and multi-reference flame method. The mixing process in the tank was calculated by tracer method. The results show that increasing the rotating speed or gas flow is conducive to a more uniform distribution of the gas phase and accelerates the mixing of the liquid phase. When the rotating speed exceeds 93 r/min, the relative power demand remains basically constant. The change in the inclination angle of the upper impeller has minimal effect on the gas phase distribution. When the inclination angle is 50°, the relative power demand reaches the maximum. An appropriate increase in the impeller distance from the bottom improves the gas holdup and gas phase distribution but increases the liquid phase mixing time.     

开颅手术中面向低损伤制孔的钻头结构优化设计

为降低颅骨钻孔过程中的钻削温度与轴向力,通过有限元仿真软件ABAQUS建立颅骨钻削模型,探究麻花钻主要几何参数（顶角、螺旋角、腹板厚度与横刃斜角）对机械损伤与热损伤的影响规律。制备可减小机械损伤与热损伤的优化钻头,进行试验。结果表明：麻花钻最优几何参数为顶角96°、螺旋角38.802°、腹板厚度0.8 mm、横刃斜角131.018°;与优化前的钻头相比,优化后的钻头具有更低的轴向力与钻削温度。     

Formation of integral fins function-surface by extrusion-ploughing process

1 Introduction The ever-increasing integrity of electronic chips results in high heat flow density, which makes the cooling become the ever more serious[1-5]. The traditional single-scale and simple figure surface heat-function macro-structure can not mee…     

Evolution of deformation microstructures of cold-rolled Ta–2.5W alloy with coarse grains at low to medium strains

Ta–2.5W alloy with coarse grains was cold-rolled to reductions ranging from 5 to 40%. The evolution of the microstructure was investigated by optical microstructure, electron backscatter diffraction (EBSD). A few microbands appear when the reduction reaches 20%. The density of microbands increases with increasing reduction. When the reduction reaches 40%, grains are composed of one or two groups of microbands except the {001}<110 > orientations. Most of the inclination angle between microbands and RD in this condition is 20–35°. As the strain increases, the inclination angle between microbands and RD gets smaller. The habit plane of microbands can be {110} plane. The microbands and matrix usually share a common < 110 > or < 111 >. The mature body-centered cubic rolling texture, including α and γ fibers, is not developed until the reduction reaches 40%. Meanwhile, shear bands appear. New grains can be seen in shear bands and a model is proposed to explain this process.