基于机器视觉的异形弹簧快速缺陷检测方法研究

为实现异形弹簧的尺寸和变形缺陷在线检测,基于机器视觉设计一套零件快速定位、测量和缺陷检测的方法.详细论述图像处理算法,即图像预处理、图像定位、尺寸测量和变形缺陷检测算法等.基于形状的模板匹配对零件进行定位,通过创建测量矩形完成对零件的尺寸测量.基于微分和自身对照的思想,对零件易变形区域进行微分,通过对比微分的小区域,实...     

基于机器视觉的轴类零件几何尺寸测量

基于轴类零件的几何特征与CCD获取的零件图像,利用数字图像处理技术对轴类零件进行边缘检测,提出了一种自适应开关中值滤波算法,该方法滤除噪声效果明显,开发了轴类零件尺寸测量系统,实现了轴的尺寸及其参数的测量.实验结果表明,改进的滤波器可以较好的保存图像的二维边缘信息,且在允许误差范围内采用机器视觉的非接触测量方法可以实现对轴的基本参数的快速准确测量.     

大型橡胶零件直径测量仪

当今普遍使用显微镜、卡尺和量规来测量橡胶零件,但能保证最高测量精度的,乃是非接触式的光学仪器,其中,—21型显微镜可测尺寸200×100毫米的零件。已知还有一种以非接触法测量大尺寸零件的装置,它包括一支有刻度的测量尺和沿着测量尺移动的光学     

夹簧级进模设计

介绍了某插座零件之一夹簧级进模的设计,该零件尺寸小,成形后成半封闭,为了确保零件有一定的挟持力,挟持面之间有严格的尺寸及毛刺要求.该零件产量较大,对尺寸的一致性要求高,通过对该夹簧零件结构和成形工艺的分析,确定该零件成形过程.介绍了为保证零件尺寸要求而采用的成形组件结构.该模具实际使用情况良好,零件得到设计师的认可.     

零件尺寸机器视觉测量中的测量比

在机械零件尺寸视觉测量中,普遍采用标定测量比的方法进行测量。推导出测量比的计算公式,给出测量比严格的定义。根据新的定义,必须保证零件到相机的距离和标定件到相机的距离严格相等,否则测量结果毫无意义。以空间两点高程差测量为例,给出用测量比法进行尺寸测量的详细过程,可作为修正由于零件到相机距离变化而引起的测量误差的参考。     

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     

铸造闭式叶轮内型面荧光渗透检测

铸造闭式叶轮零件的内型面液浸法荧光渗透检测中存在内型面清洗困难、内型面荧光显示区域观察及尺寸测量困难等问题,利用自制的补充清洗工具,采用带UV光源的柔性紫外线视频内窥镜观察荧光显示及双目显示尺寸测量,研究结果表明:采用补充清洗工具清洗后,大大减少了内型面检测中的背景干扰显示,双目测量中必须控制轴线内窥镜与缺陷平面法线夹角在20°以内才能保证荧光显示尺寸测量精度±0.2 mm要求。经过实际零件检测和金相解剖分析,零件的内型面荧光显示主要集中在流道面的转接R处,其主要呈现片状分布,少数有线状显示,荧光显示来源于铸造疏松,荧光渗透检测有效显示尺寸采用双目测量的结果与解剖后直接测量结果的误差在±0.2 mm内。     

谈谈零件工艺尺寸链计算中尺寸换算问题

谈谈零件工艺尺寸链计算中尺寸换算问题安徽农业大学方筱萍在零件工艺尺寸链中最常碰到的反计算问题就是尺寸换算──这是已知尺寸链封闭环尺寸公差。求某一组成环尺寸公差的反计算问题。在零件机械加工过程中，经常出现基准不重合的情况。如为了便于加工或测量，会出现原...     

汽车覆盖件重力变形的数值模拟方法

汽车覆盖件尺寸较大、形状复杂,容易因自身重力产生变形,从而对零件在检具上的测量产生影响。GDT(Geometric Dimension and Tolerance几何尺寸与公差)是测量零件尺寸的依据,其合理与否对零件合格率有重要影响。传统评估GDT的方法是依靠模板和现场经验,准确性和效率不高。为了提高效率,采用数值模拟方法计算零件在基准位置的变形,通过分析基准的变形是否超出图纸公差来评估GDT是否合理。应用实例表明,采用数值模拟方法评估GDT能够提高效率,效果良好。     

基于SKIP宏程序编程CNC无线测头在线智能检测系统设计

针对数控铣削加工精密零件尺寸精度测量时,因离线测量易产生测量误差、效率低、成本高等问题,通过赋值相关检测路径及补偿的参数,编写零件在线检测及误差补偿宏程序,开发了基于三菱M70数控系统跳过指令SKIP在线检测与误差补偿宏程序控制系统。应用结果表明：该系统在线检测重复定位精度能达到0.001~0.003 mm,能适用于精密零件数控铣削加工,具有一定的推广使用价值。     

Suspension and solution thermal spray coatings

The emerging methods of coating deposition by suspension and solution thermal spraying are described. The liquid suspensions of fine powders and liquid precursors are injected into flames and/or jets generated in the torches. The formulation and stability of suspensions as well as the methods of fine powders synthesis are briefly described. Typical solutions, being often the liquid organo-metallics are also briefly described. An important problem of injection of liquids into jets and flames is then presented. Two principal modes of injection, used at present, are outlined, i.e.: (i) atomization; and, (ii) injection of a continuous jet. Subsequently, the phenomena occurring in flames and plasma jets are discussed and the major differences to these occurring during conventional spraying are stressed up. The build up of coatings starting from the impact of fine particles on the substrate is described and typical microstructures of suspension and solution sprayed coatings are shown. Some properties of the sprayed coatings, including mechanical, electrical, chemical, and thermophysical ones are collected and presented. Finally, the emerging applications of coatings are shown and the possible future applications are discussed.     

A 3-D modular fixture with enhanced localization accuracy and immobilization capability

Modular fixtures are distinguished for their high flexibility. Previous researches focused on 2-D objects or 3-D objects with regular geometry. This paper introduces our systematic study of 3-D modular fixtures, particularly for complex objects. For the sake of both function and simplicity, three baseplates are arranged equilaterally. One baseplate is fixed horizontally, on which three fixels are installed to support the object. The other baseplates are moveable and at least one fixel is set on either of them. Totally, seven fixels are adopted. Efficient algorithms are presented for computing optimal fixel locations for the given object pose regarding localization accuracy and immobilization capability. On account of the manufacturing errors, measuring and adjusting techniques are developed to improve the localization accuracy. Case studies are investigated to illustrate applications. Experiments are performed for verifying the principles, including the well-known theoretical proposition that seven fixels are necessary and sufficient for fixturing a 3-D object of nonrevolutionary surface.     

超声电镀锡铋合金研究

研究了超声波对锡铋合金电镀的影响.通过赫尔槽试验优选出最佳镀液配方和工艺条件,用SEM法观测了镀层形貌,并测试了镀层和镀液性能.结果表明:超声波的作用扩大了电流密度范围和温度范围;所得镀层表面光亮、结晶更细致、均匀,镀层结合力、抗氧化性和可焊性改善明显,耐蚀性增强;镀液性能稳定,阴极电流效率和沉积速度得到提高.因此,超声波对电镀工艺条件、镀层质量和镀液性能都有明显的改善作用.     

Structure and corrosion endurance of dies from aluminum alloys

Dies produced from castable and deformable aluminum alloys are studied. The dies are used for molding articles from foaming plastics. Specimens for studying the microstructure are cut from the surface zone of dies. The stress state of the dies is determined by computation. The chemical composition of water and deposits on the surface of dies are studied in order to determine the causes of corrosion cracking. The effect of the composition of the alloy and of water on the composition of corrosion products deposited on die surfaces is studied by means of thermodynamic computation with the help of TERRA software. The materials of dies and alloys suitable for their production are studied and corrosion tests under actual operating conditions are performed. Anodized, epoxy, and epoxy-phenol coatings for the dies are tested. The causes of failure of aluminum dies are analyzed and recommendations for raising their endurance are given.     

镁合金抗氧化及合金化阻燃研究进展

综述了镁合金氧化燃烧及燃点的测定方法、镁合金抗氧化和阻燃机理及合金元素(Ca，Be，RE，Y)对镁合金阻燃性能影响的研究现状。介绍了抗氧化和阻燃镁合金研制进展及应用现状，指出了研究中存在的问题及发展方向。     

平板类气体辅助注射成型产品的CAE模拟研究

通过建立具有代表性的平板类气体辅助注射成型产品模型,借助注塑成型CAE软件Moldflow对该模型进行了一系列分析模拟。通过对模拟结果数据的综合分析和数学处理,得到了气体注射参数对气道穿透长度的影响规律、气体注射参数设置及气道穿透长度预测公式。     

An ab initio study of Ti-Y-O nanocluster energetics in nanostructured ferritic alloys

So-called oxide dispersion strengthened steels or nanostructured ferritic alloys (NFAs) contain nanoprecipitates which give them exceptional mechanical properties and resistance to radiation effects. However, the structure and composition of these nanoprecipitates are still uncertain. To help clarify the nature of the smallest nanoprecipitates, density functional theory calculations are used to investigate the most stable Ti, Y, and O nanocluster computational units in Fe. Two distinct methods for searching for stable nanoclusters are proposed: one in which nanoclusters are restricted to the body-centered cubic Fe lattice and one in which the nanocluster structures are strained variants of bulk Ti and Y oxides. We discovered that nanoclusters that are structurally similar to bulk Ti and Y oxides are significantly more stable than nanoclusters that are restricted to the Fe lattice. Consequently, the most stable nanoprecipitates in Ti-Y-O NFAs are more likely to be small oxide phases than coherent solute-enriched clusters.     

凝胶注模成型技术的研究与进展

对凝胶注模成型技术的研究与进展情况进行综述。阐述成型原理和工艺过程;总结凝胶体系,并根据凝胶体系的来源将其分为合成凝胶体系和天然凝胶体系两类;介绍该技术在粗颗粒粉体材料、复合材料、多孔材料、功能材料和粉末冶金等领域的应用研究情况;探讨凝胶注模成型技术存在的问题和研究发展方向。     

Modeling Residual Stress Development in Thermal Spray Coatings: Current Status and Way Forward

An overview of analytical and numerical methods for prediction of residual stresses in thermal spray coatings is presented. The various sources and mechanisms underlying residual stress development in thermal spray coatings are discussed, then the various difficulties associated with experimental residual stress measurement in thermal spray coatings are highlighted. The various analytical and numerical models used for prediction of residual stresses in thermal spray coatings are thoroughly discussed. While analytical models for prediction of postdeposition thermal mismatch stresses are fully developed, analytical quenching and peening stress models still require extensive development. Various schemes for prediction of residual stresses using the finite element method are identified. The results of the various numerical and analytical models are critically analyzed, and their accuracy and validity, when compared with experiments, are discussed. Issues regarding the accuracy and applicability of the models for predicting residual stresses in thermal spray coatings are highlighted, and several suggestions for future development of the models are given.     

2219铝合金不同气氛下TIG焊焊接接头组织性能

为研究氦弧TIG焊焊缝质量,对比分析了2219铝合金氦弧TIG焊与氩弧TIG焊焊缝成形及组织性能.结果表明,在背部熔宽相同的条件下,氦弧TIG焊焊缝正面熔宽、下塌量及热影响区宽度均小于氩弧TIG焊,氦弧TIG焊与氩弧TIG焊焊缝的微观组织及第二相组织基本相似,焊缝区晶粒为等轴晶,热影响区晶粒为粗大的板条状,组织为粗大的α铝基体与金属间化合物Al₂Cu及少量的共晶组织,焊缝区的第二相组织明显多于热影响区,无法发挥弥散强化的作用.氦弧TIG焊与氩弧TIG焊焊接接头的断裂方式均为韧性断裂,抗拉强度基本保持一致,氦弧TIG焊焊接接头的断裂总延伸率高于氩弧TIG焊,维氏硬度高于氩弧TIG焊焊缝的硬度.