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再制造产业中产品的质量评价体系是重中之重,在再制造产业中,汽车发动机的再制造生产更是重点领域。但是目前缺乏综合健全的评价体系。根据人为主观的评价方法以及客观评价方法综合得到一个全面的评价方法,其中,主观评价方法采用可拓层次分析法(EAHP);客观评价方法应用了熵权法。另外,利用主客观得到的综合权重来建立加权标准化决策矩阵,利用基于TOPSIS的评价方法算出各个方案与理想解的距离,即贴近度,再根据贴近度的大小来评价该汽车发动机的再制造优劣程度。通过实际案例,对该综合评价方法进行了分析验证,并在实际案例中最终确定了最佳再制造方案,证实了该综合评价方法的可靠性。 相似文献
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供应链质量系统集成就是实现质量系统和质量过程的无缝联接,对其评价是建立供应链协作关系时的重要考虑因素之一。本文运用模糊数学中多级模糊综合评判的理论与方法,建立合理的模糊综合评价模型,全面考虑影响决策与评价过程的各种因素。该方法在评价因子的定量性方面更加准确可靠。实例表明这种方法简单、实用,能较好地解决该类决策问题。 相似文献
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管式褐煤干燥机两端管板采用圆形特厚钢板制作而成,且钢板表面钻有大量圆孔,部件质量大。该结构主要依靠焊接及机加工完成,焊缝数量多,焊接任务量大,部件加工及部件之间组装精度要求高,对制造质量要求非常严格。分析某大型管式褐煤干燥机管板结构,总结出一套合理的焊接、机加工工艺以及对关键部位的质量控制措施,为其他大型旋转机械设备的制造提供参考和借鉴。 相似文献
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《组合机床与自动化加工技术》2017,(9)
围绕再制造机床质量不稳定的问题,建立了废旧机床再制造全过程的质量模型,反映了质量特性的传递与映射,并识别出导致质量不稳定的关键过程。并针对废旧零部件回收质量不确定的问题,提出了一种基于多指标区间数的可拓综合评价与分类方法:将回收质量分为三个等级,从经济可行性、质量可行性和绿色可行性三方面建立可再制造质量评价指标体系;采用区间数物元描述废旧零部件;改进序关系分析法,将区间数与群组判断结合,确定客观合理的指标权重;构建综合关联函数,确定废旧零部件的质量等级与可再制造度。最后,通过某废旧机床导轨的再制造实例,验证了该方法的可行性和有效性。该方法能够科学合理地对废旧零部件进行质量评价与分类,并为后续的再制造工艺决策提供理论依据。 相似文献
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基于因子分析的多元工序能力指数 总被引:6,自引:0,他引:6
工序质量最终决定着机械产品的制造质量。通过工序能力指数的分析,可以得到产品在制造过程中工序质量的保证能力,由于很多机械产品需要综合分析多个质量特性评价工序质量,而针对个质量特性的一维工序能力指数无 到这一目的,因此本文提出一种基于因子分析的多元工序能力指数计算方法,通过分析多元工序能力指数这一综合指标,实现工序质量的综合评价,为保证和提高生产制造质量提供依据。最后,给出一个多元工序能力指数的计算实例,该实例表明,提出的方法是非常有效的。 相似文献
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在数字图像相关测量计算过程中,直接参与互相关计算的是散斑子图,而散斑子图质量对测量精度具有重要影响。因此,如何有效评价散斑子图质量是数字图像相关方法研究的热点问题。将信息论中用于衡量信息量的“熵”概念引入散斑子图评价,提出以图像熵为评价参数的散斑子图质量评价方法。为验证该评价参数的有效性,对采用不同方法采集的3幅不同类型散斑图进行位移测量实验。实验结果表明:位移测量精度与散斑子图熵有紧密的关系,散斑子图熵越大,位移测量精度越高。实验结果验证了图像熵可有效用于散斑子图的质量评价。 相似文献
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采用离心铸造生产缸套时,涂料质量不良、上涂料工艺和涂层厚度不当会使铸件局部产生白口,难以加工,也可能引起铸件外表面产生缺陷,因而介绍了离心铸造对涂料质量的要求及评定方法,涂料质量的控制,上涂料方法的选择,铸型温度的控制以及涂层厚度的选择。 相似文献
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球墨铸铁曲轴应用前景的评估 总被引:4,自引:3,他引:4
目前球铁曲轴应用中存在的主要问题是疲劳强度满足不了发动机爆发压力不断提高的要求,以及球铁质量不够稳定。提出了以疲劳强度为核心对曲轴质量进行评估,并通过抗拉强度与伸长率的合理匹配、使用等温淬火、圆角滚压等措施提高球铁曲轴的疲劳强度。为提高球铁曲轴质量可靠性,建议:(1)限定铁液中有害元素的含量;(2)控制原材料质量,并采用感应炉熔炼;(3)对原铁液脱硫,降低其硫量;(4)改进球化、孕育工艺;(5)采用先进检测仪器,提高在线检测水平;(6)重视疲劳性能测试,寻求适合于曲轴的检测方法;(7)开展球铁曲轴强度评价的研究。 相似文献
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针对水下湿法焊接质量评定中缺乏简便、客观的评价指标的现状,提出利用焊缝余高的变异系数表征焊接质量. 该指标具有支持定量分析客观性强、步骤简单易操作等优点. 余高变异系数越大,焊缝外观成形均匀性越差,焊接质量越低;反之,焊缝越平滑、美观,焊接质量越好. 为验证该指标的准确性,设计了相关的工艺试验. 依据脉冲电流对焊接过程稳定性的影响,开展不同脉冲频率条件下焊接. 鉴于送丝方式对焊接过程影响较大,利用焊缝余高变异系数分析送丝方式对水下湿法药芯焊丝焊接过程稳定性研究. 结果表明,余高变异系数评价结果与焊接质量相关度较高. 焊接过程中采用X射线高速成像技术,从焊接过程稳定性与熔滴过渡类型等方面深入分析了焊接过程对余高变异系数的影响,进一步验证了该指标的可靠性. 相似文献
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针对水下湿法焊接质量评定中缺乏简便、客观的评价指标的现状,提出利用焊缝余高的变异系数表征焊接质量. 该指标具有支持定量分析客观性强、步骤简单易操作等优点. 余高变异系数越大,焊缝外观成形均匀性越差,焊接质量越低;反之,焊缝越平滑、美观,焊接质量越好. 为验证该指标的准确性,设计了相关的工艺试验. 依据脉冲电流对焊接过程稳定性的影响,开展不同脉冲频率条件下焊接. 鉴于送丝方式对焊接过程影响较大,利用焊缝余高变异系数分析送丝方式对水下湿法药芯焊丝焊接过程稳定性研究. 结果表明,余高变异系数评价结果与焊接质量相关度较高. 焊接过程中采用X射线高速成像技术,从焊接过程稳定性与熔滴过渡类型等方面深入分析了焊接过程对余高变异系数的影响,进一步验证了该指标的可靠性. 相似文献
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C. H. Cáceres 《Journal of Materials Engineering and Performance》2000,9(2):215-221
The ductility of casting alloys is usually low and it is thus important to simultaneously assess the effect of changes to
the microstructure and heat treatment on both ductility and strength of the material. The use for this purpose of the quality
index charts* is common in the casting industry with regard to the Al-Si-Mg casting alloys A356 and A357.
An analytical method of generating quality index charts for any alloy system is presented. Applications of the method are
illustrated with case studies involving Al-Si-Mg, Mg-Al-Zn, and Al-Si-Cu-Mg casting alloys. The analytically determined charts
indicate the limits to microstructural improvement available for each material. The possibility of using the charts to optimize
the relation between mechanical performance, chemical composition, solidification conditions, and temper is discussed. 相似文献
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《Science & Technology of Welding & Joining》2013,18(5):449-454
AbstractResistance spot welding is one of the major joining techniques widely used for car body assembly. Weld quality may significantly influence the durability and reliability of the automobile body. Automotive manufacturers often rely on destructive testing and monitoring variables which indirectly reflected weld quality to assess the weld quality and control the welding process. However, these approaches have inherent limitations and are difficult to be implemented in plant environments. Therefore, it is imperative to develop an online inspection method to evaluate weld quality. In the present study, a method of producing a series of substantially uniform spot welds between two metal parts using a servomotor driven movable electrode and an axially opposing fixed electrode is proposed. The indentation in the workpiece surface is suitably measured by the displacement of the movable electrode as it applies an electrode force and welding current is passed through the weld site of the workpiece. The optimal indentation range is determined by peel test and metallographic examinations with respect to various sheet gages and grades. Consequently, online weld quality inspection results are achieved based on developed optimal indentation range. 相似文献
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A Method for Estimation of Free Mica Particles in Aggregate Fine Fraction by Image Analysis of Grain Mounts 总被引:1,自引:0,他引:1
Eva Johansson Karel Miskovsky Karl-Johan Loorents Ola Löfgren 《Journal of Materials Engineering and Performance》2008,17(2):250-253
The need to evaluate free mica grains in fine fraction of aggregate products has initiated the development of a statistically
and scientifically acceptable method. The proposed method is based on a modified point-counting approach using digital micro
photos of thin sections of aggregate grains and a software package to sustain sample analysis. A thin section of aggregate
grains provides permanent sample documentation readily available for complimentary or other analysis. Statistical analysis,
together with a repeatable analysis of samples (permanent mounts), confirms the robustness of the method. The method is appropriate
as a complementary assessment tool to estimate and trace changes or variations in quality of rock aggregate. Though, the estimation
of free mica particles in fine fraction needs to be combined with other analyses, e.g., petrographic analysis and analyses
of mechanical properties, to assess the quality of any rock material. As the samples can be collected from drill cuttings,
i.e., an accessible residual product obtainable from surveying or production, the present method is particularly useful as
a surveying tool and in prospecting and projecting activities. 相似文献
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G.O. Verran R.P.K. Mendes L.V.O. Dalla Valentina 《Journal of Materials Processing Technology》2008,200(1-3):120-125
This paper discusses the application of a design of experiments (DOEs) experimental method for analysing the influence of three injection parameters (slow shot, fast shot and up set pressure) on the internal quality of die casting SAE 305 alloy parts. Initially, the experimental methods applied to the manufacturing process are described. An experimental design was followed: it employed different combinations of injection parameters and aimed to assess the presence of porosity in the die casting parts. The quality assessment of the die casting parts was based on density measurements and qualitative image analysis. Results were evaluated by means of variance analysis, which assessed how the variation in the three different injection parameters influenced the integrity of the components. 相似文献