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对国外大铝挤压机概况作了简要介绍,较详细地介绍了中国铝挤压机的建设情况。2013年年底中国有不小于45 MN的挤压机至少73台,占全球总数的61.3%强。它们中的92%以上都是在2001年以后建设的,2012年有1台从西马克梅尔公司引进的150 MN挤压机投产,是世界装机水平最高的重型挤压机。中国正在设计制造2台225 MN挤压机及1台300 MN的卧式挤压机,2015年或晚些时候投产,2015年保有的大挤压机可望超过95台。2013年中国有24个企业拥有大挤压机,总挤压力约4 800 MN,大铝型材生产能力超过486 kt/a。 相似文献
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对铝挤压机主剪刀剪切过程受力进行了分析,介绍了不同铝挤压机主剪刀结构形式,提出了旋转式大型挤压机主剪刀结构,建立了旋转供油装置,提出了旋转式主剪刀剪切过程控制方法,应用重型运动部件惯性控制手段显著提高了主剪刀的运行速度。研究结果在120MN铝型材挤压机上得到了应用,结果表明:旋转式主剪刀可有效提高剪切效果。 相似文献
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忠旺集团铝挤压厂是全球拥有现代化铝材挤压机最多的单独铝挤压厂,现正在制造与安装四台新挤压机。除一台31.5MN的外,其他都是大于50MN的大型挤压机,其中:125MN的一台,双动,西安重型机械研究所设计,上海重型机械集团制造,可于9月制造完毕,11月开始安装,2006年3月投产;75MN的一台,单动, 相似文献
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本文应用有限单元法,研究目前国内设计生产的最大的铝挤压机关键部件固定挤压垫的结构特性,根据原设计方案和改进设计方案的计算结果和对已制造的36MN挤压机固定挤压垫的校核计算结果,确定出75MN铝挤压机挤压套φ胀量。现场挤压结果表明,该固定挤压垫工作状态良好,达到了预期目标,从而证明了计算的可靠性。 相似文献
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我厂1987年引进日本宇布兴产制造的1800美吨铝型材挤压机成套设备。该设备全部采用微机自动程序控制,自动化水平很高。牵引机和前梁锯是挤压机主要的辅助设备。近两年来先后多次发生牵引机高速返回时与前梁锯相撞的设备事故。由于操作工人采取了紧急措施,设备没有造成严重损坏。为解决这一问题,我们经过仔细观察分析,找 相似文献
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山东南山铝业公司一次性向德国西马克梅尔公司订购14台挤压机将从2011年12月起陆续投产,挤压力11 MN起至150 MN,有单动的,也有双动的,有正向的,也有反向的。一次性引进这么多先进的一流挤压机,不但在中国铝加工业前所未有,也是近50年世界所未有的。日本在上世纪60年代初发展铝挤压工业时, 相似文献
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Effects of the friction coefficient on the minimum cutting thickness in micro cutting 总被引:9,自引:2,他引:9
Seong Min Son Han Seok Lim Jung Hwan Ahn 《International Journal of Machine Tools and Manufacture》2005,45(4-5):529-535
In the ultra precision diamond cutting process, the rake angle of the tool is likely to become negative because the edge radius of tool is considerably large compared to the sub-micrometer depth of cut. The round edge of the tool might sometimes cause plowing results in a poor surface, or burnishing which results in a shiny surface depending on the depth of cut. This study deals with the relationship between the friction of a tool-workpiece and the minimum cutting thickness in micro cutting. Proposed is an ultra precision cutting model in which the tool edge radius and the friction coefficient are the principal factors determining the minimum cutting thickness with a continuous chip. According to the model, a smaller edge radius and a higher friction coefficient make the cutting depth thinner. The experimental results verify the proposed model and provide various supporting evidence. 相似文献
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水射流切割是一种特种加工方法,对那些因其他方法难以切割的先进复合材料是非常理想或唯一的加工手段。分析了复合材料的性能和切割方向对断面质量的影响。研究发现,当沿着垂直于纤维的方向进行切割且复合材料中的树脂基体和纤维之间的相容性好,则其断面质量较好。 相似文献
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This paper presents a methodology to determine simultaneously (a) the flow stress at high deformation rates and temperatures that are encountered in the cutting zone, and (b) the friction at the chip–tool interface. This information is necessary to simulate high-speed machining using FEM based programs. A flow stress model based on process dependent parameters such as strain, strain-rate and temperature was used together with a friction model based on shear flow stress of the workpiece at the chip–tool interface. High-speed cutting experiments and process simulations were utilized to determine the unknown parameters in flow stress and friction models. This technique was applied to obtain flow stress for P20 mold steel at hardness of 30 HRC and friction data when using uncoated carbide tooling at high-speed cutting conditions. The average strain, strain-rates and temperatures were computed both in primary (shear plane) and secondary (chip–tool contact) deformation zones. The friction conditions in sticking and sliding regions at the chip–tool interface are estimated using Zorev's stress distribution model. The shear flow stress (kchip) was also determined using computed average strain, strain-rate, and temperatures in secondary deformation zone, while the friction coefficient (μ) was estimated by minimizing the difference between predicted and measured thrust forces. By matching the measured values of the cutting forces with the predicted results from FEM simulations, an expression for workpiece flow stress and the unknown friction parameters at the chip–tool contact were determined. 相似文献
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介绍了滚切双边剪的剪切机构和剪切原理,用解析方法对滚切双边剪的剪切角和切板时间进行了分析和研究,提出了求解方法和数学模型,应用计算机计算得出了不同钢板的剪切角变化曲线以及切板起始和结束时间,为进一步分析剪切过程以及准确计算剪切力和等效电机功率等打下了基础。 相似文献
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回顾了数控切割技术在我国造船行业中的应用状况,并揭示了大力推广高新切割技术对船舶工业未来发展的重要意义。 相似文献
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From the basic mechanics of orthogonal metal cutting toward the identification of the constitutive equation 总被引:1,自引:0,他引:1
N. Tounsi J. Vincenti A. Otho M. A. Elbestawi 《International Journal of Machine Tools and Manufacture》2002,42(12)
This paper proposes a methodology to identify the material coefficients of constitutive equation within the practical range of stress, strain, strain rate, and temperature encountered in metal cutting. This methodology is based on analytical modeling of the orthogonal cutting process in conjunction with orthogonal cutting experiments. The basic mechanics governing the primary shear zone have been re-evaluated for continuous chip formation process. The stress, strain, strain rate and temperature fields have been theoretically derived leading to the expressions of the effective stress, strain, strain rate, and temperature on the main shear plane. Orthogonal cutting experiments with different cutting conditions provide an evaluation of theses physical quantities. Applying the least-square approximation techniques to the resulting values yields an estimation of the material coefficients of the constitutive equation. This methodology has been applied for different materials. The good agreement between the resulting models and those obtained using the compressive split Hopkinson bar (CSHB), where available, demonstrates the effectiveness of this methodology. 相似文献
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