共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
以石墨颗粒作为固体润滑剂及液体润滑剂的添加剂,在不同的润滑状态下进行了板料拉深成形物理试验,运用探针测试技术实时测试了矩形件的不同变形部位在拉深成形过程中所产牛的摩擦冈数大小及分布状况,评估纳米石墨颗粒作为润滑添加剂在矩形件拉深成形中的实际摩擦特性及润滑效果.研究表明纳米石墨颗粒作为润滑添加剂对板料拉深成形性能的影响显著. 相似文献
3.
4.
5.
润滑对板料胀形和拉深性能的影响 总被引:2,自引:0,他引:2
胀形和拉深是板料成形中重要的工序,摩擦状况直接关系到成形效果.在胀形和拉深实验中其他条件不变的情况下,通过采用6种不同的润滑剂、液压成形和无润滑剂,对同样形状的板料进行胀形和拉深实验,比较润滑剂对钢和铝板料成形性能的影响.实验结果表明:在板料成形中,干润滑剂润滑效果好于湿润滑剂润滑效果;润滑剂对钢和铝板两组试件成形性能的影响基本一致,并对结果进行了分析. 相似文献
6.
方盒形件分区压边方式拉深压边力的数值模拟 总被引:1,自引:0,他引:1
板料拉深成形是冲压生产中的一种少、无切削的先进加工方法,拉深成形的重要工艺参数之一是压边力,是保证零件成形质量的关键.根据方盒形件的拉深成形特点,将压边圈设计为直边区域、法兰转角区域及直边与转角交界区域的十六块分区压边方式,并对分区压边圈在不同压边力加载模式下进行了模拟分析.分析结果表明:对于方盒形件的拉深,将压边圈设计为适当的分区结构、各分区压边圈采取合理的变压边力加载模式可以充分改善板料的成形性能、达到抑制板料起皱和延缓破裂以及提高板料拉深成形质量. 相似文献
7.
8.
9.
10.
11.
Zhu Wei Z.L. Zhang X.H. Dong 《The International Journal of Advanced Manufacturing Technology》2006,29(9-10):885-889
When deep drawing rectangle parts, instead of adopting elastic or several segmented blank holders, a new thought of applying dual layers of blank holders, which are parallel to each other, has been achieved to asynchronously vary blank holder force (BHF) at different regions of sheet flange, by dint of replacing different little mandrils in length between dual layers of blank holders, thus to further improve the formability of products. At the same time, in order to solve two problems of how to judge which one distribution of one desired integral variable BHF, which was obtained from the thickness analyses with products in advance, on blank holder for asymmetric parts is the best and to evaluate lubricant in deep drawing, a probe sensor with structure of dual cantalevers, based on the theory of resistance strain slice, fixed into the inner space of die, was developed for measuring real-time friction coefficient of sheet flange’s surface. Through this special probe sensor, not only real-time BHF on sheet flange could be measured out, but also the real-time friction coefficient could be figured out. Finally, one example of rectangle part was carried out in tests to validate the feasibility of this thought. By the way of analyzing the distribution of variation with products’ thickness on products and judging whether the whole distribution of friction on sheet flange’s surface was uniform or not, one optimized BHF loading profile could be finally obtained over the whole punch stroke. 相似文献
12.
圆筒形件拉深失稳及各因素影响分析 总被引:4,自引:2,他引:4
对板料成形中圆筒形件拉深的破裂失稳及产生破裂失稳的临界压边力进行研究.由于凸、凹模圆角及其间隙的存在,圆筒形件拉深的筒壁区实际为凸、凹模圆角之间的公切线部分.根据Mises-Hill屈服函数及Tresca准则求出凸缘变形区、凹模圆角区和筒壁区的应力分布,得到危险断面处的应力表达式,从而求出不产生破裂失稳的临界压边力的解析表达式,并进一步分析获得拉深比、硬化指数、厚向异性系数、摩擦因数以及径向推力等因素对临界压边力的影响规律.采用液压压边与周缘加径向推力的拉深模具对08Al板料进行拉深试验,试验结果与理论计算结果具有很好的一致性. 相似文献
13.
非回转对称拉深成形中压料面上摩擦的研究 总被引:3,自引:0,他引:3
在大量拉深试验的基础上,结合法兰、矩形盒底部产生的应力应变状态以及载荷的变化情况,分析了相对凸模半径较大的薄板非回转对称成形过程中,压料力对拉深载荷以致断裂载荷所产生的复杂影响。指出法兰曲边部的滑动摩擦因数对于成形过程中的压料力相当敏感,并且对法兰部和断裂危险部材料的应力应变状态产生直接影响。特别是在面压较高的成形后期,由于法兰部润滑效果恶化,导致拉深载荷增大、成形极限降低。 相似文献
14.
N. Malatji A.P.I. Popoola O.S.I Fayomi 《The International Journal of Advanced Manufacturing Technology》2017,88(9-12):2443-2459
In this paper, an improved approach is proposed to determine the optimal profiles of two controllable process parameters (hydraulic pressure and blank holder force), which improve the forming condition and/or make better use of forming limits in hydromechanical deep drawing (HMD) process. A method based on adaptive finite element analysis coupled with fuzzy control algorithm (aFEA-FCA) was developed using LS-DYNA to determine the optimal loading profiles and thus to maximize the limiting drawing ratio (LDR). Maximum thickness reduction, maximum wrinkle height in the flange region of the sheet metal blank, and position of the nodes in the unsupported portion of the sheet metal blank between punch and die were used as criteria in the fuzzy control algorithm. Different rule-based matrices were compared by considering the maximum thinning occurred in the sheet metal blank, and thus, the most accurate matrices were determined for the control algorithm. The optimal loading profiles could be determined in a single FEA, thus reducing the computation time. The proposed approach enables determining the optimal loading profiles and also could be applied to complex parts easily. In addition, effects of initial blank diameter and coefficient of friction between the sheet-blank holder and sheet-die on the optimal loading profiles were investigated. An attainable LDR of 2.75 for AA 5754-O sheet material in hydromechanical deep drawing process was proven experimentally using the optimal loading profiles determined by adaptive FEA. 相似文献
15.
16.
17.
PREDICTION AND CONTROL OF BOTH WRINKLE AND FRACTURE LIMITS ON CYLINDRICAL CUP MULTI-DEEP-DRAWING 总被引:3,自引:0,他引:3
Lei Junxiang Yantai UniversityKang Yonglin University of Science Technology Beijing 《机械工程学报(英文版)》1999,12(4)
0 INTRODUCTIONCylindricalcupdeepdrawingisboththemostcommonandrepresentativetechnologyinsheetmetalformingandtheimportanttestmethodsofevaluatingsheetformingproperties.Whenthedeformationquantityofcylindricalcupisgreaterthanforminglimitdeterminedwiththe… 相似文献
18.
19.
针对轴承的故障早期诊断和在线实时监测,提出了一种新型过约束平面并联三维力/力矩传感器。通过采用分支轴线均不过传感器中心的6条对称分布的测力分支,该传感器可同时测量轴承径向载荷和轴向力矩。根据静力学平衡方程,求解了其测量数学模型;基于传感器测量模型与性能指标分析了传感器性能,进而对其各结构参数进行优化设计。研制了传感器样机及其加载标定实验系统,开展了加载标定实验,得到了该传感器的测量精度。标定实验结果显示:传感器径向力测量精度为2.56%,力矩测量精度为0.92%,Ⅰ类误差为2.56%,最大Ⅱ类误差为2.29%。文中所做工作,为将该新型过约束平面并联三维力/力矩传感器应用于在线实时测量轴承径向载荷和轴向摩擦力矩奠定了基础。 相似文献
20.
混合压边液体内向流动动态充液拉深 总被引:1,自引:1,他引:1
为抑制液体内向流动动态充液拉深中凸缘增厚而造成的拉深阻力急剧增长,提出混合压边液体内向流动动态充液拉深新方法。对定间隙下设定恒定压边力的混合压边充液拉深压边形式实质进行分析,采用有限元研究混合压边方式下压边间隙、压边力以及径向压力的变化对成形过程的影响。研究结果表明:定间隙下设定恒定压边力的混合压边充液拉深压边形式的实质是设定压边间隙和设定压边力压边方式的混合;采用混合压边方式可以降低实际最大压边力,降低凸缘区的摩擦阻力,减少第二个谷底点的减薄率;压边力影响零件直壁部分壁厚分布,较大的压边力得到的零件直壁壁厚较薄;压边间隙的变化影响成形零件直壁壁厚分布,较小的压边间隙成形零件直壁较薄,第二个谷底点越接近零件底部。 相似文献