金属双极板电磁微成形工艺研究

发布时间：2018-03-13 11:28

本文选题：电磁微成形　切入点：微冲孔　出处：《哈尔滨工业大学》2015年博士论文　论文类型：学位论文

【摘要】：近年来,随着微机电系统(Micro-electro-mechanical system,MEMS)技术的迅速发展,微通道类零件如微通道换热器、微型燃料电池双极板以及微生物芯片等在能源、微电子、航空航天和生物医疗等领域得到了广泛应用。电磁微成形技术是一种金属利用强脉冲磁场中所受到的电磁力作用使之产生变形的高能率微塑性加工技术,该技术能够有效提高材料的延展性和成形极限,避免了微成形工艺对模具装配精度的苛刻要求,成为一种重要的微型零件柔性成形方法。本文以燃料电池金属双极板为研究对象,通过实验和有限元模拟相结合的方法研究金属箔板电磁微胀形变形行为,分析工艺参数对金属双极板成形质量的影响规律,揭示金属箔板电磁微成形机理,实现微型燃料电池金属双极板的高质量成形。首先利用ANSYS有限元模拟软件中多物理场耦合分析模块,建立金属箔板电磁微胀形三维有限元模型,分析了金属箔板在电磁微胀形过程电磁力分布规律和金属箔板电磁微胀形变形特点。模拟结果显示,金属箔板在电磁微胀形过程中所受到的电磁力随着放电能量的增大而增大,随着放电电容的增大而降低,在箔板变形区域内电磁力始终保持均匀分布。金属箔板电磁微胀形过程中,沿微通道横截面轮廓方向由通道边缘到中间位置等效应变分布逐渐增大,沿微通道纵向等效应变分布均匀。阵列通道电磁微胀形过程中各通道等效应变分布一致,模拟结果表明,电磁微成形技术能够成形出一致性好的微通道零件。研制了基于均匀压力线圈驱动的金属箔板电磁微胀形实验装置,开展单通道电磁微胀形实验研究。实验结果显示,随着放电能量、放电次数以及放电频率的增加,微通道成形性能显著提高,而随着箔板厚度和晶粒尺寸的增加,微通道成形性能降低。在电磁微胀形过程中使用凸模具或采用有较大圆角的凹模具均有利于提高金属箔板电磁微胀形成形性能。进行了阵列通道电磁微胀形工艺研究。结果显示,随着放电能量和放电频率增大,阵列通道胀形高度和均匀性提高,在放电能量7.2k J时阵列通道成形质量好;材料性能对电磁微胀形工艺影响显著,T2紫铜薄板屈服强度和电阻率小,阵列通道成形性能优异,而SS304不锈钢箔板屈服强度和电阻率较高,并且是典型的率相关材料,成形性能相对较低。进行了金属箔板电磁微冲孔工艺实验研究,对电磁微冲裁变形过程进行了分析,探讨了工艺参数对微冲孔质量的影响规律,揭示了金属箔板电磁微冲裁断裂机制。结果显示,随着放电能量增加、凹模孔径增大,微孔断面毛刺和圆角带减小,而随着坯料厚度增大,微孔断面圆角带增大,毛刺逐渐减小。SS304不锈钢箔板冲裁断裂模式为有韧窝的韧性断裂,而T2紫铜箔板在电磁微冲孔过程中出现断口平整的无韧窝拉伸断裂、无韧窝的拉伸断裂和有韧窝的拉伸断裂等多种断裂模式。微孔质量检测结果显示,电磁微冲孔微孔轮廓尺寸精度较高、断面质量好,可以实现微孔的高效率、低成本、高质量的生产加工。针对燃料电池金属双极板,进行了燃料电池金属双极板电磁微成形工艺实验研究,分析了金属双极板电磁微成形过程中材料参数、放电参数和模具参数对双极板成形质量的影响规律,确定了双极板最佳成形工艺,并对电磁成形金属双极板的成形质量进行评价。实验结果显示,随着放电能量增加双极板微流道胀形高度和均匀性提高;随着放电频率的增大,双极板微流道胀形高度增大,均匀性下降;坯料与模具之间的距离对双极板微流道胀形高度和均匀性的影响表现为先增大后减小,在间距为1.0mm时双极板成形质量最佳;随着坯料厚度的增大,双极板微流道胀形高度和均匀性迅速降低。当微模具脊宽比S/W1时,选用凸型模具,而脊宽比S/W≤1时,使用凹型模具进行双极板成形可以获得更高的质量。在放电频率7.424k Hz,放电能量为7.2k J条件下,采用脊宽比为2.0的凸型模具成形出质量优异的紫铜箔燃料电池双极板。
[Abstract]:In recent years, with the development of microelectromechanical system (Micro-electro-mechanical system MEMS) the rapid development of technology, micro channel parts such as micro channel heat exchanger, micro fuel cell bipolar plate and microbe chip in energy, microelectronics, aerospace and biomedical and other fields has been widely used. The electromagnetic micro forming technology is a kind of metal utilization high energy rate strong pulse electromagnetic force by the magnetic field in the deformation of micro plastic forming technology, this technology can effectively improve the ductility and the forming limit of the material, avoid the micro forming process of die assembly precision demanding requirements has become one of the most important parts of micro flexible forming method. In this paper, metal bipolar in the fuel cell as the research object, research method of deformation behavior of metal foil electromagnetic by both experimental and finite element simulation of micro expansion, analysis of process parameters on double metal Influence of plate forming quality, reveal the electromagnetic metal foil micro forming mechanism, to realize the high quality metal bipolar plate of micro fuel cell forming. Firstly, multi physics finite element simulation software ANSYS coupled analysis module, a metal foil electromagnetic micro bulging three-dimensional finite element model of metal foil in micro electromagnetic the bulging process of electromagnetic force distribution and metal foil electromagnetic micro bulging deformation characteristics. The simulation results show that the electromagnetic force of metal foil by electromagnetic micro bulging process increases with the increase of discharge energy, reduce with the increase of discharge capacity and maintain uniform distribution in the electromagnetic force region foil the deformation of sheet metal foil. Electromagnetic micro bulging process, the micro channel cross-sectional contour direction from the channel edge to the middle position of the strain distribution gradually increased along the longitudinal micro channel strain distribution are Well. Array channel electromagnetic micro bulging process of each channel strain distribution, the simulation results show that the electromagnetic micro forming technology can form micro channel parts good consistency is developed. The electromagnetic metal foil driven uniform pressure coil micro bulging test device based on single channel, carry out electromagnetic micro bulging experiments. The experimental results show that the discharge energy, discharge times and discharge frequency increase, the micro channel forming performance is significantly improved, with the increase of foil thickness and grain size, micro channel forming performance decreased. In the micro electromagnetic bulging process using the convex mold or the concave mold has a large fillet to improve metal foil electromagnetic micro dome forming performance. The array electromagnetic micro bulging technology research. The results showed that with the increase of discharge energy and discharge frequency, array channel bulging height and uniformity. High energy 7.2k J array in the discharge channel forming good quality; effect of material properties on the electromagnetic micro bulging process of T2 copper sheet significantly, yield strength and low resistivity, excellent formability and channel array, SS304 stainless steel foil yield strength and high resistivity, and is typical of rate dependent material, forming a relatively low performance the electromagnetic metal foil. Experimental research of micro punching process, micro blanking deformation of electromagnetic process was analyzed and discussed the influences of process parameters on the micro punching quality, reveals the electromagnetic metal foil micro blanking cutting crack mechanism. The results show that with the increase of discharge energy, die size, microporous section burr and round with reduced, with the blank thickness increases with increase of micropore section fillet, burr decreases.SS304 stainless steel foil stamping with dimple fracture mode was ductile fracture, and T2 copper foil In the process of electromagnetic micro punching smooth fracture without dimple fracture, tensile fracture without dimple and dimple fracture mode. Tensile fracture and other test results show the quality of microporous, microporous electromagnetic micro punching contour size precision, section quality is good, can achieve high efficiency and low cost, micro, production high quality machining. For the metal bipolar plate of fuel cell, the electromagnetic metal bipolar plate of fuel cell technology experimental study on micro forming, analysis of electromagnetic micro forming process of metal bipolar plate material parameters, influence of discharge parameters and die parameters on forming quality of bipolar plate, the optimum forming process of bipolar plate, and electromagnetic forming quality of metal bipolar plate was investigated. Experimental results show that with the increase of discharge energy of bipolar plate micro channel bulging height and uniformity is improved with the increase of the frequency of discharge; Large, bipolar plate micro channel bulging height increases, the uniformity of decline; influence between blank and die from the bipolar plate micro channel bulging height and uniformity is increased first and then decreased in the space of 1.0mm bipolar plate forming the best quality; with the increase of blank thickness, bipolar plate micro channel bulging the height and uniformity decreased rapidly. When the micro mold ridge width is S/W1, the convex mould, and ridge width ratio S/W = 1, forming bipolar plate using concave die can obtain higher quality. In the discharge frequency of 7.424k Hz 7.2k J, the discharge energy conditions, the ridge width ratio the forming quality of copper foil fuel cell bipolar plate excellent convex die 2.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TH16;TM911.4

【参考文献】