板厚对冲裁力影响规律的研究

理论分析和生产实践表明，在一定范围内，间隙对冲裁力的影响是很小的，而板材相对厚度是影响单位厚度上冲裁力的主要因素。当材料性能等其它条件一定时，冲裁力随着板厚的增大而增大，但单位板厚上的冲裁力则随着板厚的增加而减小，在有限元模拟和实验分析的基础上，提出了计算冲裁力的新方法，对揭法剪切加工机理及正确确定冲裁力有理论和实际意义。     

圆形冲裁件斜刃冲裁力的计算

板材剪切加工时,因变形集中在狭小的区域内,变形过程复杂,冲裁力多采用近似的方法进行计算。斜刃冲裁时,变形过程更加复杂,对这方面的理论研究较少,文献［１］给出的剪切线为直线的斜刃冲裁力的计算式,不能普遍适用。而对圆形冲裁件的斜刃冲裁的研究,还几乎是个空...     

基于电涡流传感器的锻锤锤头位移检测系统设计

针对锻压现场强振动、高温度、多粉尘的特点,提出了一种基于电涡流位移传感器的锤头位移检测方案,以解决锻件尺寸在线监控的问题。该方案在锤头侧面垂直方向上加工出等距凹槽作为刻度标尺,电涡流传感器探头安装在机架上且正对凹槽刻度标尺的位置,通过采集锤头运动过程中传感器输出电压信号的动态数据计算锤头位移。在设计过程中,首先采用有限元软件对该方案进行仿真研究,通过分析凹槽刻度标尺表面磁场特征,确立了方案的可行性;其次,采用金属板材加工凹槽刻度标尺进行实验,建立位移测量数学模型。实验结果表明,该方案可行且具有较高的测量精度。     

实用冲裁件优化排样系统的研究与开发

建立了冲裁件排样的合理数学模型，分析了普通单排、普通双徘、对头单排和对头双排四种不同的排样方式，以及连续模排样与非连续模排样两种不同的加工方式排样的特点，有针对性地构造出与它们相适应的优化排样算法。配合图形识别和图形处理技术，计算机能够根据零件的图形信息精确、快速、自动地确定排样零件的最优冲裁步距、最优冲裁角度、对排件的最优位移以及板材的最优分割方式等优化的排样参数，由此得到一个以板材上的最多可冲裁零件个数为目标的优化排样方案，达到了整体上的最优。     

基于数字图像相关技术的金属冲裁过程材料变形分析

为准确分析金属板料冲裁过程中材料变形及断裂行为,构建了一个基于二维数字图像相关方法的原位应变测量系统。对Cu Sn0.15铜合金板材开展系列冲裁实验,通过该原位应变测量系统有效地跟踪记录了冲裁过程的局部大变形,获取了冲裁过程的各应变分量的应变场分布,在此基础上分析了应变演变规律和不同冲裁间隙的应变场差异。结果表明,剪切应变在冲裁过程前期起主导作用,而拉伸应变的急剧增大是在冲裁过程后期材料内部出现微裂纹的主要原因。不同冲裁间隙的应变场差异主要体现在拉伸应变的分化上,拉伸应变的差异是影响光亮带占比的主要因素。研究结果不仅为冲裁工艺的制定提供基础数据,还可为评定数值模型的有效性提供依据。     

特厚板冲裁技术

冲裁加工中,常用的最大板厚为几毫米。对板厚大于110mm 的冲裁加工,则很少介绍.笔者积累了厚度为10～25mm 特厚板材冲裁加工的经验和数据,现对此做一介绍。1.特厚板冲裁的机理与冲裁力的计算众所周知,一般冲裁时,为了获能良好的冲裁断面,需选取合适的凸凹模间隙。该间隙一般是随板材厚度增加和板料强度的提高而增大。但对于普通板厚来说,该间隙值总是很小的。因此一般以为,冲裁时的板料处于单向应力状态(图1)。即认为在冲裁力的作用下,冲裁面上受到单向剪应力σ的作用。当σ的值达到材料的抗拉强度极限σ_b 时,材料即被冲离.由此得出冲裁力的计算公式为:     

实用冲裁件优化排样系统的研究与开发

建立了冲件排样的合理数学模型,分析了普通单排,普通双排,对头单排和对头双排四种不同的排样方式,以及连续模排样与排样排样两种不贩加工方式排样的特点,有针对性地构造出与它们相适应的优化排样算法,配合图形识别和衅形处理技术,计算机能够根据零件的图形信息精确,快速,自动地确定排样零件的最冲裁步距,最优冲裁角度,排对排件的最优位移以及板材的最优分割方式等优化的排样参数,由此得到一个以板材上的最多可冲裁零件个     

矩形冲裁件排样优化设计与板材库存构成决策

在单一下料的情况下，库存同一型号规格但尺寸不同的板材种数、板材的具体尺寸和冲裁件的排样方案，对板材的下料利用率都有明显的影响。本文阐述了合理选择库存板材尺寸与矩形毛坯剪切下料排样方案的科学方法，用所研制的排样与板材库存构成决策微机软件对例题数据进行了分析。采用此方法进行决策可使板材下料利用率得到明显提高。     

矩形冲裁件排样优化设计与板材库存构成决策

在单一下料的情况下，库存同一型号规格但尺寸不同的板材种数、板材的具体尺寸和冲裁件的排样方案，对板的下料利用率都有明显的影响。本文阐述了合理选择库存板材尺寸与矩形毛坯剪切下料排样方案的科学方法，用所研制的排样与板材库存构成决策微机软件对例题数据进行分析。采用此方法进行决策可使板材下料利用率得到明显提高。     

差动微位移机构在激光板厚测量中的应用

激光板厚测量系统中,需要动态调节系统中传感器的位置,以适应被测板材表面位置的变化。采用步进电机驱动的差动微位移机构动态地调节系统中传感器位置,实现保证板厚测量有效性和扩展系统的测量范围的目的。应用表明,差动微位移机构能够方便地实现传感器位置的控制,系统的位置调节精度达到0．0025mm。     

Experimental investigation of the cutting force reduction during the blanking operation of AHSS sheet materials

Within the manufacturing process of sheet metals, blanking represents an essential process operation. As the industrial application of high-strength multi-phase steels grows, the blanking process must consider high blanking and shear forces which are characteristic of these materials. This paper presents possibilities for reducing these forces. Experiments were performed utilizing a novel tool concept which can correlate necessary blanking forces to the punch stroke in three dimensions and in direct force path. Results from three different AHSS materials are presented showing the variation of decisive blanking parameters such as clearance, shearing angle and sheet positioning angle.     

Condition-based maintenance in punching/blanking of sheet metal

This paper provides a review and proposal for condition-based maintenance (CBM) in blanking of sheet metal. To date, little research on this topic can be found in literature, which is probably due to the complex nature of the process. Previous statistical, artificial intelligence (AI) and model-based approaches are analysed. Special attention is given to inherent assumptions and other sources of inaccuracy. In addition, it is demonstrated how the signature of the force–displacement relation changes significantly with increasing tool wear in a typical configuration of sheet steel blanking. An analysis follows as to how such behaviour could be used in CBM. A practical implementation of CBM in sheet metal blanking is proposed based on a hybrid solution.     

基于剪切面分析的冲裁模具磨损预测

针对薄板冲裁过程中模具与板料的摩擦分析,推导出凸模侧壁的摩擦力公式,得到了板料剪切面光亮带与凸模侧壁磨损之间的量化关系。在此基础上,建立凸模磨损的灰色预测模型,并采用端子高速冲裁试验,对该模型进行验证,通过比较实际磨损值与模型预测值以及残差计算,证明了该模型对于凸模磨损预测的准确性。     

金属板材无毛刺精密分切新工艺分切断面形貌特征

基于负间隙冲裁加工原理,针对圆盘剪纵向分切加工,通过分析控制分切过程的材料应力状态,将分切过程分解为塑性剪切和压迫分离两个阶段,提出金属板材无毛刺精密分切新方法,即塑性剪切压迫分离精密分切工艺。采用镀锌板对无毛刺精密分切新工艺加工过程进行实验研究,分析塑性剪切压迫分离精密分切材料变形过程及板材受力特点;通过显微形貌观察,研究无毛刺精密分切新工艺分切断面的双塌角、双剪切区、中部剪切断裂区的形貌特征,并与传统圆盘剪分切工艺的分切断面特征进行对比。结果表明,采用塑性剪切压迫分离精密分切新工艺,可以消除分切毛刺从而提高金属带材的质量。     

斜刃冲裁与平刃冲裁的关系及斜刃冲裁力的计算

摘要通过比较平刃冲裁与斜刃冲裁的特点,介绍了斜刃冲裁最大冲裁力的计算公式及其在不同刃口高度与板厚关系时的应用。     

Improving the sheared edge in the blanking of commercial AZ31 sheet through texture modification

Commercial rolled magnesium sheets of alloys AZ31 (Mg–3 mass%Al–1 mass%Zn) and ZE10 (Mg–1 mass% Zn–<1 mass% Rare Earths) in O-temper condition were used for blanking experiments near room temperature. A serrated fracture surface can be observed in case of AZ31 but not in case of ZE10. During the shearing process of the AZ31 sheet, many micro cracks parallel to the sheet plane are generated in the shearing zone. These micro cracks lead to the formation of loose particles during the shearing operation, which interfere with further processing of the part and incur additional costs by increasing the scrap rate.It is found that the strong basal texture of this alloy is an important reason for the generation of such serrated cracks. In this paper a new method of selective texture modification is described to locally change the mechanical properties of the AZ31 sheet. Subsequent shearing experiments show a significant change in the material behavior, especially regarding the direction of crack propagation, which leads to a better shearing performance. The commonly observed serrated crack does not occur any more after this local treatment and the sheared edge is clearly improved.     

Experimental device for tribological measurement aspects in deep drawing process

The purpose of this paper is to improve strip drawing test in order to simulate sheet/tool contact conditions during a stamping operation. An original multi-pass strip drawing test in cylinder/sheet/cylinder contact geometry is presented and we emphasize the influence of certain factors rarely taken into account in the experimental simulation. In particular, we present examples where the bulk plastic deformation and the tools average temperature influence the level of friction and the sheet surface asperities flattening. To try to readjust the friction evolutions with the modifications of surface microgeometry, the tribometer is equipped with various measurements of relative sheet/tool displacement, including or not the stiffness machine and the stiffness of the contact. This was made possible by a potentiometric measurement where the tool plays the part of potentiometer and sheet that of the track, coupled to a measurement using a LVDT sensor.     

多弯曲型材冲裁刀具刃口形状的研究

分析平刃切刀、斜刃切刀、单尖对称切刀和双尖对称切刀4种冲裁刀具冲裁多弯曲型材的工作过程,通过比较冲裁力大小、多弯曲型材所受最大力矩和多弯曲型材变形大小分析冲裁效果,选出最合适的冲裁刀具刃口形状,可减小多弯曲型材冲裁过程中的变形,提高冲裁加工的质量。     

Numerical simulation and optimization of clearance in sheet shearing process

1　INTRODUCTIONThesheetmetalshearingprocessisverycompli catedduetoitsdeformationandfracture .Duringtheprocess,thefiercedeformationandlimitstrainaremuchgreaterbeforefracturethananyotherprocess .So ,uptillnow ,theintricateappearancesduringtheshearingprocesscannotbeexplainedproperly .Withregardtodeformation ,shearingprocessismorecomplicatedthanotherformingprocessessuchasdeepdrawing ,bending ,bulging ,andburring .Inanalysisofformingprocesses ,thepredictionandeval uationofstress ,strain ,veloc…     

基于零件冲裁毛刺高度的冲压模具磨损预测

冲压模具的磨损会引起冲裁间隙的增大,导致零件冲裁毛刺高度的增加。利用DEFORM-2D软件对0.8 mm料厚的CK75弹簧钢板料的冲裁过程进行有限元仿真,分析了冲裁模具的磨损过程,深入研究了冲裁工艺参数对冲裁毛刺高度与模具磨损的影响变化趋势。研究结果表明:在研究的冲裁工艺参数范围内,零件冲裁毛刺的高度随着冲裁间隙与冲裁速度的不断增加而增大,而随着模具刃口圆角半径的增大则表现出先增加后减小的变化规律;冲裁凸模的磨损深度伴随着冲裁间隙的增大而逐渐减小,随着冲裁速度的增加而增大,而随着模具刃口圆角半径的增加表现出先增大后减小的变化规律。此外,借助冲压模具进行冲裁试验,冲裁毛刺高度的仿真值与试验值之间的最大相对误差为17.7%,从而为衡量模具磨损状况提供了一种比较直接的方法。