天花灯金属外罩模具设计

分析了天花灯金属外罩的结构和冲压工艺。首先,设计级进模具,生产天花灯金属外罩的成形部分,并详细介绍了该级进模具的料带图,对该级进模具中的撕裂工序模进行了分析,在撕裂工序模的凹模上开两条槽,以防止工序料与条料完全断开;然后,设计弯边模,对级进模具生产的半成品口部材料进行弯边。在弯边模的下模中,设计了4个滑块和4个斜顶,先用滑块将产品口部材料向内弯边,再用斜顶将弯边后的产品从下模的定位型芯中顶出。最后,设计了两套卷边模,第1套是预卷边模,对弯边后的产品初步卷边;第2套是成形卷边模。在天花灯金属外罩模具中,弯边模是关键模具。     

基于S型皮卡纵梁起皱扭曲回弹的工艺优化及模具设计

重点围绕S型皮卡纵梁的起皱、扭曲、回弹难点,进行前期制件分析,并结合冲压CAE仿真分析,从材料优化、采用压料翻边一次成形、压料翻边空开设计、过弯成形、采用合理的成形凸凹模间隙以及设计弹性感应检测器和浮料顶升6个方面进行解决。研究结果表明：采用压料翻边一次成形工艺可以很好地控制成形过程中的材料流动,产品不再起皱和扭曲。同时采取过弯成形,可减少成形过程中的回弹量。在模具设计方面,对压边进行空开设计可避免顶坏产品;设计合理的凸凹模间隙不仅可以提高镶块的使用寿命,也可对产品回弹做进一步控制。该工艺实践结果良好,满足预期要求,不仅提高了产品质量,也降低了生产成本。     

基于“水滴”造型积料补偿机制的天窗翻边工艺再设计

针对汽车顶盖天窗的翻边成形工艺普遍存在的产品面变形问题,分析面缺陷产生的原因;依据变形程度与产生区域将缺陷分为两类。基于补偿原理,通过模面预处理设计一种解决天窗非翻边面变形的优化方案,即"水滴"造型与弧形凸起补偿两类局部特殊结构,有效的解决了局部欠料、局部积料和局部补料的工艺难题。利用有限元数值建模分析及生产现场验证,翻边区域最大减薄率降低到4%,面缺陷完全消除。优化后顶盖的产品面与天窗的翻边面均符合产品质量精度要求。     

车身制件翻边整形模设计研究

对翻边整形模结构进行了分类,阐述了其压料板行程、压料力及压力源设定原则,基于实例探讨了翻边整形模典型结构工作原理及设计要点。结果表明:依据压料板使用情形的不同,翻边整形模结构有下压料板式、上压料板式及双压料板式等3种类型,分别适用于向上、向下及双向翻边整形工序。     

双凸缘边Ⅱ形筒零件切边模设计

1 引言 图1所示零件是我厂生产的某产品上所用重要联接零件,由于其壁厚较薄,且生产批量大,为此我们编制了一套冲压加工生产工艺,主要工序有:落料拉伸→二次拉伸→切边(大凸缘边)→切底→一次翻边(小凸缘边)→二次翻边(小凸缘边)→切边(小凸缘边)→整形→去毛刺→成品检验.     

汽车零件翻边压弯过程失效分析与解决方案

为解决翻边压弯过程中的失效问题,通过对翻边压弯过程中零件翻边局部的线长变化和变形受力情况的分析,研究了翻边压弯过程中弧长变化的关联因素,指出挤料和开裂缺陷产生的原因是零件局部多料或少料。优化零件的结构和成形尺寸以及分步成形使材料均匀变形是解决零件局部多料、少料的有效方案。在产品设计、制定工艺方案和模具结构设计时,需合理选择和正确运用挤料和开裂的解决方案(或几个方案组合使用)。     

汽车后安全带固定座冲压模拟及模具设计

分析计算了汽车后安全带固定座的冲压工艺,确定了落料冲孔翻边复合模冲压方案。利用DYNAFORM软件得到了制件翻边前的落料形状并模拟了制件翻边成形过程,验证了落料冲孔翻边复合模冲压加工的可行性。设计了1副落料冲孔翻边复合模,并阐述了模具结构、工作过程及设计制造要点。生产实践表明,该模具能够一次完成落料、冲孔、翻边工序,操作方便可靠,保证了制件的形状和精度。     

螺纹用变薄翻边孔的几何尺寸及凸模形状尺寸

<正> 电器产品中广泛使用翻边螺纹孔,它是将板料上预先冲好的孔进行变薄翻边形成一定高度的凸缘,以增加薄料在螺纹部分的高度,增加螺纹牙数,有利于产品零件的紧固性能,在达到同样螺纹牙数的情况下,可节省材料,减轻零件重量。 目前虽有一些有关变薄翻边孔的几何尺寸参考资料,但介绍的数据不一致,使产品     

端盖落料拉深冲孔翻边局部成形复合模设计

分析了端盖的冲压工艺,设计了落料—拉深—冲孔—翻边—局部成形复合模,详细阐述了模具结构、工作过程及设计技巧。实践表明,模具能实现一次完成落料、冲孔、拉深、翻边、局部胀形工序,保证了产品的形状和尺寸精度。     

筒套的冲压工艺方案选择及模具设计

针对筒套的结构特点及生产加工批量，对其各种冲压加工工艺方案进行了对比、分析，通过采用管料扩口和翻边复合加工工艺，同时设计出相应的扩口——翻边复合模，一次性顺利地实现了该零件经济、合理的加工，加工的零件满足产品要求。     

冷弯中梁成型过程数值模拟研究

对大型外卷边槽钢产品冷弯中梁的辊弯成型过程进行了三维弹塑性有限元模拟,详细的分析了成型过程当中的变形情况、应力分布情况、应变分布情况,并与现场情况进行了比较,趋势吻合较好,验证了模型的准确性,为成型相关产品的过程提供了理论基础。     

金相组织和夹杂物对40Cr边部裂纹形成的影响

针对永洋特钢集团公司40Cr轧材边部裂纹的成因和影响因素进行系统调查研究,通过一系列取样、检验和分析发现,某纵裂纹内含有与钢渣反应产物、结晶器保护渣类似的残存物,结合160 mm×225 mm 铸坯热轧工艺过程,最终得出该钢种产生裂纹的主要原因是由于脆性夹杂物较多、铸坯表面粘渣或有细小裂纹,以及加热过程脱碳严重、轧制变形制度不合理。     

压缩机上外罩制作的工艺实施

为了制作合格的上外罩零件,对其结构、成形工艺难点和工序内容进行了分析,确定了落料拉深、冲凸台、车边、冲孔、整形、压印等8道制作工序。结合冲压模具设计的知识和经验,设计了1副复合模和各单工序模,并对每1道制作工序和各模具工作过程进行了详细的阐述。为了保证车边工序的质量,设计了1副车边夹具,并对夹具的工作原理进行了详细说明。经批量生产证明:上外罩零件的制作工艺、成形方法和工序顺序符合零件的结构特点;所生产的产品完全符合图纸要求,且质量稳定,不良品率低;模具的结构紧凑、操作方便、制造成本低、可互换性好;车边夹具操作简便、工件拆装快捷、夹紧力可调,解决了薄壁类零件装夹的难题,为结构类似的零件的生产提供了借鉴与依据。     

Clean-sheared and rectangular edges through counter-shaving

A various number of products exist which require a clean-sheared edge due to function or surface feel. Traditionally, these parts are produced on fine blanking presses with three separate and distinct movements. Shaving, in particular counter-shaving is a shearing operation to improve the edge quality of a blanked part or punched hole. This paper introduces a progressive die tool to realize the counter-shaving process on a single acting press. Advancing the chip flow through choosing a cutter angle can achieve up to a 85% clean-sheared edge and rectangular edge. Thereby, a sharp-edged transition—without any rollover depth—between the upper surface of the sheet metal and the sheared-edge are formed. The end of the clean-sheared edge is followed by a tear which shapes a burr in the form of a triangular lappet, which can be deburred in a subsequent vibratory grinding process. Experimental results of different process parameters for two sheet metal materials at three thicknesses are discussed and compared to finite element calculations. The presented research work was supported by the German Research Foundation (DFG).     

方坯轧制在线感应加热数值模拟与设计优化

针对方坯感应加热轧制过程容易发生边角升温不均匀的问题,建立了轧件移动式感应加热工况的电磁-传热耦合模型,并进行了有限元数值模拟分析。基于感应加热轧制工业运行数据,验证了模型的合理性,并对感应线圈设计进行了结构优化改进。结果表明,改进设计的感应线圈在钢坯边角部位的磁通密度分布得以明显地改善,工件边角部位的温差得以显著地降低,这有利于解决合金钢方坯轧制过程中常见的边角开裂问题。     

Product quality prognosis in plastic injection moulding

Plastic injection moulding is a typical complex manufacturing process. Its product quality is difficult to assure because of the nonuniform material shrinkage. This research introduces a prognostic concept for predicting the product quality (four edge shrinkages). The prognostic model is developed by path analysis through LISREL which can define the model’s reliability when only few sensory data are retrieved from the smoothly running system. The prognostic model is validated by 25 test runs. In each run, each of the nine manufacturing conditions is randomly set at the extreme limit, i.e., either the lower limit or the upper limit. By comparing the actual edge shrinkages defined by the finite element software Moldflow with the results predicted by the prognostic model, this research concludes the prognostic model can successfully predict the quality of products and prevent the production of defective products.     

细长端子多工位级进模设计

分析了细长端子的成形工艺.介绍了冲压零件的排样设计及凸模刃口外形的分割方式.针对细长端子针脚偏摆、跳屑等成形缺陷,给出了解决方案,可为细长端子类模具设计提供参考.     

Influence of the cutting edge rounding on the chip formation process: Part 1. Investigation of material flow, process forces, and cutting temperature

In order to meet the ever-increasing demand for high quality and low cost products, machining processes with geometrically defined cutting edges such as high speed cutting, or hard turning are being used. Due to the fact that cutting is accomplished through a physical interaction between the cutting edge and the workpiece, the characteristics of the cutting edge itself play a key role in influencing the machining process, which determines the product quality and the tool life. As a result, cutting edge design has attracted the focus of many researchers, and crucial improvements have been achieved. Rounded cutting edges have been found to improve the tool life, and the product quality. However, to better understand the impact of prepared cutting edges on the aspects of the machining processes, and to produce tailored cutting edges for specific load profiles, further investigation on the influence of the cutting edge design on the machining processes needs to be carried out. In this study, the effect of symmetrically and asymmetrically rounded cutting edge on the material in the vicinity of the cutting edge has been investigated using finite element simulation techniques. The results obtained from this investigation show that process forces and material flow under the flank face are mainly influenced by the micro-geometry S_??. However, the magnitude and the location of maximum nodal temperature are influenced by S_?? as well as S_??.     

不锈钢厨刀锋利度和耐用度影响因素分析

为全面分析不锈钢厨刀锋利度和耐用度的影响因素,对不同品牌的不锈钢厨刀进行硬度、锋利度、耐用度、刀包角、刃口厚度、材质及微观组织检测。结果分析表明：1)厨刀的硬度对锋利度及耐用度影响不大。但当刀片硬度位于(55～57)HRC区间时,产品的锋利度及耐用度较高;2)刀包角对厨刀锋利度和耐用度有较大影响,对耐用度的影响比锋利度更大;3)当刃口厚度小于0.46 mm时,随着刃口厚度的逐渐增大,锋利度及耐用度无明显的变化趋势;当刃口厚度大于0.46 mm时,厨刀的锋利度及耐用度迅速降低;4)在材料相同、刀包角和刃口厚度很接近的情况下,厨刀微观组织中的回火马氏体组织形态及分布、残余奥氏体含量及碳化物的形态和数量对最终产品的锋利度和耐用度影响很大。     

Investigation of machine vision assisted automatic resharpening process of micro-drills

The micro-drill used in electronic industry is getting smaller in diameter especially for printed circuit board/ball grid array processing; making it is easier to have many defective drills produced in manufacturing process. Defective drills can be resharpened to become conforming products. Focusing on the planar micro-drills less than 0.5 mm in diameter, the paper proposes using machine vision technique to assist the double-wheel grinding mechanism of moving-drill and fixed wheel to achieve resharpening function. First, we find and adjust the posture of micro-drill from vision system for grinding, then detect the line equation of cutting edge of primary facet grinded micro-drill and rotate cutting edge to be horizontal; final we grind the secondary facet of micro-drill. All grinding parameters for resharpening process are found automatically with machine vision technology. As known from the experimental results, the automatic resharpening method proposed by this paper is feasible.