平面冷精压在生产中的应用

针对某些锻件特殊尺寸精度、表面粗糙度要求,选用平面冷精压工艺,依据被精压件具体技术要求和所需设备工况,设计了合理的精压模,并成功进行了批量生产,提高了劳动生产率,降低了生产成本,取得了良好的经济效益。     

在摩擦压力机上精密锻压

精密锻压通常是在专用的精压机上进行,但精压机较贵,一般中小型企业均无这种设备,但大都有摩擦压力机.摩擦压力机能否代替精压机,用来作精密锻压,这是一般中小厂关心的问题.我厂经过对几十种平面精压件和体积精压件的加工,确认,用摩擦压力机完成精压工艺是可以的,而且有很好的经济效益.     

两种新型压力机

最近,两种性能较好的新型压力机在四川内江地区试制成功。现介绍如下。 1.J84—400型4000kN精压机一种通用型精压压力机,用于工作行程小、阻力大的各种冷精压、压印、成形、校平等工艺,精压后的工件精度可达0.05mm,可获较好的表面粗糙度,一般可达Ra3.2μm。     

伺服螺旋精压机控制系统及成型工艺数据库设计

为了有效提高成型设备的工艺适应性并增加其适用范围,提出一种交流伺服螺旋精压机控制系统方案设计,并研发相应控制运动的自定义成形工艺数据库。采用闭环方式实现螺旋精压机控制系统的运动控制,提高控制精确度。建立的通用运动控制自定义工艺模型,能够实现复杂的成形,从而充分发挥伺服螺旋精压的优势。测试应用结果表明,提出的伺服螺旋精压机控制系统运行有效、稳定,具有较好的工艺适应性。     

压脚板扳手精冲工艺分析与数值模拟

对缝纫机压脚板扳手成形工艺进行了分析,在原有模具基础上进行了改进,设计了1副精冲模,经过生产验证,产品满足要求。利用Deformed-2D软件对零件的精冲过程进行了模拟,分析了精冲过程中的应变、损伤及冲裁力变化情况。     

超声滚压强化7075铝合金工件表面性能的研究

目的探究超声滚压强化技术对7075铝合金工件表面性能的影响。方法对7075铝合金棒状试样精车加工后进行了超声滚压强化处理。综合使用粗糙度测量仪、表面显微硬度仪、金相显微镜以及X射线衍射应力分析仪,研究了处理前后工艺参数中的压下量对试样的表面粗糙度、表面显微硬度、表面微观组织及表面残余应力等表面性能的影响。结果超声滚压强化处理后,试样表面粗糙度由0.976μm降低至0.047μm,表面显微硬度由105.6HV0.2提高至119HV0.2,显微硬度提高了15%。精车加工后,精车试样的表层组织与心部组织几乎无变化。超声滚压强化后,相对心部组织而言,表层晶粒组织得到显著细化,表层均为残余压应力,压应力深度为1.75 mm。残余压应力最大值位于最表层,最大为-174.0 MPa,且距离最表层越远,残余压应力总体呈减小趋势。结论通过对比研究精车试样与超声滚压试样,发现超声滚压强化工艺可以大大地降低试样表面粗糙度,显著地细化表层试样晶粒与提高表面硬度,改善残余应力的分布,并引入一定深度的残余压应力。     

金属成形CAD/CAM(四)

五、冷锻(冷挤压) 冷挤压是特种形式的锻造工艺。冷挤压时,常温金属在挤压力作用下塑性变形至各种形状。这些形状通常是轴对称或稍有非对称特征,它与开式模锻不同,这种工艺不产生飞边。从左到右:剪切下料、杯—杆复合挤、正挤压、反挤杯部,同时镦压法兰和精压肩部术语“冷锻”和“冷挤压”常常可交换使用,例如它涉及众所周知的挤压、镦锻或顶锻、精压、变薄拉深和施压等成形工艺。这些工艺通常是在机械压力机或液压机上完成。生产复杂几何形状的零件,需采用几个成形工步,先挤压简单形状,如图1所示。图2所示为冷锻的一些基本工艺过程。     

差速器行星齿轮新工艺及新型模具设计

针对汽车差速器行星齿轮原挤压模具结构存在的问题,改进了挤压工艺,设计了新型预成型挤压模和精压模。工艺试验表明:新工艺可显著降低挤压变形力、材料消耗和生产成本,提高模具寿命和生产效率。     

镀锡板表面白条缺陷原因分析及改进措施

客户在使用首钢镀锡板时发现带钢表面存在白条缺陷,严重影响产品美观和使用,通过对缺陷进行扫描电镜等微观分析、工艺优化及试验跟踪,明确了白条缺陷的根本成因是热轧带钢表面的氧化麻点压入。通过优化钢坯加热工艺、优化精轧高压水除鳞、机架间冷却水和轧辊防剥落水开启制度等改进措施,基本消除了热轧带钢表面氧化麻点压入,有效控制了镀锡板表面白条缺陷的发生,提高了产品质量。     

矩形章精压坯料形状的确定方法

矩形章精压成形的坯料形状一般为非矩形,若坯料几何参数选取不当,加工过程中容易出现图纹填充不足或边部毛刺等问题.本文提出了矩形章精压坯料形状的确定方法,建立了通过反算法获得坯料形状几何参数的数学模型.采用DEFORM-3D软件,由数值模拟获取模型参数进行计算,对精压过程速度分布及变形材料最小距离分布进行分析,确定了合理的矩形章精压坯料的形状尺寸,并由物理试验得到验证.     

加热印压微孔工艺与检测分析

为提高室温印压铜片所得微孔的质量,减少微孔内部裂纹以及获得孔径更小的微孔,提出加热印压的新工艺方法。通过大量印压实验,对影响微孔成形的各因素进行分析与验证,得到最佳的加热印压工艺参数。结果表明：采用加热印压可获得孔径更小的微孔,而且微孔边缘隆起高度有所降低,成形质量更高。     

应用压印工艺控制弯曲回弹

在精密成型中,弯曲后的回弹是造成工件尺寸、位置和形状精度不合格的主要原因之一。在内圆角处施加压印是广泛应用在精密级进模中控制回弹的一种有效方法。针对某一特定产品,通过数值模拟的方法探讨了压印工艺中的两个重要参数(压印深度和压印宽度)对回弹的影响,并分析了其原因。     

A critical review of the current end-coining practices for container end closures

A finished two-piece drawn and ironed aluminum can is composed of a bottom, sidewall, neck, flange, and applied end. Each requires attention to detail and each has proponents for particular methods of manufacture. A recent program developed at Alcoa for lightweighting of cans in a cost-effective manner leads to the present research effort. This effort is aimed at increasing the fundamental understanding of end-coining processes and in developing a stronger and lighter can end. This article provides a critical review of the current coining practices used for container end enclosures. A significant number of patents were studied, but only those that were relevant to this work are summarized in the present article. It was found that the classical definition of coining has been loosely used in the can industry and is misinterpreted at times. Therefore, a new terminology has been given to coining of ends, namely,end-coining. The termend-coining is used to describe any restriking operation which improves the strength or slightly modifies the geometry of the can end closures. The word “end” refers to a container (beer/beverage/food can) lid.     

长筒形件侧壁滚字模设计

介绍了一种长筒形件侧壁立式、浮动滚字模通用结构，叙述了模具设计时应注意的问题。     

Numerical and experimental analysis of electric conductive heating for micro warm coining of stainless steel

The aim of this study was to investigate the electric conductive heating of stainless steel, which is the initial step in the research of micro warm coining of high strength metals. This paper presents the numerical and experimental analysis of the electric conductive heating under variation of heating time, electric current and heating atmosphere. The material used was stainless steel X5CrNiMo17-12-2 (1.4401). The geometry of the samples was 100 × 50 mm² with an initial thickness of 1 mm. A 3D coupled thermal-electrical model in Abaqus/Standard was used to help analyzing the heating process. The results of FEM simulation show that using 1,600 A electric current within 5 s conductive heating could give a uniform temperature distribution area of 20 mm × 20 mm as the micro warm coining zone at a temperature around 900°C. The simulation was confirmed by experimental results showing a similar temperature distribution, heating rate and cooling rate. Heating under vacuum increased the maximum temperature slightly as compared to heating under argon or air during the electric conductive heating. Closed die micro warm coining with integrated electric conductive heating of stainless steel has been successfully realized.     

A multi-region model for numerical simulation of micro bulk forming

Due to the small billet size in micro forming, each grain, especially that on the surface layer, has direct influence on the deformation behavior of the billet. The multi-region model was proposed for simulating the micro bulk forming process in this paper. The object in the model is divided into three different regions: the inner polycrystal region, the grain interior of the surface region and the grain-boundary layer in the surface region. Each surface grain has different orientation. Depending on the Hall-Petch formula, which is applicable to describe polycrystal materials, and introducing scale parameters, the constitutive equation of each region is deduced based on the unidirectional compression tests data of the copper specimen. Using the multi-region model, the coining process with micro feature is simulated to investigate the size effect in micro forming. Moreover, an experiment of coining process with micro-feature is performed to verify the correctness of the multi-region simulation model. The experimental results show a good agreement with those in numerical simulation.     

交流伺服螺旋精压机控制系统的研究

介绍了交流伺服螺旋精压机的机械结构及工作原理,并对其控制系统进行了研究和分析,提出了控制系统的三种设计方案,最后进行了控制方案的比较和选择.     

Computer aided analysis of screw press dynamics

Dynamic mechanical and mathematical models for screw press and plastic-working processes of die forging and coining were developed, verified with experimental observations and used for analysis of screw press dynamics. Some results helped to optimise nut design elements of a screw-working mechanism.