基于Sagnac干涉的光纤对冲床脉动电流计量技术的研究

基于Sagnac干涉原理的全光纤光电互感器具有响应特性好、精度高、安全性好的特性,是解决脉动电流测量的新技术之一。以J21-40T普通冲床为研究对象,应用光波的偏振性和法拉第磁光效应理论,探究了全光纤光电互感器测量冲床脉动电流的工作机理。通过对Sagnac调制技术的全面分析,设计了系统框图。借助测量数据,阐述了测量重复性、温度变化、1／4波片、Verdet常数误差。研究结果表明：这一技术可以普遍用于冲床脉动电流的准确测量,是一种有效的大电流计量技术。     

LED TV铝基板外形加工冲压板面裂纹问题的分析和改善

对LED TV铝基板外形加工冲压板面裂纹问题进行了分析,主要讲述了问题形成的要素和原因,并提出了相对应的改善措施。     

Exact solution of a flat smooth punch on a piezoelectric half plane

This paper derives an exact solution for a flat smooth punch applied on a piezoelectric half plane. The piezoelectric solid occupies the lower half plane, and a flat rigid punch is applied on it. As the permittivity of the air (environment) is far less than that of the piezoelectric material, the electric induction of air may be neglected. The permittivity of the punch is also far less than that of the piezoelectric material and consequently the normal component of the electric displacement vanishes at the contact boundary. The exact solution is obtained by eigen-function representation and analytic continuation. The distribution of pressure under the punch has been found. The electric field along the surface of the lower half plane is extracted in a closed form.     

Deep punching PMMA

The authors performed deep punching experiments on PMMA (polymethyl methacrylate) using cylindrical-shaped punches with conical and hemispherical noses. The test samples cracked when no lateral confinement was provided. Application of proper lateral confinement suppressed the cracks. The punching force recorded from the experiments correlates very well with cavity expansion theory. Because the use of a single friction coefficient gives excellent agreement between theory and experiments for two different-shaped punches, the authors propose deep punching as a new technique to measure the friction coefficient.     

从IC封装产品可靠性谈封装冲切模具优化设计

随着电子产品市场日益升温,电子产品朝超薄、超小等方向发展,产品量的需求越来越大,产品可靠性越来越高,塑料封装模具的冲切工艺产生的分层现象是影响产品可靠性的主要原因之一。文章首先叙述了冲切过程产生的分层情况,其次从模具结构方面说明冲切产生分层的原因,并针对产生分层的原因提出冲切模具的优化设计,最后总结从实际生产过程中防分层要求设计冲切模具和框架,可避免在实际生产过程中IC胶体分层导致产品可靠性问题。     

一种刚-挠结合板的制作工艺简介(半冲开盖)

概述了刚-挠结合板的一种制作工艺(半冲开盖),主要内容包括其制作原理、设计要点、制作问题等。     

Experimental analysis of contact for the indentation of a flat rounded punch

The ‘plane vs. plane’ contact involving flat punches has been the subject of many investigations, even in recent years, mainly due to the crucial role that such components play in phenomena, such as fretting fatigue and indentation tests. While the problem has been deeply approached from a theoretical point of view, there is a noteworthy lack of experimental verifications due to the limited number of laboratory techniques capable of supplying detailed information about contact parameters. In order to make a partial contribution towards gaining an understanding of such problems, this study proposes the investigation of flat rounded punch contact with an ultrasound-based technique, which exploits the properties of ultrasonic waves to be differently reflected by a contact interface depending on its stress state. A suitable setup was built in such a way as to ensure a good level of control of contact conditions, and the interface was scanned with a high-frequency ultrasonic transducer so as to acquire the reflection data. While the graphic processing of the ultrasonic coefficient of reflection may easily be displayed as a ‘contact map’, the quantitative accuracy of the method was also investigated by comparing experimental results with those obtained from a Finite Element model of the system. The results show a good level of agreement between the two approaches, thus confirming that the ultrasonic technique can be effectively employed to investigate many contact problems which to date have never (or scarcely) been experimentally validated.     

一种用于冲床的压力测试系统设计

冲床的输出主要依靠设定平衡器来实现,为了克服传统冲床调试过程中主要依赖技术人员进行理论值估算或者经验进行调节平衡器的输出而存在估算误差大的弊端和局限性,为此设计了一种用于冲床调试的高精度压力测试系统方案。系统中自行设计了由轮辐式应变片来构成的压力传感器,该压力传感器的结构设计可有效消除环境温度等对系统的影响,采用STM32F051芯片为核心构成压力测试数据的处理模块。该压力测试系统的压力测试范围为0Kg-2000Kg,阈值可以灵活设定,测试系统的线性度约为1.3%,分辨率为1Kg。该压力测试系统经实际测试表明：具有成本低、性能稳定,抗干扰能力强等优点,可用于各类低速冲床的压力数据采集和处理。     

铝基板钻孔披锋改善研讨

通过用模冲冲针，改善铝基板钻孔披锋。     

Singular integral equation method for contact problem for rigidly connected punches on elastic half-plane

In the contact problem of a rigid flat-ended punch on an elastic half-plane, the contact stress under punch is studied. The angle distribution for the stress components in the elastic medium under punch is achieved in an explicit form. From obtained singular stress distribution, the punch singular stress factor (abbreviated as PSSF) is defined. A fundamental solution for the multiple flat punch problems on the elastic half-plane is investigated where the punches are disconnected and the forces applied on the punches are arbitrary. The singular integral equation method is suggested to obtain the fundamental solution. Further, the contact problem for rigidly connected punches on an elastic half-plane is considered. The solution for this problem can be considered as a superposition of many particular fundamental solutions. The resultant forces on punches are the undetermined unknowns in the problem, which can be evaluated by the condition of relative descent between punches. Finally, the resultant forces on punches can be determined, and the PSSFs at the corner points can be evaluated. Numerical examples are given.