Thermal investigation of an infrared reflow oven with a convection fan

A two-dimensional numerical model for an infrared reflow soldering with a convection fan is used my modifying the Eftychiou’s numerical modeling. The two-dimensional tunnel model which predicts convective conditions within the reflow oven are solved using the finite volume method with the SIMPLER algorithm. The card model solves the transient two-dimensional heat conduction equation in conjunction with a radiative heat transfer analysis. We also performed an experiment to validate the numerical modeling. The numerical result shows excellent agreement with experimental data. Based on the capability of this model, parametric simulations are performed to determine the thermal response of the solder to variations in the oven operating conditions and heat transfer conditions. This study shows that radiation and conveyor velocity are important factors in the preheat region.     

回流焊的工艺特点及研究

本文详细介绍了回流焊的特点,并对典型的回流焊工艺过程及参数进行了相关研究,分析了回流焊过程中的典型问题,具有很高实用价值。     

无磁钎焊炉的制作

无感应磁场加热是无磁钎焊炉的突出优点。制作的三段双线并绕无交变磁场钎焊可以保证管壳与管芯焊接时不产生移位，且良好的温控特性。     

印制电路板的波峰焊接

本文较系统地介绍了印制电路板波峰焊接的焊前处理,焊接材料的选用与配制,焊接设备的设计与改进,焊接工艺规范参数的选择与调整。     

Random failures not allowed here—the u.s. roland case history

When U.S. ROLAND production hardware was first assembled, the resulting reliability was far below the requirement. Rather than rationalizing the failures as ‘random’, each was pursued to correct the cause in design, manufacturing processes, or workmanship. A process and quality plan was implemented with improvements to such items as soldering techniques and circuit-board fabrication. Many design improvements were also incorporated. The test programme was halted and replanned to benefit from an iterative test-fix-test process. The final result was an increase in the reliability to 3.6 times the contract MTBF.     

再流焊常见缺陷的成因及解决办法

对采用表面贴装技术生产的印制电路组件在再流焊接中出现的桥接、焊料球、立碑等焊接缺陷进行了分析，并提出了一些有效的解决办法。     

从焊点形成机理 谈焊接质量控制

从焊点形成机理着和探讨焊接质量控制措施，以便快速准确地分析处理生产过程中出现的焊接质量问题。     

焊锡渣双金属电解

根据双金属电解原理，对所回收的焊锡渣经硅氟酸盐双金属电解精炼，可得到锡—铅合金，不仅为焊料的生产提供了优良的锡—铅合金原料，而且能获得较好的经济效益。     

Bi-Pb-Sn-Cd易熔合金的设计与性能研究

根据铋基合金的特点与合金相图,设计了不同成分的Bi Pb Sn Cd易熔合金;并利用差热分析仪、X射线衍射仪及力学检测设备等研究了成分对合金熔点、组织和抗拉强度的影响。结果表明,设计的易熔合金由Bi、Pb7Bi3、Sn和Cd等物相组成;合金的熔点均在72℃左右。随Cd、Bi元素含量的增加,液相线温度逐渐降低;Cd元素对合金熔程、抗拉强度的影响最大,Sn元素次之,Pb元素的影响最小。正交试验表明,Bi 30Pb 15Sn 9Cd合金的综合性能最佳。     

一种不锈钢过滤毡钎焊方法

针对不锈钢过滤毡元件难以用熔化焊方法焊接的问题,使用钎焊方法焊接不锈钢过滤毡。主要针对在不同加热温度和加热时间的综合作用下不锈钢过滤毡的氧化程度、软钎料和硬钎料对不锈钢过滤毡的润湿性、以及不锈钢过滤毡的软钎焊接头和硬钎焊接头的剪切强度等方面进行研究,并在生产上得到应用。结果表明,钎焊是一种焊接不锈钢过滤毡的有效方法,工艺可靠、工装简单,而且成本低、效率高,适合多种工况条件下不锈钢过滤毡的连接。