在将SMT引入科研开发中的作用

简介反修工作台,着重阐述它在将SMT引入科研开发中所起的独特作用（即可不必去配置SMT设备线－指印、贴、焊等设备,也能采用SMT开发新产品）,还探讨其选用中的若干问题。     

手工软钎焊工艺技术(续二)

手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一。主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据。     

BGA返修工艺

表面组装技术(SMT)的应用是电子装联时代的一场革命,随着电子装联的小型化、高密度化的发展,随着无铅焊接工艺的应用,相关的焊接工艺和返修工艺受到了越来越多的挑战.对BGA的种类和封装材料特性做简要说明,重点阐述BGA的返修步骤以及各步骤的具体操作方法.特别介绍了返修工艺中BGA的植球方法以及BGA重整锡球技术的应用.对BGA的返修有针对性地施加一些措施,对相关的返修工艺制程进行改良,寻求一种最佳的工艺方案,有效地抑制缺陷的产生.     

手工软钎焊工艺技术(续完)

手工软钎焊是PCB组装和返修工艺中基本的工艺技术之一.主要针对现场要求、焊接工具选择、工艺参数设定、元件组装焊接及返修拆焊等相关内容,对手工软钎焊工艺技术进行详细阐述,为手工焊接从业者提供重要参考依据.     

Multi-skilled project scheduling with level-dependent rework risk; three multi-objective mechanisms based on cuckoo search

In many projects, multi-skilled workforces are able to perform different tasks with different quality levels. In this paper, a real-life version of the multi-skilled resource constrained project scheduling problem is investigated, in which the reworking risk of each activity depends on the assigned level of multi-skilled workforces. The problem is formulated mathematically as a bi-objective optimization model to minimize total costs of processing the activities and to minimize reworking risks of the activities, concurrently. In order to solve the resulting problem, three cuckoo-search-based multi-objective mechanisms are developed based on non-dominance sorting genetic algorithm, multi-objective particle swarm and multi-objective invasive weeds optimization algorithm. The parameters of the algorithms are tuned using the Taguchi method to improve the efficiency of the solution procedures. Furthermore, a competitive multi-objective invasive weeds optimization algorithm is used to evaluate the performance of the proposed methodologies. Finally, a priority based method is employed to compare the proposed algorithms in terms of different metrics.     

Overlapping design and construction activities and an optimization approach to minimize rework

Construction industry often faces challenge to complete project in minimum possible time. Overlapping design and construction activities with early information from the precedent activities shortens project completion with the expense of rework in downstream design and construction activities. However, the expected amount of rework must be properly quantified to decide on the overlapping strategy. This study presents an integrated framework to overlap design and construction activities using the concepts of upstream evaluation and downstream sensitivity characteristics and develops a simulation model in order to ascertain project performance in terms of total project duration and expected amount of rework. The results indicate that reduction in project duration and expected rework amount vary based on the accuracy of upstream early information and sensitivity of downstream activities. Moreover, unplanned overlapping may not necessarily reduce project duration but may result in excessive design and construction rework which can be very costly. This study also describes a decision-making framework to optimize project schedule with minimal rework. The search for an optimal overlapping strategy is carried out using an Overlapping Strategy Matrix (OSM) with the genetic algorithm (GA) to eliminate unnecessary rework. The proposed optimization method minimizes the expected amount of rework while maintaining the project completion contract date and provides an effective means to decide on the overlapping strategy.     

Lot sizing in a production system with rework and product deterioration

Producing new and recovering defective products often takes place on a common facility, with these activities carried out in lots. Consequently, there is a necessity to coordinate the production and rework activities with respect to the timing of operations and also regarding appropriate lot sizes for both processes while completely satisfying a given demand. Thereby, it has to be taken into account whether the state of defective items may change in the course of time while they wait to be reworked. Such a deterioration of reworkable goods can result in increasing rework time and rework cost per unit. In this paper an EPQ model which addresses all of these aspects is presented. Considering set-up and inventory holding costs as well as set-up times, optimization algorithms are developed covering different planning situations. Closed-form results for optimal lot sizes can be obtained and exploited for new analytical insights into coordinated lot sizing in the case of returns and product deterioration.     

BGA的焊接接收标准与返修

讨论了BGA器件的种类和特性，同时对BGA器件的焊接、验收标准等技术进行了分析，也论述了BGA器件的返修、及其相应的返修工艺。     

印制板焊接试验方法与测试评价

焊接试验方法是考察印制板质量和可靠性的重要方法之一,本文通过对3种具体试验方法的标准介绍和比较,结合实际试验案例进行原因分析,为PCB检验人员正确掌握以上试验方法提供技术指导。