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Rework is an integral part of printed circuit board assembly (PCBA) manufacturing. However, the state‐of‐the‐art for PCBA rework still relies on operator activity and is therefore semi‐automatic. As a result, the quality of rework depends very much on the skill of the operator. When developing an automatic PCBA rework cell, the cell controller is an essential part which organises and controls the overall rework operation. This paper describes the software modelling of the cell controller for the PCBA rework cell which has been implemented for reworking through‐hole and surface mounted components. The software model is based on hybrid representations and rule‐based control.

Although rework is labour intensive and conflicts with most modern manufacturing/assembly philosophies, realistic defect levels in surface mount technology (SMT) printed circuit board (PCB) assembly render rework indispensable on the shop floor. Most commercially available rework tools are manual or require very skilled operators for their efficient operation. The challenges of automating SMD rework are significant because the tools, their specifications and rework processes required are not fully understood, and the impact of rework processes on assembly quality and reliability are hotly debated. This paper describes an automated robotic rework cell for SMD and TH boards, and the method used for process characterisation of the solder paste dispensing system. The paper also describes equipment selection, the integration and interfacing of the dispensing equipment to the cell controller and the process characterisation experiments.

The purpose of this paper is to investigate effects of the multiple rework of ball grid array (BGA) components on mechanical strength of BGA balls, as well as any possible intermetallic (IMC) embrittlement, and obtain data correlated with possible estimation on the maximum permitted limits of BGA rework.

In this paper, mechanical strength of BGA components assemblies with multiple numbers of rework operations was evaluated. Mechanical evaluation was conducted using BGA ball shear tests and four‐point bending tests of BGA assemblies. Test samples were prepared under the following conditions: virgin, one, two, three and five BGA reworks. Failure mechanism was evaluated using cross‐section and SEM analysis.

The results show that both ball shearing tests and four‐point bending tests indicates that strength of BGA solder ball itself was not reduced significantly after repair/rework operation from one to five cycles. The IMC structure layer after rework is a mixture of IMC, Sn‐rich and Pb‐rich phases. This mixture layers with thickness even more than 10 μm in thickness does not show reduction of strength of BGA solder balls and do not cause premature embrittlement. However, the bonding strength of the copper pads to the laminates is reduced with rework/repair operation, with the great reduction coming from the first and second rework operation.

In general, the industry recommends two rework cycles for BGA components on the same spot. This study indicates that further rework (up to five) causes little degradation, therefore there is room to increase the total rework cycle limit beyond recommended two for plastic BGA components.

Presented test results shows that in most cases industry overestimates risks associated with increased embritlement of the BGA solder joints due to the intermetallics growth after multiple BGA rework operations. Strength reduction of BGA assemblies is mostly associated with reduction of bonding strength of the copper pads to the laminates is reduced with rework/repair operation and number of reworks could be increased in most cases.

A survey of rework practices of the UK electronics assembly industry has been undertaken. Rework of electronics components in the UK was found to be dominated by the use of soldering irons. Many companies did not control tip temperatures, rework times, background heating or the number of rework operations which could be undertaken on any one component. Few companies followed the recommendations of the component manufacturers aimed at preventing damage to thermally sensitive components. It was found that those companies which did control rework temperatures, did reduce rework temperatures for surface mount components. In general, rework temperatures were much higher than those recommended by the component manufacturers. A great deal of cleaning was undertaken after rework, with most companies doing some form of local cleaning. Most companies reused components even if only on an occasional basis.

Managing project completion within the stipulated time is significant to all firms' sustainability. Especially for software start-up firms, it is of utmost importance. For any schedule variation, these firms must spend 25 to 40 percent of the development cost reworking quality defects. Significantly, the existing literature does not support defect rework opportunities under quality aspects among Indian IT start-ups. The present study aims to fill this niche by proposing a unique mathematical model of the defect rework aligned with the Six Sigma quality approach.

An optimization model was formulated, comprising the two objectives: rework “time” and rework “cost.” A case study was developed in relevance, and for the model solution, we used MATLAB and an elitist, Nondominated Sorting Genetic Algorithm (NSGA-II).

The output of the proposed approach reduced the “time” by 31 percent at a minimum “cost”. The derived “Pareto Optimal” front can be used to estimate the “cost” for a pre-determined rework “time” and vice versa, thus adding value to the existing literature.

This work has deployed a decision tree for defect prediction, but it is often criticized for overfitting. This is one of the limitations of this paper. Apart from this, comparing the predicted defect count with other prediction models hasn’t been attempted. NSGA-II has been applied to solve the optimization problem; however, the optimal results obtained have yet to be compared with other algorithms. Further study is envisaged.

The Pareto front provides an effective visual aid for managers to compare multiple strategies to decide the best possible rework “cost” and “time” for their projects. It is beneficial for cost-sensitive start-ups to estimate the rework “cost” and “time” to negotiate with their customers effectively.

This paper proposes a novel quality management framework under the Six Sigma approach, which integrates optimization of critical metrics. As part of this study, a unique mathematical model of the software defect rework process was developed (combined with the proposed framework) to obtain the optimal solution for the perennial problem of schedule slippage in the rework process of software development.

The general objective of this research was to identify the practices of the mass production industries, on the decisions related to the detection of defective products and to identify relevant criteria, actions, effects and variables to be used in a decision-making model.

A survey questionnaire was developed and structured in 20 questions, with 18 closed questions and 2 open questions. The questions were constructed based on the literature review, with the identification of 15 theoretical and practical concepts of quality. Seven other information requests were included, concerning the initial characterization of the defective items and industry. The company, the product, the processes and the defects were contextualized, and then the decision-making process was framed, to understand the factors that influenced it.

The industries of the Industrial Pole of Manaus discard or rework their defective products influenced by promoting the lowest cost and the required quality. The factors with the biggest influence on decisions are rework and disposal costs, and time available for rework and replacement. The main requirements defined for the decision-making model were: 1) compare the rework and discard options, only if the rework reaches the required quality level; and 2) identify and account the effects of defective items on quality, productivity and costs.

Overall, 109 questionnaires were sent, representing 21.3% (109/512) of the companies at the Industrial Pole of Manaus. The respondents represent 14.6% (75/512) of the population.

Defects can occur, requiring a decision that promotes the lowest cost and the required quality. Quality cost models do not show a systematic analysis for identification, accounting, evaluation of effects and criteria associated with the destination of manufactured defective items. Therefore this research was done to fill this gap.

The purpose of this paper is to study the effect of rework operations on the shopfloor control’s strategies, including order release and dispatching. An attempt is made to determine the performance of various production control strategies on the system performance indicators under different levels of rework rate. Also the interaction of order release and dispatching strategies under different rework operations is investigated. Some representative shopfloor control (SFC) strategies are considered in our simulation model. It was found that the effect of rework operation on the system performance is significant. The order release and dispatching strategies’ performance is affected by the rework operation. The performance is improved dramatically if a suitable combination of order release and dispatching strategies is adopted. Under different rework rates and performance indicators a suitable combination of SFC strategies is suggested in this paper.

Australian construction organisations have generally refrained from implementing quality management principles. As a result, little is known about the costs of poor quality and the impact it has on an organisation’s performance and competitiveness. With respect to rework, it is suggested that most organisations have learnt to accept it as part of their operations, inasmuch as they have not realised its true extent or its influence on their own and a project’s performance. This paper uses a case study approach to develop a series of benchmark metrics for the causes and costs of rework, which were derived from two construction projects that were procured by the same contractor using different procurement methods. From the findings a conceptual model for benchmarking and reducing rework throughout the quality‐chain is presented and discussed.

The purpose of this paper was to assess the magnitude of the impact of construction-related rework on selected project budgets and schedule in public building construction in Uganda. The magnitude of construction-related rework was the mean determined over construction contracts under a selected project and expressed as a percentage of the construction contract sum.

A single case multi-unit study approach was adopted. A case study protocol was prepared that included a checklist, observation schedules and an interview guide. The three instruments were used to collect data from building contractors and end-users (the teaching staff and medical assistants). Representatives of the client entity and the end-users provided sufficient project documentation and related supplementary information for the study.

Construction-related rework was predominantly attributable to design information omissions, unacceptable workmanship and inadequate supervision of the contractor. Lightning conductor, electrical and roofing installations were the building elements that had the highest frequency of rework. It was further determined that the mean percentage of rework related impact on project budget and schedule was approximately 4.53 and 8.42 per cent, respectively.

The findings inform policy makers about likely areas that contribute to significant wastage and value loss in quality management of public sector projects. The research advocates for improved data collection protocols, integration of adequate design management and a whole life value philosophy during the public building construction process.

In the assembly process of high reliability printed wiring boards (PWBs), rework cycles seem to be an unfortunate fact of life. The question repeatedly arises as to how many times a solder joint incorporating plated‐through‐holes (PTHs) can be reworked without degrading the configuration. By performing a controlled experiment, the authors were able to answer that question and make recommendations as to the limits that should be placed on the number of reworks. They were further able to look at the following factors: operators, board type, number of layers and solder temperature to determine which were the most significant in determining limits to the number of rework cycles. The results showed that the more layers the board contained, the more at risk the PTH was to rework‐induced defects. This perhaps defies conventional wisdom that the board type or temperatures were the driving contributors. The increased number of board layers corresponds to thinner dielectric layers. The experimental results were repeated in a theoretical review using a finite element analysis (FEA) model that was developed showing the thermally induced stresses in the solder joint and PTH region. For multilayer boards, it is recommended that rework be limited to three cycles. The present work shows that there is evidence of degradation by the fifth cycle on boards with thinner dielectric (10‐layer board, dielectric thickness 0.008 in.). By limiting the number of reworks, the risk of inducing failure mechanisms into PWAs (printed wiring assemblies) is dramatically reduced.