Search results

The introduction of surface mount technology has changed the approach which is needed for successful rework of components. This has been brought about by the requirement of simultaneous reflow of all joints to remove the component from the board. To meet this need, manual soldering methods have been adapted, and subsequently complemented, with dedicated hot bar, hot gas and infra‐red systems. Each of these techniques with their respective applicability is considered, prior to a discussion of the parameters which need to be addressed before embarking on successful rework. All aspects of component, board and the joint itself are considered. The procedure for addressing rework is then laid out, providing a standard methodology to obtain rework joints which maintain the quality of the production joints.

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 popular reflow day was repeated at Henley and commenced with Mike Judd giving an overview of current reflow techniques.

Effective control of the rework process for surface mount production rework or for field repair requires a knowledge of the process variables involved in the rework system and of the interaction between them. This paper presents the method by which a test was constructed for one particular system to characterise that system's thermal performance. The system tested is described. Process variables for that system are identified and classified as operator, set‐up and use variables. A description of the test board and instrumentation is provided, and the test method is presented. Results of the testing are presented along with a sensitivity analysis for the most critical process variables. Although performed on one particular system, the testing shows a method which can be followed for any system and, even simpler, rework and repair tools.

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.

Despite continuous efforts in improving process reliability in printed‐circuit board assembly (PCBA), a zero‐defect situation is difficult to achieve because of the complexity of the process and the multitude of components involved. PCBA rework is necessary in many companies due to economic as well as commercial reasons. Presents the intermediate results of a research programme aimed to investigate the technical and economic feasibility of extending the use of a robotic assembly cell to perform single‐board rework. Outlines various manual rework practices and the equipment available. Examines the role of industrial robots and machine vision in PCBA and defines the objectives and overall boundary of the research programme in automatic rework. Describes individual equipment selected to assist the robot, the layout and the manner in which it is used in the cell. Concludes with the development of the cell controller and the methods of equipment integration.

It made a pleasant change to travel a mere 15 miles from base to report on the above two‐day event held at The Hospitality Inn, Irvine. Bypassing Troon en route, and glimpsing the vast marquees and stands erected in preparation for the British Open, there was a sense of relief at escaping the inevitable traffic snarl‐ups predicted for the following week when the international golfing fraternity would invade this normally sleepy, small seaside town.

New from Hollis Europe is an infra‐red soldering system, the IR16, for energy efficient reflow of all types of surface mount boards.

To design a flexible integrated robotic assembly and rework (remanufacturing) cell for assembly, selective assembly and rework of advanced surface mount components (SMCs) using the generic methodology developed in this paper.

Manual rework procedures are investigated for all advanced SMCs. General and specific component‐related rework considerations are obtained and necessary tooling candidates for automation are determined. This is followed by determination of the specific automated rework procedure and selection of suitable tooling for automated robotic rework and generation and evaluation of design concepts.

The developed methodology, which considers the reflow tool at the centre of the development process, has worked well in designing a flexible integrated robotic assembly and rework cell.

This study identified the rework requirements for advanced SMCs, the essential features for rework reflow tools, criteria for comparing reflow tools, and a generic procedure for design and concept selection.

It provides valuable knowledge for designers of flexible integrated robotic assembly and rework cells for assembly, selective assembly and rework of advanced SMCs.

Electronics exhibitions are the same the world over, very tiring affairs. If your stand is busy, time flies; if not, the strain is more noticeable.