Search results

Printed wiring board placement optimization of high‐speed placement machines in a high volume surface mount line was studied based on more careful analysis of the board layout beforehand. In this method, the target is to get the board area to be assembled as small as possible in each successive placement machine, paying the most attention on component coordinates already during preliminary line balancing phase. Optimization and line balancing principles, that had showed promising results already in the first studies when compared to globally used well‐known commercial optimization systems, were now further developed. Results presented and illustrated in this paper show remarkable, comparable, improvement in both cycle time reduction and in balance of the whole surface mount line. The main difference between this method and the advanced commercial solutions is explained in detail. Board layout, feeder arrangement, sequence of fiducial registration, and XY‐table movement were taken into deeper consideration in the method.

Little interest has been shown in pickup conditions and parameters and their effect on placement accuracy in the literature before. The purpose of this paper is to find out the possible link between pickup conditions and placement accuracy of typical discrete chip components.

A dedicated test board was developed and used to study the ultimate critical pickup conditions. Then the same board was used to find out the best parameters between ultimate conditions and perfect conditions in order to define working limits for good enough pickup that would work well in practice.

The link between pickup conditions and placement quality was found and converted into measurable controllable values. Additionally, a problem was surprisingly detected in the placement machine's vision performance resulting in inaccuracy, and parameters were re‐defined to avoid this problem in real‐world production. Based on all the findings, the best parameters were defined for component pickup.

This paper discusses the effect of component pickup conditions on accuracy which is seldom handled in the literature. Owing to smaller spacing between chip components in the future, pickup is becoming more important; components will simply have to be picked up more and more on the centre to avoid collision with components already been placed. This paper clearly shows the requirement for placement machine manufacturers to develop more accurate pickup tools for the future.

The electronics industry will implement lead‐free soldering in the near future. Lead‐free implementation steps are divided into lead‐free process and lead‐free product. The eutectic Sn/Ag/Cu alloy seems to have become the most widely used alloy in the implementation of lead‐free processes. In this study, the requirements for component placement are discussed from the lead‐free process point of view. Experiments concerning the self‐alignment capability and tack strength of both tin‐lead and lead‐free solder pastes are presented. According to the results, a bigger variation in self‐alignment capabilities can be expected when using a lead‐free paste. The paste properties affecting the self‐alignment mechanism and tack strength are also discussed.