Surface Mount Device Placement Research Articles

Component pick and place scheduling for surface mount device placement machine

Component pick and place scheduling for surface mount device placement machine

A survey of surface mount device placement machine optimisation: Machine classification

The optimisation of a printed circuit board assembly line is mainly influenced by the constraints of the surface mount device (SMD) placement machine and the characteristics of the production environment. This paper surveys the characteristics of the various machine technologies and classifies them into five categories (dual-delivery, multi-station, turret-type, multi-head and sequential pick-and-place), based on their specifications and operational methods. Using this classification, we associate the machine technologies with heuristic methods and discuss the scheduling issues of each category of machine. We see the main contribution of this work as providing a classification for SMD placement machines and to survey the heuristics that have been used on different machines. We hope that this will guide other researchers so that they can subsequently use the classification or heuristics, or even design new heuristics that are more appropriate to the machine under consideration.

Automatic visual measurement of surface-mount device placement

An experimental system for automatic visual measurement of surface-mount device placement on printed circuit boards has been developed. Infrared illumination is used to aid in segmentation of component lead and solder pad images from the background. Best fit lines through centroids of the lead and soldering pad images are calculated from which the displacement and angular orientation of the component relative to the pads is computed. Measurements are derived from a combination of slope and mean centroids from opposite sides of a device to reduce the effects of sensor resolution, missing pads, or missing leads. Since leads and pads are viewed simultaneously, the accuracy of the system is not dependent on precise positioning of the board within the inspection station. The system accuracy has been tested with 50 commercially manufactured printed circuit boards containing 500 samples of J-leaded plastic leaded chip carriers and small-outline integrated circuits of various sizes. The positions of the components were measured manually and are compared with measurements determined by the system. >