1 Optimization of the Optical Setup for a SMT Devices Infrared Soldering Rework Station M. Félix, C. Anguiano, A. Medel, D. Salazar*, H. Márquez* mfelix@uabc.edu.mx Universidad Autónoma de Baja California (UABC), Facultad de Ingeniería *Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE) Abstract In this work, we present a preliminary design for an optical setup for SMT devices infrared soldering rework station, which is currently in development. The collimated infrared light soldering method offers several advantages over other methods for soldering SMT devices, for example, lower electrical power consumption and better heating control capacity. Besides this, the infrared soldering method reaches high enough temperatures to solder lead-free SMT devices, which are required to achieve RoHS compliance of new electronic products. The ray tracing simulation of the optical setup, composed by an infrared light source and lenses, is analyzed for different conditions, in order to find optimal optical parameters, which brings an efficient control of the spot size of the infrared beam collimated or focused onto SMT device to be soldered. The infrared soldering rework station under development is intended to be used in the consumer electronic products industry. Keywords: Infrared, SMT device, optical setup 1. Introduction The latest technological advances have grown very fast in recent years, offering the community efficient, complete and simply operated services. The consumer electronics market demands a great variety of electronic devices, which are required to have small sizes, and are capable to run complex applications 1 . For this reason, the complexity of the electronic devices has been increasing, as well as has been reduced in dimension. Nowadays, the electronic devices mostly deployed are based on Surface Mount Technology (SMT), which present the advantage of having a great number of connection terminals, but require a more complex technological technique to be soldered due to the small size of the connection terminals, compared with conventional thru-hole electronic devices 2 . In order to achieve RoHS (Restriction of Hazardous Substances) compliance, the SMT devices must be lead-free. This requires higher solder melting temperatures between 210 and 280 ºC, compared with conventional solder melting temperatures 183 and 188 ºC. The conventional technique used to solder integrated circuits (IC’s) was the soldering iron, but it became inefficient for soldering big quantities of electronic devices used for high volume production of consumer electronic products 3 . In addition, the reduced size of the latest IC’s does not allow simple joint, thus requiring alternative methods which allowed their assembly. The soldering technique mostly used to solder SMT devices is hot air flow, which can reach the required soldering temperatures, with electric power consumption between 400 and 1000 Watts 2 . Different soldering