ME547-Laser Material Processing Laser Soldering What is soldering? The term soldering denotes thermal processes for joining parts. In contrast to welding, they work not by melting the parts to be joined, but rather only melting a solder .When the solder solidifies after removing the heat source, it forms a firm connection with the parts to be joined. Need for Laser Soldering ? ● Miniaturization of electronic devices and the use of expensive, temperature –sensitive components used in the electronic equipment industry have led to the demand for laser soldering technology ● Modern electronic components usually have complex circuit geometries that cannot be soldered using conventional techniques What is Laser Soldering? Laser soldering is a technique where a precisely focused laser beam provides controlled heating of the solder alloy leading to a fast and non-destructive joint. The process uses a controlled laser beam to transfer energy to a soldering location where the absorbed energy heats the solder until it reaches its melting temperature leading to the soldering of the contact and this completely eliminates any mechanical contact. Schematic Diagram Process parameters ● Laser power ● Process time ● Geometry of laser beam. ● Ratio of crown size and through hole. Advantages of Laser soldering ● Contactless, locally limited application of energy ● Well-controlled energy input, ● Low thermal stress ● It reduces intermetallic compound formation due to rapid joint formation which results high quality joint. ● It is also has low maintenance ● Very flexible and easily adapted. Disadvantages of Laser soldering ● ● Limited ability to solder large areas. high relative price ● Additional cost for safety requirements. ● Extreme non-equilibrium nature. ● Needs precise laser impulse. ● Any slight deviation can lead to an open or destroyed joint. Soldering profile Thermal profile control which is different for different joints optimizes soldering parameters. Difference between conventional soldering techniques and laser soldering. Iron soldering process Laser soldering process Contact heating Contactless heating High maintenance Low maintenance Heat spreads beyond joint area Heat is focused on joint area Long soldering time Less soldering time Need for removal of oxide buildup No compound formation Industrial applications ● Laser soldering is also very important in micro-electronics, where it is used mostly for making electrical contacts. A single laser pulse can melt the solder to produce a solid connection.Such techniques are particularly needed where many closely spaced contacts need to be made. ● Laser application for soldering permits highly automated production system in the automobile industry , providing enormous flexibility for a wide variety of fabrication tasks at a very high processing speed because it is a non-contact technique. ● Laser tissue soldering is the process of using laser energy to join tissues without sutures and it is based on some soldering material ( such as albumin proteins – a biomedical solder) that coagulates on interaction with a laser beam to form joint . References ● https://www.japanunix.com/en/method/laser/ ● https://www.intechopen.com/chapters/38865 ● https://www.rp-photonics.com/laser_soldering.html Thank You
