Sunday, December 22, 2013

Why SMT Reflow Soldering Oven Cannot Be Avoided By Electronic Assembling Firms

By Harriett Crosby


When it comes to soldering of electrical components on to printed circuit board (PCB), surface mount technology (SMT) is the most widely used method. The SMT reflow soldering oven is the machine that has greatly contributed to this technology. Highly technical principles in bonding are all put together to ensure optimal functionality of this particular machine that has literally transformed the electronics industry. In addition to precise control of this process, the machine consumes less power than other methods used and produces more products per unit time than any other method.

The reflow soldering is the process of joining electronic devices to the printed circuit boards as the contact pads. This requires the use of solder paste and heat to attach the components. It is the SMT reflow soldering oven that is best in this. It allows for better control of heating process that minimizes chances of defective components.

The beginning point is making of the soldering paste. This is a mixture of flux, some chemical used as cleaning agent and small solder particles. This makes a sticky paste that is used to loosely hold the electronics on to their predetermined positions on the PCB.

SMT soldering ovens are designed with specific zones, stages which numbers to a total of four. It all starts from the preheat zone. In this stage, the melting temperature of the solvent in paste is set. The time/temperature relationship also known as ramp is determined to help control heating in other zones.

This is followed by thermal soak zone where the PCB and its components are exposed to heating at specific temperature for between 60 to 120 seconds to remove paste volatiles. The third stage is reflow zone. At this stage, PCB gets exposed to the maximum possible temperature that is tolerable by all the electronics on it. This is usually set below the liquidus temperature-the temperature above which the electronics get destroyed. At this point, the surface tension at the joints and the joints is reduced, melting the solder and as such bonding the pads and electronics.

The cooling zone is the last phase where controlled cooling is done to avoid thermal shock. This result of this is permanent bonding of the electrical components to PCB ready for use in electronic market after cleaning and testing.

The oven gets heated by ceramic heaters and heat transfer to the assembly points can be through radiation (hot air) or the infrared electromagnetic radiation depending on the machine make. Other technologies of heat transfer are also used.

They are simpler to operate and work much faster with high accuracy level. They also have higher production level with ability to produce more that 136,000 components in a single hour. Attachment of the components can also be done on both sides at the same time with better electrical efficiency.

Electronic assembly just like any other industry is highly competitive. In order to remain a relevant market player, a firm must acquire the latest technology and most efficient production methods. The use of SMT reflow soldering oven is no longer optional in electrical assembly. In addition to higher level of production, efficiency and lower power consumption, the machine guarantees firms future survival and profitability.




About the Author:



No comments:

Post a Comment