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

By Harriett Crosby


In the electronic assembly industry, the process of soldering is so significant that it determines the success or failure of a business firm. In order to facilitate this, many companies today use SMT reflow soldering oven. The initials SMT refers to surface mount technology. In this technology, highly technical principles of solder are used to bond electronic components on to the printed circuit board (PCB).

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.

The PCB and loosely attached components is then drawn into the heating chambers through a conveyor belt. This then undergoes into four distinct phases in this machine. The first phase is known as preheat zone. This is where the melting point of the solvent is set. The ramp rate (time/temperature rate) is also determined and used to control heating in the following stages.

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.

In the fourth and final zone, the process of cooling takes place. This too is a controlled process. The heating and cooling is such controlled that the PCB and components are not exposed to thermal shock. This is perhaps what makes SMT reflow soldering oven outperform all other methods of bonding.

Most of these ovens use ceramic heaters as the source of heat. The heat flows to the assemblies through hot air using fan (radiation) or just the infrared electromagnetic radiation. As the new models are introduces, the techniques of heat transfers are improved.

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.




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