Tuesday, April 15, 2014

Understanding The SMT Reflow Ovens

By Anita Ortega


The performance of any electronic gadgets depends on components used as well as how they are soldered on the mother bother that acts as the contact pad. Normally, high level of accuracy and precision is necessary when arranging and soldering the components on their position. This is difficult to achieve without causing damages and assembly firms normally resort to machines designed for the job. The most common of these machines are the smt reflow ovens.

The ovens are designed to assist in the process of reflow soldering; the technique whereby some sticky soldering paste made of solder and flux is used to temporarily attach electrical components to the contact pads. This is then followed by highly controlled heating aiming to melt the solder so as to permanently connect the components to the circuit board.

With this machine, the assembly of surface mount (smt) parts on to the circuit board is much easier and several units can be produced in minutes. This eliminates unnecessarily long labor hours as it is usually the case when the traditional method of soldering individual component separately is done. The oven is able to heat and melt the solder at the right temperature leaving no damage to the components or the circuit board. The commonplace reflow oven operates in four stages which are preheat, the thermal soak, the reflow and the cooling zone.

In the preheat zone, the incline rate is secured. This is the rate of temperature rise per second. It is normally 1 to 3 degrees for every second. It should not surpass the most extreme incline as this can damage the parts or split the mother board. It can likewise prompt the scattering impact. The solvent in the mixture too begins to dissipate in the zone.

The next process after this is the thermal soak that lasts for one to two minute. This allows for removal of all the solder paste volatiles. The process of oxidation also starts with flux components through flux activation. The temperature has to be right in order to achieve the best results. Higher than required temperatures for instance may cause spattering, oxidation of paste or even balling. If it is too low, the flux may fail to fully activate.

The third stage of reflow takes over from the second phase at the highest possible temperature known as the peak is reached. The peak has to be at least 5 degrees below the tolerable temperature of the component with the lowest temperature toleration.

Cooling zone is the final stage. It comes in to cool the transformed board in a controlled way hardening the resulting joints in the process. With appropriate finishing, it ought to form intermetallic structuring that is of the highest quality. To accomplish fine grains that has the required mechanical soundness, faster the cooling may be the option.

If the company intends to improve the efficiency of their production, it pays to buy a new reflow oven. They can be ordered online sometimes with very favorable discounts. The online orders should be done with a lot of care and caution. It is appropriate to fast carry out due diligence, go through the website of the sellers, gather all the information about the specific model to be purchased and talk to customers who have experience dealing with the store. This ensures that the company does not fall prey to substandard products or fraudulent deals as a whole.




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