Looking At The Reflow Soldering Oven

By Marci Glover


The world today is full of electronic devises that help you live an easier life. They come in the form of smart phones, tablets, lap top computers and too many other things to list. The thing most of these items have in common is they all use circuit boards to help maintain continuous service. The reflow soldering oven is one of the machines used to create the circuit boards that are so vital to the communications industry.

Using this machine companies can solder two flat parts together permanently. To do this the machine operator uses powdered solder and places it on the circuits at precise points on a board. When preparations are complete the boards are placed in ovens and heat is applied to melt the solder. This action is permanent and special steps must be taken to insure proper results.

The preheating step is first on the list. This process determines a ramp up rate for the amount of heat that can be applied to the boards in question. When heat is applied too fast it can cause thermal shock to the components or boards. Thermal shock can cause cracking of components or boards and solder paste spattering. Conversely, heating too slow causes the flux in the paste to be incomplete.

The second step is called a thermal soak. In this zone the board sits for up to two minutes in the heat and works to activate flux components that starts the oxide reduction and removes the excess paste from the actual circuit ends and pads. As with all steps in this process the temperature must be exact. Too high and there will be spattering or balling of any solder being used. Before moving to the next level the boards receive a complete thermal assessment.

Next is the reflow zone. This is one of the most sensitive zones in the process. It is when the highest temperatures will be used on the board. Every piece has a temperature where the most fragile component is damaged by heat. If this temperature is surpassed thermal damage will occur making the piece non-functional. Operators must closely monitor the process to ensure this does not happen.

Finally the cool down zone where the board gradually cools allowing solder to solidify. Although not as critical as the ramp up process an appropriate cooling process can also help prevent damage to the boards. Specialists recommend a rate of under five degrees per second for cool down.

Having a window to watch the entire process is one of the ways the manufacturer helps the operator. Most of the machines are computerized and can be pre-programmed to do the work without human assistance but being able to see what is happening is important especially on a new run. Many have USB connections so the operators can view them on their computers.

These ovens make it possible for you to enjoy the technical electrical gadgets that make life easier. As the technology advances they will become more streamlined and advanced to keep pace.




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