Assembling electronic components on to printed circuit board (PCB) traditionally depends on soldering them on to that motherboard. In a well functioning reflow soldering oven, the best possible results are usually achieved. The technique is one of the most modern the widely used for this kind of attachments although just like other forms of technologies, it is too undergoing revolution.
One or more ceramic infrared heaters can be used for heating the oven. The heat is then directed through the radiation process to the assembly compartments although infrared ovens use fans to direct heat to the assembly. The target is usually to expose PCB to the optimum heat conditions enough to melt the solder into the correct positions without damaging the PCB or devices on it.
A basic reflow oven has four stages through which the operation goes to be complete. The starting point is the preheat zone. This is where the temperature/time rate (ramp rate) is determined. It is the rate at which the temperature of the mounting board and the electrical components on it changes relative to time. This is significant as it helps determine the maximum temperatures possible that can be reached and for how long. The solvent in the mix also starts evaporating at this point.
Thermal soak zone with temperature ranging from 60 to 120 is the next stage for the circuit board. The purpose is the removal of solder paste volatiles and flux activation (oxide reduction from leads and pads). Temperature control at this phase is also very essential. Too high temperature leads to damage to the PCB and the components while too low temperature leads for failure of full oxidation of flux.
The third phase is the reflow zone where the maximum possible temperatures are reached. The objective is to reduce the surface tension of the flux at the points of metal juncture which leads to metallurgical bonding involving combination of all the available solder powder. The maximum possible operating temperature is set slightly below the maximum tolerable temperature of that component with the lowest operating temperatures. The oven should therefore be efficient in heat control and monitoring.
The last phase for the PCB is the cooling zone where the board and its components cool and the soldier solidifies. The temperature control is also significant here to avoid thermal shock excess intermetallic formation. The primary goal here is to achieve a mechanically sound and fine grain structure.
In the modern ovens with the most up to date technology, there is usually no need for solder to flow more than once as these advances techniques guarantees that the granules in the paste can surpass the reflow temperature of the solder used. The trick is therefore to select an oven that can perform optimally at all the phases resulting into the best possible PCB with attached components.
The changing customer needs, competition, market condition and the general technology all calls for adopting measures that optimizes operating efficiency in terms of yield and profitability. It is such measures that can ensure the survival of a firm into the future. For assembly firms in particular, an efficient and modern reflow soldering oven is more than necessary as it increases the production rate and minimizes on power consumption.
One or more ceramic infrared heaters can be used for heating the oven. The heat is then directed through the radiation process to the assembly compartments although infrared ovens use fans to direct heat to the assembly. The target is usually to expose PCB to the optimum heat conditions enough to melt the solder into the correct positions without damaging the PCB or devices on it.
A basic reflow oven has four stages through which the operation goes to be complete. The starting point is the preheat zone. This is where the temperature/time rate (ramp rate) is determined. It is the rate at which the temperature of the mounting board and the electrical components on it changes relative to time. This is significant as it helps determine the maximum temperatures possible that can be reached and for how long. The solvent in the mix also starts evaporating at this point.
Thermal soak zone with temperature ranging from 60 to 120 is the next stage for the circuit board. The purpose is the removal of solder paste volatiles and flux activation (oxide reduction from leads and pads). Temperature control at this phase is also very essential. Too high temperature leads to damage to the PCB and the components while too low temperature leads for failure of full oxidation of flux.
The third phase is the reflow zone where the maximum possible temperatures are reached. The objective is to reduce the surface tension of the flux at the points of metal juncture which leads to metallurgical bonding involving combination of all the available solder powder. The maximum possible operating temperature is set slightly below the maximum tolerable temperature of that component with the lowest operating temperatures. The oven should therefore be efficient in heat control and monitoring.
The last phase for the PCB is the cooling zone where the board and its components cool and the soldier solidifies. The temperature control is also significant here to avoid thermal shock excess intermetallic formation. The primary goal here is to achieve a mechanically sound and fine grain structure.
In the modern ovens with the most up to date technology, there is usually no need for solder to flow more than once as these advances techniques guarantees that the granules in the paste can surpass the reflow temperature of the solder used. The trick is therefore to select an oven that can perform optimally at all the phases resulting into the best possible PCB with attached components.
The changing customer needs, competition, market condition and the general technology all calls for adopting measures that optimizes operating efficiency in terms of yield and profitability. It is such measures that can ensure the survival of a firm into the future. For assembly firms in particular, an efficient and modern reflow soldering oven is more than necessary as it increases the production rate and minimizes on power consumption.
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