In the assembly industries, the process of attaching electronic components on to a printed circuit board (PCB) is usually done by soldering them onto the board. Reflow soldering oven is one of the most modern devices used for to achieve this attachment. The process starts with a sticky mixture of flux and powdered solder that helps to attach the components on to their correct positions on to the board. A process of controlled heating and cooling then follows to achieve permanent joints.
The heat in the majority of these ovens is produced from ceramic infrared heaters, and then directed to assembly chambers through radiation process. The infrared ones uses fans to force heat into the assembly chambers where the PCB and the components are exposed to optimal temperatures for melting of the solder for permanent fixing of the components on to the PCB.
The process starts with loose attachments of the components to the desired positions on the PCB using sticky solder powder and flux mixture. This is then directed to first of the four phases through which the process undergoes. The first of this is the preheat zone which involves determination of temperature/time relationship (ramp rate). This significance of this comes in other stages as the maximum temperature and time exposure should be maintained to avoid destroying the PCB and the components on it.
The PCB is then taken to the thermal soak zone where the removal of solder paste volatiles takes place. Flux activation which involves freeing of leads and pads of any oxide then follows. The temperature range is anywhere between 60 to 120 degrees primary depending on the predetermined ramp rate.
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 stage is the cooling zone where the circuit board and its component are cooled. This process too is done under efficient temperature control as sudden temperature changes may result to thermal shock. It is also important to avoid excessive metallic formation at this stage as the desired finished circuit board should have components attached with fined grained structured solder making it mechanically sound.
With the modern sophisticated ovens, the most up to date technologies are employed to give the best possible yields. These are operated by modern setup processes that identify the best possible combination of zonal temperatures and conveyor speed. Among other things, the production time has been significantly minimized greatly increasing efficiency.
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.
The heat in the majority of these ovens is produced from ceramic infrared heaters, and then directed to assembly chambers through radiation process. The infrared ones uses fans to force heat into the assembly chambers where the PCB and the components are exposed to optimal temperatures for melting of the solder for permanent fixing of the components on to the PCB.
The process starts with loose attachments of the components to the desired positions on the PCB using sticky solder powder and flux mixture. This is then directed to first of the four phases through which the process undergoes. The first of this is the preheat zone which involves determination of temperature/time relationship (ramp rate). This significance of this comes in other stages as the maximum temperature and time exposure should be maintained to avoid destroying the PCB and the components on it.
The PCB is then taken to the thermal soak zone where the removal of solder paste volatiles takes place. Flux activation which involves freeing of leads and pads of any oxide then follows. The temperature range is anywhere between 60 to 120 degrees primary depending on the predetermined ramp rate.
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 stage is the cooling zone where the circuit board and its component are cooled. This process too is done under efficient temperature control as sudden temperature changes may result to thermal shock. It is also important to avoid excessive metallic formation at this stage as the desired finished circuit board should have components attached with fined grained structured solder making it mechanically sound.
With the modern sophisticated ovens, the most up to date technologies are employed to give the best possible yields. These are operated by modern setup processes that identify the best possible combination of zonal temperatures and conveyor speed. Among other things, the production time has been significantly minimized greatly increasing efficiency.
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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