Reflow ovens are used during the assembly process to bond electrical components to the PCB, printed circuit board. During the process solder paste with flux is used to achieve bonding. The perfect balance of heating the solder paste is needed to ensure success. When the temperature is too high, the PCB or the components could be damaged, yet the temperature must be high enough for the bonding to occur. These soldering ovens can now be purchased in a desktop version, the desktop reflow oven.
The name of this technology is surface mount technology, referred to as SMT. The ovens are often called P&Ps, for pick and place machines. The costly floor models take up floor space and are many time more expensive than the desktop versions. The needs of businesses vary. Some small companies may only need the desktop model, while larger manufacturers may need one or more of the floor models, but may want the desktop as an added piece of equipment.
The process is very scientific and really quite amazing. Most of the computerized electronic equipment you use every day was in part manufactured in this manner. As you can imagine, the manufacturing of an electronic device with a PCB is a very precise process that includes the use of robotic technologies such as SMT.
There are four stages to the reflow process. First is the preheat zone, next the thermal soak, then the reflow zone and last the cooling zone. Each zone accomplishes a different purpose. The preheat stage must be sensitive to the maximum slope, the rate at which the heat increases. If heat increase too quickly or too slowly the components could be damaged or the flux will not evaporate sufficiently.
The thermal soak zone is brief, typically only one to two minutes. This stage activates the flux, which is the chemical cleaning agent in the solder paste. The activation of the flux causes oxide reduction on the various component pads and leads. Again, precision is needed to attain the exact temperature. At the end of this zone there should be thermal equilibrium before going into the next zone.
The next stage is the reflow zone. The highest temperature occurs during this stage. Precision still is necessary. As a guideline the rule is that the highest temperature must be 5 degrees C less than the degrees tolerated by the component with the lowest heat tolerance. At this time the solder paste liquefies as it reflows through the PCB and components to achieve metallurgical bonding.
During the final state, the cooling zone, everything in the oven cools and the solder joints solidify. The cooling must occur at the appropriate rate of cooling, which is around 4 degrees C for each second. When this phase is complete the assembly is ready to move on to the next step of production.
There are several brands of ovens manufactured. If you are experienced in the use of these ovens, you are likely equipped to make an informed decision about which brand to purchase. Buyers who are new to the product should do some thoughtful research and consult experienced users of various brands.
The name of this technology is surface mount technology, referred to as SMT. The ovens are often called P&Ps, for pick and place machines. The costly floor models take up floor space and are many time more expensive than the desktop versions. The needs of businesses vary. Some small companies may only need the desktop model, while larger manufacturers may need one or more of the floor models, but may want the desktop as an added piece of equipment.
The process is very scientific and really quite amazing. Most of the computerized electronic equipment you use every day was in part manufactured in this manner. As you can imagine, the manufacturing of an electronic device with a PCB is a very precise process that includes the use of robotic technologies such as SMT.
There are four stages to the reflow process. First is the preheat zone, next the thermal soak, then the reflow zone and last the cooling zone. Each zone accomplishes a different purpose. The preheat stage must be sensitive to the maximum slope, the rate at which the heat increases. If heat increase too quickly or too slowly the components could be damaged or the flux will not evaporate sufficiently.
The thermal soak zone is brief, typically only one to two minutes. This stage activates the flux, which is the chemical cleaning agent in the solder paste. The activation of the flux causes oxide reduction on the various component pads and leads. Again, precision is needed to attain the exact temperature. At the end of this zone there should be thermal equilibrium before going into the next zone.
The next stage is the reflow zone. The highest temperature occurs during this stage. Precision still is necessary. As a guideline the rule is that the highest temperature must be 5 degrees C less than the degrees tolerated by the component with the lowest heat tolerance. At this time the solder paste liquefies as it reflows through the PCB and components to achieve metallurgical bonding.
During the final state, the cooling zone, everything in the oven cools and the solder joints solidify. The cooling must occur at the appropriate rate of cooling, which is around 4 degrees C for each second. When this phase is complete the assembly is ready to move on to the next step of production.
There are several brands of ovens manufactured. If you are experienced in the use of these ovens, you are likely equipped to make an informed decision about which brand to purchase. Buyers who are new to the product should do some thoughtful research and consult experienced users of various brands.
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