A reflow oven is used to attach electrical components to a printed circuit board, PCB. This is achieved with the use of solder paste. The process is a delicate balance of heating the solder paste just enough to attach the component or components, but the initial heat cannot be so high that is damages the components or the circuit board. The ovens are now available in the desktop reflow oven model. The prices range from around four to six thousand dollars.
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 soldering process is highly sophisticated and must be managed with precision. Computerized electronic systems are in many of the products people use every day. Computers, calculators and cars are only a few. Robotic surface mount technology, SMT, is used in manufacturing many of these products.
The reflow process includes four heating stages, referred to as zones. These are the preheat zone, the thermal soak zone, the reflow zone and the cooling zone. The preheat zone involves a measurement known as the maximum slope. Generally, during this zone the temperature will rise at the rate of 1 degree C to 3 degrees C. If the temperature rises to quickly there could be damage to the components. Conversely, if the rise is too slow, evaporation of the flux in the solder paste will be incomplete.
Next is the thermal soak zone. This stage is brief lasting less than two minutes. This stage is to activate the flux, the chemical cleaning agent found in the solder paste. Precision is still of ultimate importance. When the heat is too low the flux will not activate sufficiently. When it is too high the solder can spatter or the paste may become damaged. At the close of the thermal soak that thermal equilibrium be achieved.
The reflow zone is where the machine got its name. Peak temperature is reached during this phase. It is critical that the highest temperature be 5 degrees C less than the component with the least tolerance for heat. The solder paste at this point is liquid and actually reflows through points of the assembly. This is when metallurgical bonding occurs and the components are successfully bonded to the PCB.
During the fourth and last stage, the cooling zone, the entire assembly will cool and solder joints will become solid. In the previous stage the assembly was at its maximum heat. During this stage it will cool at the rate of about 4 degrees C per second. The PCB and the bonded components are now ready for the next stage of assembly in the manufacturing process.
Take the time to research the various manufacturers of soldering ovens before making a purchase. Check with professionals knowledgeable in this area to get some brand recommendations. People who have used the machines can give you the best advice, if this is your first purchase of a 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 soldering process is highly sophisticated and must be managed with precision. Computerized electronic systems are in many of the products people use every day. Computers, calculators and cars are only a few. Robotic surface mount technology, SMT, is used in manufacturing many of these products.
The reflow process includes four heating stages, referred to as zones. These are the preheat zone, the thermal soak zone, the reflow zone and the cooling zone. The preheat zone involves a measurement known as the maximum slope. Generally, during this zone the temperature will rise at the rate of 1 degree C to 3 degrees C. If the temperature rises to quickly there could be damage to the components. Conversely, if the rise is too slow, evaporation of the flux in the solder paste will be incomplete.
Next is the thermal soak zone. This stage is brief lasting less than two minutes. This stage is to activate the flux, the chemical cleaning agent found in the solder paste. Precision is still of ultimate importance. When the heat is too low the flux will not activate sufficiently. When it is too high the solder can spatter or the paste may become damaged. At the close of the thermal soak that thermal equilibrium be achieved.
The reflow zone is where the machine got its name. Peak temperature is reached during this phase. It is critical that the highest temperature be 5 degrees C less than the component with the least tolerance for heat. The solder paste at this point is liquid and actually reflows through points of the assembly. This is when metallurgical bonding occurs and the components are successfully bonded to the PCB.
During the fourth and last stage, the cooling zone, the entire assembly will cool and solder joints will become solid. In the previous stage the assembly was at its maximum heat. During this stage it will cool at the rate of about 4 degrees C per second. The PCB and the bonded components are now ready for the next stage of assembly in the manufacturing process.
Take the time to research the various manufacturers of soldering ovens before making a purchase. Check with professionals knowledgeable in this area to get some brand recommendations. People who have used the machines can give you the best advice, if this is your first purchase of a reflow oven.
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