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Reflow soldering is widely used to manufacture a wide range of electrical components. The tabletop reflow oven forms an integral part of the soldering process, and are also great for DIY component makers. The bench top design of it calls for minimal installation and simple operation for the home or commercial user.
Surface mounted components are often connected to circuit boards via re-flow soldering. Sometimes, the same technique may be used in connecting circuit boards to through-hole components as well. When connecting any electric component to the desired contact pad, a mixture of solder and flux called solder paste is applied. The connected pieces are heated so that the paste melts and acts as permanent glue. These soldering machines or equipment are used here to ensure that the right temperature heats the entire piece.
The use of a this kind of oven is important in the re-flow process because it melts the solder and heats the adjoining surfaces without overheating the electrical components, which would result in component damage. The oven operates in various stages or zones which have distinctive thermal profiles. These are usually classified as preheat, soak, re-flow and cooling.
The preheat zone takes the longest time out the four stages. During preheating, the heat increases between 1 to 3 degrees Celsius per second. This rate of increase in heat is called the ramp-up rate. The equipment offer a controlled ramp-up rate so that the component is gradually heated, rather than giving it a heat shock that can cause damage.
The thermal soak zone follows the preheat stage, which typically lasts one to two minutes. This short exposure allows for the removal of solder paste volatiles and activation of the fluxes. The thermal soak temperature must be within a narrow range, since too high a temperature will cause splattering as well as oxidation of the paste, attachment pads and component terminals. Additionally, too low a temperature will not allow for the activation of the fluxes.
The re-flow zone, or "time above liquidus" (TAL), is the peak temperature stage. This is usually a temperature 20 to 40 degrees Celsius above liquidus. The appropriate temperature is determined by the component that has the lowest heat tolerance.
The temperature will never exceed 60 degrees Celsius in the machine because the parts inside may burn up at that point. The time above liquidus (TAL) comes to play in determining the required length of time of this stage that will properly meld the component together. Incomplete TAL may cause the paste to stay dry instead of melting, thus creating a defective connection.
The cooling stage is the final step the re-flow oven performs. As the name suggests, this involves the gradual cooling of the board and newly attached components. This process is important in inhibiting the formation of excess intermetallic formations, as well as avoiding thermal shock. This is a short process because fast cooling rate creates the most mechanically sound structure. A commonly used cooling rate is around four degrees Celsius per second.
Surface mounted components are often connected to circuit boards via re-flow soldering. Sometimes, the same technique may be used in connecting circuit boards to through-hole components as well. When connecting any electric component to the desired contact pad, a mixture of solder and flux called solder paste is applied. The connected pieces are heated so that the paste melts and acts as permanent glue. These soldering machines or equipment are used here to ensure that the right temperature heats the entire piece.
The use of a this kind of oven is important in the re-flow process because it melts the solder and heats the adjoining surfaces without overheating the electrical components, which would result in component damage. The oven operates in various stages or zones which have distinctive thermal profiles. These are usually classified as preheat, soak, re-flow and cooling.
The preheat zone takes the longest time out the four stages. During preheating, the heat increases between 1 to 3 degrees Celsius per second. This rate of increase in heat is called the ramp-up rate. The equipment offer a controlled ramp-up rate so that the component is gradually heated, rather than giving it a heat shock that can cause damage.
The thermal soak zone follows the preheat stage, which typically lasts one to two minutes. This short exposure allows for the removal of solder paste volatiles and activation of the fluxes. The thermal soak temperature must be within a narrow range, since too high a temperature will cause splattering as well as oxidation of the paste, attachment pads and component terminals. Additionally, too low a temperature will not allow for the activation of the fluxes.
The re-flow zone, or "time above liquidus" (TAL), is the peak temperature stage. This is usually a temperature 20 to 40 degrees Celsius above liquidus. The appropriate temperature is determined by the component that has the lowest heat tolerance.
The temperature will never exceed 60 degrees Celsius in the machine because the parts inside may burn up at that point. The time above liquidus (TAL) comes to play in determining the required length of time of this stage that will properly meld the component together. Incomplete TAL may cause the paste to stay dry instead of melting, thus creating a defective connection.
The cooling stage is the final step the re-flow oven performs. As the name suggests, this involves the gradual cooling of the board and newly attached components. This process is important in inhibiting the formation of excess intermetallic formations, as well as avoiding thermal shock. This is a short process because fast cooling rate creates the most mechanically sound structure. A commonly used cooling rate is around four degrees Celsius per second.
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