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 longest stage of the soldering machine is the first preheating feature. Between 1 to 3 degrees Celsius rises per second through the entire time. This gradual increase by a static number of degrees Celsius is often referred to as ramp-up rate. The ramp-up rate is an important feature the machine offer so that the intensity of heat on the component is safely progressive rather than abrupt.
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.
Peak temperatures are reached in the re-flow zone. Temperatures in the oven goes as high as 20 to 40 degrees Celsius. There is a 20 degree difference in range because the specific degree depends on the lowest heat tolerance of the electric components. In order to bring about any damages, the oven will never heat up higher than 60 degrees.
Apart from the temperature itself, the required amount of time the oven stays in this stage to fully melt the paste relies on the TAL calculations, or time above liquidus. The component must stay in the reflow stage throughout the TAL, or else the paste might not melt fully and produce a dry and frail connection.
The re-flow process ends with the completion of the cooling stage. This is where the oven slowly cools the fully combined component. The steady decrease in heat prevents thermal shock, while also preventing intermetallic formations in the component to occur. Although it is gradual to prohibit shock, a fairly quick cooling rate is needed to create the strongest connection for the component. Compared to the 1 to 3 degree Celsius rate during heating, cooling requires about 4 degrees Celsius per second. As mentioned, extreme care should be taken in all the processes.
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 longest stage of the soldering machine is the first preheating feature. Between 1 to 3 degrees Celsius rises per second through the entire time. This gradual increase by a static number of degrees Celsius is often referred to as ramp-up rate. The ramp-up rate is an important feature the machine offer so that the intensity of heat on the component is safely progressive rather than abrupt.
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.
Peak temperatures are reached in the re-flow zone. Temperatures in the oven goes as high as 20 to 40 degrees Celsius. There is a 20 degree difference in range because the specific degree depends on the lowest heat tolerance of the electric components. In order to bring about any damages, the oven will never heat up higher than 60 degrees.
Apart from the temperature itself, the required amount of time the oven stays in this stage to fully melt the paste relies on the TAL calculations, or time above liquidus. The component must stay in the reflow stage throughout the TAL, or else the paste might not melt fully and produce a dry and frail connection.
The re-flow process ends with the completion of the cooling stage. This is where the oven slowly cools the fully combined component. The steady decrease in heat prevents thermal shock, while also preventing intermetallic formations in the component to occur. Although it is gradual to prohibit shock, a fairly quick cooling rate is needed to create the strongest connection for the component. Compared to the 1 to 3 degree Celsius rate during heating, cooling requires about 4 degrees Celsius per second. As mentioned, extreme care should be taken in all the processes.
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