Manufacturing a variety of different electrical components often requires a process called reflow soldering. In addition to being great DIY components producers, tabletop reflow oven makes up a key portion in the soldering process. The oven is hassle-free for both home and commercial users in terms of installation and operation thanks to its simple bench top design.
Reflow soldering is commonly used to attach surface mounted components to a circuit board. Less commonly, reflowing can also be used to attach through-hole components to the circuit boards. Solder paste (solder mixed with flux) is used to temporarily attach electrical components to a contact pad. This newly assembled contact pad and attached electrical components are then subject to heating in order to melt the solder, creating a permanent joint. This second step is where the use of this machine comes in.
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 oven begins at the preheat zone, which is often the lengthiest of the stages. During this stage, the temperature increases at a rate of between 1 and 3 degrees Celsius per second. This temperature change is referred to as the ramp-up rate. The controlled ramp-up rate is essential in avoiding thermal shock or cracking of the components.
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.
Reflow soldering is commonly used to attach surface mounted components to a circuit board. Less commonly, reflowing can also be used to attach through-hole components to the circuit boards. Solder paste (solder mixed with flux) is used to temporarily attach electrical components to a contact pad. This newly assembled contact pad and attached electrical components are then subject to heating in order to melt the solder, creating a permanent joint. This second step is where the use of this machine comes in.
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 oven begins at the preheat zone, which is often the lengthiest of the stages. During this stage, the temperature increases at a rate of between 1 and 3 degrees Celsius per second. This temperature change is referred to as the ramp-up rate. The controlled ramp-up rate is essential in avoiding thermal shock or cracking of the components.
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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