Reflow soldering is generally used as a way to improve on the mainboard chipset, though not exactly known as a "fix". Reflow soldering is the process used to repair the mainboard chpset either on a laptop or PC. It's actually similar to the conventional re-solder electronic devices macro.
Reflow was performed in which the solder paste (a sticky mixture of powdered solder and flux) is used temporarily in one or more electrical components on the contact pads and after that object terikontrol heated at high temperature to melt the solder and connect seingga foot permanent component of the board.
Heating can be done using a special tool or the reflow oven with an infrared lamp or soldering individual who combines hot air soldering pencil. Reflow with the place or mount components onto a circuit board is the most common method. The purpose of the reflow process is to melt the solder and heat the surface of the one-way, without damaging other electrical components. In the conventional reflow process, there are usually four stages, called "zones", each having a different thermal profile:
The process of heating (preheat). The maximum slope of the relationship temperature / time that measures how quickly the temperature changes on the circuit board board. Increased rate of heat usually in a section between 1.0 ° C and 3.0 ° C per second, and often fall between 2.0 ° C and 3.0 ° C (4 ° F to 5 ° F) per second. If the slope exceeds the maximum level, the potential damage to the components of thermal shock cracking can occur. Solder paste can also have a splash effect. Preheat section is the process whereby the solvent in the paste begins to evaporate, and if the rate of temperature rise is too low, the evaporation of volatile flux is incomplete.
Thermal . The second part, namely thermal soak usually lasts 60 to 120 seconds to remove volatiles from the solder paste and flux activation, where the reduction of oxides components of the flux begins to lead components and bearings. Temperature is too high or too low can cause a spark or solder balling and oxidation of pasta, bearings and suspension component attachment. Similarly, the flux may not be fully active when the temperature is too low. At the end of the zone of thermal soak the thermal balance of all the component parts should be complete before the reflow zone. In the thermal soak is recommended to reduce the delta T between each component of any size or if the PCB board is very large.
Reflow. The third section, reflow zone, also referred to as "time above reflow" or "time above liquidus" (TAL), and is part of the process by which the maximum temperature is reached. An important consideration is the peak temperature, which is the maximum temperature of the entire process. A peak temperature is generally 20-40 ° C above the liquidus. This limit is determined by the board components on the board with the lowest tolerance to high temperature on the components that are susceptible to thermal damage. A standard guideline is to reduce the temperature 5 ° C from the maximum of the component most vulnerable to the maximum temperature for the reflow process. Important to monitor the temperature so as not to exceed this limit. In addition, high temperature (above 260 ° C ) can cause damage to internal components as well as foster the intermetallic. In contrast, the temperature is not hot enough to prevent the paste from reflowing adequate.
Cooling. Last zone is the zone gradually cooling to cool the board or board components and solidify the solder. Proper cooling or inhibit the formation of intermetallic excess thermal shock to components. Typical temperature in the range of the cooling zone is 3-10 ° C (86-212 ° F). Even this cooling rate should be running normally. If it is too accelerated the components can be damaged or not work optimally. Cooling rate of 4 ° C / s are generally recommended 4 ° C mean temperature is lowered every second. This is the parameter to be considered when analyzing the results of the process.
Thus reflow soldering, how to fix the chipset on the mainboard
