Everything you purchase today that is electronic uses circuit boards to keep them running. How these circuit boards are made demands use of complicated specialty equipment designed specifically for making the components for tablets, smart phones and virtually every other electronic devise available. One of the machines needed to create these mobile connections and ensure they work is the reflow soldering oven.
By placing a powdered solder mixture on the circuit board manufacturers can bond two materials. The boards are heated in ovens until the solder becomes liquid and will, when cooled, permanently bind the circuits to the board. To complete the process the boards and circuits must travel through four stages of heat and cooling. These stages are called zones by the manufacturers.
The first zone is a preheat period where the boards and other components are heated to determine the ramp up rate. If the boards and circuitry heat up too fast it can cause damage to the components from thermal shock causing cracking and also spattering of solder paste. If the heating process is too low the needed evaporation of the flux in the paste will be incomplete.
The second step is called a thermal soak. In this zone the board sits for up to two minutes in the heat and works to activate flux components that starts the oxide reduction and removes the excess paste from the actual circuit ends and pads. As with all steps in this process the temperature must be exact. Too high and there will be spattering or balling of any solder being used. Before moving to the next level the boards receive a complete thermal assessment.
The reflow zone is also called the time above liquidus or TAL. This is the point where the highest temperature is reached. This is a very important component because it must not surpass the highest temperature that can be tolerated by the part most sensitive to thermal damage. The process takes approximately one minute and should be closely monitored to ensure the temperatures do not surpass the limit set for the piece.
The final step is the cooling zone. This is a slow process that gradually cools the board and causes the liquid solder to become solid. When done properly it can help to prevent excess thermal shock to the boards and their components. Many companies pay little attention to the cool down rate because it is less critical than the ramp up rate but a cooling rate of four degrees Celsius per second is recommended.
Having a window to watch the entire process is one of the ways the manufacturer helps the operator. Most of the machines are computerized and can be pre-programmed to do the work without human assistance but being able to see what is happening is important especially on a new run. Many have USB connections so the operators can view them on their computers.
These ovens come in many different sizes. They may range from small units that can be placed on the surface of a bench to units that are longer than six feet. The importance of them is demonstrated everyday in products used to communicate with others as well as for mobile intelligence and gaming. They help to make the world smaller with each new devise they help to create.
By placing a powdered solder mixture on the circuit board manufacturers can bond two materials. The boards are heated in ovens until the solder becomes liquid and will, when cooled, permanently bind the circuits to the board. To complete the process the boards and circuits must travel through four stages of heat and cooling. These stages are called zones by the manufacturers.
The first zone is a preheat period where the boards and other components are heated to determine the ramp up rate. If the boards and circuitry heat up too fast it can cause damage to the components from thermal shock causing cracking and also spattering of solder paste. If the heating process is too low the needed evaporation of the flux in the paste will be incomplete.
The second step is called a thermal soak. In this zone the board sits for up to two minutes in the heat and works to activate flux components that starts the oxide reduction and removes the excess paste from the actual circuit ends and pads. As with all steps in this process the temperature must be exact. Too high and there will be spattering or balling of any solder being used. Before moving to the next level the boards receive a complete thermal assessment.
The reflow zone is also called the time above liquidus or TAL. This is the point where the highest temperature is reached. This is a very important component because it must not surpass the highest temperature that can be tolerated by the part most sensitive to thermal damage. The process takes approximately one minute and should be closely monitored to ensure the temperatures do not surpass the limit set for the piece.
The final step is the cooling zone. This is a slow process that gradually cools the board and causes the liquid solder to become solid. When done properly it can help to prevent excess thermal shock to the boards and their components. Many companies pay little attention to the cool down rate because it is less critical than the ramp up rate but a cooling rate of four degrees Celsius per second is recommended.
Having a window to watch the entire process is one of the ways the manufacturer helps the operator. Most of the machines are computerized and can be pre-programmed to do the work without human assistance but being able to see what is happening is important especially on a new run. Many have USB connections so the operators can view them on their computers.
These ovens come in many different sizes. They may range from small units that can be placed on the surface of a bench to units that are longer than six feet. The importance of them is demonstrated everyday in products used to communicate with others as well as for mobile intelligence and gaming. They help to make the world smaller with each new devise they help to create.
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