Temperature Control Affect The SMT Assembly Process
Temperature control is a common feature in consumer products such as home heating/cooling, space-heaters, refrigerators, water-heaters and electric stoves. Automobiles also have multiple temperature control systems including cabin air heating/cooling, seat heaters and engine/transmission cooling. In industrial applications, temperature control is vital for manufacturing and process systems that deal with food products, chemicals, metals, plastics and coatings. The failure to properly control the temperatures in these systems can compromise sanitation, ruin the processed material and in extreme cases cause fires and explosions.
Surface mount technology is a popular method of making electronic devices. It allows for high-density components to be placed on a small PCB that can fit inside a compact device. In order to produce quality SMT devices, a lot of work goes into ensuring that all the steps in the assembly process are completed correctly. This is especially true for temperature control, as any fluctuations can cause a major problem in the final product.
In order for smt assembly to function properly, all the individual components must be connected using solder. The first step in the process is called preheating, which involves applying soldering paste to the pads on the PCB. This is done using a machine that uses stainless-steel stencils to “print” the paste on the PCB, with different stencils used for each product type. The preheating stage is extremely important, as the exact amount of heat needed must be carefully controlled. Too much heat can burn the board or melt the soldering paste, causing the components to move around or fall off the board.
How Does Temperature Control Affect The SMT Assembly Process?
The next step in the process is reflow soldering, which occurs in a reflow oven with various temperature zones. The temperature zones are set so that the reflow soldering can be carried out in a relatively short time, while avoiding any overheating problems. The peak temperature and the time-above-liquidus must be lowered as much as possible, while still allowing for enough heat to create the necessary intermetallic connections between the soldering materials.
Once the reflow soldering is complete, the resulting PCBs need to be cleaned through a dedicated cleaning machine. This is an essential part of the process because traces of toxins and hazardous residues can remain on the PCBs after the reflow soldering.
Another crucial step in the process is chip mounting, which requires high accuracy. This is because the chip mounter is responsible for sticking SMCs (Surface Mount Components) onto corresponding pads on the PCB based on the adhesion of the soldering paste that has been applied to each pad. The chip mounter must be able to precisely determine the position of each component, and its data must be perfectly compatible with the program that is sent to it by the SMT assembly line. In addition, the chip-mounter must be able to accurately scrape off any excess solder paste from the pads on the PCB. If the chip-mounter can’t do this, the entire assembly process will be thrown off.
