How to improve the soldering yield of fine-pitch CSP and other components? What are the advantages and disadvantages of welding types such as hot air welding and IR welding? In addition to wave soldering, is there any other soldering process for PTH components? How to choose high temperature and low temperature solder paste?
Welding is an important process in the assembly of electronic boards. If it is not well mastered, not only many temporary failures will occur, but also the life of solder joints will be directly affected.
Reflow soldering technology is not new in the field of electronic manufacturing. The components on various PCBA boards used in our smartphones are soldered to the circuit board through this process. SMT reflow soldering is formed by melting the pre-placed solder surface Solder joints, a soldering method that does not add any additional solder during the soldering process. Through the heating circuit inside the equipment, the air or nitrogen is heated to a high enough temperature and then blown to the circuit board where the components have been pasted, so that the two components The solder paste solder on the side is melted and bonded to the motherboard. The advantage of this process is that the temperature is easy to control, oxidation can be avoided during the soldering process, and the manufacturing cost is also easier to control.
Reflow soldering has become the mainstream process of SMT. Most of the components on our smartphone boards are soldered to the circuit board through this process. Physical reaction under airflow to achieve SMD welding; the reason why it is called “reflow soldering” is because the gas circulates in the welding machine to generate high temperature to achieve the purpose of welding.
Reflow soldering equipment is the key equipment in the SMT assembly process. The solder joint quality of PCBA soldering depends entirely on the performance of the reflow soldering equipment and the setting of the temperature curve.
The reflow soldering technology has experienced different forms of development, such as plate radiation heating, quartz infrared tube heating, infrared hot air heating, forced hot air heating, forced hot air heating plus nitrogen protection, etc.
The improvement of the requirements for the cooling process of reflow soldering also promotes the development of the cooling zone of reflow soldering equipment. The cooling zone is naturally cooled at room temperature, air-cooled to a water-cooled system designed to adapt to lead-free soldering.
Due to the improvement of the production process, the reflow soldering equipment has higher requirements for temperature control accuracy, temperature uniformity in the temperature zone, and transmission speed. From the initial three temperature zones, different welding systems such as five temperature zones, six temperature zones, seven temperature zones, eight temperature zones, and ten temperature zones have been developed.
Due to the continuous miniaturization of electronic products, chip components have appeared, and the traditional welding method can no longer meet the needs. First of all, the reflow soldering process is used in the assembly of hybrid integrated circuits. Most of the components assembled and welded are chip capacitors, chip inductors, mount transistors and diodes. With the development of the entire SMT technology becoming more and more perfect, a variety of chip components (SMC) and mount devices (SMD) appear, and the reflow soldering process technology and equipment as part of the mounting technology have also been developed accordingly, and its application is becoming more and more extensive. It has been applied in almost all electronic product fields, and reflow soldering technology has also undergone the following development stages around the improvement of equipment.
Post time: Dec-05-2022