Soldering techniques and processes in assembly
In the manufacture of electronic products, PCBA assembly is a key link. As one of the most important steps in PCBA assembly, soldering is essential to ensure the normal operation and reliability of electronic equipment. This article will introduce the soldering techniques and processes commonly used in PCBA assembly, including surface mount technology (SMT) and plug-in mount technology (THT), and introduce the key elements of the soldering process to help readers better understand and apply PCBA soldering technology and craft.
1. Surface mount technology (SMT):
Surface mount technology is one of the commonly used soldering techniques in PCBA assembly. It pastes the components directly on the surface of the PCB and adheres to the PCB by melting the solder. SMT technology has the advantages of high welding density, low cost, and high degree of automation. During the SMT soldering process, the key elements that need to be paid attention to include: the selection and application of adhesives, the positioning and placement of components, the temperature and time control of reflow soldering, etc.
2. plug-in placement technology (THT):
Plug-in mounting technology is another commonly used soldering technology in PCBA assembly. It is fixed and connected by inserting the pins of the components into the holes of the PCB and soldering. THT technology is suitable for components with larger size and higher power consumption. During the THT soldering process, the key elements that need attention include: positioning and insertion strength of components, melting and wettability of solder, temperature and time control of soldering, etc.
3. the key elements of the welding process:
In PCBA assembly, the key elements of the soldering process have an important impact on soldering quality and product reliability. These include:
1. Soldering equipment: Choose suitable welding equipment, such as hot air stove, reflow oven, wave soldering machine, etc., to meet different welding needs.
2. Welding materials: Select appropriate welding materials, including solder wire, welding flux, etc., to ensure welding quality and reliability.
3. Welding parameters: Control welding temperature, time, speed and other parameters to ensure welding quality and product reliability.
4. Quality control: Carry out quality control and testing of the welding process, such as reliability testing of welding contacts, detection of welding defects, etc., to improve product quality and reliability.
Soldering technology and process in PCBA assembly are crucial to ensure soldering quality and improve product reliability. Surface mount technology (SMT) and plug-in mount technology (THT) are commonly used soldering technologies, each with its own applicable scenarios. In the welding process, it is necessary to pay attention to key elements such as welding equipment, welding materials and welding parameters to ensure welding quality and product reliability. By controlling the soldering process and conducting quality control, the soldering quality of PCBA can be improved to ensure the normal operation and reliability of electronic equipment.
In surface mount technology (SMT), the selection and application of the adhesive is a critical step. An adhesive is usually a viscous liquid or semi-solid substance used to adhere components to a PCB. Selecting a suitable adhesive should take into account the size, shape and material of the component, as well as the characteristics of the PCB surface. When applying the adhesive, it is necessary to ensure that it is evenly and accurately applied to the pads of the PCB to avoid soldering defects.
The positioning and placement of components is also a key step in SMT soldering. Automated equipment is often used to remove components from the feeder and position them on the PCB. Accurate positioning and placement is a key factor to ensure welding quality, so it is necessary to ensure the accuracy and stability of automated equipment.
Reflow soldering is a common method for SMT soldering. The temperature and time control of reflow soldering is very important for soldering quality. Too high temperature or too long time may cause soldering defects such as excessive melting, poor pad wetting, etc. Therefore, it is necessary to accurately control the temperature and time of reflow soldering according to the requirements of components and PCB.
In through-hole technology (THT), the positioning and insertion force of components are key steps. Ensure components are properly aligned and inserted into PCB holes to ensure reliable solder contact. The insertion force should be moderate, not only to ensure that the plug-in is firmly fixed on the PCB, but also to avoid damage to the PCB and components.
Solder melting and wettability are key factors for THT soldering. Solder wire is usually heated and melted by a wave soldering machine, and then wetted to the pins of the PCB and the plug-in. The melting temperature and wettability of the solder should be selected according to the composition of the solder wire and the material of the PCB to ensure the soldering quality.
The quality control of welding process is an important part to ensure welding quality and product reliability. During the welding process, the reliability test of welding contact can be carried out, such as contact resistance test and reliability life test. In addition, the detection of soldering defects is also an important quality control measure, such as solder short circuit, poor pad wetting, etc.