What is SMT and how IT+OT achieves smart operation of SMT processes.

SMT process is an important technology for producing PCBA today. As a highly automated member, there are still many production difficulties that cannot be solved in the face of changes in external conditions and internal management factors. Now that technology is advanced, IT+OT assists production line operations. It is no longer difficult. How to effectively integrate and assist SMT processes in smart operations becomes a huge unanswered question for SMT manufacturer to deal with. In this article, we will dive deep into details for answering these questions and give a broader perspective on these concepts.

First, let‘s introduce SMT. SMT is a surface mount technology. It is a technology that mounts electronic components such as resistors, capacitors, transistors, integrated circuits and other parts on a printed circuit board. It uses solder paste to be printed on the surface of the circuit board, and the solder feet of the electronic components are placed in the solder paste position, use high temperature to melt the solder paste. The maximum temperature of the high-temperature furnace must be higher than the melting point of the solder paste, but it must not be so high that the electronic components are burned. When the solder pastes melts, it will turn into a liquid. After coating the solder legs of the electronic components, it will be cooled and solidified at the temperature, and the PCBA is completed. The biggest difference between SMT technology and the original via technology lies in the “volume” of the finished production. In the past, through-hole soldering technology required additional solder legs for electronic components to pass through the circuit board to solder the parts to the board.

The solder legs had a minimum size limit, which also prevented the volume of the overall PCB board from being reduced. SMT technology uses solder paste, which eliminates the volume of the solder legs, so the size of the produced PCBA is getting smaller and smaller, which is more in line with the needs of existing electronic product designs that become thinner and thinner.

Second, we always hear different terms that are derived from SMT, let‘s explore these terms and we will explain each one by one in detail. First term is SMT, it is just simply the current modern mass production technology for mounting electronic components on a circuit board, a special soldering process is used to adhere electronic components to achieve the purpose of soldering them on the circuit board; Second term is SMD, also known as Surface Mount Device, refers to electronic components that are soldered to a circuit board, such as chips, resistors, capacitors, etc.; Third term is SMA, also known as Surface Mount Assembly, is suitable for surface mount modules when an electronic component is composed of one or more electronic components inside. The more common module types include SMA composed of different performances such as Bluetooth modules and WIFI modules; Fourth term is SME, also known as Surface Mount Equipment, refers to a facility used for SMT technology to solder SMD components. SME covers a variety of machines, including solder paste printers, hot air reflows furnaces, ICT online testing machines, AOI automatic optical detectors, etc. This equipment automates the placement and soldering of various electronic components during the PCBA production process. 

Third, we want to discuss some advantages of using SMT in modern industrial manufacturing. First advantage is miniaturization of electronics, because the advantage is more on the aspect of their size. When electronic components are soldered in the form of direct SMT attachment, both the area and volume are reduced. Saving more board space, electronic products can move towards miniaturization, or circuit boards with the same space can be placed into more electronic components to enhance more functionality and performance; Second advantage is high product precision, because when SMD components are smaller and thinner, the fields and dimensions in which electronic products can be applied can be greatly expanded, such as smaller and lighter electronic products, higher performance CPUs, or now more powerful GPUs because AI drives computing power, all of which are more sophisticated performance of SMD components; Third advantage is quality and production stability, because it is different from through-hole soldering technology, where SMT technology itself does not require too much manual work. It uses automated equipment to carry out electronic parts placement and soldering operations almost throughout the entire process. It is more suitable for mass production. The process is also more stable than through-hole soldering, and the quality is relatively guaranteed; Fourth advantage is the improvements of cost-effectiveness, because when equipment is automated in production, in addition to stabilizing the process, reducing errors, and promoting the improvement of production efficiency, manpower and working hours are effectively reduced, helping companies save labor and time costs.

Fourth, we want to discuss the manufacturing procedure of SMT. First step is PCB installation preparation: the circuit boards produced by the manufacturer include printing lines, setting the installation locations of electronic components, printing points of solder paste, etc., or outsourcing them to the PCB factory and sending them to the factory for continuous board production; Second step is the preparation of electronics components: according to the design requirements, select the corresponding electronic components and configure them in subsequent SMT mounters for material placement; Third step is solder pasting: the design drawings are imported into the solder paste printer, and the PCB enters the solder paste printer through the conveyor belt, and solder paste is applied at the locations where electronic components need to be soldered; Fourth step is component placement: the mapped electronic components are arranged at predetermined positions on the PCB according to the design drawings. The electronic components will be pasted on solder paste. Because the solder paste is in paste shape, it can be easily fixed, so that the components will not be displaced due to transportation; Fifth step is reflow soldering: the finished SMT chips enter the reflow oven and use high temperature to melt the solder paste, so that the electronic components floating on the surface can stick to the PCB. After the temperature drops, the solder paste solidifies to make the components firmly on the PCB; Final step of this production line is SMT inspection. This is where X-ray inspection machines come into place. Nectec‘s NX-EF PCB/BGA X-ray inspection machines are equipped with the most advanced X-ray technology with a maximum geometric magnification of 125X.

Fifth, we want to discuss some possible challenges during the production of SMT. First possible challenge is quality control: the miniaturization of electronic components has become an inevitable trend along the development, and the high-density configuration of components in PCB boards has become the norm. In addition to small size, the functional orientation becomes more complex, and the difficulty in initially placing components becomes higher, and welding is prone to poor technical problems such as welding also indirectly lead to increased difficulty in subsequent testing, maintenance, and component handling; Second possible challenge is the needs of personnel and experience: since different types of SMD components have different packaging equipment, processing and soldering may require the use of different equipment and technologies, relying on the experience of personnel; and although the SMT process is highly automated, experienced personnel are still needed to assist in processing monitoring, adjusting and maintaining equipment. In view of today’s rapid technological advancement and aging manpower, how to have sufficient manpower to maintain process operation is a challenge; Third possible challenge is the difficulties of managing production materials: the materials used in the SMT process are complex, including a variety of electronic components, solder pastes, packaging materials, various styles of PCB boards, etc. In addition to the variety of materials, the complexity of unified quality control has also increased, making it easy to be affected by market demand changes, price fluctuations, and supply chain problems further affect the SMT production schedule.

Sixth, we want to discuss the importance of IT+OT and intelligence to help the entire SMT process. There are few important points that are worth highlighting. First point is intelligent import and automation operate together: the SMT process itself is a highly integrated automation. From electronic component placement, solder paste printing, welding, testing, etc., the automated execution process is used during production to achieve consistency in production quality. Intelligent introduction helps identify abnormalities in the production line, eliminate possible output errors, reduce manpower and improve production efficiency, which is the key to intelligent cooperative automated production; Second point is actual monitoring and data analysis: during the process, equipment networking is used to achieve actual monitoring of the overall SMT process. Sensors are connected to the monitoring equipment system. By collecting data such as production status, equipment operating status, product quality values, etc., after data analysis and processing, you can gain insight and identify process problems to achieve process improvement and optimization; Third point is faster response capabilities and instant decision-making: when information and operations are combined with high-speed networking capabilities, the monitoring system can provide real-time data search and analysis during the SMT process, and even early warning, allowing managers to immediately discover potential risks and make faster and more accurate decisions during process operations. Make judgments and take appropriate actions immediately to avoid possible production interruptions or quality problems.

To conclude, the advent of SMT technology has promoted the lightness of electronic products, and the technical power and design and production capabilities of electronic components have also been united and improved. Although it is highly automated, it has also resulted in the dilemma that materials in the SMT process are relatively difficult to manage. In addition to the improvement of production technology, the integration capabilities of IT, OT and intelligence in the production environment are a necessary part in responding to the future trend of smart production. Promoting the improvement of environmental adaptability is also the key to strengthening the competitiveness of SMT companies.