Industry Insights | SMT: The Core Processes Enhancing Efficiency in Electronics Manufacturing
November 12, 2025
In the field of electronics manufacturing, surface mount technology (SMT) has become a critical process for improving production efficiency and ensuring product quality. From March 25–27, 2026, productronica China 2026 will be held grandly at the Shanghai New International Expo Centre (Halls E1-E5, W1-W4). The exhibition is expected to cover an area of nearly 100,000 square meters and bring together over 1,000 leading companies in the electronics manufacturing industry to showcase the latest achievements and systematic solutions in SMT. Below are the core processes through which SMT enables efficient production.
I. Ensuring Precise Equipment Selection to Lay the Foundation for Efficient Production
Precise equipment selection forms the basis for highly efficient production. Core equipment in an SMT production line includes printers, pick-and-place machines, and reflow soldering ovens, whose performance directly impacts production efficiency and product quality. Equipment requirements vary significantly across different application fields. Taking automotive electronics as an example, product reliability requirements are extremely high, where any solder joint defect could potentially lead to serious safety hazards. For manufacturing key components like Engine Control Units (ECUs) and Advanced Driver-Assistance Systems (ADAS), it is essential to utilize high-precision printers to ensure accurate solder paste deposition in both position and volume. This also requires pick-and-place machines capable of high-speed, high-precision placement of miniature components, and reflow soldering ovens that guarantee uniform and stable temperature profiles to ensure solder joint reliability.
In contrast, for the consumer electronics sector, such as smartphones and tablets, manufacturers face mass market demand and intense competition, necessitating high-capacity and high-cycle production capabilities. Companies need to select high-speed pick-and-place machines and printers to shorten production cycle times. Simultaneously, PCB dimensions and assembly complexity must be considered. For large-sized, high-density PCBs, equipment with a larger working area and stronger processing capabilities is required to achieve precise component placement.
II. Optimizing Stencil Design to Ensure Solder Paste Printing Quality
The stencil, a critical tool in solder paste printing, has a design quality that directly impacts printing accuracy and consistency. In SMT processes, solder paste printing forms the foundation for component placement and soldering. Improperly designed stencil aperture dimensions, shapes, or thickness can easily lead to defects such as skipping, insufficient solder, or bridging. These defects, in turn, can cause soldering quality issues like cold joints or short circuits, ultimately compromising product performance and reliability.
Optimal stencil design requires precisely matching aperture size, shape, and thickness to the characteristics of the component packaging. According to IPC-7525 "Stencil Design Guidelines," stencil apertures must meet specific criteria: a Width-to-Thickness Ratio ≥ 1.5 (aperture width/stencil thickness) and an Area Ratio ≥ 0.66 (aperture area/aperture wall area). This ensures a solder paste release rate exceeding 80%. Micro-components require correspondingly fine apertures to ensure precise control over solder paste volume. Special pad shapes need custom-designed apertures to guarantee complete coverage. The stencil foil thickness must also be appropriately selected based on the required solder joint height, as either excessive or insufficient solder paste will adversely affect soldering quality.
III. Selecting Solder Paste Materials to Enhance Soldering Reliability
Solder paste is a critical material in the SMT soldering process, whose performance directly impacts the mechanical strength, conductivity, and long-term reliability of solder joints. It serves to temporarily fix components before reflow and melts during the reflow process to form the solder joints, ensuring stable electrical connections and robust mechanical support. Inappropriate selection or poor quality of solder paste can lead to insufficient joint strength, reduced electrical conductivity, or oxidation failures, ultimately affecting product lifespan and operational safety. Enterprises should select suitable solder paste types based on their product's application scenarios and process requirements. For instance, automotive electronics require high-reliability solder paste capable of withstanding high temperatures and vibration, such as Sn-Ag-Cu alloy solder paste (melting point 217°C) compliant with the J-STD-006 standard, which offers a 40% improvement in anti-fatigue life compared to traditional Sn-Pb solder paste. Consumer electronics, however, may prioritize soldering efficiency and cost. Many companies in the exhibition's Electronic Chemical Materials zone have also showcased low-residue solder pastes suitable for consumer electronics, which can reduce cleaning steps, thereby enhancing efficiency.
IV. Precise Process Tuning to Ensure Stable Soldering Quality
The configuration of the reflow soldering process parameters directly determines soldering outcomes. The temperature profile is divided into four stages: preheat, soak, reflow, and cooling. Take commonly used lead-free solder paste as an example: The preheat stage has a ramp-up rate of 1-3°C/sec (to 120-150°C); the soak stage maintains 150-180°C for approximately 60-120 seconds; the reflow stage has a peak temperature of 230-250°C (held for 30-60 seconds); the cooling stage has a cool-down rate of 3-6°C/sec. Each stage must be precisely configured according to the solder paste characteristics and component heat tolerance. The preheat stage allows for gradual solvent volatilization. The soak stage promotes flux activation and oxide removal. The reflow stage achieves solder melting and wetting. The cooling stage determines the solder joint crystallization quality and mechanical properties.
An improper temperature profile can lead to component thermal damage, solder balling, cold joints, or cold soldering. Therefore, strict control over the temperature, duration, and ramp rates for each stage—combined with real-time monitoring and iterative optimization—is essential for achieving consistent and reliable soldering quality.
The introduction of online inspection equipment, such as Automated Optical Inspection (AOI) and Solder Paste Inspection (SPI), enables real-time identification of defects in the printing, placement, and soldering processes. This allows for timely adjustments to process parameters. By feeding the inspection data back into the production control system, rapid diagnostics and closed-loop optimization are achieved. This prevents defects from propagating to subsequent process stages, reduces scrap costs, and improves the overall production yield.
*Source: Standards such as IPC-7525, J-STD-006, and exhibitor materials. Please contact us for removal if any infringement is involved.
About productronica China Scheduled for March 25–27, 2026, at the Shanghai New International Expo Centre (Halls E1-E5, W1-W4), productronica China 2026 is dedicated to the electronics manufacturing industry. The exhibition will comprehensively showcase high-precision placement equipment and integrated solutions, covering core manufacturing equipment and intelligent production line systems. Whether you are from automotive electronics, new energy, industrial electronics, consumer electronics, medical electronics, or other related sectors, the exhibition serves as an ideal platform to source advanced equipment and technological insights tailored to your specific capacity, precision, and process requirements. Featuring nearly 1,000 domestic and international enterprises across approximately 100,000 square meters of exhibition space, the exhibition will offer visitors the opportunity to witness equipment in live operation, test key performance metrics, and engage in in-depth discussions with technical experts on industry trends and equipment selection strategies, thereby completing evaluation and matchmaking efficiently in one stop. We sincerely invite professionals from the electronics manufacturing industry to visit the exhibition. Join us in collaborating to explore pathways for technological innovation and industrial upgrading, and collectively drive the industry toward higher precision, intelligent manufacturing, and enhanced reliability.
Secure your booth now and join the premier electronics manufacturing event productronica China 2026 will deliver an unmissable gathering for the electronics manufacturing industry, showcasing cutting-edge technologies, deep insights, and precise business opportunities. Contact your exhibition sales representative or call Ms. Xing at 021-20205553 to secure premium booth space. Showcase your innovations on the world's leading stage for electronics manufacturing technologies and tap into global business prospects!
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