Comparison of SMT and THT: Which Electronic Assembly Technology is Best for Your Project?
In the world of electronics manufacturing, the careful selection of component assembly technology—SMT (Surface Mount Technology) versus THT (Through-Hole Technology)—plays a crucial role in the performance, reliability, and cost of the final product. This article takes an in-depth look at the differences between these methods and helps you choose the optimal solution for your project.
What is SMT (Surface Mount Technology)?
SMT is a surface mount assembly method in which components such as resistors, capacitors, and BGA packages are soldered directly onto the surface of the PCB, eliminating the need for through-hole insertion.
Benefits of SMT
- Compact Design – SMD (Surface Mount Devices) components are significantly smaller than their traditional counterparts, enabling circuit miniaturization and reducing the overall product size.
- Lower Production Costs for High Volumes – Automated assembly processes significantly reduce both the time and costs involved in production.
- Optimized for High-Frequency Circuits – The small size of SMT components, their dense placement, and short signal path connections help reduce electromagnetic interference (EMI) by lowering radiated emissions while increasing the circuit’s resilience to radio-frequency disturbances.
- Reduced Requirement for Protective Coatings – Smaller amounts of solder mask and conformal coating are needed.
- Enhanced Vibration Resistance – The low mass and inertia of SMD components, combined with the rigidity of their solder joints, result in a compact construction that is highly resistant to vibrations.
Limitations of SMT
- Challenges in Manual Rework – The precise soldering process required for SMT often necessitates specialized equipment, making manual repairs difficult when component failures occur.
- Lower Mechanical Durability – SMT components may be less robust under vibrations and other mechanical stresses, which can pose problems in harsh operating environments.
What is THT (Through-Hole Technology)?
THT is a traditional assembly approach where components—such as electrolytic capacitors and connectors—with leads that pass through PCB holes are soldered on the underside.
Benefits of THT
- Superior Mechanical Durability – Ideal for heavy components like transformers, chokes, and high-capacity capacitors, THT offers excellent resistance to mechanical stress.
- Ease of Prototyping – THT components can be easily replaced or modified manually, greatly simplifying the prototyping and testing processes.
- Enhanced Cooling – The larger size of THT components and their extensive contact surface with the environment facilitate more effective heat dissipation.
Limitations of THT
- Higher Material Consumption – The need to drill holes in the PCB increases both material costs and production time.
- Reduced Component Density – THT limits the ability to pack components into small spaces, which is especially important in the production of compact devices.
When to Choose SMT vs. THT?
The decision to use SMT or THT depends on the product’s intended application and the specific technical requirements of your project. Here are our recommendations:
| Application | SMT | THT |
| Portable devices (smartphones, IoT) | ✔️ | ❌ |
| Industrial equipment (PLC controllers) | ✔️ | ✔️ |
| High-frequency circuits (RF) | ✔️ | ❌ |
| Power connectors/high-current connectors | ❌ | ✔️ |
| Mass production (>1000 units/series) | ✔️ | ❌ |
| Prototyping/small series (<10 units) | ❌ | ✔️ |
| Systems requiring miniaturization | ✔️ | ❌ |
| High-power components (transformers) | ❌ | ✔️ |
Interested in Collaboration?
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EMAG-SERWIS’s Expertise in SMT/THT Assembly
Our projects are driven by the collaboration of specialists from various fields:
- Process Engineers – Optimize PCB layouts with regard to the chosen assembly technologies and their efficiency.
- Soldering Technologists – Select appropriate solder pastes and reflow profiles crucial for ensuring quality connections.
- SMT Machine Operators – Manage automated assembly lines and optimize the pick & place process for component placement.
- Assemblers – Specialize in THT component assembly, ensuring high precision in the final product.
Equipment
- SMT Machines – Including automatic JUKI assembly lines.
- THT Soldering Equipment and Hand Tools.
Conclusion
SMT and THT technologies do not compete—they complement each other perfectly. At EMAG-SERWIS, we select the most appropriate technology based on the specific requirements of each project. By combining the automation of SMT with the durability of THT, we produce products that are not only efficient but also resilient under extreme operating conditions.
Bibliography:
- IPC-A-610H (2020) – Requirements for the Acceptability of Electronic Assemblies.
- Górecki P. (2019) – Surface Mount Technologies in Electronics. PJWSTK Computer Publishing, Warsaw.
- PN-EN 61760-1:2020-06 – Surface Mount Technology – Part 1: Standard Methodology for Describing SMD Components. PKN.
- JUKI Official Documentation (2023) – Technical Specifications and Best Practices.
- Zieliński T. (2017) – PCB Design. Wrocław University of Technology Publishing House.
- IPC-7711/7721C (2022) – Rework, Modification and Repair of Electronic Assemblies. IPC.
- SMTconnect Whitepaper (2023) – Hybrid SMT/THT Assembly for Industrial Applications.
- Institute of Electronic Technology (2022) – Report: Trends in Industrial PCB Assembly Technologies in Poland. ITE, Warsaw.
- Sikora A. et al. (2021) – Modern 3D SPI Optical Inspection Systems in EMS Production. Elektrotechnical Review, 97(9), 145–149.