Surface mount technology dominates headlines, but through-hole soldering quietly holds together the most demanding electronic products on the market. From automotive control units to industrial power supplies, components that carry high current, endure mechanical stress, or require field replaceability still depend on plated through-hole joints. Understanding why this technology persists helps product teams make better manufacturing decisions.
Through-hole technology (THT) places component leads through drilled holes in a printed circuit board and solders them on the opposite side. This creates a physical bond that extends through the entire board thickness. While surface mount components save space and enable automation, through-hole joints offer superior mechanical retention that no adhesive-bonded SMD can match.
Connectors that experience repeated mating cycles, electrolytic capacitors in power circuits, transformers, relays, and large heat-dissipating components all rely on through-hole mounting. The leads anchored through the board distribute mechanical stress across the hole barrel and surrounding pads, preventing pad lifting and trace damage under vibration or thermal cycling.
For products destined for automotive, industrial, and medical environments, this mechanical robustness is not optional. It is a design requirement that makes through-hole soldering service an indispensable part of any comprehensive electronics manufacturing chain.
In volume production, hand soldering through-hole components is neither practical nor consistent. The industry standard solution is wave soldering, an automated process that solders all through-hole joints on a board in a single pass. Farway Electronic operates Nitto wave-soldering equipment across two dedicated DIP plug-in production lines at its LongGang, Shenzhen facility.
The wave soldering process follows a carefully controlled sequence:
A properly executed wave soldering service produces consistent, repeatable joints across an entire production run. The key is controlling parameters: solder temperature, conveyor speed, wave height, flux density, and preheat profile all interact to determine joint quality.
Most modern circuit boards are not purely SMT or purely through-hole. They combine both. A typical design might place microcontrollers, resistors, and capacitors on the surface using SMT, while connectors, power components, and mechanical switches use through-hole leads. This is called mixed assembly, and it requires a manufacturer that can handle both processes on the same production line.
Farway runs two SMT production lines alongside two DIP plug-in lines, allowing boards to flow from surface mount placement through reflow soldering, then to DIP insertion and wave soldering without leaving the facility. The company pairs Yamaha medium- and high-speed placement machines with Jintuo ten-zone reflow ovens for the SMT stage, then transitions to Nitto wave soldering for through-hole components. This integrated approach eliminates the handoff delays and quality gaps that occur when SMT and DIP are split across different vendors.
For product teams, choosing a partner that offers both smt pcb assembly and DIP processing under one roof means faster turnaround, tighter process control, and a single point of accountability for the entire board.
Farway Electronic, established in 2018 and based in LongGang, Shenzhen, has built a 2,000-square-metre production workshop dedicated to high-reliability electronics manufacturing. The company's DIP through-hole assembly operation includes:
The published DIP process runs from component forming and insertion through wave soldering, lead cutting, repair welding, board washing, and functional testing. Every stage is documented and standardized to ensure that the first board and the thousandth board meet the same quality benchmark.
Through-hole joint quality directly affects long-term product reliability. Farway adheres to IPC-A-610 as its PCBA assembly standard and maintains certifications across four management systems: ISO 9001 for quality management, ISO 13485 for medical devices, IATF 16949 for automotive supply, and ISO 14001 for environmental management.
Inspection covers multiple stages of the DIP process. Plug-in AOI checks for insertion errors and solder defects immediately after wave soldering. FAI (first-article inspection) verifies the first board of each production run against the BOM and Gerber data. X-ray inspection can detect hidden issues in complex joints, while functional testing confirms that the assembled board performs to specification before it moves to the next stage.
For applications requiring additional protection after assembly, Farway also offers conformal coating and low-pressure injection moulding services. These post-assembly protections shield through-hole joints and surrounding circuitry from moisture, dust, chemicals, and mechanical shock, extending product life in harsh operating environments.
Through-hole soldering is one link in a longer manufacturing chain. Farway positions itself as a one-stop partner, covering PCB fabrication, component sourcing, SMT assembly, DIP welding, conformal coating, low-pressure moulding, PCBA testing, and finished-product box-build assembly. Customers can start with a bare board design and receive a packaged, tested, shipping-ready product without managing multiple suppliers.
The finished product assembly service combines tested PCBA boards with enclosures, wiring harnesses, human-machine interfaces, connectors, and other mechanical modules. SOP-based production, station self-inspection, QC full inspection, and QA and OBA sampling ensure that the final product meets the same standards as the individual components. Barcode traceability ties every finished unit back to its manufacturing records.
This integrated model is particularly valuable for automotive, security, medical, and industrial customers who need consistent quality across small prototype runs and large-volume production orders. Farway reports serving more than 100 industry customers across more than 20 countries and regions.
Through-hole soldering is not a legacy process being phased out. It is a critical technology for any product that carries power, connects to the outside world, or operates in demanding environments. Choosing the right manufacturing partner for this process determines whether your boards survive field conditions or fail prematurely.
Farway Electronic combines industrial wave-soldering equipment, certified operators, IPC-standard inspection, and a complete one-stop manufacturing chain to deliver through-hole assemblies that hold up in the real world. Whether your project needs a quick prototype run or ongoing volume production, the engineering team in Shenzhen is ready to review your BOM and process requirements.
Contact Farway at sales@farway.hk or call 181 2472 7402 to discuss your through-hole assembly project. Visit www.farway.hk to explore the full range of PCB, PCBA, and EMS services.
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