Despite the rapid expansion of surface-mount lines, through-hole technology (THT) continues to hold a critical place in PCBA manufacturing. The reason is straightforward: through-hole joints physically anchor component leads through the board and secure them with solder on both sides. This delivers far stronger mechanical bonds than surface-mount pads alone, which matters whenever a board will face vibration, thermal cycling, repeated mating cycles, or heavy in-line current.
Power supplies, automotive controllers, industrial I/O modules, and medical instruments routinely mix SMT and through-hole parts on the same board. For these mixed-technology assemblies, a capable dip plug-in welding service is what bridges the gap between fine-pitch surface mounting and the rugged connectors and power components that a product depends on.
A controlled DIP plug-in welding line is not a single operation but a sequenced workflow. Each stage is engineered to protect component integrity and produce consistent, inspectable solder joints. The process used at Farway Electronic runs from component preparation through final functional verification:
Wave soldering is the core technique that makes high-volume wave soldering service practical. A pump lifts molten solder from a heated bath into a standing wave. As the populated board glides across the wave at a controlled angle and conveyor speed, liquid solder contacts the underside of the board, fills the plated through-holes, and bonds each lead to its pad.
Modern wave soldering systems use a dual-wave arrangement to manage defect formation. A turbulent first wave, sometimes called a chip wave, washes into dense pin fields and breaks through surface tension that would otherwise shield tight-pitch leads. A smooth second laminar wave then refines the fillets, draining away excess solder and preventing bridges between adjacent pins. Precise control of solder temperature, contact time, conveyor angle, and flux application determines whether a board emerges clean or needs extensive rework.
Even on a well-tuned line, through-hole soldering can produce characteristic defects. Recognizing them and controlling their root causes is what separates a reliable welding partner from a commodity board house.
Farway controls these defects through a layered inspection regime. Plug-in AOI catches visual defects right after soldering, IPQC samples the line during production, and QA performs outgoing sampling so that no board ships without verified joint quality.
Farway Electronic operates its through-hole soldering service from a 2,000-square-metre production workshop in LongGang, Shenzhen. The DIP plug-in welding line is equipped to handle mixed-technology boards that combine SMT and through-hole components in a single build.
| Resource | Details |
|---|---|
| Plug-in production lines | 2 dedicated DIP through-hole lines |
| Wave soldering machines | 2 Nitto wave-soldering systems |
| Rear-welding stations | 24 manual touch-up positions |
| Board washing | Dedicated board-washing machine |
| Inspection | Plug-in AOI, IPQC, and QA sampling |
| Order flexibility | Prototype from 1 piece through medium and large batches |
This configuration allows Farway to run prototype validation, medium-volume builds, and mass production on the same controlled line, with trained and certified operators following standardized SOPs at every station.
A through-hole assembly service is only as trustworthy as the standards behind it. Farway builds its through-hole welding under an IPC-A-610 assembly standard framework and operates within four management-system certifications: ISO 9001 for quality management, IATF 16949 for automotive industry quality, ISO 13485 for medical devices, and ISO 14001 for environmental management.
For customers in transportation, new energy, security, medical, and communications markets, these certifications mean that through-hole welding is documented, traceable, and repeatable rather than dependent on individual operator skill. The company has served more than 100 industry customers across more than 20 countries and regions.
Through-hole soldering is the right choice whenever a design calls for components that surface-mount cannot reliably accommodate. Large electrolytic capacitors, transformers, heavy inductors, D-sub and pin-header connectors, relays, and power modules all benefit from the mechanical anchoring that plated-through-hole joints provide.
For mixed-technology boards, Farway also offers a combined SMT-plus-DIP assembly flow. This means surface-mount placement, reflow soldering, through-hole insertion, wave soldering, and final functional testing can all be coordinated under one roof, shortening lead times and keeping a single quality accountability chain from bare board to shipped product.
Selecting a through-hole welding partner should go beyond price quotes. The questions that matter are operational: How many wave soldering lines does the factory run, and is equipment from reputable manufacturers? Are operators trained and certified? Is there AOI coverage after plug-in soldering, or is inspection purely visual? Does the line include board washing and controlled rear-welding capacity? Are the relevant ISO, IATF, and IPC standards in place and actively maintained?
Farway Electronic answers each of these with documented capability: Nitto wave-soldering equipment, certified operators, plug-in AOI, dedicated board washing, twenty-four rear-welding stations, and a certified quality management system spanning automotive, medical, and general industrial standards.
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