Wave soldering is a bulk soldering process in which a printed circuit board loaded with through-hole components passes over a continuously flowing wave of molten solder. The molten alloy — typically a lead-free SAC formulation heated to roughly 250–265°C — wets the exposed component leads and plated through-holes, forming reliable metallurgical joints as the board cools.
Despite the rise of surface-mount technology, through-hole technology (THT) persists because through-hole joints offer superior mechanical retention. A connector that will be plugged and unplugged hundreds of times, a transformer that vibrates inside an engine compartment, or a high-power resistor that dissipates significant heat — all benefit from the physical anchoring that a plated through-hole provides. Wave soldering remains the most cost-effective way to form those joints in medium-to-high volume production.
A well-run through-hole assembly service follows a tightly controlled sequence. Understanding each stage helps buyers ask the right questions when evaluating a potential manufacturing partner.
Wave soldering is not without its difficulties. Solder bridges between closely spaced pins, cold or insufficient joints, pinholes from trapped moisture, and shadowing effects where tall components block the wave are all well-known issues. The difference between a mediocre result and a reliable one lies in process control, equipment quality, and operator expertise.
A capable manufacturing partner mitigates these challenges through several measures: precise flux deposition control, carefully tuned preheat profiles that match board thickness and component mass, stable dual-wave geometry, conveyor angle and speed optimization, and rigorous post-soldering inspection including AOI and visual checks. Nitrogen blanketing over the solder pot further reduces oxidation and improves wetting on difficult finishes.
Not every PCBA factory offers robust through-hole capabilities. When sourcing dip plug-in welding services, evaluate potential partners against these criteria:
| Criterion | What to Verify |
|---|---|
| Equipment | Dedicated DIP lines with reputable wave soldering machines, sufficient rear-welding stations, and board-washing capability |
| Quality Standards | ISO 9001 at minimum; IATF 16949 for automotive work; ISO 13485 for medical devices; IPC-A-610 assembly acceptance criteria |
| Inspection Coverage | Plug-in AOI, visual inspection, ICT, FCT, and X-ray where needed |
| Material Compliance | RoHS and REACH compliance; lead-free and leaded process capability |
| Mixed-Assembly Support | Ability to handle SMT-plus-DIP boards with proper masking or selective soldering for sensitive areas |
| Volume Flexibility | Support for prototype, medium-batch, and large-batch orders without excessive setup cost |
| Downstream Services | Conformal coating, testing, and finished-product assembly under one roof to reduce logistics risk |
Farway Electronic Co., Limited, based in LongGang, Shenzhen, operates a 2,000-square-metre production facility equipped for the full PCBA manufacturing chain — from PCB fabrication through finished-product assembly. Established in 2018, the company has served more than 100 industry customers across over 20 countries and regions.
For through-hole assembly specifically, Farway runs two dedicated DIP plug-in production lines equipped with Nitto wave-soldering machines, 24 rear-welding stations for touch-up and repair, and a board-washing system. The published DIP process covers component forming, insertion, wave soldering, lead cutting, repair welding, board washing, and functional testing — giving buyers a complete one-stop smt + dip assembly service without the need to coordinate multiple subcontractors.
Quality is anchored by four management-system certifications: ISO 9001 (quality), ISO 13485 (medical devices), IATF 16949 (automotive), and ISO 14001 (environmental). Assembly work follows IPC-A-610 acceptance standards, and product certifications include UL, RoHS, SGS, and REACH. This combination matters because it means the same partner can support consumer electronics prototypes today and automotive or medical production tomorrow without requalification.
Wave soldering rarely exists in isolation. Most real-world boards combine surface-mount and through-hole components, and finished products require protection, testing, and mechanical assembly. Choosing a partner that offers the entire chain reduces handoff risk, shortens lead times, and simplifies traceability.
Farway's nine core manufacturing services connect end to end. PCB board making covers rigid, flexible, and rigid-flex boards from 1 to 32 layers. SMT pcb assembly handles 01005 components and 0.2 mm BGA pitch on Yamaha placement lines with Jintuo reflow ovens. After DIP welding, boards can move directly to automated conformal coating on an Anda spraying line that supports boards up to 550 mm × 470 mm, protecting against moisture, dust, corrosion, and thermal cycling.
Testing spans SPI, AOI, FAI, X-ray, ICT, FCT, thermal imaging, high- and low-temperature reliability testing, and oscilloscope-based checks. For products that need environmental sealing, Farway also offers PCBA low-pressure injection moulding — ideal for medical sensors, automotive electronics, and waterproof devices. Finally, box-build assembly combines tested PCBA boards with enclosures, wiring harnesses, connectors, and HMI modules into ready-to-ship products, complete with SOP-based production, barcode traceability, and OBA sampling.
Wave soldering remains an essential process for any product that includes through-hole components, and the quality of that process depends heavily on the partner you choose. Look for dedicated DIP lines, reputable wave-soldering equipment, multi-standard certifications, robust inspection, and the ability to handle both SMT and DIP under one roof. Farway Electronic brings all of these together in a Shenzhen facility designed for prototype-to-production flexibility across automotive, medical, new energy, security, and communications markets.
Whether you need a single prototype or a high-volume production run, a partner that controls the entire PCBA chain — from PCB fabrication through conformal coating, testing, and box-build assembly — saves time, reduces risk, and keeps your project on schedule.
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