SMT places components directly onto the PCB surface using solder paste, automated pick-and-place machines, and reflow soldering. It enables high component density, miniaturized layouts, and high-speed automated production — making it the preferred choice for consumer electronics, communication devices, and any product where space and signal performance matter.
DIP through-hole technology, by contrast, inserts components with leads into drilled holes and bonds them with wave soldering. The resulting solder joints are mechanically robust, resistant to vibration, and easier to inspect and rework. This makes DIP indispensable for power devices, connectors, and components that must withstand physical stress or thermal cycling.
Neither process alone covers every design requirement. A mixed-assembly approach combines the density and speed of SMT with the durability and power-handling capability of through-hole — the reason it has become standard practice across industrial controls, automotive electronics, medical devices, and new-energy systems.
A well-executed one-stop smt + dip assembly service follows a clearly defined sequence so that the two technologies do not interfere with each other. The general flow is:
The order matters. SMT is completed first because the reflow temperatures (typically 240–260°C) would damage many through-hole components. DIP wave soldering follows, and its lower thermal exposure on the component side is tolerable for the already-attached SMT parts. Getting this sequence right is one of the most critical process controls in mixed-assembly production.
| Design Requirement | Recommended Process | Typical Component |
|---|---|---|
| High-density IC placement | SMT | QFN, BGA, 0402/0201 passives |
| High-frequency signal paths | SMT | RF transceivers, high-speed memory |
| Power handling and heat dissipation | DIP | Transformers, large electrolytic capacitors |
| Mechanical stress and vibration resistance | DIP | Connectors, relays, terminal blocks |
| Field serviceability and rework | DIP | Socketed ICs, replaceable modules |
| Combined density and durability on one board | Mixed SMT + DIP | Industrial controllers, automotive ECUs |
Industries that routinely rely on mixed assembly include automotive electronics, industrial automation, security systems, medical devices, and new-energy power management. These products all share a common trait: they pack sophisticated signal-processing circuitry alongside rugged power and interface components on the same PCB.
Not every factory can run both SMT and DIP under one roof with consistent quality. When evaluating a partner for combined assembly, several capabilities separate reliable manufacturers from those who simply subcontract one of the two processes.
The manufacturer should operate its own SMT placement lines and DIP wave-soldering lines in the same facility. This eliminates handoff delays, reduces logistics risk, and ensures that process engineers can coordinate the transition between reflow and wave soldering without leaving the building. A true smt assembly service provider that also offers through-hole soldering service under one quality system is far easier to manage than two separate vendors.
Mixed-assembly BOMs are inherently more complex because they combine SMT reels and through-hole bulk packaging. A capable partner checks the BOM for sourcing risk, procures from authorized distributors, performs incoming quality inspection, and manages inventory with ERP tracking, first-in-first-out rotation, anti-static storage, and controlled temperature and humidity. Without this level of component management, shortages and counterfeit parts become a recurring problem.
Quality verification must cover both technologies. For SMT, look for SPI solder-paste inspection, AOI, and X-ray for hidden joints such as BGA. For DIP, visual plug-in inspection and thermal imaging help catch cold solder joints and insufficient hole fill. Functional testing — ICT, FCT, and oscilloscope-based checks — should be standard, not optional. Without multi-layer testing, defects that pass visual inspection can still reach the field.
Formal certifications provide third-party evidence that a factory follows disciplined process controls. For mixed-assembly electronics, the most relevant standards are:
IATF 16949 matters for automotive work, ISO 13485 for medical devices, and IPC-A-610 defines the acceptability criteria for both SMT and through-hole solder joints. A manufacturer holding these certifications has invested in the documentation, traceability, and corrective-action systems that mixed-assembly production demands.
Even when the SMT side is clean, DIP processing can drag down overall yield if process controls are weak. The following issues are among the most frequent causes of field failures in mixed-assembly boards:
These problems are preventable with trained, certified operators, documented SOPs, IPQC in-process sampling, and a dedicated QA final inspection. This is why the quality system behind the assembly matters as much as the equipment itself.
Farway Electronic Co., Limited operates a 2,000-square-metre production facility in LongGang, Shenzhen, equipped to run both SMT and DIP under a single quality system. The factory houses two SMT production lines with Yamaha medium- and high-speed placement machines and Jintuo ten-zone reflow ovens, alongside two DIP plug-in lines, two Nitto wave-soldering machines, 24 rear-welding stations, and a board-washing system.
On the inspection side, the facility runs SPI, AOI, FAI, X-ray, ICT, plug-in visual inspection, thermal imaging, high- and low-temperature reliability testing, and FCT functional testing — covering both SMT and through-hole quality verification in-house. The company holds ISO 9001, ISO 13485, IATF 16949, and ISO 14001 certifications, and assembles to IPC-A-610 acceptability standards with UL, RoHS, SGS, and REACH product-certification scope.
Farway supports the full mixed-assembly workflow — from PCB fabrication and component sourcing, through SMT placement, DIP wave soldering, conformal coating and low-pressure injection moulding, to finished-product and box-build assembly. This makes it possible to consolidate an entire oem pcba manufacturing project with one accountable partner rather than splitting it across multiple vendors.
The company has served more than 100 industry customers across more than 20 countries and regions, with application experience spanning transportation and automotive electronics, new energy, security, communications, medical devices, and other electronic product fields. Orders are accepted from prototype quantities of a single piece through medium and large production batches.
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