Walk into most electronics plants today and the surface-mount lines steal the show. Still, DIP plug-in assembly holds its place in PCBA manufacturing. Surface-mount parts get placed and reflowed quickly, yet plenty of components simply cannot go through that route. Large connectors, relays, power resistors, transformers, big electrolytic capacitors and many switch and socket parts are too big, carry too much power, or have awkward body shapes for automated SMT placement. Through-hole mounting fixes these parts firmly because the leads pass through the board and are soldered on the far side. That mechanical bond is exactly what high-vibration and higher-power applications rely on.
At DIP plug-in assembly is therefore not an afterthought; it is one of the nine core manufacturing services Farway builds its one-stop offering around. The company operates a 2,000-square-metre workshop in LongGang, ShenZhen, and has served more than 100 industry customers across more than 20 countries and regions since it was established in 2018.
DIP work normally happens after the SMT side has been placed and reflowed, so that larger through-hole parts are not exposed to unnecessary thermal stress. Farway follows a controlled sequence that moves from component preparation to full functional testing.
1. Component forming and preparation. Leads on plug-in components are formed and cut to length before insertion, which helps the parts seat cleanly against the board and keeps later trimming simple.
2. Manual or semi-automated insertion. Operators ｉｎｓｅｒｔ the leads of through-hole components into the plated holes on the PCB. Trained operators verify polarity and orientation so that electrolytic capacitors, diodes and connectors are seated correctly and fully against the surface.
3. Wave soldering. The loaded board passes over a wave of molten solder. A clean flux is applied to the underside, the board is preheated, and the solder wave flows up through the plated holes to form the metallic joints. Farway runs two DIP plug-in lines with two wave-soldering machines to keep this stage moving.
4. Lead cutting and repair welding. Excess leads protruding from the underside are cut to length to avoid short circuits inside the product enclosure. Any joints that need attention are corrected, and 24 rear-welding stations give the team capacity to complete rework in step.
5. Board washing. Flux residue is cleaned from the board after soldering, because leftover residue can cause corrosion or leakage paths over time.
6. Inspection and functional testing. Finished boards are checked and tested before they move on. This is where plug-in specific review comes in alongside the rest of the inspection flow.
Plug-in assembly involves a lot of manual handling, so the quality controls around it matter more than people often expect. Farway uses plug-in AOI alongside a broader inspection toolkit that includes SPI, AOI, FAI first-article inspection, X-ray, ICT in-circuit testing, FCT functional testing, thermal imaging and high- and low-temperature reliability testing. Certified and trained operators handle the through-hole assembly service, and controlled work-in-process areas keep boards moving in an orderly flow.
Process discipline is enforced through IPQC in-process checks and QA sampling at the end of the line. ESD protection is treated as a basic requirement because the process relies on manual insertion. Operators follow the BOM and assembly drawings strictly, and the wave-soldering profile is managed against the recommended preheat, flux activity and wave-contact settings for each board type.
Modern products almost always mix surface-mount and through-hole parts on the same board, and reliability depends on both halves being done well. Working with a partner who can handle one-stop SMT + DIP assembly, component sourcing, conformal coating and finished-product assembly means there is a single owner for the chain from bare board to shipped product. Farway combines two SMT lines and two DIP plug-in lines under the same roof, so mixed-assembly boards move between the two technologies without changing suppliers.
If you are specifying an industrial, automotive, medical or energy product that needs reliable through-hole mounting, it is worth talking to an assembly partner that treats DIP as a core capability rather than a side task. Contact Farway via its sales desk at sales@farway.hk or through the website, and the team can advise on the right ｉｎｓｅｒｔ, solder and test approach for your board.
Hey there! Your message matters! It'll go straight into our CRM system. Expect a one-on-one reply from our CS within 7×24 hours. We value your feedback. Fill in the box and share your thoughts!