In May 2026, Suzhou DRUTEK held an SMT soldering skills competition. The entrants came from downstream SMT, through-hole insertion, rework and assembly stations. The contest had a theory paper and a practical part, with the practical split into three tasks — SMT rework, through-hole component soldering and wire/terminal soldering — all performed at production workstations with the boards and irons used every day.
The reason for holding it is simple: the placement machine determines 95% of a board's solder joints, but the remaining 5% depends entirely on people.
Our SMT lines already handle 01005 and 0.4 mm pitch BGA on the same board, with equipment parameters covering printing, placement and reflow, and SPI and AOI standing guard in between. But those machines cannot touch three kinds of work:
These three are precisely where problems concentrate. "It's soldered" is not a criterion: is the wetting angle good, is there enough solder, is there a cold or disturbed joint, was flux residue cleaned, was the component scorched by the iron? The machine will not tell you; only the operator knows. And none of it shows up in functional test — it surfaces when the customer assembles the system, or months into field operation.
| Task | Content | What it assesses |
|---|---|---|
| Theory | Soldering principles, IPC-A-610 acceptance criteria, ESD and moisture-sensitive device basics, flux and solder paste characteristics | Knowing why a joint is made this way |
| SMT rework | Removal and reflow of 0603 / 0402 parts, clearing bridges on QFP leads | Temperature control and feel; limiting thermal damage |
| Through-hole and terminals | Through-hole component soldering, wire and terminal soldering, joint formation | Solder fill, absence of voids and cold joints |
Scoring did not stop at "does it power up". The judges were process and quality engineers working together, marking item by item against acceptance criteria: is the wetting good, does the joint show a concave fillet, is there bridging, a spike or a cold joint, was flux residue removed, is there thermal damage to component or laminate — plus workstation 5S, ESD discipline and completion time. Medical products fall under the stricter class 3 acceptance requirements, and that carries its own weighting in the score sheet.
The most valuable part of the contest was not the ranking but the process. One entrant soldered quickly and neatly, yet left the iron on the pad two seconds too long during removal. Another finished a rework without cleaning; the residue is almost invisible, but in high humidity it absorbs moisture and causes leakage. A third picked up boards bare-handed, forgetting the wrist strap — behaviour that spot checks rarely catch and a competition shows plainly.
So when the contest ended, the score sheets became training material. Every deduction was photographed and turned into a side-by-side reference posted next to the workstations, which works better than saying "mind the solder quality" ten times.
Machine accuracy can be bought. Hand skill cannot. The part that cannot be bought is built by practice, by comparison, and by correcting the same thing again and again.
A competition is a concentrated review, not the finish line. The results have been folded into the job skills matrix: for the key positions of rework, insertion and terminal soldering, staff will be graded under an internal certification scheme, and only those at the required level work independently. New-hire induction now includes practical hours and an assessment on manual soldering.
None of this appears on a quotation, but it decides one thing: when you hand us a board that needs hand soldering, the person doing it is at the same level as someone who has soldered thousands of that same board.
