Spray fluxing & preheat
Flux deposited by spray, then the board is brought up to temperature so the wave does not have to do the heating.
THROUGH-HOLE & DIP · WAVE, SELECTIVE, PRESS-FIT
Through-hole joints: wave, selective, press-fit.
Dual-wave heats the whole board; robotic selective soldering heats one joint at a time. On mixed-technology boards the industry-typical defect rate runs 500–2,000 PPM for wave against 50–200 PPM for selective, which is why the choice is made on through-hole count and batch size — and why the method we quote is named on the quotation. Both run on 2 THT lines.
METHOD SELECTION FIRST
Which of the three solders your board
The decision is not quality against cost. It is how much of the board you are willing to heat, and how the tooling is paid for. Answer both and the method chooses itself.
Dual-waveWhole-board heat · palletised · >10,000 boards a run
SelectiveSingle-nozzle · localised heat · 100–5,000 boards a run
Hand & press-fitConnectors, rework, solderless compliant pins
Line ownership2 THT assembly lines
THE TWO METHODS, QUANTIFIED
Wave against selective, row by row
Every figure in the first three columns is an industry-typical value published for these two processes, not a measurement from our own line. Read it as the shape of the trade-off, then confirm the numbers for your board at quotation.
| Parameter | Dual-wave soldering | Robotic selective soldering | Basis |
|---|---|---|---|
| Throughput | 5,000+ joints per minute, whole board at once | 1–4 joints per second | Industry-typical value |
| Cost per joint | USD 0.02–0.05 above 10,000 boards | USD 0.05–0.15 | Industry-typical value |
| Positioning accuracy | ±0.5 mm, board level | ±0.1 mm, joint level | Industry-typical value |
| Solder temperature | Pot 255–265 °C lead-free | Nozzle 260–280 °C lead-free | Industry-typical value |
| Defect rate, mixed-technology board | 500–2,000 PPM | 50–200 PPM | Industry-typical value |
| Tooling setup cost | Pallet or carrier USD 3,000–8,000 per design | Programming USD 500–1,000 | Industry-typical value |
| Batch sweet spot | >10,000 boards per run | 100–5,000 boards per run | Industry-typical value |
| Heat-affected zone | Whole board heated | Single-point local heating, no thermal shock to neighbouring SMD parts | Process description |
| Process identity | Dual-wave: turbulent wave then laminar wave | Robotic selective soldering, single-point nozzle | Process description |
| Flux application | Spray fluxing with a preheat zone | Point fluxing at the nozzle | Process description |
| Hole fill and wetting criterion | To IPC J-STD-001 | To IPC J-STD-001 | Standard clause |
| Hand touch-up dependency | High — fine pitch and masked areas usually need repair | Low | Industry-typical value |
| Changeover | Swap the pallet | Swap the program | Process description |
| Line ownership | 2 THT assembly lines | 2 THT assembly lines | Same floor, same work order |
THE NUMBER THE PURCHASER SCREENSHOTS
Where the tooling money goes, and when it comes back
Tooling is one-off NRE. It does not grow with the batch, which is exactly why it hurts at 200 boards and disappears at 20,000. Below is the arithmetic we quote from, with the crossover the industry publishes.
Pallet or carrier tooling, waveUSD 3,000–8,000 per design
Selective soldering programmingUSD 500–1,000 per new product
Below about 5,000 boardsSelective wins: programming is the only setup cost
Published crossover point5,000–8,000 units, typical mixed board, about 20 through-hole joints
Above about 10,000 boards per runWave wins once the pallet is amortised
Lead-free pot temperature255–265 °C
Dross versus tin-lead30–50% more
Copper dissolution rate0.8–1.2 µm/s lead-free, against 0.3–0.5 µm/s tin-lead
What that means in practiceNozzle and pot lining maintenance cycles are shorter on lead-free
LINE SEQUENCE
Six stations between bare board and carton
Boards arrive from the SMT line, pick up their through-hole parts, and leave as tested assemblies.
Dual-wave
Turbulent wave drives solder into the barrels, laminar wave finishes the fillet. Control point: hole fill to IPC J-STD-001.
Robotic selective
Single-nozzle soldering programmed joint by joint, holding heat away from neighbouring surface-mount parts.
Hand soldering & rework
Connectors, repairs and touch-up to IPC-A-610 Class 2 or Class 3, with procedures to IPC-7711/7721 and each action recorded.
Depanelisation
V-CUT or router separation, with edge and burr inspection before the assembly moves on.
Inspection & electrical test
Visual acceptance, ionic contamination check where specified, then ICT or functional test to the agreed test plan.
PROCESS CAPABILITY
Six through-hole processes on this floor
WHOLE BOARD
Dual-wave soldering
A turbulent wave followed by a laminar wave, with spray fluxing and a preheat zone. This is the downstream process for boards that leave the SMT line, and it handles a whole board of joints in one pass.
LOCALISED
Robotic selective soldering
A single-point nozzle solders joint by joint under program control, so the heat stays where the joint is. On a mixed-technology board that is the difference between 500–2,000 PPM and 50–200 PPM, industry-typical.
AUTO-INSERTION
Axial and radial auto-insertion
Sequenced insertion of axial and radial leaded components for volume passive content, with the insertion program built from the same centroid data as the SMT build.
ONE PASS
Pin-in-paste
Through-hole parts soldered in the same reflow cycle as the surface-mount side. The paste volume is 2–3× a normal print, delivered by a stepped stencil or a print-plus-dispense step.
NO SOLDER
Press-fit
Compliant-pin press-fit assembly, where the joint is a controlled interference fit rather than a solder fillet. Insertion force is set by the tooling, so the process has no solder-joint defect mode at all.
MANUAL
Hand soldering and rework
Connectors, shielded parts and repair work to IPC-A-610 Class 2 or Class 3, using procedures defined by IPC-7711/7721 and recorded against the assembly.
WHAT COUNTS AS A GOOD JOINT
The criteria a through-hole joint is judged against
None of these are our own thresholds. They are clauses in standards your quality team already audits against, which is the point: the acceptance argument should not depend on trusting the supplier.
Hole fill and wettingIPC J-STD-001
Class 2 wettingSolder-side pad wetting ≥75%
Class 3 wettingFull circumferential fillet wetting, hole fill ≥75%, visible fillet
Rework and repairProcedures per IPC-7711/7721, recorded
Ionic contaminationROSE per IPC-TM-650 Method 2.3.25: Class 2 ≤1.56, Class 3 ≤0.78 µg NaCl eq/cm²
Visual acceptanceIPC-A-610 Class 2 / Class 3
MATERIALS AND TOOLING
What you can specify
ALLOY
Alloy and solder pot
Lead-free pot operation at 255–265 °C. Lead-free running costs more to maintain than tin-lead: 30–50% more dross and a copper dissolution rate of 0.8–1.2 µm/s against 0.3–0.5 µm/s, which is what sets the nozzle and pot-lining service interval. Industry-typical values.
FLUX
Flux and residue
Spray fluxing with a preheat zone on the wave; point fluxing at the nozzle on the selective machine. Residue class and cleaning are set by your cleanliness requirement and checked against the ROSE limit for the acceptance class on the drawing.
TOOLING
Pallets and carriers
Synthetic-stone and composite carriers, machined with apertures that mask the surface-mount areas from the wave. Budget USD 3,000–8,000 per design, industry-typical, and treat it as one-off NRE rather than a per-board cost.
NOZZLE
Nozzles and press-fit tooling
Single-point selective nozzles operating at 260–280 °C lead-free, plus press-fit insertion tooling and support tooling that holds the insertion force inside the connector maker's specification.
COMMERCIALS
Order size, lead time and setup charges
| Item | Value |
|---|---|
| Minimum order, chip passives 0603–2225, SOT, SOD, MELF | 50 pcs + 30 spares |
| Minimum order, all other packages | 100 pcs + 50 spares |
| Prototype quantities | Quoted per order |
| 1–10 pieces | 3–7 working days |
| 10–1,000 pieces | 5–10 working days |
| 5,000 pieces | About 3 weeks |
| Volume, after components are kitted | 3–4 weeks ex-works |
| Long-lead semiconductors | Can add 12–26 weeks |
| NRE | USD 0–150, waived on most projects |
| Pallet or carrier tooling | USD 3,000–8,000 per design |
| Selective soldering programming | USD 500–1,000 per new product |
| Unit premium, 5–20 pieces | +30–40% |
| Unit premium, 101–499 pieces | +5–15% |
Every date above is an assembly lead time ex-components, counted from the point the last component is kitted. An anonymised example of what the method change is worth: a Nordic EV charging-module brand building a 6-layer, 3 oz heavy-copper power board replaced hand touch-up with selective soldering and took joint rework from 4.1% down to 0.3%.
Related lines: all capabilities · SMT assembly · mixed-technology · testing & inspection · box build · DFM guides
WHERE THIS LINE IS USED
Six sectors with through-hole content
Automotive & EV
Charging and power modules
Heavy-copper power stages, high-current terminals and −40…+125 °C cycling, with PPAP documentation and 8D reporting.
Energy, power & gridConverters, meters and protection relays
Heavy copper from 2 oz to 6 oz, high creepage distances and a 15–25 year field life with no rework window.
Industrial automationControllers and drive boards
Connector-heavy assemblies, wide-temperature components and 2–3 engineering changes across a 15-year PLC lifetime.
Telecom & data centreBackplanes and line cards
Press-fit connectors by the hundred, where the joint is an interference fit and insertion force is the quality variable.
Medical devicesInstrument and monitor boards
Lot-level traceability, change control on every process change and validation documentation for each build step.
Consumer & IoTPower adapters and hubs
Mixed boards where a handful of through-hole parts sit beside dense surface-mount content and cost per joint decides the method.
NEXT STEP
Tell us the through-hole count and the batch size
Those two numbers pick the method, and the method picks the tooling charge. Send the board with its hole count, the annual quantity and any connector that must not see wave heat — the quotation will name wave, selective or press-fit and say why.
Reply within one business day
Useful with the enquiry: hole count per board, batch size, board thickness, copper weight and which areas must stay clear of the wave.