Selective Wave Soldering Machine SM-LII
Dual electromagnetic pump selective soldering with ±0.1mm positioning accuracy. Designed for mixed assemblies where full-board wave soldering is not possible.
Product Overview
The SM-LII is Sun & Mountain’s dual-pump selective wave soldering machine for high-mix production environments where standard full-board wave soldering is not viable. It uses two independent electromagnetic pumps to deliver precise point-by-point solder flow, targeting only the through-hole joints you specify — leaving adjacent SMT components untouched.
With ±0.1mm positioning accuracy and programmable soldering sequences, the SM-LII is ideal for boards with through-hole connectors, pin headers, or power components surrounded by SMT parts. The drop jet selective fluxer applies flux only to target areas, minimizing contamination and cleanup. Optional nitrogen atmosphere further improves joint quality for sensitive applications.
Key Highlights
- Dual electromagnetic pumps — simultaneous or sequential multi-point soldering
- ±0.1mm positioning accuracy — reliable targeting of tight-pitch through-hole components
- 13kg per-pot capacity — compact solder pots with precise flow control
- Drop jet fluxer — selective flux application to target zones only
- Bottom IR preheat — controlled board heating without disturbing SMT components
- Up to 610×610mm PCB — handles large mixed-assembly boards
- Air or optional nitrogen — flexible atmosphere for different alloys and quality requirements
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | SM-LII |
| Machine Dimensions | L2980 × W1910 × H1662 mm |
| Weight | 1800 kg |
| Total Power | 30 KW |
| Solder Pot Capacity | 13 kg (per pot) |
| Pump Type | Dual electromagnetic pump |
| Positioning Accuracy | ±0.1 mm |
| Max PCB Size | 610 × 610 mm |
| Flux System | Drop jet fluxer (selective) |
| Preheat Method | Bottom IR preheat |
| Atmosphere | Air or optional nitrogen |
Selective vs. Full-Board Wave Soldering
Understanding when to choose selective soldering over a standard wave soldering machine.
| Factor | SM-LII Selective | SA-350 / SA-450 / SA-610 Wave |
|---|---|---|
| Board type | Mixed SMT + THT | Through-hole or simple SMT+THT |
| SMT components near THT | ✅ No problem — point soldering avoids SMT | ❌ Risk of SMT reflow or damage |
| Flux application | Selective (drop jet) — target zones only | Full-board spray fluxer |
| Throughput | Lower (sequential points) | Higher (one pass, full board) |
| Production volume | High-mix, low-to-mid volume | High-volume, consistent boards |
| Nitrogen option | ✅ Available | Air atmosphere standard |
Who Is the SM-LII For?
✅ Best For
- Mixed assemblies where SMT components prevent full-board wave soldering
- Through-hole connectors and pin headers on boards with nearby SMT components
- High-mix, low-volume production requiring flexible, programmable soldering points
- Tight-pitch through-hole components requiring ±0.1mm accuracy
- Applications where nitrogen atmosphere improves joint quality
🔄 How It Compares
- vs SA-350/450/610: SM-LII solders point-by-point; wave machines solder the full board in one pass — choose SM-LII when SMT components are adjacent to THT pads
- Dual electromagnetic pumps: allows two solder points to be processed simultaneously, improving cycle time over single-pump selective machines
- Drop jet fluxer: unlike spray fluxers on full-wave machines, applies flux only to target points, reducing residue and cleaning requirements
Related Products
SA-450 Wave Soldering
Full-board wave for 450mm PCBs
SA-610 Wave Soldering
Full-board wave for 610mm large boards
SA-350 Wave Soldering
Compact full-board wave for 350mm boards
Need Selective Soldering for Your Mixed Assembly?
Our applications team can review your board layout and recommend the optimal soldering strategy — selective, full-board wave, or a combination of both.