Selective Wave Soldering Machine SM-LI
Single electromagnetic pump selective soldering with plus or minus 0.1mm positioning accuracy. The entry-level selective soldering solution for mixed assemblies with moderate through-hole density.

Product Overview
The SM-LI is Sun and Mountain’s single-pump selective wave soldering machine, designed for production lines that need selective soldering capability without the complexity of a dual-pump system. It uses one electromagnetic pump to deliver precise point-by-point solder flow, targeting only the through-hole joints you specify, leaving adjacent SMT components untouched.
With plus or minus 0.1mm positioning accuracy and programmable soldering sequences, the SM-LI is well suited for boards with a moderate number of through-hole components such as connectors, pin headers, or power components surrounded by SMT parts. The drop jet selective fluxer applies flux only to target areas, minimizing contamination. Where the dual-pump SM-LII processes two points simultaneously, the SM-LI processes one point at a time, making it the right choice when cycle time is not the primary constraint.
Key Highlights
- Single electromagnetic pump — precise point-by-point selective soldering
- Plus or minus 0.1mm positioning accuracy — reliable targeting of through-hole components
- 8kg solder pot capacity — compact and efficient solder management
- Drop jet fluxer — selective flux application to target zones only
- Bottom IR preheat — controlled board heating without disturbing SMT components
- Up to 460x460mm PCB — suited for standard mixed-assembly board sizes
- Air atmosphere standard — optional nitrogen upgrade available
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | SM-LI |
| Machine Dimensions | L2400 x W1650 x H1580 mm |
| Weight | 1200 kg |
| Total Power | 18 KW |
| Solder Pot Capacity | 8 kg |
| Pump Type | Single electromagnetic pump |
| Positioning Accuracy | plus or minus 0.1 mm |
| Max PCB Size | 460 x 460 mm |
| Flux System | Drop jet fluxer (selective) |
| Preheat Method | Bottom IR preheat |
| Atmosphere | Air (optional nitrogen) |
SM-LI vs SM-LII: Which Selective Soldering Machine Do You Need?
Both machines use selective soldering technology. The key difference is pump count, board size, and throughput.
| Factor | SM-LI (Single Pump) | SM-LII (Dual Pump) |
|---|---|---|
| Pumps | 1 electromagnetic pump | 2 electromagnetic pumps |
| Simultaneous soldering points | 1 point at a time | 2 points simultaneously |
| Max PCB size | 460 x 460 mm | 610 x 610 mm |
| Solder pot capacity | 8 kg | 13 kg per pot |
| Throughput | Moderate, suited for low-to-mid THT density | Higher, suited for high THT density boards |
| Best for | Standard mixed assemblies, moderate THT count | Complex mixed assemblies, high THT count |
| Footprint | More compact | Larger |
Who Is the SM-LI For?
Best For
- Mixed assemblies with a moderate number of through-hole components
- Production lines where cycle time per board allows sequential single-point soldering
- Facilities entering selective soldering for the first time, simpler operation than dual-pump
- Standard board sizes up to 460x460mm
- Applications where full-board wave soldering risks damaging adjacent SMT components
How It Compares
- vs SA-350/450/610: SM-LI solders point-by-point; wave machines solder the full board in one pass. Choose SM-LI when SMT components are adjacent to THT pads.
- vs SM-LII: SM-LI uses one pump and handles boards up to 460mm. Choose SM-LII when you need two simultaneous solder points or larger 610mm boards.
- Drop jet fluxer: applies flux only to target points, reducing residue compared to full-board spray fluxers on wave machines.
Related Products
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.