S-WS350 Wave Soldering Machine: Compact Dual-Wave THT Soldering for EMS Lines
Southern Machinery's S-WS350 is a 350 mm-class lead-free wave soldering machine: dual wave, 1800 mm hot-air preheat, PC + PLC control for repeatable THT joints.
Aug 7, 2026 · Updated Aug 7, 2026 · Southern Machinery
S-WS350 Lead-Free Wave Soldering Machine: Compact Dual-Wave THT Soldering for EMS Lines
The S-WS350 is Southern Machinery's 350 mm-class lead-free wave soldering machine, engineered for mid-size THT boards in EMS, power supply, appliance, and automotive electronics production. Its dual-wave configuration, 1800 mm four-stage hot-air preheat, and PC + PLC control deliver repeatable solder joints with lead-free and conventional alloys.
What Is the S-WS350 Wave Soldering Machine Used For?
The S-WS350 is a dual-wave soldering machine that solders through-hole (THT) components to a PCB in a continuous inline process. The board travels on a stainless steel conveyor through four stages: flux application, preheating, soldering over a turbulent wave and a smooth wave, then forced-air cooling.
It is designed for PCB widths from 50 mm to 350 mm and suits production lines where boards are too wide for desktop machines but do not require a 450 mm-class system. Typical outputs include power supply PCBs, appliance control boards, LED drivers, ballasts, and automotive electronic modules.
Why Choose a Dual-Wave Solder Configuration?
Most THT boards with connectors, relays, and electrolytic capacitors need two waves to guarantee hole fill without solder bridges:
- Turbulent (choppy) wave — forces solder into plated through-holes and breaks surface tension on dense layouts.
- Smooth (laminar) wave — removes excess solder and clears bridges left by the first wave.
The S-WS350 pairs a 30 mm high wave with a 5-12 mm flat wave, both adjustable from the control system, so process engineers can tune the profile to board density and component mix.
Typical Application Scenarios
| Industry | Typical Boards | Why It Fits |
|---|---|---|
| Power supply | SMPS, chargers, inverters | Mixed THT power components, lead-free alloys |
| Appliances | Control boards, display boards | Mid-size FR4 boards, medium volume |
| LED lighting | Drivers, ballasts, LED modules | Flux-heavy boards, consistent hole fill |
| Automotive electronics | Body control modules, sensors | Traceability-friendly PC control, repeatable profiles |
| EMS / ODM | Multi-product mix | Quick recipe changeover for different board sizes |
How the S-WS350 Integrates into a Complete PCB Assembly Line
The S-WS350 is a standalone inline unit that connects to standard PCB handling equipment on both ends:
- Upstream — boards arrive from SMT placement and Reflow Oven processes, or from THT auto insertion machines (radial, axial, and odd-form inserters such as the S4000 and S7900 series).
- Infeed — the conveyor accepts boards directly; board-loading sensors count production quantities automatically.
- Process — spray fluxing (up to 5 L tank, 0.4-0.6 MPa), 1800 mm hot-air preheat, dual-wave soldering, and forced cooling run continuously.
- Downstream — boards exit to inline lead cutters, cleaning, or AOI inspection before final assembly.
Because the control system stores PCB recipes for different board sizes, a single S-WS350 can serve multiple products in the same line — the configuration relevant for EMS factories running mixed SKUs.
Key Selection Parameters for Buyers
These are the verified S-WS350 specifications to check against your process requirements:
- PCB width: 50-350 mm, adjustable transport rail
- Conveyor: special stainless steel chain; speed 0.5-1.8 m/min (Delta inverter drive)
- Preheating: 1800 mm four-stage hot-air preheat, 3-zone PID control, 9 kW, adjustable to ~220 °C
- Soldering: dual wave — 30 mm high wave, 5-12 mm flat wave; soldering angle 3-7 degrees
- Solder pot: 316 stainless steel, ~380 kg tin capacity, 18 kW heating, up to ~350 °C
- Flux: spray fluxing, max 5 L tank, 0.4-0.6 MPa
- Cooling: forced cooling
- Control: Lenovo PC + Siemens PLC, PID temperature control, ±2 °C preheat stability
- Safety: thermocouple abnormal alarm, high/low temperature alarm, emergency stop buttons front and tail
- Utilities: 3-phase 5-wire 380 V/50 Hz, ~19 kW
- Footprint: L4200 x W1350 x H1650 mm, approx. 1200 kg
Verify with Southern Machinery: your largest board width, solder alloy (lead-free vs. conventional), required throughput per shift, and available floor space.
ROI, Quality, and Throughput Perspective
- Quality: PID-controlled preheat with ±2 °C stability and automatic cold-junction-compensated thermocouple sensing reduce voids, cold joints, and thermal shock — a direct lever on first-pass yield for EMS customers.
- Repeatability: Recipe storage for multiple PCB sizes shortens changeover time between products, improving OEE on mixed lines.
- Labor: Wave soldering replaces manual or batch soldering stations and removes operator-dependent joint quality variation.
- Compliance: Supports lead-free (RoHS) and conventional solder, and the closed control loop keeps temperature data consistent for process audits.
FAQ
What is the maximum PCB width the S-WS350 can process?
The S-WS350 handles PCB widths from 50 mm to 350 mm with an adjustable transport rail.
Does the S-WS350 support lead-free soldering?
Yes. The machine supports both lead-free and conventional solder, with a 316 stainless steel pot rated to approximately 350 °C.
How long is the preheating zone?
The preheat section is 1800 mm long, using four-stage hot air with 3-zone PID control at 9 kW.
What is the difference between the S-WS350 and the S-WS450?
Both are Southern Machinery wave soldering machines; the S-WS450 handles larger boards (up to 450 mm width), while the S-WS350 is the 350 mm-class system with a smaller footprint for mid-size boards.
Can the S-WS350 be integrated into an existing SMT line?
Yes. It connects to standard PCB handling conveyors and can follow SMT placement, Reflow Oven, or THT auto insertion processes, with board-loading sensors and recipe storage for mixed products.
How is the machine controlled?
The S-WS350 uses a Lenovo PC plus Siemens PLC with PID temperature control, allowing operators to set conveyor speed, wave height, and zone temperatures directly from the computer.
Get a Configuration Recommendation
Southern Machinery has served 237+ global customers since 2011 from Shenzhen, China, providing SMT/THT PCB assembly automation equipment and complete line solutions — SMT placement, THT auto insertion, Wave Soldering, board handling, and inspection. Share your board size, solder alloy, and throughput targets to get a tailored S-WS350 configuration.
- Contact: Jason Wu — jasonwu@smthelp.com | +86 13602562576
- Product catalogs and PDFs: https://file.autoinsertion.com
- Machine photo gallery: https://ph.smthelp.com
- Website: https://www.smthelp.com
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