S-WS250 Lead-Free Dual-Wave Soldering Machine for Compact THT PCBs

A through-hole board soldered by hand or with a single wave leaves bridges under a connector and cold joints at the filter can — defects that pass visual inspection and fail on the first power-up. Manual THT also can't keep up with the pace a 250 mm board line needs, so wave soldering becomes the bottleneck. The S-WS250 automates lead-free dual-wave soldering with spray flux, hot-air preheat and fan cooling for boards up to 250 mm wide.

The Cost You Haven't Named

• Bridging and cold joints. A single wave or hand soldering leaves bridges under connectors and cold joints at large parts; both pass visual inspection and fail at power-up or in the field.
• Inconsistent flux coverage. Manual or uneven fluxing leaves bare pads and excess residue, so joint quality swings between boards and between shifts.
• Throughput limit. Hand THT can't match the rhythm of a compact-board line, so soldering queues behind insertion and starves test.
• Dross and maintenance load. An open pot and sticky claws waste solder and drop boards; the downtime and scrap add up over a shift.

The Four-Stage Wave Solder Audit

Frame the purchase as a wave-solder audit so the machine fits your board and alloy. Call it the Four-Stage Wave Solder Audit.

1. Profile the board set. List every THT board up to 250 mm wide, component mix and alloy (lead-free), so conveyor speed and wave size match the actual work.

2. Set the thermal budget. Fix preheat at up to 250°C across the 600 mm zone and solder at 300°C ±1–2°C, then confirm the profile holds across board thickness and density.

3. Score the flux and wave need. Confirm ST-6 spray fluxing (5.2 L) and the dual wave so wide and dense boards get full coverage without bridging on the second pass.

4. Confirm handling and build. Verify the 0–1.8 m/min conveyor, 3–7° angle and patented titanium claws so boards transfer without sticking or dropping through the run.

The Vehicle: S-WS250 Wave Soldering Machine

The S-WS250 is a compact lead-free wave soldering machine for through-hole PCBs up to 250 mm wide, combining spray flux, hot-air preheat, dual wave and fan cooling in one pass.

• Profile the board set → 250 mm capacity. Boards from 50 to 250 mm wide run on a 0–1.8 m/min conveyor at a 3–7° angle, matching power, LED, appliance and automotive THT work.
• Set the thermal budget → preheat and dual wave. A 600 mm preheat zone reaches 250°C (3 kW), and the dual wave holds 300°C ±1–2°C in a ~200 kg pot for repeatable joints.
• Score the flux and wave need → ST-6 spray + dual wave. ST-6 spray fluxing (5.2 L) with a low-dross nozzle and isolated fluxing gives even coverage; the dual wave removes bridges on dense layouts.
• Confirm handling and build → titanium claws. Patented titanium alloy claws are non-stick to tin and prevent board drop, with PLC and touch-screen control (P.I.D + SSR) over the run.

Specification note: conveyor speed, solder-pot size, preheat profile and claw configuration should be confirmed at quotation, because they depend on your board width, alloy and throughput.

Specifications

| Parameter | Value |

| --- | --- |

| PCB size | Max 50–250 mm |

| Conveyor | 0–1.8 m/min, 3–7° adjustable |

| Solder pot | Dual wave, ~200 kg, up to 300°C ±1–2°C |

| Preheat / cooling | 600 mm zone up to 250°C, 3 kW; 1 fan |

| Control / flux | PLC + touch screen, P.I.D + SSR; ST-6 spray, 5.2 L |

| Power | 3P 380V AC, max 9 kW |

| Air pressure | 4–7 kg/cm² |

| Machine dimensions | L 2100 × W 1200 × H 1400 mm |

| Weight | ~400 kg |

The Loop: Re-Audit Wave Solder Every Quarter

Alloy and board mixes change as products ramp. Build a loop: every quarter, repeat the Four-Stage Wave Solder Audit, compare joint yield and dross rate against the baseline, and review flux consumption, preheat profile and claw condition with your process lead. If a new board width or alloy appears, reconfirm the conveyor and wave settings before volume builds rather than after. The S-WS250's titanium claws and adjustable conveyor give you margin to absorb that change — the loop is what keeps joint quality at spec instead of drifting as boards change.

Your Next Step

Send us your board widths, alloy and target throughput. We will return a wave-solder review showing where the S-WS250 fits, which preheat and flux settings to specify, and what to confirm at quotation for your line. Reach Jason at jasonwu@smthelp.com or on WhatsApp +86 13602562576.

FAQ

What board sizes can the S-WS250 solder?

Through-hole PCBs from 50 to 250 mm wide, on a 0–1.8 m/min conveyor at a 3–7° angle.

Is it lead-free?

Yes — it is built for lead-free soldering, with a dual wave held at up to 300°C ±1–2°C.

How is flux applied?

An ST-6 spray fluxer (5.2 L) with isolated fluxing and a low-dross nozzle gives even coverage without excess residue.

What prevents boards from dropping?

Patented titanium alloy claws are non-stick to tin and stop board drop through the run.

What controls the process?

A PLC with touch-screen interface using P.I.D + SSR control over preheat, wave and cooling.

Jason Wu

Founder & CEO, Southern Machinery (Shenzhen Southern Machinery Sales and Service Co., Ltd.)

Email: jasonwu@smthelp.com / info@smthelp.com

WhatsApp: +86 13602562576

Catalog & manuals: file.autoinsertion.com | Machine photos: ph.smthelp.com

LinkedIn: linkedin.com/in/smtsupplier | YouTube: youtube.com/c/Smthelping