SO-300B Selective Soldering for Power Supply PCBA

Power-supply PCBs mix transformers, large electrolytic capacitors, connectors and relays with SMD circuitry; hand soldering is operator-dependent and full wave can stress SMD areas. The SO-300B Offline Single-Head Selective Soldering Machine from Southern Machinery (est. 2011, Shenzhen) solders only programmed THT joints with ±0.1 mm accuracy and N2-assisted heating.

SO-300B Offline Single-Head Selective Soldering Machine

What is this machine used for?

Selective jet-valve fluxing and soldering on one XYZ platform — solder touches only target joints.

THT soldering on mixed SMT/THT power-supply PCBs
PCB rework and repair
Prototypes, engineering samples, low-volume high-mix THT

Why power-supply quality improves

SMD areas never pass over molten solder — less thermal stress and rework
N2 improves wetting and cuts dross on lead-free boards
PC recipes store path, speed, dwell, Z and wave height; a scanned PCB image can be the programming background
Five standard nozzles; custom shapes available

Verified specifications

| Parameter | Specification |

|---|---|

| Model | SO-300B, offline single head |

| Max soldering area | 300 x 250 mm (customizable) |

| PCB thickness | 0.2-6 mm, edge >=3 mm |

| Accuracy | +/-0.1 mm (servo XYZ) |

| Flux | Selective jet valve, 1 L tank |

| Solder pot | 15 kg, PID, max 350 deg C |

| Nozzles | 5 pcs (ID 4 mm x3, 5, 6 mm) |

| N2 | Standard, 0-350 deg C, >99.998% |

| Power | 220 V 50 Hz, 3 kW / ~1 kW operating |

| Size / weight | 1100x790x1500 mm, ~280 kg |

Values from the official smthelp.com product page; confirm at quotation.

Line integration

SMT side printed, placed, reflowed; THT parts inserted by radial or odd-form machines; SO-300B solders programmed joints; AOI/AVI and test close the loop.

ROI

One SO-300B replaces operator-dependent hand soldering and cuts rework. Offline operation avoids conveyor integration cost; recipe recall speeds changeover.

FAQ

Q: Inline or offline?

A: Offline — manual load/unload; ideal for rework and high-mix batches.

Q: PCB sizes?

A: Max area 300 x 250 mm; PCB 0.2-6 mm, edge >=3 mm.

Q: Nitrogen?

A: Yes — standard N2 heater (>99.998%) improves wetting, reduces dross.

Q: Full wave instead?

A: Full wave suits high-volume board-wide THT; the SO-300B solders joints selectively, without flooding SMD areas.

Next steps

Contact: jasonwu@smthelp.com | WhatsApp: +86 13602562576

Catalog: https://file.autoinsertion.com | Images: https://ph.smthelp.com

Watch selective soldering in action: https://www.youtube.com/watch?v=En1lAH-C_jY

Product page: https://www.smthelp.com/so-300b-offline-single-head-selective-soldering-machine.html

Southern Machinery — cost-effective SMT/THT automation with global support. Founded 2011, Shenzhen. 237+ customers worldwide.

SO-300B Selective Soldering for Power Supply PCBA | Southern Machinery