SO-300B Offline Single-Head Selective Soldering Station for Rework and High-Mix THT

A board comes back from the field with one failed connector. An operator masks the SMD side with tape, flips the panel, and walks an iron across fourteen joints while the connector housing softens and the neighbouring electrolytic capacitor absorbs heat it was never rated to take. Two boards later the shift reports lifted pads and a warped body. The rework bay is doing volume work with a hand tool, and the scrap log books the loss as "rework" rather than as method.

The cost you haven't named

Rework volume never appears on the routing. Repair, engineering changes and prototype builds are booked to overhead, so the hours spent hand-soldering through-hole joints are invisible when you argue for equipment.
A hand iron heats everything nearby. Through-hole joints sit next to parts that already survived reflow. Uncontrolled heat reaches electrolytic capacitors, relay bodies and connector housings, and the damage shows up as an intermittent fault weeks later.
Low-volume batches cannot justify pallets. Wave soldering a mixed-technology panel means designing, buying and storing a pallet and booking line time — a poor trade for a batch of twenty boards.
Every joint looks different. Fillet shape, solder volume and dwell depend on who is holding the iron, so a repair that passes today is not the repair that passes on the night shift.
There is no process record. Hand soldering leaves nothing to review, so when a customer asks how a joint was made, the answer is a name rather than a temperature, nozzle and program.

The Four-Point Rework Bay Soldering Audit

Specifying an offline station starts with the work you already turn away or push to a bench. Run this audit before you compare machines.

1. Map the joint population. List every through-hole joint you solder off-line by part type — connectors, relays, electrolytic capacitors, terminal blocks, harness pins — and note which sit close to a heat-sensitive SMD or plastic body, because that proximity is what rules out a hand iron.

2. Measure the heat shadow. For each joint family, record what gets hot when you solder it. Parts that discolour, deform or drift during hand rework are the argument for selective soldering rather than for a better operator.

3. Size the board envelope. Check the largest and smallest panels the station must accept against the soldering area and thickness range, including boards already populated on both sides.

4. Define the changeover routine. Count how often the station switches board type in a shift. A rework bay may see five programme changes a day, so nozzle swaps, flux top-up and program recall matter more than raw cycle time.

The vehicle: SO-300B Offline Single-Head Selective Soldering Station

The SO-300B is the single-head, offline member of Southern Machinery's selective soldering range. Where the SO-300 is the high-speed, multi-purpose machine built for production throughput, this configuration targets the other end of the building: one head, manual load and unload, and selective fluxing and soldering on the same XYZ platform. It belongs in the rework bay, the prototype room or beside a low-volume high-mix cell.

Map the joint population → single head on an XYZ platform. One fluxing and soldering head moves to each programmed joint at ±0.1 mm positioning accuracy, so a board with scattered through-hole points is processed point by point without a pallet or a mask.
Measure the heat shadow → selective flux and solder, not a full wave. Flux and solder are applied only at the joint, which leaves SMD areas and heat-sensitive parts already on the board outside the thermal path.
Size the board envelope → 300 × 250 mm area on 0.2–6 mm boards. The soldering area (customizable) covers prototype and rework panels, and the thickness range accepts thin prototype laminate as well as populated backplanes.
Define the changeover routine → 15 kg PID pot with a standard nozzle set. A 15 kg solder pot under PID control to 350 °C holds temperature through repeated board changes, and five nozzles are supplied as standard so common joint geometries are covered without waiting on tooling.

Specification note: soldering area, nozzle geometry, flux type, nitrogen supply and programme capacity should be confirmed at quotation, because they depend on your joint population, board mix and regional power standard.

Specifications

| Parameter | Value |

| --- | --- |

| Configuration | Offline, single-head, manual load/unload |

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

| PCB thickness | 0.2–6 mm |

| Positioning accuracy | ±0.1 mm |

| Solder pot | 15 kg capacity, PID control, max 350 °C |

| Nozzles | 5 nozzles as standard |

| Nitrogen heating | Standard, 0–350 °C |

| Process | Selective fluxing and soldering on one XYZ platform |

| Power supply | 220 V, 50 Hz, 3 kW |

| Dimensions (L × W × H) | 1100 × 790 × 1500 mm |

| Weight | Approx. 280 kg |

| Typical applications | PCB rework and repair, prototypes, low-volume high-mix THT |

The loop: re-audit the rework queue every quarter

A rework bay is the one place where the work mix changes without anyone approving it, so the audit has to repeat. Set a loop: every quarter, pull the repair log and re-run the Four-Point Rework Bay Soldering Audit, comparing which joint families dominate now against the baseline recorded at commissioning. Review nozzle wear and pot temperature stability in the same pass, and check whether boards have grown past the 300 × 250 mm window. When a new connector or relay family enters the queue, confirm nozzle geometry and flux before volume arrives. Treat any saving as a planning benchmark: removing a repetitive hand-soldering step shortens the queue and frees technician hours, and Southern Machinery models that case by case.

Your next step

Send us your rework and prototype panel drawings, the through-hole part types you solder off-line, and your board thickness range. We will return a station review showing where the SO-300B fits, which nozzle set and flux to specify, and what to confirm at quotation. Reach Jason at jasonwu@smthelp.com or on WhatsApp +86 13602562576.

FAQ

Is the SO-300B inline or offline?

Offline — boards are loaded and unloaded by hand. That is deliberate: it suits a rework bay, a prototype room or a low-volume high-mix cell where the panel mix changes faster than a conveyor schedule could absorb.

How is it different from the SO-300?

The SO-300 is the high-speed, multi-purpose selective soldering machine built for production throughput. The SO-300B is the single-head offline configuration aimed at rework, repair, prototypes and low-volume high-mix THT — one head, one station, no line integration.

What board sizes and thicknesses does it handle?

Maximum soldering area 300 × 250 mm, customizable on request, with PCB thickness from 0.2 mm to 6 mm.

Does it support nitrogen soldering?

Yes. N2 heating is standard, adjustable from 0 to 350 °C, with purity above 99.998%.

What components can it solder?

Through-hole parts on mixed-technology boards, including connectors, relays and electrolytic capacitors — the joints that sit beside heat-sensitive SMD work and are difficult to reach with a hand iron. Installed in a rework room it needs 220 V, 50 Hz at 3 kW and roughly 1100 × 790 mm of floor for a 1500 mm-high machine weighing about 280 kg.

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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

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