S100B Desktop Selective Soldering Machine: Fixture-Less HMLV Soldering for High-Mix PCB Assembly

What Is the S100B Desktop Selective Soldering Machine Used For?

The S100B is a compact desktop machine that solders through-hole components on PCBs also carrying SMDs. Unlike full-wave soldering—which hits the whole board with molten solder—selective soldering uses a precise nozzle to target only the THT joints. That makes the S100B perfect for boards that can't go through a wave, like double-sided SMD assemblies or boards where certain areas must stay dry.

Desktop Selective Soldering for HMLV Production

The S100B tackles a common challenge in electronics manufacturing: handling high-mix, low-volume (HMLV) PCBA without the high labor cost of hand soldering or the fixture expense of traditional wave soldering.

Fixture-less operation is the big differentiator. Wave soldering usually needs custom pallets to protect SMD areas—each one takes time and money to design, build, and store. The S100B skips all that. It directs solder only where needed, so you can run board A, then board B (a completely different layout), with no hardware changeover at all.

Ultra-fast changeover means switching products in minutes, not hours. For EMS facilities running dozens of SKUs daily, this agility directly improves OEE and cuts WIP inventory.

Typical Application Scenarios

The S100B fits many production environments:

EMS / Contract Manufacturing: High-mix runs of 50–500 boards per SKU where wave solder fixture costs don't make sense
Prototyping & NPI: Engineering teams that need fast solder validation without waiting for fixtures
Automotive Electronics: Sensor modules, control units, and power boards with mixed SMD/THT components
Medical Electronics: Low-volume, high-reliability PCBs where every joint must be verified
Industrial Control: PLC modules, I/O cards, and relay boards with odd-form or high-power THT parts
Repair & Rework Centers: Selective solder removal and re-soldering on assembled boards

How the S100B Fits into a Complete PCB Assembly Line

The S100B works as a flexible soldering station after auto-insertion or manual assembly. Here's a typical flow:

Solder Paste Printing (for SMD side) — SP-1008 or SP-1200 stencil printer
Pick and Place — S-200V or S-530S placement machine for SMD components
Reflow Soldering — STE-800 lead-free reflow oven
Through-Hole Component Insertion — S-3010B radial inserter, S4000 axial inserter, or S-70LD odd-form inserter (or manual for low volumes)
Selective Soldering — S100B desktop selective soldering machine for THT joints
Inspection — AOI (S-AO600C) and/or X-ray (SM-X3000A) for quality
Cleaning — S1688 stencil cleaner, SME6200 inline PCBA cleaner (as needed)
Depaneling — S-D601 or S380A PCB separator for panelized boards

The small desktop footprint makes the S100B easy to place at the end of a placement line or in a dedicated HMLV cell alongside other benchtop gear.

Key Selection Parameters for a Desktop Selective Soldering Machine

When evaluating a machine like the S100B, check these parameters with the manufacturer:

| Parameter | What to Consider |

|-----------|------------------|

| PCB Size Range | Maximum and minimum board dimensions the machine can handle |

| Soldering Nozzle Type | Single vs multi-nozzle; nozzle diameter range |

| Flux Application | Spray fluxing, dip fluxing, or integrated flux module |

| Preheat Configuration | Number of preheat zones, heating method (IR / convection), temperature range |

| Programming Method | Offline CAD import, teach pendant, or manual jog programming |

| Changeover Speed | Time needed to switch between different PCB layouts |

| Fixture Requirement | Whether dedicated pallets/fixtures are needed or fixture-less operation is supported |

| Solder Feed | Wire solder feed or preformed solder; automatic vs manual |

| Nitrogen Compatibility | Support for nitrogen atmosphere to improve wetting and reduce dross |

| Extraction / Ventilation | Fume extraction requirements and exhaust connection |

| Control Interface | PC + PLC, touch screen, MES connectivity options |

| Footprint | Desktop dimensions and weight for benchtop or cart mounting |

ROI, Quality, and Throughput Considerations

Return on Investment: For HMLV facilities, the S100B eliminates fixture costs (typically $100–$500 per fixture per product) and cuts changeover labor. A shop running 20+ SKUs per week can recoup the investment within months just from fixture savings.

Quality Impact: Selective soldering delivers consistent joint quality that hand soldering can't match. Each joint gets the same controlled thermal profile, cutting cold joints, bridges, and damage from operator variability.

Throughput: Desktop selective soldering has lower per-board throughput than full-wave, but it's much more flexible. The S100B can run 20 units of board A, then immediately switch to board B without stopping to change fixtures—enabling continuous production across multiple SKUs.

Frequently Asked Questions

1. What's the difference between selective soldering and wave soldering?

Wave soldering runs the whole PCB over a standing wave of molten solder, soldering all THT joints at once. Selective soldering uses small, programmable nozzles to apply solder only to specific joints, one or a few at a time. Pick selective when boards have mixed SMD/THT, double-sided SMD assemblies, or when some areas must stay solder-free.

2. Does the S100B need custom fixtures or pallets?

No—it's designed for fixture-less operation. Unlike wave soldering, which needs custom pallets to protect SMD areas, the S100B's selective nozzle touches only the intended joints. No physical masking is required. That's the main advantage for HMLV production where fixture costs and changeover time matter most.

3. What types of through-hole components can the S100B solder?

It handles standard THT components: connectors, relays, capacitors, transformers, pin headers, terminals, and power modules. Check with Southern Machinery for specific lead diameter ranges and component height limits based on your board stack-up.

4. Can the S100B integrate into an existing SMT line?

Yes. It's a desktop unit with a small footprint that can sit inline or serve as a standalone station. It supports standard conveyor heights for integration with upstream and downstream equipment. SMEMA communication protocols are available for automated line control.

5. What training is needed to run the S100B?

The S100B has a user-friendly PC + PLC control interface. Operators with basic SMT experience typically learn programming and operation in a few days. Southern Machinery provides on-site installation, commissioning, and training as part of the standard after-sales package.

6. How does Southern Machinery support customers after purchase?

Southern Machinery offers global support: phone and email response within 2 hours, remote diagnostics, spare parts, and field service. The service ecosystem includes installation, training, software updates, process optimization, and equipment retrofitting. For detailed questions, contact Jason Wu at jasonwu@smthelp.com.

Get a Configuration Assessment for Your HMLV Soldering Needs

Whether you're replacing manual soldering, expanding HMLV capacity, or adding selective soldering to a new line, Southern Machinery helps you match the right equipment to your board profile, volume targets, and automation level.

Contact Southern Machinery:

Jason Wu — Co-Founder / CEO / Sales & Service Engineer
Email: jasonwu@smthelp.com
Phone: +86 13602562576
Website: https://www.smthelp.com

Product Resources:

View product catalogs and PDF datasheets: https://file.autoinsertion.com
Browse machine photos and gallery: https://ph.smthelp.com
Watch product demonstrations on YouTube: Southern Machinery Channel

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Southern Machinery — Your Smart EMS Factory Partner. Established 2011 in Shenzhen, serving 237+ global customers across EMS, automotive, medical, industrial control, and consumer electronics manufacturing.