S100B Desktop Selective Soldering Machine | Southern Machinery

What is the S100B Desktop Selective Soldering Machine used for?

The S100B Desktop Selective Soldering Machine is a compact, benchtop solution designed for High-Mix, Low-Volume (HMLV) PCB assembly environments where traditional wave soldering is impractical. Unlike full-size wave soldering systems that require dedicated tooling and fixtures for every board shape, the S100B operates without custom fixtures, enabling ultra-fast changeovers between different PCBA designs.

Selective soldering is the process of precisely applying solder to specific through-hole (THT) components on a PCB while leaving surrounding SMT components untouched. The S100B accomplishes this through a programmable XYZ motion system that positions a miniaturized solder nozzle — with integrated flux dispensing, preheating, and soldering — directly onto each target joint. This makes it the ideal bridge between hand soldering (slow, inconsistent) and full-wave soldering (high-volume, fixture-dependent).

For EMS factories and PCB assembly shops running frequent job changes with small batch sizes, the S100B eliminates the bottleneck of fixture fabrication and dramatically reduces changeover time from hours to minutes.

Typical Applications

1. HMLV Contract Manufacturing (EMS Providers)

EMS factories serving multiple clients with diverse product mixes benefit most from the S100B's fixture-free operation. Changing from a telecom board to a consumer electronics board requires no hardware swap — just load the new program and start.

2. Prototype and NPI Runs

During new product introduction (NPI), PCB designs change frequently. The S100B's programmable nozzle path and adjustable soldering parameters allow engineers to validate THT solder joints without committing to production tooling.

3. LED Lighting and Power Supply Assembly

Power supply PCBs for LED lighting often contain a mix of SMT components and through-hole transformers, capacitors, and connectors. The S100B selectively solders only the THT joints, protecting nearby SMT parts from thermal stress.

4. Automotive and Industrial Electronics

Automotive-grade PCBs (ECUs, sensors, control modules) require repeatable, high-quality solder joints with full traceability. The S100B's PC-controlled parameter logging supports compliance with ISO/TS 16949 and IPC-A-610 requirements.

5. Retrofit and Repair Operations

For legacy boards where wave soldering isn't cost-effective or rework stations are too slow, the desktop selective soldering machine offers a production-grade alternative that fits on any benchtop.

How it Fits into a Complete PCB Assembly Line

The S100B occupies a specific position in the post-SMT, pre-test segment of a PCB assembly line:

Typical SMT + THT Hybrid Line:

Solder Paste Printing → Pick and Place → Reflow Oven → AOI → S100B Selective Soldering → Board Handling → Functional Test → Packaging

In this configuration, the S100B handles THT components selectively after SMT reflow, eliminating the need for a full wave soldering bath. This saves floor space, energy, and solder consumption compared to a traditional wave soldering line.

For factories that already operate wave soldering, the S100B serves as a complementary tool for boards that are too small, too complex, or too thermally sensitive for wave contact.

Southern Machinery's complete ecosystem — including board handling conveyors, PCB magazine loaders/unloaders, AOI/SPI inspection systems, and THT auto insertion machines — means the S100B can be fully integrated into a seamless automated production line.

Key Selection Parameters

When evaluating a desktop selective soldering machine like the S100B, buyers should consider the following parameters. Actual specifications should be verified with the manufacturer for your specific process requirements:

• PCB Size Capacity — Maximum board dimensions the machine can accommodate. Ensure it fits your largest PCBA without custom fixturing.
• Number of Soldering Nozzles — Single or multi-nozzle configurations affect throughput.
• Motion System Configuration — Look for servo-driven XYZ axes with closed-loop control for repeatable positioning accuracy.
• Flux Application Method — Jetting flux valves (spray) vs. foam fluxing. Jetting offers precise, programmable flux deposition per joint.
• Preheating Capability — Bottom-side or top-side preheating ensures proper wetting and reduces thermal shock on the PCB.
• Software and Programming — Offline programming from Gerber/CAD data, ease of teaching points, and real-time parameter adjustment.
• Nozzle Management — Quick-change nozzle system for different through-hole diameters and component heights.
• Nitrogen Compatibility — If soldering requires inert atmosphere for improved wetting and reduced dross.
• Footprint and Power Requirements — Desktop or standalone; single-phase vs. three-phase power.

Always request a process qualification run with your actual boards before finalizing equipment selection.

ROI and Quality Perspective

From a production manager's perspective, the S100B delivers ROI through three primary channels:

1. Eliminating Fixture Costs

Traditional wave soldering requires a dedicated pallet/fixture per board design at $50-$500 each. For a factory running 50+ different SKUs, annual fixture costs can exceed $25,000. The S100B's fixture-free operation eliminates this entirely.

2. Reducing Changeover Time

Manual changeover between different THT soldering jobs typically takes 30-90 minutes (fixture swapping, conveyor adjustment, temperature stabilization). The S100B reduces this to a program-load sequence under 5 minutes. Over 200 changeovers per year, that is hundreds of hours of reclaimed production time.

3. Minimizing Rework and Thermal Damage

By directing heat only to the target solder joints, selective soldering reduces PCB warpage, component thermal stress, and adjacent SMT component reflow. This directly improves first-pass yield (FPY) and reduces rework costs, especially on dense mixed-technology boards.

Quality Compliance:

The PC-controlled environment with programmable profiles, temperature monitoring, and data logging supports traceability requirements for ISO 9001, IATF 16949, and IPC standards.

Frequently Asked Questions

Q: What is the difference between selective soldering and wave soldering?

Selective soldering uses a programmable nozzle to apply solder only to specific THT joints, while wave soldering contacts the entire bottom of the board with a standing wave of molten solder. Selective soldering is ideal for mixed-technology boards (SMT + THT) where wave soldering would damage nearby SMT components.

Q: Does the S100B require compressed air or nitrogen?

Desktop selective soldering machines typically require compressed air for the flux jetting valve and pneumatic actuators. Nitrogen is optional for inert atmosphere soldering.

Q: How long does it take to change from one board design to another on the S100B?

Because the S100B operates without custom fixtures, changeover primarily involves loading a new PCB program and allowing the preheater to stabilize — typically under 5 minutes.

Q: Can the S100B handle lead-free soldering?

Yes. Desktop selective soldering machines generally support lead-free solder alloys (SAC305, SAC405, etc.) with appropriate temperature settings.

Q: What PCB sizes can the S100B accommodate?

The S100B is designed as a compact desktop unit. For specific board size capacity, contact Southern Machinery with your maximum PCB dimensions.

Q: How does the S100B integrate with my existing SMT line?

The S100B can be placed inline with standard PCB conveyors (SMEMA-compatible) or operated as a standalone offline unit.

Ready to Eliminate Fixture Bottlenecks?

If your factory runs frequent changeovers, mixed-technology boards, or HMLV production, the S100B Desktop Selective Soldering Machine from Southern Machinery can transform your THT soldering workflow. Contact us for a process evaluation with your actual PCBA samples.

Southern Machinery Sales And Service Co., Ltd

• Contact: Jason Wu
• Email: jasonwu@smthelp.com
• Phone: +86 13602562576
• Website: https://www.smthelp.com
• Product Catalog: https://file.autoinsertion.com
• Image Gallery: https://ph.smthelp.com
• Video Demo: https://www.youtube.com/watch?v=5R8P21iaOZg

Shenzhen, China — Serving 237+ EMS factories globally with SMT/THT automation solutions since 2001.