S100B Desktop Selective Soldering Machine

<p>The S100B Desktop Selective Soldering Machine from Southern Machinery (Smthelp) is a benchtop THT soldering solution engineered for electronics manufacturers running high-mix, low-volume (HMLV) production schedules. Designed for facilities that cannot justify a full wave solder line for small batch runs, the S100B brings selective soldering capability to the workbench—without the changeover overhead of traditional wave or selective solder systems.</p>

<h2>What Is the S100B Selective Soldering Machine?</h2>

<p>The S100B is a desktop-format selective soldering system built around a single solder pot with programmable nozzle positioning. It solders individual through-hole pads or pad groups on a PCB, leaving surrounding components and areas untouched. This makes it particularly suited to assemblies where wave soldering would expose heat-sensitive components to unnecessary thermal stress, or where only a handful of THT connections need to be made after reflow soldering of surface-mount parts.</p>

<p>The machine's defining feature is its <strong>fixture-free changeover</strong> design. Operators programme the solder positions via the machine's control interface, and the system moves the board relative to a stationary solder fountain or moves the nozzle to the target pads. For production runs of 10–200 boards with varied THT component layouts, this eliminates the lead time and cost of custom fixtures.</p>

<h2>Typical Application Scenarios</h2>

<p>The S100B serves several distinct production scenarios:</p>

<ul>

<li><strong>Power electronics assemblies</strong> — PCBs for motor drives, SMPS, LED drivers, and vehicle power supplies often carry a mix of MOSFETs, transformers, and connectors that require careful thermal management. Selective soldering lets these boards be processed after SMT reflow without second-pass wave exposure.</li>

<li><strong>Industrial control boards</strong> — Relay boards, sensor modules, and instrumentation panels frequently run in batches of 20–100 units with high bill-of-materials variability. Fast changeover between SKUs keeps per-unit labour low.</li>

<li><strong>After-rework touch-up</strong> — Boards that fail ICT or AOI at specific THT joints can be selectively re-soldered without full wave re-processing, reducing scrap on high-value assemblies.</li>

<li><strong>Prototyping and NPI lines</strong> — New product introduction runs benefit from the S100B's flexibility: engineers can revise THT component placement and immediately re-solder without changingover a production wave solder machine.</li>

</ul>

<h2>Integrating the S100B into a PCB Assembly Line</h2>

<p>In a typical SMT + THT line, the S100B sits downstream of the reflow oven. After SMT placement and reflow, boards enter THT insertion (radial or axial) and then proceed to the S100B for through-hole solder joints. The machine's small footprint (desktop form factor) allows it to be placed inline or as a offline work cell, depending on floor layout.</p>

<p>Key integration considerations:</p>

<ul>

<li><strong>Flux application</strong> — The S100B supports pre-fluxed boards or in-line flux coating. Consistent flux coating weight is critical to wetting quality.</li>

<li><strong> solder temperature control</strong> — The solder pot maintains stable temperature; nozzle approach speed and dwell time are programme-controlled per joint group.</li>

<li><strong>Board fixturing</strong> — Simple vacuum or magnetic pallet fixtures hold boards flat during soldering. No custom carriers needed for changeover.</li>

<li><strong>Downstream cleaning</strong> — Boards with no-clean flux can proceed directly to AOI or ICT. For aqueous-clean processes, a batch PCB cleaner follows the S100B.</li>

</ul>

<h2>Selecting a Desktop Selective Soldering System: Key Criteria</h2>

<p>When evaluating the S100B or comparable benchtop selective solder equipment, procurement and process engineers should weigh the following:</p>

<table>

<thead><tr><th>Criterion</th><th>What to Assess</th></tr></thead>

<tbody>

<tr><td><strong>Solder pot capacity</strong></td><td>Smaller pots reduce dross formation but require more frequent solder replenishment in high-throughput scenarios.</td></tr>

<tr><td><strong>Nozzle programme depth</strong></td><td>Verify the machine can address board thicknesses and component clearances relevant to your product mix.</td></tr>

<tr><td><strong>Positioning repeatability</strong></td><td>Critical for fine-pitch through-hole connectors; specify tolerance against your tightest THT pitch.</td></tr>

<tr><td><strong>Changeover time</strong></td><td>The S100B's fixture-free design is a major advantage — quantify real changeover (programme load + board swap + heat-up) for your batch sizes.</td></tr>

<tr><td><strong>Flux compatibility</strong></td><td>Confirm no-clean vs. water-wash flux preference and whether the machine supports both.</td></tr>

<tr><td><strong>Solder type support</strong></td><td>Standard SAC305 lead-free; confirm if your application requires tin-lead or specialty alloys.</td></tr>

</tbody>

</table>

<h2>ROI and Quality Angle: Why Facilities Choose Selective Solder over Wave</h2>

<p>For facilities currently using full wave soldering for small-batch THT assemblies, the economic case for a benchtop selective solder system rests on four factors:</p>

<ul>

<li><strong>Eliminated fixture cost</strong> — Custom wave solder pallets for each PCB variant can cost €200–€1,000+ per SKU. Fixture-free selective soldering removes this recurring expense entirely.</li>

<li><strong>Reduced changeover labour</strong> — Wave solder changeovers (drain, cool, swap pallet, reheat) can consume 2–4 hours. The S100B changeover is a board-swap and programme-recall operation measured in minutes.</li>

<li><strong>Lower scrap on high-value boards</strong> — Boards with heat-sensitive SMT components (electrolytic caps, connectors with plastic housing) that are damaged by full wave exposure represent pure scrap. Selective solder's localised thermal application protects these components.</li>

<li><strong>Small-batch feasibility</strong> — Facilities running batches under 100 units of mixed SKUs historically avoided THT automation due to changeover overhead. Desktop selective soldering makes these batches economically viable on automated equipment.</li>

</ul>

<h2>Frequently Asked Questions</h2>

<h3>What board sizes can the S100B handle?</h3>

<p>The S100B's desktop format accommodates PCBs up to approximately 300 × 250 mm, suitable for most consumer electronics and industrial control board footprints. Larger boards may require the S-series floor-standing selective solder models.</p>

<h3>Does the S100B support lead-free soldering?</h3>

<p>Yes. The S100B solder pot operates at standard lead-free temperatures (SAC305 alloy nominal 260 °C peak). Temperature profiles are programme-adjustable per joint group.</p>

<h3>How does selective soldering compare to hand soldering for THT?</h3>

<p>Hand soldering introduces operator variability, ergonomic risk (repetitive iron use), and throughput limits (~200 joints/hour per operator). The S100B delivers consistent, repeatable solder joints at significantly higher throughput for multi-joint boards, while eliminating operator skill as a variable in joint quality.</p>

<h3>Can the S100B be used for rework?</h3>

<p>Yes. The S100B is commonly used as a rework station for correcting individual THT solder joints that fail ICT or AOI, without exposing the full board to another wave solder pass.</p>

<h3>What is the typical throughput of the S100B?</h3>

<p>Throughput depends on joint count and programme parameters (dwell time, approach speed). For boards with 20–50 THT joints, a cycle time of 3–8 minutes per board is typical. Actual throughput should be characterised on a production representative board.</p>

<h3>Does Southern Machinery offer installation and training?</h3>

<p>Yes. Southern Machinery provides on-site installation, process parameter development, and operator training as part of its after-sales service ecosystem. The company has served 237+ global clients across power electronics, LED, automotive, and general electronics sectors since its founding in Shenzhen in 2011.</p>

<h2>Learn More About Southern Machinery's THT Soldering Solutions</h2>

<p>Southern Machinery (Smthelp) specialises in SMT and THT PCB assembly automation, offering a full line of insertion machines, wave solder systems, board handling equipment, and process support machines. The S100B Desktop Selective Soldering Machine is one of several selective solder solutions in the portfolio, alongside floor-standing selective solder systems and wave soldering equipment.</p>

<p>To discuss whether the S100B fits your production mix, contact the Southern Machinery team with your board specifications and THT joint requirements.</p>

HMLV PCBA Ultra-fast changing without fixture - S100B Desktop Selective Soldering Machine

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