Radial Auto Insertion by Southern Machinery: Clinch-Quality Lead Forming for Reliable THT Joints

Before a through-hole radial component ever reaches the Wave Soldering bath, its fate is already settled by how its leads are cut and clinched. An electrolytic capacitor seated loosely, a transistor with leads bent at the wrong angle, or an LED floating slightly off the board surface will — at best — trigger rework and, at worst, escape into the field as a latent open joint. Southern Machinery's S3000 radial auto insertion machine targets exactly this failure point with a servo-driven insertion head and an "N"-type clinch base that form every lead to a controlled, repeatable geometry before soldering.

What Is This Machine Used For?

Q: What does a radial auto insertion machine actually do?

A radial auto insertion machine takes vertical tape-packed through-hole components — electrolytic capacitors, radial LEDs, transistors, key switches, resistors, connectors, and fuse blocks — and automatically cuts, inserts, and clinches their leads into pre-drilled PCB holes. The S3000 combines a 10-station feeder, a servo-driven insertion head (13.0 mm stroke), and a dedicated clinch base, so each component is placed and its leads folded under the board in one continuous motion.

Q: Why does clinching matter?

Clinch is the mechanical step that holds the component in place until solder forms the electrical and structural joint. If the clinch is too short, the part can lift or fall out during handling and Wave Soldering; if it is too long or at the wrong angle, adjacent leads can short or interfere with neighboring components. The S3000 forms leads to a controlled 1.5–2.2 mm clinch length and a 10°–35° clinch angle, so parts stay seated at a consistent height and orientation.

Q: What component variety can it handle?

The machine supports triple lead-span settings of 2.5 mm, 5.0 mm, and 5.7 mm, plus an insertion direction of 0°–360° in 1° increments — the flexibility to place both compact and larger radial parts on the same line without retooling.

Typical Application Scenarios

Radial through-hole components remain standard in power and control circuits where higher current, mechanical robustness, or legacy design requirements keep THT assembly relevant. The S3000 serves the same sectors Southern Machinery supports across its full SMT/THT line:

Electrical appliances — AC power boards for air conditioners, televisions, microwave ovens, electric kettles, and induction cookers, where large radial capacitors and power resistors are inserted in volume.
Power supply — vehicle power supplies, energy-saving power supplies, and ballasts, where consistent lead clinching directly affects solder-joint reliability under thermal cycling.
Vehicle electronics — car audio, vehicle power supplies, and lighting modules that demand repeatable, vibration-resistant through-hole joints.
Energy-saving lighting — industrial, outdoor, street-lamp, and floodlight drivers populated with radial LEDs and high-value film capacitors.

How It Integrates Into a Complete PCB Assembly Line

The S3000 slots into the THT segment of a mixed SMT/THT assembly flow. In a typical line, surface-mount devices are placed by a Pick and Place machine and reflowed in a Reflow Oven, after which the board moves on to through-hole processing. The radial inserter receives the populated board, inserts and clinches the radial components, and passes it downstream to Wave Soldering.

Board dimensions are a key compatibility factor: the S3000 accepts PCBs from 50×50 mm up to 400×400 mm and 0.79–2.36 mm thick. Machine-vision coordinate correction and calibration align the insertion head to the actual hole positions, compensating for board-to-board variance so the clinch lands precisely even on dense layouts. After soldering, inline AOI or manual inspection verifies the completed through-hole joints.

Key Selection Parameters

When evaluating a radial insertion machine, confirm these parameters against your product mix and quality targets:

Lead span range — verify coverage of 2.5 mm, 5.0 mm, and 5.7 mm spans to match your capacitor and resistor lead pitches.
Clinch length and angle — confirm the machine forms leads to your specified clinch length (1.5–2.2 mm) and angle (10°–35°) and holds them consistently across a shift.
Insertion direction — full 0°–360° control in 1° increments preserves polarity and orientation for directional parts.
Component envelope — confirm the insertion head and feeder accept your vertical tape-packed parts (body diameter, lead diameter, and height).
PCB size and thickness — match your panel range (50×50–400×400 mm, 0.79–2.36 mm) to avoid re-fixturing.
Throughput — 18,000 CPH rated speed against your required daily volume and takt time.
Vision and polarity detection — machine-vision coordinate correction plus polarity checks prevent reversed or mis-seated parts.
Utilities and footprint — 220 V single-phase power and 0.6 MPa air, with a 1800×1600×1800 mm footprint and ~1000 kg weight to fit your floor plan.

ROI, Quality & Throughput Considerations

The economic case for clinch-quality insertion is measured in rework avoided. Loose or lifted radial leads are among the most common sources of Wave Soldering defects — and every touched-up joint costs labor, slows the line, and risks secondary damage. A machine that clinches consistently reduces float and lead-lift so boards clear soldering on the first pass, protecting first-pass yield and letting downstream inspection focus on genuine process exceptions rather than routine manual fixes.

At 18,000 CPH, the S3000 also removes the manual-insertion bottleneck that caps THT throughput in mixed high-mix/low-volume production. Consolidating cutting, inserting, and clinching into one automated station lowers per-board labor cost while tightening the tolerance band around every lead — the combination that turns through-hole assembly from a cost center into a controlled, repeatable process.

FAQ

Q: What components can the S3000 insert?

A: Vertical tape-packed radial parts — capacitors, transistors, LEDs, key switches, resistors, connectors, and fuse blocks — across 2.5/5.0/5.7 mm lead spans.

Q: How precise is the clinch?

A: Leads are formed to a 1.5–2.2 mm clinch length at a 10°–35° angle, driven by a servo insertion head and "N"-type clinch base for shift-to-shift consistency.

Q: Does it handle polarity?

A: Yes — 0°–360° insertion in 1° increments plus machine-vision coordinate correction support correct orientation of directional components.

Q: What board sizes does it accept?

A: PCBs from 50×50 mm to 400×400 mm, 0.79–2.36 mm thick.

Q: What are the utility requirements?

A: 220 V single-phase power and 0.6 MPa compressed air.

Q: Where does it fit in the line?

A: Between SMT placement/reflow and Wave Soldering, feeding and clinching radial components before the board enters the solder wave.

Contact Southern Machinery

Radial insertion is only as good as the clinch that holds the part in place until solder takes over. If you are reworking lifted leads, fighting inconsistent part height, or capping THT throughput with manual insertion, Southern Machinery can help you quantify the fix.

What is your current first-pass yield at Wave Soldering, and how much of your rework traces back to loose or mis-clinched radial leads?
How many radial parts per board are inserted manually today — and what would recovering that labor save across a full shift?

Founded in 2011 in Shenzhen, China, Southern Machinery serves 237+ global customers with full-line SMT and THT PCB assembly automation, including insertion machines, Wave Soldering, board handling, and inspection. Every system is backed by spare parts, training, and global after-sales support.

Email: jasonwu@smthelp.com
Phone/WhatsApp: +86 13602562576
Website: https://www.smthelp.com
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Watch in Action: S3010A Radial Insertion Machine — YouTube