Sipu Automatic Relay Coil Soldering Machine

In-Line Automatic Relay Coil Soldering Machine Hits 800 PCS/H with One Operator

Xiamen Sipu Mechanical has successfully delivered a custom automatic relay coil soldering machine to a relay manufacturer. Built on a straight, in-line conveyor layout, this relay coil soldering machine reaches a throughput of about 800 pieces per hour in a double-cavity configuration. 

A single operator loads unfinished relay coils at the front end and collects finished parts at the back end; every other process — fluxing, pre-forming, soldering, cooling, lead forming, inspection and sorting — runs automatically.

Why We Built This Relay Coil Soldering Machine

Large power relay coils carry thick enameled wire, multiple pins and tight lead-form requirements. Manual soldering and hand bending depend on worker skill: temperature, solder feed and dwell time vary shift by shift, leading to cold joints, solder balls and bent-pin inconsistencies. Visual inspection alone cannot catch internal inter-turn short circuits. This automatic relay coil soldering machine replaces those scattered manual stations with one enclosed, repeatable line.

Process Flow on the Straight In-Line Layout

Parts move left-to-right on a linear conveyor. After manual loading, the relay coil soldering machine picks up parts with a variable-pitch pick-up mechanism, dips leads in flux via a small rising flux cup, performs pre-bending, then dips leads into the solder pot. A multi-zone heated solder pot keeps temperature stable, and an integrated brush removes stray solder balls. Parts pass through a cooling section before entering the two-stage lead forming station.

Lead Forming Accuracy: ±3°

Lead forming is completed in two stages — outer pins first, then inner pins — to avoid wire distortion. The cooling stage ensures leads are fully solidified before bending, and final lead-forming accuracy holds to ±3 degrees. This two-step forming method replaces manual bending jigs and delivers consistent pin geometry for downstream plug-in or assembly operations.

Three On-Line Inspections: CCD, Resistance, Surge

The CCD inspection soldering machine station captures every solder joint on camera and flags insufficient solder, excess solder, solder ball, cold joint and misalignment. A multi-channel resistance meter tests pin continuity and coil resistance in parallel. A surge testing unit checks inter-turn insulation and catches internal short circuits that neither visual inspection nor a resistance meter can see. Any NG part is automatically diverted by a two-axis sorting gantry and never mixes with good parts.

Resistance testing

Visual check

before→after

Single-Standalone or Ready for Line Integration

The automatic relay coil soldering machine ships as a compact standalone unit. The belt out-feed can also be directly connected to upstream winding or downstream assembly and aging equipment, so customers can start with one machine and scale into a full relay assembly line later. Cycle rate, coil envelope compatibility and additional test stations are all specified at the design stage.