Key Factors to Consider When Selecting a Reflow Soldering Equipment Manufacturer

The requirements for lead-free technology in reflow soldering are primarily reflected in strictly controlled process parameters, equipment performance, and material compatibility to ensure soldering quality, prevent component damage, and meet environmental standards. The following is a detailed description of the core requirements:

‌1. Temperature curve control‌

‌Peak Temperature‌: Set between 240–250°C to match the high melting point of lead-free solder (e.g., tin-silver-copper alloy); for precision components like BGAs, this can be relaxed to 260°C, but exposure time must not exceed 40 seconds to prevent thermal damage.

‌Preheating Zone‌: Temperature 100–150°C, duration 120–180 seconds, with a temperature rise rate controlled at 0.7–1.5°C/second to prevent PCB deformation or uneven evaporation of solder paste solvents.

‌Insulation Zone‌: Temperature 150–200°C, duration 60–90 seconds, to ensure uniform heating of the solder and activation of the flux.

‌Cooling Zone‌: Cooling rate must be >6°C/second (e.g., forced air cooling) to ensure rapid solidification of the solder joints and minimise voids and thermal stress defects.

‌2. Equipment Performance Requirements‌

‌Number and Length of Temperature Zones‌: At least 7 temperature zones (recommended 8–10 zones), with a heating zone length >2950 mm; multi-zone design supports precise curve adjustments to accommodate high-density PCBs (e.g., boards wider than 400 mm).

‌Temperature Uniformity‌: Cross-sectional temperature difference in the furnace chamber ≤±2°C (≤±1°C when unloaded), temperature control accuracy ±0.1–0.3°C, to prevent cold solder joints or bridging.

‌Conveying System‌: Servo motor-driven chain track + mesh belt, speed range 0–2000 mm/min (variable frequency adjustable), vibration接近 zero to prevent component displacement.

‌Cooling and safety‌: Forced air cooling system with UPS power failure protection, with output board temperature controlled between 38–50°C; the equipment must be sealed to support nitrogen welding (to reduce oxidation).

‌3. Material and process compatibility‌

‌Solder and flux: Lead-free compatible materials (e.g., tin-silver-copper solder paste compliant with RHS standards) must be used, matched to PCB substrate and component characteristics to enhance wettability and reliability.

‌Calibration and monitoring: Regularly calibrate equipment temperature and conveying speed, and use an external temperature curve data logger (e.g., furnace temperature tester) for real-time curve testing to ensure process consistency.