Evaluating reflow soldering quality requires a comprehensive assessment across five core dimensions: exterior size and weight, internal chamber structure, heating element performance, conveyor stability, and professional operating parameters. The specific methods are as follows.
1. Exterior Size and Weight
Size and heating performance: Reflow soldering relies on high temperatures inside the chamber to solder PCBs. The longer the board remains in the heated area, the better the soldering result. Larger equipment usually has a longer heating zone and better heating performance. For example, large reflow ovens may have a heated length of over 1.5 meters, while smaller units may be less than 0.8 meters, directly affecting soldering uniformity.
Weight and material: If the same model weighs one-third less than the standard, it may indicate substandard materials. Quality equipment typically uses thick steel plates (≥3 mm) and high-temperature-resistant materials, while low-quality units may use thin sheets or ordinary metal, leading to chamber deformation or temperature fluctuation.
2. Internal Chamber Structure
Heating method:
Infrared heating: Uses heating tubes to radiate heat directly. It is low cost but has poor temperature uniformity and can easily cause localized overheating of PCBs.
Hot air heating: Adds circulation fans to the heating elements for forced hot air circulation, improving temperature uniformity by more than 30% and making it suitable for high-precision soldering.
Fan configuration: Quality equipment usually has dual fans for upper and lower circulation to ensure hot air covers the entire chamber. Poor equipment may have only one fan or none, leading to temperature differences exceeding ±5°C.
3. Heating Element Performance
Heating tube type:
Finned heating tubes: Large heat dissipation area, high thermal efficiency, and a service life of over 20,000 hours. Suitable for medium and large equipment.
Smooth rod heating tubes: Poor heat dissipation, prone to aging, and usually last less than 10,000 hours. Often found in low-end equipment.
Heating wire application: Medium and large equipment uses heating wires such as nickel-chromium alloy, with heat exchange efficiency of 90% or more and a service life of up to 50,000 hours. Small equipment cannot use these due to size limitations.
For non-standard finned heating tubes, custom heating element brackets, or precision replacement parts used in the heating system, Hansheng Automation can provide custom machining based on customer drawings.
4. Conveyor Transport Stability
Mesh belt smoothness: Quality equipment uses a stainless steel chain-driven mesh belt that runs smoothly without vibration, keeping solder joint displacement below 0.1%. Poor equipment may use belt drive, and vibration can increase defects such as bridging and cold solder joints to more than 5%.
Speed control: Quality equipment supports stepless speed regulation from 0.1 to 2 m/min to accommodate different PCB sizes. Poor equipment may offer only fixed speeds, limiting flexibility.
5. Professional Operating Parameters
Anti-interference capability: Quality equipment is equipped with anti-interference circuits such as filters to withstand frequency converter or external voltage impacts, improving stability by 40%. Poor equipment lacks this function and is prone to temperature fluctuations.
Temperature profile control: Quality equipment maintains a temperature difference of ≤±2°C, meeting lead-free soldering requirements. Poor equipment may have differences as high as ±5°C, causing cold joints or component damage.
Energy efficiency: Quality equipment uses intelligent temperature control and frequency conversion technology to reduce overall power consumption by 20%–30%. Poor equipment lacks energy-saving design and may consume more than 5 kW per hour.
Summary and Recommendations
Prioritize equipment that is larger and heavier to ensure adequate heated length and reliable materials. Confirm that the chamber uses hot air heating and check whether the fan configuration is reasonable. Choose finned heating tubes or heating wire rather than smooth rod tubes. Test mesh belt smoothness and speed control to ensure no vibration and flexible adjustment. Request temperature profile reports and anti-interference test data from the manufacturer, and compare energy consumption parameters.
By following these methods, reflow soldering quality can be systematically evaluated to avoid purchasing low-cost, low-quality equipment.
