The Importance of PCB Cleaning
Printed circuit boards (PCBs) are the core components of electronic products, and their proper cleaning and maintenance are crucial for long-term stable operation. Unlike regular surface cleaning, PCB cleaning requires specialized techniques and careful handling. Improper cleaning methods may cause:
- Connector contact failure
- Component loosening or damage
- Circuit board material corrosion
- Performance degradation of sensitive components
Common Contaminant Types and Corresponding Cleaning Solutions
1. Dry Contaminant Treatment (Dust, Particles)
Recommended Methods:
- Precision Brush Cleaning: Use horsehair or anti-static nylon brushes (5-10mm width) for gentle cleaning
- Low-pressure Air Gun Blowing: Maintain pressure at 0.2-0.3MPa with 15-20cm distance
- Professional Vacuum Equipment: Use ESD-safe vacuum cleaners with suction power below 50W
Precautions:
- Avoid using regular compressed air cans (may produce condensation)
- Maintain a 45° board tilt during cleaning to facilitate particle removal
- Exercise special care with BGA and other packaged components to prevent solder joint damage
2. Sticky Contaminant Treatment (Flux, Grease, Beverage Residues)
Professional Cleaning Solutions:
| Contaminant Type | Recommended Solvent | Concentration | Tools | Processing Time |
|---|---|---|---|---|
| Rosin Flux | Isopropyl Alcohol (IPA) | 99.7% | Non-woven fabric/Cotton swabs | 30-60 sec |
| Grease Residue | Specialized Electronic Cleaner | - | Anti-static brush | 1-2 min |
| Beverage Residue | Deionized Water + IPA | 1:1 | Ultrasonic Cleaning | 3-5 min |
Operation Standards:
- Pre-treatment: Remove large particles with a vacuum
- Solvent Selection: Test compatibility on inconspicuous areas first
- Cleaning Operation: Wipe unidirectionally along circuit traces
- Drying Process: 60℃ oven drying for 30 minutes
Detailed Ultrasonic Cleaning Technology
Technical Principle
Through high-frequency oscillation (25- 100 kHz), cavitation effects are created in liquid, forming microbubbles of 50-200μm diameter. The bursting of these bubbles generates localized high temperatures and pressure for microscopic cleaning.
Equipment Selection Guide
Frequency Selection:
- Low frequency (25- 40 kHz): Heavy contaminant removal
- Medium frequency (40- 80 kHz): Regular cleaning
- High frequency (80- 100kHz): Precision component cleaning
Cleaning Parameters:
- Temperature: 40-55℃ (depending on solvent)
- Time: 3-8 minutes
- Power Density: 0.5-1.5W/cm²
Applicability Assessment
Recommended Scenarios:
- High-density SMT assembled boards
- Batch production cleaning
- Hard-to-reach areas under components
Non-recommended Cases:
- PCBs with acoustic-sensitive components (e.g., MEMS)
- Liquid-containing components like electrolytic capacitors
- Boards with easily removable markings
Safety Operation Standards
- Personal Protection:
- Wear anti-static wrist straps
- Use chemical-resistant gloves (nitrile material)
- Eye protection
- Environmental Control:
- Humidity 40-60% RH
- Temperature 18-25℃
- Anti-static workbench
- Post-cleaning Inspection:
- Visual inspection (10x magnifier)
- Impedance test (>100MΩ)
- Functional testing
Special Component Handling Recommendations
- Connectors:
- Prevent solvent penetration
- Use specialized cleaning sticks
- Optical Components:
- Use only designated cleaners
- Unidirectional wiping
- Heat Dissipation Devices:
- Remove thermal paste first
- Clean heat sinks separately
By adopting scientific cleaning methods and strict operation standards, PCB service life can be effectively extended while reducing failure rates. We recommend establishing regular maintenance schedules and documenting cleaning parameters and results for each session to create comprehensive equipment maintenance records.