Views: 0 Author: Teresa WU Publish Time: 2025-12-17 Origin: Site
Imagine this: Your newly produced PCBs develop white crystalline spots after just 3 days of storage, sending the sampling yield plummeting from 98% to 83%. What seems like a minor cosmetic flaw is actually a silent productivity killer—triggering short circuits, corroding high-value components, and derailing environmental compliance. For manufacturers focused on high-reliability electronics, this issue isn't just costly—it threatens market competitiveness.
In this guide, we'll cut through the chaos of PCBA white spots, delivering actionable solutions tailored to precision manufacturing needs. From 5-minute residue diagnosis to scene-specific cleaning processes, we'll help you eliminate white spot risks, improve yield, and meet the strict standards of advanced electronics production.
PCBA white spots—including crystalline residues, hazy halos, and dull whitish films—are far more than an aesthetic problem.
They pose three critical threats to your products:
1. Electrical Failures: Moisture-absorbing flux residues form "microcircuits," increasing signal delay and short-circuit risks by 40% in high-performance devices.
2. Component Degradation: Gold or silver-plated components corrode at a rate of 15% within 3 months when exposed to corrosive residues, shortening product lifespan.
3. Compliance Risks: Halogen compounds in residues trigger environmental certification alerts, forcing mass rework and delaying market entry.
Unremoved flux after soldering contains polymerized rosin and organometallic salts. When humidity exceeds 60%—a common challenge in many production environments—these substances undergo hydration reactions, transforming from transparent to visible white crystals. This issue is amplified with "no-clean flux," where unactivated components create hard-to-remove residues.
Post-cleaning PCBA substrate - clean copper traces and unit layout
Cleaned PCBA substrate - uniform surface after residue removal
Incompatible cleaning agents: Cause flexible PCB substrates to absorb moisture and whiten post-cleaning, a major issue for thin-film electronics.
Imbalanced ultrasonic parameters: Power below 30W or temperature under 40℃ fails to remove solder balls and paste residues in recessed solder joints.
Delayed drying: Waiting over 6 hours after cleaning allows moisture to combine with residues, forming hydrate white spots that compromise reliability.
Semiconductor packaging substrates, flexible PCBs, and other advanced devices often have high base material moisture content or insufficiently dense plating. Heat during manufacturing causes moisture to migrate to the surface, while plating bath residues trigger oxidation (e.g., white nickel oxide formation on nickel layers), directly impacting device performance.
Residue Type |
Test Method |
Targeted Cleaning Solution |
Organic Rosin Residue |
Wipe with IPA—residue dissolves |
Polar solvent cleaner and ultrasonic cleaning |
Ionic Residue |
Soak in pure water—halos appear |
Neutral cleaner and multi-stage ultra-pure water rinsing |
Plating Oxidation Residue |
No change after alcohol wipe |
Non-corrosive precision cleaner soaking |
Core Pain Points: High temperature and humidity in operating environments accelerate residue corrosion, leading to sensor failure and short circuits.
Custom Solution:
Cleaner selection: Low-volatility formula resistant to -40℃~125℃, preventing secondary precipitation under extreme conditions.
Process parameters: 4% dilution ratio, 50W ultrasonic cleaning (3 mins) and spray cleaning (1 min), followed by 3-hour drying at 60℃.
Quality Guarantee: Passes 1000-hour salt spray test, with ion contamination < 1.0μg/cm²—meeting strict reliability standards for critical electronics.
Core Pain Points: Flexible PCBs often whiten or shrink after batch cleaning, reducing assembly yield and increasing costs.
Custom Solution:
Cleaner selection: Slow-evaporating neutral formula (KB value 65~70) compatible with ABS, PI, and other flexible substrates.
Process parameters: 40W ultrasonic cleaning (5 mins), paired with "stepwise drying" (40℃→55℃) to avoid substrate deformation.
Efficiency Boost: Cleaner is recyclable more than 8 times, cutting per-batch cleaning costs by 35%—ideal for high-volume production lines (more than 100,000 units/day).
cleaner effect on PCBA IGBT substrate - before (left) vs after residue removal (right)
Core Pain Points: Sensitive plating is prone to corrosion, and residues cause packaging failure in high-precision applications.
Custom Solution:
Cleaner selection: Fluorine-free, chlorine-free, low-corrosion formula (corrosion rate < 0.001mm/a) passing gold-plating compatibility tests.
Process parameters: Low-temperature cleaning (35℃), soaking time < 6 mins, paired with ultra-pure water rinsing (conductivity < 1μS/cm).
Compliance Assurance: ODP=0, GWP < 0.05, meeting strict VOC limits and environmental certifications for advanced electronics.
Reject "One-Size-Fits-All": Avoid acidic cleaners for gold-plated components; use slow-evaporating formulas for flexible PCBs to prevent shrinkage and whitening.
Prioritize "Post-Cleaning Protection": Choose cleaners with dual "cleaning and protection" functions—they form a nano-scale protective film after evaporation, reducing secondary moisture absorption.
Balance Efficiency and Cost: Opt for recyclable cleaners (recovery rate ≥80%) to cut per-batch costs by 30% without sacrificing performance.
Storage Optimization: Maintain humidity < 60% RH, use moisture-proof packaging with desiccants, and avoid prolonged exposure to ambient air.
Routine Inspection: Test 5% of each batch for ion contamination (requirement: < 1.5μg/cm²) using quick-test solutions for real-time quality control.
Process Traceability: Record cleaner batches, cleaning parameters, and drying time to build a rapid response mechanism for abnormalities.
PCBA long strip substrate - uncleaned (left) vs pre-cleaning surface condition (right)
IGBT unit array with residue - uncleaned production appearance and component state
IGBT substrate cleaned layout - pre-cleaning circuit design and surface state
A1: Fully compatible! It works with mainstream ultrasonic cleaners (20~60W power) without the need for equipment modification. Simply adjust the dilution ratio and cleaning time to match your production line.
A2: Dual verification is provided: ① Free ion contamination test solution (5-minute quick test—ion content < 1.5μg/cm² = qualified); ② Third-party authoritative testing (e.g., SGS) with RoHS/REACH compliance reports for total peace of mind.
A3: Absolutely! The formula is optimized for no-clean flux, efficiently dissolving unactivated polymerized rosin and organometallic salts. Even stubborn white halos on 15-day-old PCBs have a 99.7% removal rate—with no secondary whitening.
A4: Our "circulation filtration + concentration replenishment" system allows the cleaner to be reused 8~12 times. Concentration test reagents cost less than $0.01 per use, and replenishing stock solution maintains cleaning power—reducing per-ton PCB cleaning costs to 60% of traditional solvents.
A5: Yes! The formula is halogen-free, heavy metal-free, and low-VOC (<50g/L), complying with RoHS 2.0 and REACH 211 substance regulations. It's fully compatible with the environmental requirements of semiconductor, automotive, and consumer electronics manufacturing.
PCBA white spots don't have to be a production nightmare. With precise residue diagnosis, scene-specific cleaning processes, and long-term protection strategies, you can turn this hidden risk into a competitive advantage.
Ready to eliminate white spots and boost your yield by 11%? Claim your free cleaner sample today—includes dual technical support (residue testing and process optimization) and a customized cleaning plan within 72 hours.
Have you encountered PCBA white spots in high-reliability or mass-production scenarios? Share your challenges through Tel/WhatsApp/WeChat: +8618123969340, Email, or contact us through our website, and our team will provide tailored advice to solve your specific issues!
