Eliminate flux residue and improve coating adhesion with our controlled PCBA cleaning process.

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What Types of Contamination does OurPCB Remove?

What PCBA Cleaning Methods does OurPCB Use?

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Aqueous Cleaning (For High-Volume Batch Cleaning)

For high-throughput cleaning, we operate fully enclosed aqueous cleaning systems that combine high-pressure spray with saponified deionized water at 60 °C. These systems target assemblies with solder paste, rosin, or water-soluble flux, removing active ions and organic residue from both sides of the board.

Our InJet platforms use 2.0 bar rotary spray heads for impingement and cascade rinsing with resistivity sensors that maintain <1.56 µg/cm² NaCl equivalent. Each cleaned board is force-dried at 70 °C for 10 minutes to eliminate moisture and prepare the surface for optical inspection or downstream processing. This is the most efficient method for batch-based PCBA cleaning at scale.

Manual/benchtop cleaning (for rework and selective soldering)

When boards require post-assembly rework or selective soldering, we apply a controlled manual cleaning process to treat localized contamination. Technicians begin by applying Decotron T383 or high-purity IPA to the assembly surface, then scrubbing with anti-static brushes at a 45° angle and 250 g pressure.

Flux is then removed using a directional aerosol rinse, and drying is completed with 30 psi filtered air or lint-free polyester wipes. This method allows us to clean the PCBA without subjecting sensitive components to immersion or thermal stress. We document all manual cleaning steps for traceability on high-reliability builds in automotive, medical, and aerospace programs.

How do We Clean No-Clean Flux and Prepare for Conformal Coating?

how do we clean no clean flux and prepare for conformal coating
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What Equipment do We use for PCBA Cleaning?

At OurPCB, we use dedicated, precision-controlled PCBA cleaning systems designed to meet IPC Class 2 and Class 3 cleanliness requirements across a range of board types and assembly workflows.

All machines are qualified through validation runs using ionic cleanliness testing and surface inspection to confirm they meet our reliability targets. By combining automated and manual platforms, we deliver consistent cleaning performance across both batch production and selective rework.

ked 600 and ked di 200 offline pcba cleaning machine

KED 600 and KED DI-200
Offline PCBA Cleaning Machine

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Dry Ice blasting cleaning

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PCB Board Process

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What Cleaning Agents and Solvents do We use?

PCBA Cleaning FAQs

Why clean “no-clean” flux?

Cleaning “no-clean” flux is recommended when electrical stability, surface preparation, or downstream testing could be affected by film formation or conductive traces. These materials may leave behind hygroscopic compounds that attract moisture and reduce insulation, even if their visual profile appears benign.

Removing them with the correct cleaning solution reduces the risk of current leakage, improves coating adhesion, and helps maintain inspection clarity. For a clean PCB to be accepted in high-performance environments, post-process film removal is often necessary, regardless of initial flux classification.

What causes electrochemical migration?

Electrochemical migration occurs when moisture, surface ions, and electrical bias interact on a circuit board and trigger unwanted conductive growth. The process begins with metal dissolution at the anode, where copper atoms release into a thin film of surface moisture.

These ions then undergo ion migration, moving toward the cathode along the moisture path. Finally, dendrite growth occurs at the cathode, where the metal ions deposit and form conductive filaments between traces.

PCBA cleaning removes ionic contaminants that make this process possible, especially in high-humidity environments or boards with tightly spaced conductors.

What are acceptable residue levels?

Acceptable contamination levels are defined by industry standards such as IPC J-STD-001, which specifies limits based on ionic content and surface area.

Most manufacturers target less than 1.56 µg/cm² NaCl equivalent using resistivity of solvent extract (ROSE) testing. Some designs use SIR testing to simulate in-use conditions over time, while others require full surface rinse validation to confirm that ionic films have been entirely removed.

For surface coatings to perform correctly, a clean PCBA must meet both ionic and visual thresholds before final packaging.

What is the best cleaning method for complex PCBAs?

The best PCBA cleaning method depends on board density, component standoff height, and surface accessibility. For fine-pitch layouts and bottom-terminated packages, vapor-phase degreasing using low surface tension cleaning chemicals is often the most effective.

Boards with moderate spacing and compatible materials may be cleaned in high-pressure water-based batch systems using saponified fluid and deionized water. The cleaning method must match the design’s geometry and thermal tolerance to prevent trapped fluid or incomplete surface preparation.

How does ultrasonic cleaning work?

Ultrasonic cleaning uses high-frequency sound waves, typically around 40 kHz, to create microscopic cavitation bubbles in a cleaning solution. As these bubbles collapse near the surface of the printed circuit, they dislodge contamination from under components and within narrow gaps.

This technique is especially useful for removing debris around dense connector arrays, low standoff components, or shielded modules. To avoid part damage, the process is tuned for fluid type, frequency, and exposure time, with post-process drying used to eliminate any retained moisture.

When should vapor degreasing be used?

Vapor degreasing should be used when physical access is limited or moisture-sensitive components make water-based systems unsuitable. It condenses heated solvent vapor onto a cooler printed circuit board, dissolving contaminants without liquid immersion.

Because it leaves no water, vapor degreasing is ideal for boards requiring rapid drying, minimal residue, and immediate readiness for conformal coating or testing. The method also benefits reflowed assemblies with tight lead spacing and uncoated copper.

What standards govern PCBA cleanliness?

PCBA cleanliness is governed by IPC-J-STD-001, which sets criteria for post-solder cleaning requirements and contamination thresholds. Section 8.3 defines when cleaning is required and outlines acceptable residue limits and visual inspection rules.

Validation is performed using methods referenced in IPC-TM-650, including ROSE (resistivity of solvent extract) and SIR (surface insulation resistance) testing. For high-performance designs, Class 3 requirements demand tighter contamination control than Class 2, especially for coating adhesion and long-term electrical isolation.

How to clean selectively soldered assemblies?

Selective cleaning targets only the soldered region without exposing the rest of the board to full-system wash cycles. This is done by applying a directional cleaning solution to the affected area using controlled fluid delivery, agitation, and low-pressure rinse.

Operators isolate the region to prevent solvent migration and use air-assisted drying to avoid trapping moisture. The process is proper after hand-insertion or post-test repairs, where full immersion may damage sensitive components or coatings.

What are Signs of Contamination Failure?

Contamination failures may present as field returns with intermittent behavior, dielectric breakdown, or unexpected conduction paths between circuit nodes. Diagnostic tests show low insulation resistance, leakage during humidity exposure, or dendritic bridging visible under magnification.

Physical indicators include staining, crystalline films, or darkened areas around pad edges. Failures often appear after thermal cycling, humidity aging, or long-term bias testing.

Does Flux Residue Affect Coating Adhesion?

Yes, remaining films on the surface interfere with the wetting and adhesion properties of conformal coatings. These films reduce surface energy, resulting in poor flow, edge beading, or gaps between lead exits and the mask.

When coatings lift or pull back during curing or thermal cycling, unprotected metal can become exposed. For optimal bonding, the board surface must be clean, dry, and free from interference before any coating is applied.

Ready for a cleaner, more reliable PCBA?

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