PCBA Flux Residue & Ionic Contamination Cleaning

Flux residue can remain around component leads, solder joints, connector pins and beneath low-clearance components after reflow, wave or selective soldering.
Visible residue can interfere with inspection and conformal coating. Soluble ionic residue may be invisible but can contribute to corrosion, leakage current and electrochemical migration when moisture and electrical bias are present.
DEZ provides single-sided, offline batch and inline PCBA cleaning equipment. The cleaning method is selected according to the flux, contaminated area, component layout, required cleanliness and production volume.

PCBA Cleaning Problems

Visible Flux Residue After Soldering

Flux marks and deposits remain around SMT solder joints, through-hole leads, terminals and connector pins after soldering.

Ionic Contamination That Cannot Be Seen

A PCBA may look clean while soluble residue remains between conductors, around solder joints or beneath components. Visual inspection cannot confirm ionic cleanliness.

Residue Around Dense Components

Low-clearance components, shields, connectors and densely populated areas can restrict cleaning access, rinsing and drainage.

Contamination Before Conformal Coating

Flux residue and remaining cleaning agent can be trapped beneath conformal coating, affecting coating coverage and the condition of the protected surface.

Loose Solder Balls and Particles

Loose contamination left on the solder side can affect inspection, handling and subsequent assembly.

Flux Introduced During Rework

Component replacement, manual soldering and BGA rework can introduce new flux residue that must be removed before the PCBA returns to production.

Recommended PCBA Cleaning Equipment

PCBA Cleaning FAQ

What is the difference between flux residue and ionic contamination?

Flux residue is material remaining from soldering chemistry and may be visible on the assembly. Ionic contamination consists of electrically active soluble residues and may remain even when the PCBA appears clean.

No-clean flux is designed to remain under specified conditions, but it may still require removal when residue affects coating, inspection, electrical performance or product cleanliness.

The DEZ-C758 cleans one accessible solder-side surface. Select a complete washing and rinsing process when residue must be removed from both sides or beneath components.

Select the DEZ-C743 for offline batch cleaning when several PCBA models are produced and changeovers are frequent.

Select the DEZ-C1520 when PCB assemblies must pass continuously through washing, DI-water rinsing and drying.

No. Some residues require a compatible cleaning agent followed by DI-water rinsing. Flux and material compatibility must be confirmed before setting the process.

Yes, Cleaning depends on stand-off height, component layout, residue, chemistry and liquid access. Sample testing should be completed using the actual PCBA.

PCB Assembly Applications & SMT Process Solutions DEZ SMT

Explore More Electronics Manufacturing Problem Solving Applications

DEZ equipment also supports bare PCB surface cleaning, stencil cleaning, SMT nozzle cleaning, fixture cleaning, selective soldering, reflow soldering, X-ray inspection, BGA rework and SMT line handling.

Explore all applications to find equipment according to the production stage, assembly type and manufacturing problem.

Discuss Your PCBA Cleaning Requirement

Send us the PCBA dimensions, soldering method, flux information, component layout, contaminated areas, production volume and required cleaning result.

PCBAs containing actual post-solder residue can be tested before machine selection. DEZ will evaluate whether the application requires single-sided cleaning, offline batch cleaning or continuous inline cleaning.

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