safe & efficientSMT Electronics Cleaning
Environmentally friendly cleaning solutions for Surface Mount Technology (SMT) and Through Hole (THT) Electronics
Failure is not an option! When cleaning printed circuit board (PCB) assemblies, the primary goal is to remove contaminants from populated PCBs and hybrid assemblies that can contribute to performance failure in the field. Engineered PCB cleaning solutions are essential to ensure the cleanliness and complete removal of contaminates like flux residues from assemblies used in high-reliability applications and industries such as automotive, medical, aerospace, telecommunications, and military.
When manufacturing electronic assemblies, solder pastes, SMT adhesives, or thick film pastes are printed or applied using stencils, pump print stencils, or screens. Paste residues and remaining SMT adhesives on stencil surfaces and apertures can lead to misprints resulting in bridging and solder balling issues. For optimum print results, cleaning the stencils and screens either manually or using an automated stencil cleaning machine is necessary.
As part of a maintenance cleaning program, the most prevalent types of contamination, such as baked-on fluxes, recondensed gas emissions from the soldering process, and coating residue from pallets and fixtures, must be removed to ensure a reliable and failure-free production process.
Other parts that require maintenance cleaning include dispensing needles, solder pallets, conveyor fingers, condensation traps, reflow ovens, and wave solder machines.
Frequently Asked Questions – SMT & PCB Cleaning
Answer: SMT cleaning removes flux residues, solder pastes, adhesives, and other contaminants from printed circuit board assemblies produced via Surface Mount Technology. Proper cleaning prevents electrical failures such as leakage currents, corrosion, and dendritic growth — all of which can lead to field failures.
Answer: PCBs should be cleaned after soldering when flux residues could affect long-term reliability or when high cleanliness standards are required. Even “no-clean” flux processes may need cleaning if ionic contamination or residues affect insulation or downstream processes.
Answer: Common contaminants include solder flux residues, solder paste particles, adhesives, and recondensed gases from soldering processes. If left behind, these can lead to defects like solder bridging, leakage current, or impaired stencil performance.
Answer: SMT cleaning can be done using inline spray systems, batch cleaners, ultrasonic tanks, and manual cleaning methods depending on throughput and board complexity. Each method has advantages based on production volume and geometry.
Answer: Yes. Low-standoff cleaning — where flux residues must be removed beneath tightly spaced components — requires appropriate cleaning processes that can penetrate small gaps without leaving residue.
Answer: Absolutely. Cleaning SMT stencils removes solder pastes and adhesives that can clog apertures and cause misprints, improving solder paste deposition consistency and reducing defects.
Answer: Cleaning chemistry should match the type of flux or residue being removed and the cleaning process used. Incorrect chemistry can lead to issues like foam or incomplete cleaning, so selecting products optimized for your process is essential.
Answer: Challenges include excessive foam formation, hard-to-reach low-standoff residues, improper choice of cleaner for a given process, and residues that bind to components. Effective process control and analytics help mitigate these issues.