What’s the Best Way to Dry a PCB on the Benchtop?

There are four steps to successfully cleaning PCBs (printed circuit boards). Wet, scrub, rinse and dry . The wet, scrub and rinse operations are obvious. Wet the board with a pure cleaning fluid. Scrub it using a good quality scrubbing brush. Then rinse it off with more clean fluid. However, the dry step is often overlooked or in some instances, completely left out of the PCB cleaning plan. For reliable performance, circuit boards must not only be clean, they must be dry in order to function properly. Leftover moisture on a PCB surface can lead to a host of problems including corrosion, electrochemical migration, delamination, dendrite growth, pin holes and blow holes and adhesion problems with conformal coatings later in production. Modern PCBs often have bottom termination components like land grid arrays and QFN (quad-flat no-leads) with very tight standoff heights. Moisture can get trapped under these components, making drying even more complicated. There are different ways to dry to ensure printed circuit boards are not only clean, but also dry for optimum reliability and performance. Capture the excess spray of cleaning fluid on a circuit board or gently pushing the wipe under low-surface mounted components, wipes are a quick and effective way to dry the PCB without leaving lint or fuzz behind. There are many factors to consider when selecting a lint-free drying wipe including absorbency, material and packaging. Manual Cleaning & Drying with Wipes and Dusters One of the most commonly used methods technicians use to dry PCBs during benchtop cleaning is a simple lint-free wipe . Whether using it to capture the excess spray of cleaning fluid on a circuit board or gently pushing the wipe under low-surface mounted components, wipes are a quick and effective way to dry the PCB without leaving lint or fuzz behind. There are many factors to consider when selecting a lint-free drying wipe including absorbency, material and packaging. The most important factor when choosing a drying wipe is the ability of the wipe to absorb the type of moisture encountered. For example, some wipes will absorb cleaning fluids, but they will not absorb water. The key is to match the type of wipe absorbency to the contamination to be removed. The material makeup or the type of fiber used to make the wipe is also important. Nonwoven wipes, since they are made without glues or binders, don’t leave residue on the surface being cleaned, resulting in a cleaner PCB. Another way to limit re-contamination to the PCB is to choose pre-washed wipes or wipes with finished or heat-sealed edges. This eliminates loose fibers and dust, ultimately leaving the printed circuit board cleaner. For some benchtop post reflow (rework) assembly a good drying method is to use a dust remover . A quick blast of from a duster can be effective at blowing trapped moisture from underneath larger components that a wipe alone might not reach. The dust remover can be targeted to a very small area on the PCB and works extremely well in getting into and under intricate and hard-to-reach nooks and crannies on the circuit board. Using a duster in combination with a wipe doubles the drying power and prevents the fluid from being pushed back onto on the board and spreading contaminant around. When selecting a duster to use for a drying application, safety is key. Inexpensive canned air is readily available from a number of retail outlets. However, many of these formulations may pose a hazard due to their high flammability ratings. A safer alternative is to select a dust remover that is made with nonflammable gas. A 360° type of dust remover also adds drying convenience since the can operates at any angle, even upside down, allowing operators the flexibility to quickly dry very complex or intricate PCBs. Using the duster may take a little bit of practice, but once the operator understands the velocity of the high-purity gas, the moisture can be blown away quickly and efficiently with no residue left behind.

Which MicroCare Aerosol Cleaner is the Strongest?

Cleaning strength is measured by the Kari-Butanol rating of the solvent, shown on MicroCare product specifications as the “Kb number.” (Some competitors do not offer Kb ratings on their products, which we find odd.) A rating of 20 or so is mild while anything over 70 is a aggressive solvent that will probably not be plastic-safe. Our strongest solvent, the Lead-Free Flux Remover – PowerClean™, has a Kb value over 100. The Polar Flux Remover can be used with the TriggerGrip cleaning tool to deliver cleaner PCBs and lower cost. All that being said, if you need real muscle for age-hardened rosin fluxes or maybe some nasty conformal coatings, try these: Lead-Free Flux Remover – PowerClean™ (#MCC-PW2) or Heavy Duty Flux Remover – SuprClean™ (#MCC-SPR) for fast-drying choices, and the Uncured Epoxy Remover – ExPoxy™ (#MCC-EPX) for a slower-drying choice. If the environment permits flammable cleaning fluids, a good choice is the Polar Flux Remover (#MCC-PFR). All are superior choices for most cleaning applications. If you are cleaning residues that may be soluble in water, go with the money-saving Reflow Oven Cleaner (#MCC-ROC). Here are the details… Heavy Duty Flux Remover – SuprClean™ was first introduced late in 1998. Formulated specifically for high-powered defluxing, it cleans great, dries fast, has almost no aroma, and is nonflammable. It is a great choice for cleaning traditional fluxes, pastes, oils, grease and some inks. Ozone-safe, easy-to-use SuprClean™ rocks with cleaning power. It knows no bounds! TriggerGrip™ compatible. Lead-Free Flux Remover – PowerClean™ is the strongest of the nonflammable, fast-drying solvents. Most importantly, it works great on the high-temperature lead-free solders and pastes and easily eliminates the white residues that often occur when cleaning those materials. It’s the least expensive product in it’s class. It also can be used with the TriggerGrip™ system. The Uncured Epoxy Remover is a combination defluxer, degreaser and stencil cleaner. Based on a hydrocarbons it’s relatively slow-drying and about as strong as the old 1,1,1-TCA (especially on grease, oils and other heavy contamination). This means it is ideal when you are cleaning more than just circuit boards — such as mechanical parts, housings and work benches. Overall, it cleans well, is very versatile and highly affordable, with superior toxicity ratings and less expensive than other choices. The Reflow Oven Cleaner is a powerful, water-based cleaner. It is an aggressive, nonflammable, slow-drying solvent engineered specifically to remove baked-on fluxes from inside wave solder machines and reflow ovens. This cleaner dissolves conveyor-clogging flux residues inside the ovens. The chemical is safe on pallets, baffles, heating elements, clamps, chains, pulleys, drive gears and housings. Rinsing is never required. The refillable pump spray makes cleaning easy and fast. One final warning: all of these products are very, very aggressive cleaners. Before putting them into wide-spread use, you should test them thoroughly, especially on soft plastics, gaskets, insulation and rubber. While they will not damage today’s tough SMT components, they can easily chew up older passive components, housings and mechanical parts (e.g., platens, drive wheels) coming in for repair.

What's Best for Cleaning Under Low Clearance SMT Components?

Contamination is one of the primary drivers of field failures in electronics today. Corrosion and electrochemical migration (“ECM”) is directly caused by residues left on PCBs. Contamination-related failures are pervasive and have been observed on batteries, LCDs, PCBAs, wiring, switches, under coatings, over coatings, etc. The problem is expected to get worse as continued reductions in pitch between conductors makes future packaging more susceptible. Contaminants are concentrated under these low standoff devices. This didn’t used to be a problem. Until the 1970s, almost all electronics were built from individual components, with the labor-intensive assembly of thousands of separate diodes and transistors. The miniaturization demanded by the space race led to the first computer chips called “plated through-hole” circuit board designs. The defining physical feature of a through-hole PCB are the “legs” that extend from the components. These chips have a high “stand-off” from the board which makes it easy to clean the rosin flux residues that migrated under the components. The late 1980s saw the evolution to the first SMT “surface mount technology” components. Shorter legs and tighter stand-offs enabled more chips per-square centimeter, making the resulting tools “smarter.” Many chip designs, such as the popular QFP format, had 200+ electrical connections which made the chips extremely powerful. But by the turn of the century, ball grid array (“BGA”) components were becoming commonplace. BGA components jammed even more transistors into the smallest possible package. Each chip supported thousands of tiny solder connections (hidden underneath the chip) which make them extremely rugged, even in harsh environments. BGA designs have stand-offs measured in microns. The increased use of leadless and bottom termination components (QFN, land grid array, etc.), multi-chip modules and other advanced component designs results in a reduction in standoff height which reduces the efficiency of cleaning. These dense designs are difficult to clean, and cleaning is absolutely critical to longevity and performance. Specifically, heat from the component accelerates the reactions formed with salt complexes which can then cause corrosion or dendrite growth on the PCBs, causing the PCB to fail. Dense PCB designs run hot, so corrosion that might take years in a benign office environment can happen in just days in a hot, humid environment. For best cleaning results, PCB fabricators should seek out cleaning fluids that are very pure and uncontaminated , with a high Kb value , with low surface tension and low viscosity. Water simply will not get under these tight-fitting components, and if somehow it does get under the chip it will rarely ever comes back out. For best results, consider the Heavy Duty Flux Remover — SuprClean™ (#MCC-SPR). Other good options are the No-Clean Flux Remover — VeriClean™ (#MCC-DC1) and the General Purpose Flux Remover (#MCC-FRC). BGA components like this one link their electrical connections with thousands of tiny solder joint hidden beneath the component. These can be very difficult to clean with traditional liquids

Which Cleaner Works Best on Light Grease, Oils and Other Lubricants?

Until recently, there would have been only one recommendation and it would have stood out so far above all others you couldn’t even read the names of the second choice. The leader: the Uncured Epoxy Remover (#MCC-EPX). This cleaner is as good as than the old ozone-depleting 1,1,1-TCA, it dries reasonably quickly, is very acceptable environmentally, and it has very good toxicity ratings. The only drawback? It has a flashpoint, so it is not suitable for use in heated vapor degreasers or ultrasonic systems. But now there is a new top dog in town: the Lead-Free Flux Remover – PowerClean™ . This product was formulated first as a defluxer and then we discovered it is a great degreaser as well. It is nonflammable, dries quickly and has an excellent environmental record. The Reflow Oven Cleaner is a water-based degreaser is with exceptional handling. It’s nonflammable and slow-drying, but it works best when warm. Since many degreasers have heating capabilities, it’s ideal in applications where parts can be soaked for an hour or two in a dipping tank. For automated cleaning of large quantities of products, MicroCare recently launched another great choice: Tergo™ XCF2 Specialty Cleaning Fluid . As degreasers go, the material is unbeatable. If your degreasing problems are causing headaches, and using a vapor degreaser seems feasible, then check out the Tergo™ family of cleaning choices. Of all of these choices, we would recommend PowerClean™ as a starting point: it’s ozone-safe, nonflammable, and almost odor-free. Most of these cleaners are not completely plastic-safe, so be careful where you use them. Always test on soft plastics before deploying these cleaners widely. Get some samples and try them.

General Purpose Flux Remover C — Europe - Bulk

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Product Information

General Purpose Flux Remover C gives superior cleaning on no-clean and rosin fluxes

Applications:

Use on no-clean and rosin fluxes
Works well on hard-to-clean lead-free products
Ideal for through-hole, SMT boards and hybrids
Cleans under low-mounted BGA chips
Use as a general purpose degreaser for grease, light oils, and ink

Features:

Produced, labeled and packaged in compliance with the safety rules of the EU
Dissolves flux residue
Leaves no residue behind
Nonflammable for better safety when using or storing
Medium cleaning strength (25 Kb)
Fast-drying for speedier cleaning
Low odor for a better work environment
Non-corrosive, safe on most plastics (test on soft plastics before use)
Chemical Family: HFC blend
VOC Content: 590g/L
RoHS/WEEE/REACH/EPA/SNAP compliant

This versatile and popular all purpose flux remover has a high desnity and ultra-low surface tension. It gets under tight-fitting and low mounted components to wash contaminants away. This general purpose flux remover ozone-safe and has a medium global warming potential (GWP).

Product Details

Part Number	Package	Weight	Size	Technical Data Sheet	Safety Data Sheet
FRC2G FRC2G	MiniPail	4.54 kg 10 lbs.	3.79 L 1 Gallon	TDS UK (ENGLISH) (opens in a new tab)	SDS Lookup (opens in a new tab)
FRC2P FRC2P	Pail	22.68 kg 50 lbs.	18.93 L 5 Gallons	TDS UK (ENGLISH) (opens in a new tab)	SDS Lookup (opens in a new tab)
FRC2D FRC2D	Drum	226.8 kg 500 lbs.	208.2 L 55 Gallons	TDS UK (ENGLISH) (opens in a new tab)	SDS Lookup (opens in a new tab)

Part Number	FRC2G	FRC2P	FRC2D
Package	MiniPail	Pail	Drum
Weight	4.54 kg 10 lbs.	22.68 kg 50 lbs.	226.8 kg 500 lbs.
Size	3.79 L 1 Gallon	18.93 L 5 Gallons	208.2 L 55 Gallons
Technical Data Sheet	TDS	TDS	TDS
Safety Data Sheet	SDS	SDS	SDS

Appearance	Clear, colorless liquid
Odor	Slight, Ether
PEL (ppm, 8-hr TWA)	200
Boiling Point	37°C / 99°F
Chemical Family	Hydrofluorocarbon blend
Evaporation Rate	Fast
Cleaning Strength (Kb)	25
Active Ingredients	HFC Solvents and trans
Flashpoint	None
Global Warming Rating (100yr)	Not Available
VOC Organic Content (g/L)	590
Ozone Impact	Zero
REACH & ELINCS Compliant
RoHS & WEEE Compliant
Safety Rating	Non-flammable
Specific Gravity	1.35
Surface Tension	Not Available
Vapor Density	4.0
Viscosity	Not Available
Vapor Pressure @ 20ºC	65

Product Information

Applications:

Features:

Product Details

Safety Data Sheet

BULK

Technical Data Sheet