Why we clean; What we clean.

Selecting a Winning Combination for Electronic Assembly

Why clean?

Performance Cosmetics

Contractual Reliability

It Pays to It Pays to CLEANCLEAN

IPC/EIA J-STD 001/DRequires Clean BoardsClass B & C Electronics

• 8.3.1 No Particulate matter (all classes)– No lint, solder splash, dross, wire clippings– No loose or dislogable solder balls

• 8.3.2 Unless otherwise specified (all classes), assemblies shall be cleaned and be:– Free from flux residue (1X)– < 1.56 micrograms/cm2 NaCl equivalent ionizables

Appendix B standardizes a testing protocol to be used when implementing new flux materials or validating a cleaning process change

SIR, ROSE, Ion Chromatography

Confusion leads to poor Confusion leads to poor choiceschoices

• Saving a dollar by not cleaning may Saving a dollar by not cleaning may cost $100’s of repairs or worst, lost cost $100’s of repairs or worst, lost customerscustomers– Exponential rule of repairExponential rule of repair

• Repair @ board level = $1Repair @ board level = $1

• Repair @ assembly level = $10Repair @ assembly level = $10

• Repair @ customer level = $100Repair @ customer level = $100

Soils to Clean

Dust & Dirt Solder ballsOils Solder Paste Plating salts

Adhesives Finger prints Fluxes

Flux Type Hand solder

Wave solder

Wire solder

SMTPaste

Notes

Water soluble-Must be cleanedAbout 1/3 of market

Common Common Common Common Residues usually water solubleHigh temperature can change to non-water solubleCan use chemistry 1-5%

No-clean low residue

Common-Should be cleaned

Common Available Unusual -because of dull solder

Low solids no-cleans require heat to de-activate flux activity as the active agent evaporate only if heated

No-cleanbulk

Common Unusual because low residue is preferred

Common Common High solids no-cleans encapsulate activators in hardened flux matrixCould be a rosin or resin based flux

RRMARA

RMA commonNeeds cleaning

RMA on old military projects

Common Common Mil-F-14256 military classificationsR – Rosin non-activatedRMA – Rosin mildly activatedRA – Rosin Fully activated

Lead-free Any of the above made For higher temperature

Catagory Kyzen Petroferm Zestron other Applications Notes

AqueousWater only

Water – tapWater - DI

Water Soluble FluxesResidues usually water solubleHeat usually requiredSometimes need defoamer

Aqueous MixturesNon-reactive

I3330 AxarelEC-7RSP50

VigonSC200SC202

Some LF Fluxes, Most RMA’sWork by dissolvingmay need heatNon-foamingneutral pHDoes not affect metalsLess aggressiveLess complicated waste disposal

AqueousMixturesReactive

XJN, XJN+, 4625

Hydrex LFNew*

Atron 205, Vigon 200+

ALL FluxesReferred to as saponifierAmines react with fluxHigh pH -10 to 12Can attach metalsNeeds heat 125 to 200FMore difficult to close loop

OrganicSolvents

Cybersol MegaSolvLenium

DS-100 IPAToluene

Water Soluble and RMA Some Lead-free & no-cleanNo water – water freeClosed loop with Mega resins Combustible or flammable designAlways closed-loop

Soil type Key to success

Fluxes Process FlexibilityTime, temp, concentration, Automation

Solder balls High energy, good flux cleaning

Solder paste High energy, Process Flexibility and Waste management

Dirt & Dust High energy, Automation

Finger prints Polar/non-polar solvent

Plating salts Polar solvent - heated

Machine Oils & lubricants

Organic solvent unless water soluble

Adhesives Organic solvent, low temperatures

Soil type Key to success AAT cleaner(s)

Reflowed Fluxes Process selectionTime, temp, concentration, Automation

InlineAquaThermMegaX-CleanerEmulsionator

Solder balls High energy, good flux cleaning InlineX-cleanerAquaTherm

Solder paste High energy, chemistry selection, waste management X-cleaner

Dirt & Dust High energy CycloneInlineX-cleanerAquaTherm

Finger prints Polar/non-polar solvent MegaAquaThermInlineX-cleanerEmuslionator

Plating salts Polar solvent - heated InlineAquaThermX-cleaner

Machine Oils & lubricants Organic solvent unless water soluble MegaEmulsionatorAquaTherm

Adhesives Organic solvent, wash and rinse, high energy, time, temp X-cleanerEmulusionator

Critical Questions to answer in Selecting a Winning Cleaning Process

1. What are we cleaning?2. What standard(s) apply?3. What solvent are we using?4. What equipment is selected?5. How are we going to qualify

and control the process?