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Flux Designations and Composition

#29312

Flux Designations and Composition | 29 June, 2004

Where to find detailed information on fluxes? No one seems to know the real difference between Rosin fluxes with colophan, Resin fluxes or synthetic Resin fluxes, No Clean, Low Residues, VOC-Free, Halide-Free, Water Washable with alcohol base, Resin-Free No Clean, No Residue Flux, High Solids Flux, Halogenated and Organic Acid Activated, etc.? No one ever did a paper on all those different kind of fluxes? We can find some information on one type or another but there seems to be no comparisons between all of those different kinds.

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#29313

Flux Designations and Composition | 29 June, 2004

Where to find detailed information on fluxes? No one seems to know the real difference between Rosin fluxes with colophan, Resin fluxes or synthetic Resin fluxes, No Clean, Low Residues, VOC-Free, Halide-Free, Water Washable with alcohol base, Resin-Free No Clean, No Residue Flux, High Solids Flux, Halogenated and Organic Acid Activated, etc.? No one ever did a paper on all those different kind of fluxes? We can find some information on one type or another but there seems to be no comparisons between all of those different kinds.

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#29315

Flux Designations and Composition | 29 June, 2004

You're correct, for every dumpster full of paper written about solder, there's a sentance written about fluxes. There's dribs and drabs about fluxes in most of the soldering books [ie, Manko, Klein-Wassink, Judd, Strauss, etc] and most of that is very dated, but the better stuff is: * Reflow Soldering Processes and Troubleshooting: SMT, BGA, CSP and Flip Chip Technologies; Ning-Cheng Lee; Newnes; 2002 [0750672188] * IPC-HDBK-001 Handbook and Guide to the Requirements for Soldered Electrical and Electronic Assemblies to Supplement ANSI/J-STD-001, 4.2 Fluxes * Daan Terstegge�s excellent jump site: http://www.smtinfo.net/Db/_Flux.html

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#29411

Flux Designations and Composition | 7 July, 2004

Thank you for helping finding a direction for my answer. I found interesting things on fluxes at this site: http://www.smtinfo.net/docs/Electronic%20Production/25.htm Due to the lack of precise and concise information on the subject, I think I will write something for us and for anyone who need this kind of information. Is there somewhere that I could leave this paper so that anyone could have access to it. I am talking here about SMTnet which I don't know much since I just joined last week or so.

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#29417

Flux Designations and Composition | 7 July, 2004

There is a way to post papers [Tons of them have been posted, to date. Look in the "SMT Library" maybe.] Email info@smtnet.com for details.

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#29420

Flux Designations and Composition | 7 July, 2004

Another thought, why not contact a flux supplier that is able to give you the background information you seek? For instance: Daniel Werkhoven; Interflux Electronics/Belgium [ http://www.interflux-electronics.com ]

[We have no relationship, nor receive benefit from the company linked above.]

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Daan Terstegge

#29433

Flux Designations and Composition | 8 July, 2004

I would be glad to host your paper on http://www.smtinfo.net. You can email me via the link on my site.

Daan Terstegge http://www.smtinfo.net

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#29467

Flux Designations and Composition | 12 July, 2004

Here are some answers to my questions after a good research. I also added more definitions that could help understand this esoteric language used in assembly, specially surrounding fluxes and their use. In blue italics are comments and extracts from other sources (Sorry but this forum does not accept italics or colour. You can contact me at at my E-mail info@microniks.com if you want an original in Word, WordPerfect or pdf file).

Rosin fluxes with colophony: Fluxes containing colophony, a natural substance extracted from the sap of pine trees and distilled to be in a liquid state for easier applications. Rosin is a natural product derived from the resinous excretion of trees. It is a glassy mix of abietic acid with some related (isomorphic) compounds and numerous hydrogenated modifications of that acid. Note that while rosin is distilled from resin, resin is not rosin.

Resin fluxes or synthetic Resin fluxes: Fluxes made with synthetic components. Most synthetic fluxes are based on organic acids like rosin, although other materials are used - primarily in low solids formulations - such as polyvinyl acetate, pentaerythritol tetrabenzoate, and bile acids.

No Clean flux: Those fluxes are mainly made up of synthetic resins and their residues are non-corrosive and non-sticky. They were designed to be left on the board for applications where such residues are acceptable. However there are many occasions in which their residue must be cleaned to comply with their application, such as High Frequency applications etc. See the following comments: � Flux residue effects on circuit performance? But according to our own experience through a modification for more than 1000 boards, the flux residues remaining after manual rework are very critical. Tens of faulty boards passed all normal & burn-in tests just by cleaning the residues of the No Clean Flux. � No-clean flux residues can be either cleanable or not cleanable. The not cleanable type leave a milky white residue on the solder connection after suitable soaking in water. Your flux supplier will have suggestions on the appropriate flux. � Clean the (no-clean) assembly (post wave). The less on there to begin with, the less cleaning required. sidebar: Why clean no clean? Use water soluble flux!!!

Low Residues: This is another way of naming the �No Clean� family of fluxes. Those fluxes are mainly made up of synthetic resins and their residues are non-corrosive and non-sticky. Comments: � With a proper thermal profile and wave dwell time the interflux was the leader in remaining residue (lowest). Also keep in mind the above statement is true for ALL fluxes (including your current flavor).

VOC-Free: A flux having no Volatile Organic Compounds such as alcohol.

Halide-Free: A flux having no halides (free chlorine ions). Those halides are normally added to increase the duration of activeness of flux during the whole process of oven reflow. When the flux composition needs to be altered to meet certain requirements, such as increased corrosion, activators are added. These are organic acids, halogenated compounds and amides, or subsequent mixes of these chemicals that assort: organic halide salts, organic mono-basic and organic di-basic acids. Their primary role in this sense is to extend the oxide reduction capacity, as opposed to increasing reaction rates as is often thought.

Water Washable with alcohol base: A flux made up of a base of alcohol which�s residues can be cleaned off with water.

Water Soluble: A water soluble flux is one that its base is made up of water and by so can be cleaned easily with water.

Resin-Free No Clean: A �No Clean� flux containing no Rosin elements. It is mostly a synthetic resin which residues are non-corrosive and non-sticky.

No Residue Flux: A flux which has no residues left on the board after the soldering process. The residues are evaporated.

High Solids Flux: A flux containing a large quantity of solids such as resins. Those fluxes leave larger quantities of residues on the board. They are designed where stronger activity is required.

Halogenated and Organic Acid Activated: A flux containing halides and activators in a rosin type flux.

Activator: Agents also called catalysts which increase the reaction without interfering with the process. They are found in most Rosin fluxes and are designed as RA for Rosin Activated (strong) and RMA for Rosin Mildly Activated.

Corrosive: That attack surfaces such as metal by an acid or a base.

Organic Acid: Organic acidic elements such as the ones found in Rosin. It is made-up of long chain of organic acid molecules which are broken down during the normal heat process of soldering. Once heated and broken-down those acids are normally non-corrosives.

Inorganic Acid: Non-organic acidic elements which are corrosive in their natural state and remain also corrosive after being through the soldering process. It has to be cleaned right away after the soldering process or it might corrode the solder and unprotected conductors.

Organic Compound: A natural compound made up of a long chain molecule which are often broken up in particles during normal heat-up process of soldering.

Aqueous Cleaner: Water base cleaner.

Solvent: A liquid that dissolves an element or a compound.

Surfactant: Also called Surface Active Agent. A substance which lowers the surface tension of the medium in which it is dissolved, and/or the interfacial tension with other phases, and, accordingly, is positively adsorbed at the liquid/vapour and/or at other interfaces.

Saponifier: A compound that transforms a residue (flux in this case) into soap. Once transformed into soap, this latter can be washed off easily with water.

Neutralizer: Agents such as an acid or a base (alkali) used to neutralize or de-activated a base or an acid. The acid will neutralize a base and a base will neutralize an acid.

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Non-heated dispensing system