Some solder pastes display excellent printability and superior reflow characteristics like our nl932hf solder paste. Choosing the correct flux types and their advantages. Kester corporation abstract residues present on circuit boards can cause leakage currents if not controlled and monitored. Leadfree soldering wires include varieties with no clean flux that are used in electronics.
The flux formulation may be a noclean flux formulation that may be used in the soldering of electronic circuit board assemblies, for example, in conjunction with a support fixture having a planar back surface that minimizes vibrations during processing that might otherwise cause misalignment between a chip and a substrate prior to solder reflow. If foam fluxing, the foam fluxer should be supplied with compressed air, which is free of oil and water. Flux vapors tend to have low autoignition temperature and present a risk of a flash fire when the flux comes in contact with a hot surface. Instead, they run all their boards with no clean paste, and just clean those that need to be cleaned. Common specifications used to test soldering pastes and fluxes include ipc, bellcore telcordia, and japanese industrial standards jis. Thermal decomposition of solder flux activators under simulated wave soldering conditions. Fluxoff no clean plus flux remover is an extra strength solvent that removes heavy and encrusted flux deposits. Solder paste flux solder paste, solder flux fct solder. Keeping the track of latest happening of this domain, we present the optimum quality of low solids no clean flux. Test requirements for flux activity classification the most important test for no clean fluxes is the sirtest, where the pass criteria is the 100m. For modern solder paste technology, applicable for printing processes a flux. I have always had in the back of my head that burnt flux is a defect for all class 3 assemblies.
Similarly, questions have also risen about the reliability of flux residues resulting from the reflow of no clean solder pastes that are entrapped under rf shields or cans, where escape of the volatile ingredients of the flux is greatly hindered. The flux formulation may be a no clean flux formulation that may be used in the soldering of electronic circuit board assemblies, for example, in conjunction with a support fixture having a planar back surface that minimizes vibrations during processing that might otherwise cause misalignment between a chip and a substrate prior to solder reflow. The noclean flux composition of claim 8, wherein the first organic solvent comprises about 75% by weight of the organic solvent and the second organic solvent comprises about 25% by weight of the organic solvent. The ten most common reasons to clean circuit boards made with no clean fluxes and pastes.
An activated noclean flux composition for soldering includes a dicarboxylic acid, an organic solvent, and acetic acid in. Therefore, its necessary to carry out cleaning on no clean flux for final pcba products. Two different types of approaches have been used to eliminate the cleaning step required after traditional soldering. That should tell you why you need to wear a fume mask or use a fume extractor. A flux may be solid, pasty or liquid, depending on how it is to be used. The composition of fluxes is tailored for the required properties the base metals. Suitable protic solvents include alkanediol, alkoxy propanol and alkoxy ethanol. When used for wave soldering, fluxes are generally low solids with perhaps only a couple of percent of flux, and the balance. We set out to establish what methods would be the best to characterize compatibility and what materials would be best suited to perform the task. English safety data sheets technical documents indium. Why clean a noclean flux mike bixenman, dba, kyzen corporation mark mcmeen, sti corporation bruno tolla, ph. Flux shall be in accordance with jstd004 or equivalent. Removing white residues on pcbs microcare electronics.
Mg chemicals 8341 no clean flux paste, 10 milliliters. Jellesen, vadimas verdingovas, rajan ambat materials and surface engineering, department of mechanical engineering, technical university of denmark. Deteriorated signal integrity will therefore be neither explainable nor reproducible. The low solids no clean flux is free from halogen, noncorrosive and tackfree residue. Indium corporation does not recommend, manufacture, market, or endorse any of our products for human consumption. Nutrients in drinking water water, sanitation and health protection and the human environment world health organization geneva. The activators make the flux residues risky because they are acidic but are required for a good solder joint. Excellent wettability, no clean, nonconductive, nontacky residues, compatible with lead free and leaded solder systems, thixotropic paste and rohs compliant. Main factor determining the pcba cleanliness is the use of no clean flux systems for the wave and. Qualitek no clean paste flux pf608 product description. If all of the no clean flux is not heat activated could it.
You can, however, find noclean fluxes that wont leave residue behind. It can be used when the soldering process needs more activation than if 2005m or if 2005k provide. Soldering flux and solder paste compositions which are nonacidic, lowresidue, and noncorrosive, leaving no substantial residue after. Given the purpose of flux, it follows any chemical that removes metal oxides from common electronics materials at soldering temperatures could be used but in practice, and particularly with no clean fluxes, it is critical that the flux is not so aggressive that it dissolves a lot of metal as well as the oxides. Myth busting solder flux cleaning with isopropanol alcohol. Health, to address a number of questions relating to the nutrient composition of drinking water. An activated no clean flux composition for soldering includes a dicarboxylic acid, an organic solvent, and acetic acid in the range of about 2% to about 4% by weight.
Us103507b2 no clean flux composition and methods for. The risk and solution for no clean flux not fully dried under component terminations fen chen and ning cheng lee, ph. Issues of burnt flux on class 3 pcb assemblies eptac. The main function or use of flux in any printed circuit board assembly or rework is to clean and remove any oxide and impurities from the board. For example, for radio frequency rf circuits and high speed circuits, for performance reasons it is usually essential that assemblies have no flux residue after reflow. Fluxoff products are specially formulated to remove all types of rosin types r, ra, and rma, noclean, watersoluble and synthetic type sa flux. No clean fluxes typically use weak organic acids woas as an activator.
Archived from the original pdf on october 10, 2010. Therefore, they require lower levels of flux on final assemblies. No clean flux titration kits m hdt200 titration kit this titration kit is designed for ease in testing the acid number of no clean flux. Gas metal arc welding gmaw, by definition, is an arc welding process which produces the coalescence of metals by heating them with an arc between a continuously fed filler metal electrode and the work. Soldering flux composition and solder paste composition mec. No clean flux does not leave a residue of foreign particles after fusing. Flux residues are not the only material being removed ink, salts and solder balls, fingerprints flux residues make visual qc inspections nearly impossible. No clean flux systems are used today for the soldering of electronic printed circuit board assemblies assuming that all the aggressive substances of the flux will vanish during the soldering. Issues of burnt flux on class 3 pcb assemblies question.
Nc paste flux is a no clean tackyrework flux designed to wet. The substance left behind is flux, which cleans the metal pads on the board when heated in order that the solder has a clean surface to bond to and you get the best possible quality joint. Organic flux activity level l1 shall not be used for noclean soldering. Never trust no clean too much no clean flux cleaning. How clean is clean is neither easy nor cheap to determine. Many of the solvents used to clean printed circuit boards were classified as ozone depleting substances. Can you tell me if you have to clean an rma flux and what the issues are if we do not. Certain no clean solder pastes are geared to perform well for the incircuit test nl930pt or pin in paste applications. Kester 959 is a noclean, noncorrosive, liquid flux that is designed for the wave soldering of conventional and surface. I usually use a dedicated flux cleaner fluxclene is one brand, but many are available. As with any markertype flux pen, the tip will fray if you use it on uneven surfaces or for fluxing component leads one at a. The hand held titrator reads in digital units simplifying process control. Being no clean, its not the most aggressive flux out there, but is great for helping solder along.
Soldering flux composition and solder paste composition mec co. Flux left on these wires, after potting, can cause leakage failures. One of those alternative was noclean soldering materials. Alpha om340 is a leadfree, no clean solder paste designed for a broad range of applications. The noclean flux composition of claim 8, wherein the first organic solvent is isopropanol. The components were dried in air and subsequently heated to. Us6217671b1 composition for increasing activity of a no. Normally noclean flux is not water soluble there is water soluble flux available, but it is not noclean.
Flux deposition density and uniformity are critical to successful use of low solids noclean flux. Us5297721a noclean soldering flux and method using the same. Alpha om340 provides best in class low defect rate for head in pillow defects combined with excellent first pass yield on ictpin testing. Reliability assessment of noclean and watersoluble. No clean flux composition and methods for use thereof. The activator may be glutaric acid, levulinic acid, 2ketobutyric acid, 2oxovaleric acid, or mixtures thereof. The no clean aspect means that leaving this in place will not damage the board. Lowsolidsnoclean fluxes in general, have less active chemistry and are more challenging to solder with than rosin or water soluble. No clean pastes save not only cleaning costs, but also capital expenditures and floor space. Flux shall conform to flux activity levels l0 and l1 of flux materials rosin ro, resin re, or organic or. Noclean solder paste was supposed to obviate the need to clean circuit boards.
Solder paste flux is different than liquid flux in both physical form and activity level. Fluxtype flux composition partial designator solvent solids content most commonly designator market presenceavailability containing halides lowsolids no clean rosin ro alcohol 2%8% rol10. Although the fluxing ability approaches that of type ra flux, the flux residue after soldering is noncorrosive and nonconductive. The soldering iron tip the soldering iron tip transfers thermal energy from the heater to the solder connection. Once the montreal protocol was ratified, industry sought out alternatives to ozone depleting substances. Kester 186, under milf14256, was qpl approved as type rma. If all of the no clean flux is not heat activated could it have a negative effect on the circuit board assembly. The introduction of a cleaning process for the removal of no clean flux residues clearly adds cost. For situations where theres significant oxidation, a more aggressive flux such as a rosin flux is more appropriate.
So why are many electronics assemblers still grappling with. After processing the circuit boards we see a white residue. No clean flux low solids no clean flux manufacturer from. Problem with no clean solder flux residue we have a problem with noclean solder flux residue. Technical data sheet 959 lowsolids, noclean liquid flux. Pdf noclean solder flux chemistry and temperature effects on. The pprcs investigation found that published literature about noclean approaches focused on one specific application.
Us20010025673a1 composition for increasing activity of a no. Break down of the flux is stopped by the addition of lead carbonate, phenol or salicylic acid in the composition. The effect of flux composition and ambient climatic conditions on the corrosion reliability was studied using dc leakage current measurements. No clean fluxes with solid content less than 3% are also available for use in foam flux operations as well as application by dipping, brushing or spraying. Flux remover spray can spray in any direction, even upside down. Fluxes with low solids, sometimes as little as 12%, are called low solids flux, lowresidue flux, or no clean flux. Noclean solder flux chemistry and temperature effects on.
Safety data sheet sds according to 19072006ec, article 31. For example, the heavyduty flux remover suprclean generally will leave white residues on no clean fluxes. Choosing soldering flux simply smarter circuitry blog. No clean solder paste solder paste, solder flux fct solder. Noclean is a process, not a product noclean fluxes can save a lot of processing time, but residues that can be trapped under high density components are raising reliability concerns.
Given that there are evidently a significant number of different formulations and that one must assume that all or most of these are proprietary, i do not know of any way to obtain them for you. Composition of flux free patterns for stained glass. Flux paste is a no clean formulation therefore the residues do not need to be removed for most applications. As the name implies, flux residues from the watersoluble solder paste are designed to be cleaned using water. Solder joints appear shiny after soldering, even without cleaning. We are using a kester 186 rma flux for our assembly process. This high pressure aerosol or bulk liquid penetrates quickly to remove all types of flux, oxide particles, dust, grease and oil, then evaporates quickly leaving no residues.
Composition information on ingredients chemical name wt. Snpb and leadfree compatible suitable for spray and foam fluxing or l0 according to en and ipc standards solid content. As mentioned above, the no clean process should ideally encapsulate all soils and residues to render them ineffective as causes of corrosion and current leakage. Lead free, no clean and water washable, halogen free, high viscosity, low voiding, low temp choose amtech matching paste, flux and solder wire for exceptional results for the most sensitive tasks and environments. A novel single component electrochemical migration set up scecm was used for investigating electrochemical. Stainless steel requires an acid core soldering wire. No clean is the most popular flux to clean, he says. A noclean soldering flux consists essentially of one or more halidefree, water. Decomposition studies of noclean solder flux systems in. These are flux that doesnt need any cleaning after soldering process. The process uses shielding from an externally supplied. A flux formulation includes an activator and a protic solvent. Effect of solder flux residues on corrosion of electronics. Solids the percentage of solid material in the flux.
Soldering flux are available at mouser electronics. However, these pastes need a very clean assembly environment and may need an inert reflow environment. In most soldering iron tips, the base metal is copper or some copper alloy because of its. Unfollow no clean liquid flux to stop getting updates on your ebay feed. Flux may come in paste form, or it may be in the core of a soldering wire, which allows it to work as you are soldering the part with no extra effort. In most industrial and consumer electronics applications cleaning will not be required and the product may therefore be. By preventing the formation of metal oxides, flux enables the solder to adhere to the. Multiple uninsulated wires in the terminated assembly usually later potted. Solder paste flux typically contains 6080% by weight active ingredients, compared with liquid flux s 225%. Amtechs soldering paste and flux make soldering look easy. Since most manufacturers have finetuned their assembly lines to run no clean paste, they are reluctant to adapt their processes to accommodate other types of paste. Root cause flux on the surface of the insulator part of the connector, between contacts. No clean flux lead free tin silver copper alloy page 260512 v1. Myth busting solderflux cleaning with isopropanol alcohol.
As another example, once in a great while the ingredients in the alcohol enhanced flux remover proclean also will react with no clean fluxes and produce white residues. Pdf the influence of noclean flux residues on the performance of acrylic conformal coating used for printed circuit board pcb assemblies was. In metallurgy, a flux is a chemical cleaning agent, flowing agent, or purifying agent. If all of the noclean flux is not heat activated could it have a negative effect on the circuit board assembly. It has a low solids content and leaves virtually no residue. The test procedure shall be carried out according to iec 611895. A no clean flux is made with resins and various levels of solid residues. The present invention relates to a composition of a nonacidic, lowresidue, noncleaning soldering flux or solder paste which is inactive at ordinary temperatures, leaves substantially no residue after soldering, and requires no subsequent cleaning process. Apr 22, 2014 the behaviors and properties of noclean fluxes can vary significantly depending on their respective chemical composition. Nov 01, 2003 no clean is the most popular flux to clean, he says. Watersoluble fluxes organic fluxes are commonly called. The flux formulation may be a no clean flux formulation that may be used in the soldering of electronic circuit board assemblies, for. Pdf effect of noclean flux residues on the performance of.
Reliability assessment of noclean and watersoluble solder. Or, flux contains solder balls that are dissociated from solder paste and those balls are difficult to be eliminated without cleaning, which is a big trouble for small spacing. The problem most people find with it is that it has a dark residue and when we. The flux is employed for tinlead soldering of a range of metals and alloys including copper, nickel and nickeliron. Flux is a leaky insulator which can provide a current path. Alpha om340 also yields excellent print capability performance across various board designs and. Soldering flux composition and solder paste composition. Decomposition studies of noclean solder flux systems in connection with corrosion reliability of electronics. By weight, a mixed solder paste commonly consists of 90% metal. Soldering flux, professional use of solder application of the substance the preparation. No clean solder pastes are formulated with many different strengths. Pdf thermal decomposition of solder flux activators.