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Nov 14, 2017 | If you think the problem is occurring in the box and it is wide spread, consider replacing your solder paste with your paste supplier. There are paste formulations aimed at the solder balling issue that some LF pastes create. On tuning your reflow recipe with an experiment: * If preheat ramp rate is too low, flux thins and leaks from the paste deposit and carries raw fine solder particles across the board. * If preheat ramp rate is too high, the flux boils and ejects raw solder from the paste deposit Snarky comment about cleaning Kapton tape adhesive reside: * Kapton tape that you buy
Feb 13, 2017 | Could be that your temperature ramp up rate is too fast. This could cause the flux in the solder paste to burn off too rapidly. When that happens, it can expand as it heats up and burns off, causing the solder to get spread out from the pad.
Jun 2, 2016 | i have tried to design the stencil as attached, but the void is more than 35%. do you have any idea what is the ideal diameter for the stencil aperture for the solder to spread and the flux to be released out of the component simultaneously. thanks alot.
Feb 26, 2015 | Use the appropriate heat for that part. You can then use techspray flux remover with a brush. Spray the brush, and not the board, to reduce spreading the flux. Acetone or alcohol are less expensive and may work as well.
Jan 24, 2014 | Yeh, I worked at Wang Computer factory in a reclaimed fabric mill with wooden floors. One of the causes of grapping is flux loss. In their paper, Briggs and Laskey talk about flux loss due to spreading and suggest: * Graping is much less prevalent in solder mask defined pads, which confines the amount of flux spreading * Increasing the ramp rate (1-1.5°C/second) allows the flux solvent to volatize quickly, increasing the flux viscosity and lowering its ability to “run-away”.
Aug 30, 2012 | A common bottomside heater configuration is IR-Convection-Convection. One of the big advantages of the IR zone is its ability to allow the flux carrier to spread and dry slowly before the board reaches the convections zones, which can blow wet flux carriers off specific areas of the assembly
Dec 21, 2011 | of that product to us. * If you have some way to control the flux applied and keep it from spreading to portions of the board that don't see the entire reflow activation temperature, we're OK with your approach. Kim: We understand what you're saying. For us, fluxing the BGA and activating the flux are the issues. * If you're squirting liquid flux under the BGA with a plastic bottle with a needle tip on it and then reflowing less than the whole board with a rework tool of some sort, don't ship any
Nov 4, 2011 | When I'm Tearing down a Job, And removing the tape and reel from Agilis Feeder. Their is a gap of at least 10-12 Parts. Unpicked parts, When the knife on the feeder spreads the tape aside. and leaves this gap of feel falling parts.
Mar 25, 2011 | Are the solder balls what we would call ' mid chip ' solder balls where a single or sometimes a few larger solder balls are positioned somewhere along the side of the chip or are they the solder paste powder particles spread around the pads ?
Nov 12, 2010 | I would also be concerned about spreading solder paste on the walls/floor/equipment downstream of the air. This would then get transfered to hands, clothing and shoes. In turn, tracked out to the rest of the floor/building or even to the home of employees.
Jul 14, 2010 | So, tell us more ... * Is this at in-bound inspection? Where do you observe this? * Does this affect the whole component, just terminations, ... * Could the 'brownish' be interpreted to be 'purplish'? * How wide-spread is this [eg, multiple products, lots, etc]?
Dec 9, 2009 | built/mixed in. We do this with both no clean and water soluble type fluxes and both lead and lead free solder. The paste will start to dry out and then not flow/spread properly in our stencil printer if it is old enough to exceed the expiration date and not keeping the unused portion in the fridge I am curious as to why you need to mix.... We use a 500g cartridge with air gun. Our process is remove the cartridge from the fridge, allow it to warm up to room temperature before inserting into air gun, then apply bead of paste to the stencil. No mixing because the paste already has the flux
Oct 9, 2009 | There are two fundamental questions that must be answered, in order to manage the inventory of any physical item - when to order and how much to order.? Is there any spread sheet available to trigger Minimum , Maximum & critical levels ?
Oct 4, 2009 | I am just now recovering from the flu, probably H1N1 from symptoms and the source. I've seen worse flu's, but this one is bad because of how easily it spreads. Everyone in the family caught this one. What if it was a killer, like in years long ago?
Dec 24, 2008 | , and help assure that you are not causing any compromise in the second component by replacing the first one. You could "nuke" the one you are removing using a heat gun with a focused tip, and keep ahead of the heat spreading, but that provides you with no means to resolder the new part down without facing the same issues. Tough spot. If cost were not an issue I would replace both parts. If cost is the barrier, well, you're up against it. Most important though, is the reheating of the underfill product a real problem? Maybe you should go with it, and flux both parts during the process of removal
Nov 4, 2008 | as ball will touch the surface only in small point not across whole pad area... But on the other hand the flux should spread from ball across whole pads during heating. Regards, Martin P.S> We are using tucky flux Alpha UP78 BGA Rework - flux dispensinx issue Hi Dave, Thanks for the recommendations. Have you tried this method for the micro BGA as well? Would you mind attaching some pictures to get better understanding how you do this? At the moment my understanding is that this method is very similar to taking small cup, putting flux
Nov 4, 2008 | . * Place the BGA and get to soldering. We get the impression from the way you posed the question that you're using a liquid flux. If that's true, it's not good practice to squirt liquid flux of any type on rework areas, because the liquid spreads and flux on the outside edge does not receive the proper BGA Rework - flux dispensinx issue Sure. Here's what you should do to apply repeatable amounts of flux on BGA during rework: * Squirt some gel flux on a plate or something like that that has a flat bottom and raised sides to corral the flux. * Cut notches into one edge of an old credit card. The number and depth of the notches
Apr 30, 2008 | It's not acceptable to us. More importantly, you need to determine if it's acceptable to your customer. Recognize that your little IPA scrub does NOT remove the OA flux residues from the board. It mearly spreads them out across the board and under components. We have ranted on about this practice
Apr 28, 2008 | Here's a crude wettability test. Take a PCB - both types of finish - print them, and reflow with no components using your standard profile. Observe the wetting spread and flow of the solder paste. This rules in/out that it's PCB solderability.
Mar 17, 2008 | is concerned, detected contamination is evenly divided over the entire board�s surface. In reality, contamination is not evenly spread across an assemblies surface rather there are concentrated deposits of ionic contamination in specific areas and there are areas that are very clean. The removal and testing only the areas subjected to flux, they would also determine that no-clean residues leave considerable residue in their wake. Michael Konrad Aqueous Technologies email@example.com www.aqueoustech.com
Dec 17, 2007 | I recently had the same problems, solder bridges on every thing I made, different customers boards, etc. I wave with no-clean flux. As I sorted out problems (pin holes, blow holes, splatter, etc.) I found a lot of variable factors. I changed flux, went more aggresive. It improved solderability million opportunities), you can trend chart PPM, also use collected data for Pareto (top ten defects per assembly). Contact me for excel spread sheet format. I can help get you started if you do not collect data. DaveF- chime in if I missed sumtin, I know you have much more. Happy Holidays to you
Nov 12, 2007 | Using Isopropyl alcohol as flux thinner in the flux, thereby improving its ability to mitigate oxidation." The flux mfgrs. do exactly just that. They sell you IPA (rubbing alcohol) and at a premium! However, now that the perception is there in the Supervisor's eyes, that using pure IPA and not Kester's IPA is a detriment, he'll be quick to "spread the perception" the minute you get even 1 solder short that "never existed" before. Then you'll have to answer to people even DUMBER than the Supervisor (plant and/or quality manager)...
Sep 8, 2007 | We expect to see a copper shadow along the edge of pads when soldering boards with organic solderability protection [OSP]. IPC-A-610 has defined this as acceptable for years. During early reflow stages, the flux in paste dissolves the OSP where there is contact. Generally, the flux does not spread
Sep 7, 2007 | what type of solder paste are you using? Why the concern over wetting spread to the edge of pads? Are the solderjoints formed correctly at the component? Russ
Jul 10, 2006 | You are right, RSS profile is not the correct description. I am using a profile which heats up quickly to let the flux spread. Next linear up to activate the flux and prevent thermoshock. My experience is however, that small changes in this profile do make a big difference in the results.
Jul 4, 2006 | Calling for an input from the Experts our there. Our customer is questioning the cleanliness of the no-clean product that we produced for them. We were asked to clean the board (localised cleaning) after rework (IC need to be changed due to an up rev.). Excessive touch up flux spreaded
May 27, 2006 | it will wet to the top of the PTH if given time and provide good filleting. This wetting depends also on the condition of the flux, if you are using a VOC flux you may not want to use forced convection preheats this will drive off the carriers (alcohol) and limit the spread of flux up the barrel. If you Flux Residues In Lead Free Wave Soldeing Process Gentlemen I have managed to pull myself together after banging my head. I am not sure the flux volume is the total solution here. All spray processes deposit flux in a similar manner, that is to say the vast majority of material sprayed onto the PCB surface is not sprayed directly on the centerline
Dec 6, 2005 | What rubber had or the liquid medicines spreads has been possible to guard against the oxidation?
Sep 28, 2005 | I would like to get some feedback on the use of DEK 2D Inspection feature. We are in the process of implementing this feature and question how wide spread it's use is and how successfully it has been implemented.
Jul 8, 2005 | We've tried many of the different brands and we like the FCT SN100. The nickle really makes it spread out and wet nicely. You add a few degrees to reflow it but we think the results have been worth it. mk
Jul 7, 2005 | Tombstone caused by flux residue Ahh. sorry for the foul up - and thanks for stopping the spread of misinformation!! Sarag
Jul 7, 2005 | strictly the instructions, the vast majority of the reworked BGA were not successfully reballed. I have realized in time that the best solution is to spread a thin layer of flux on the preforms as well, not only on the BGA package. Since then, I never had any failure while reballing BGAs. I am surprised to see that the manual does not recommend this and I bet many people have hard time reballing BGAs just because they don't apply flux on the preforms. The reballing manual from WinslowAutomation/Solderquik can be found at
Jun 6, 2005 | We did the trial by dispensing (both the thermal & the electrical), but in production I would definitely use a stencil for the Conductive adhesive, as the shape, spread & volume of the adhesive is critical. (No wicking or spread) We also looked at Robotic soldering as you can control the heat
Jun 6, 2005 | Yes, Loctite 3880. It works out at about $160 for a tube of 30ml. It can be dispensed or printed. We found you needed a lot less than with solder as it doesn't wick or spread much.
Apr 25, 2005 | Hi Carl / Bill, I seem to miss your point regarding disclosure. As I CLEARLY stated, it is the perception of damage more than the possibility of damage. As a twenty year veteran of de-fluxing systems, I can assure you that there remains enough controversy regarding the use of ultrasonic technology on populated assemblies to prevent its wide spread use. I am not saying that it is not a good technology. What I am saying is that if a user chooses to apply ultrasonic energy to populated assemblies, they should be prepared to defend it. May I remind you of the military cleaning standard
Mar 15, 2005 | of your process temp. window. Also, aggressive fluxes will assist the cleaning and promote wetting on Ni. However, if you have good wetting spread on the gold you're probably ok (temp wise). If you have a single homogenous solder mass, you're probably ok. But, again, the profile can not be rulled out.
Mar 7, 2005 | Oh silver and its...improved solderability over tin / copper. BS if you ask me. Look to your flux and thermal profile for wetting spread. Ask yourself just how much "wetting spread" do you need to fill a barrel? I have the same 100% barrel fill on Immersion silver boards as with multi thermal
Jan 28, 2005 | SMT Solder paste and wave flux evaluation We use the exact same method Chunks outlined for evaluating just about anything we're going to roll out worldwide, whether it's a material or a machine. List your factors (print speed, solder spread, etc), assign each a weight, evaluate each paste and give them a score for each factor
Jan 28, 2005 | SMT Solder paste and wave flux evaluation is 10 times 9 which is a score of 90, 123 is 10 time 3 which is 30. Continue down your Criteria list and get scores for each paste Criteria till you�re done. Now add up the Scores and the highest one meets your Criteria with the best resulting score. You can use one spread sheet with a group of people � or have the group of people do their own spread sheets and then compile a final spreadsheet � it�s up to you. This would be million times easier to show you with a spread sheet � but we don�t seem to have the technology on this forum. Hmmm, go figure! I can e-mail a completed one I used
Jan 25, 2005 | Good info, thanks for passing along. The company I work for (equipment supplier) ran some tests with lead free material in air and N2 environements for reflow. In the air reflow environement it was noticed that the material does not spread, much like you found in your studies. The solder joint was strong, looked good, etc.. but the centering and spreading of the material was poor. Once N2 was used in reflow then the material spread much better to cover the whole pad and centering was a bit better but no impact to the actual solder joint. From what I have been researching air reflow works just fine with most lead free materials. I have seen more lead free stenicls go to a 1 : 1 relationship on pad to stencil apetures due to the lack of spreading in air reflow. Of course this brings in other issues like extra wiping, gasketing, etc.. Good luck and thanks for sharing your experience
Oct 6, 2004 | Does anyone have any experience with any lead free solder paste and the "paste in hole " or intrusive reflow process? I am interested in how the lower "spread" of lead free paste reacts in a through hole soldering process.
Sep 28, 2004 | Adam, I would first check hole to lead sizes on the components that you are having hole fill issues with to see that the spacing is withing spec. Second, check for oxides on lead tips, and contaminated leads that cause poor wetting and insufficient solder fillets. Last I would check flux spread process, flux spread/coverage, chip wave coverage area, parrelism, and delta wave coverage area, parrelism. Adjust all those parameters until you get what you want and that should solve your problem. Regards, VS
Sep 23, 2004 | We are printing on an assembly using SAC305 Alloy Sn96.5 Ag 3 Cu .5 with a no clean flux and getting virtually NO spread with either a ramp to spike or straight ramp profile. We are printing to standard FR4 board with immersion Ag finish. I am trying both Indium and Senju pastes along with our normal No Clean paste which is an Aim no clean 293+ tin lead paste. The eutectic solder spreads fine, looks smooth and shiny, and wets fine to the lead free components, but we must use a no lead. Both lead free pastes are stiff, have poor release, stay put on the pad where printed and look very dull and very grainy. The indium stuff has tons of little solder balls on top of the joint on the flux residue. With the lead free both profiles are about 4 minutes with a peak of 245 C. Any suggestions ? We need to decide on a process and lead free paste for some proto boards which must ship next week.
Sep 21, 2004 | : This goes back to the �surface free energy� of Q1. This is basically saying that is the solder mask surface is real slick or greased-up [with maybe nc flux res], it will more difficult for the conformal coat to stay spread-out and will cause it to "rolling back" on itself [dewet].
Sep 21, 2004 | . * IPA will not do dip in removing flux residues from your board. 'Cleaning' with IPA just spreads the res uniformly across the board. The proper cleaning method depends on the type of flux that you use in your soldering process. We know nothing about Envivar UV 1244 and you weren't real clear about the details of the problem or the materials [eg, ws flux, solder mask, etc], but we'd speculate your adhesion problem goes back to the cleanliness of your board. First by 'alcohol', we assume you mean isopropanol, isopropyl
Aug 26, 2004 | Cleaning Water Soluble Flux After Touch-up 're TRYING to clean the OA from the boards [instead of just spreading it around the board, like the IPA-people are doing].
Aug 12, 2004 | Hi Guys I am looking for a spread sheet to calculate the PAM results for Fuji chip shooters do any of you guys have such a thing Johnw
Jul 1, 2004 | Standard for Solder Spread Test For a quantatative measure of solder spread use: * IPC-S-804/805 * Mil-F-14256E,4.7.5
Jun 30, 2004 | Standard for Solder Spread Test I get always a lot of evaluations including results from Solder Spread tests, but it seems everybody creats his own test methode. Is there a official Standard or test instruction for Solder Spread Testing such as IPC, MIL, DIN... Thanks Chris
Jun 28, 2004 | on inbound bare circuit boards.] If your hand soldering people are using squirt bottles filled with wave soldering NC flux; shut-down the line, throw all the bottles in the dumpster, and plan your product recall. When using squirt bottles, the raw flux spreads across the board, under components, etc. It �s uncontrolled. The heat of the soldering iron makes it spread faster / further. * When using water washable fluxes, squirting flux �all over the board� is reasonable from a contamination control stand-point [not from an employee health / safety stand-point], because the board is cleaned after hand soldering talks about contamination level specific contaminants [ie, bromide, chloride, sulfates, etc]. If you know the type on contaminate, it would help focus your search. Next, possible sources are: * Flux contamination from assembly process (typically a halide ion being present). * Inadequate cleaning