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Oct 12, 2017 | IPC-A-610 interpretation of wetting angle (Chapter5) It is the two conditions pictured in IPC-A-610F, Figure 5-1 C, D. In the old, simplier days, we wanted our solder connection to have: * Low wetting angle * Shiny metal Today, the metal doesn't have to be shiny and the wetting angle can be a high as 90*. If fact, in some cases, the wetting angle
Aug 4, 2017 | PCB Contaminated by minerail oil / wetting problem Dear all, I´d like to ask You, if somebody faced similar situation like we are facing in our plant right now. We have wetting problems with some of our products. During SEM/EDX we found on non-wetted parts residues of Mineral oil - white - heavy. Do You have an idea whete this contamintaion could
Apr 20, 2017 | To overcome the dewetting issues of the past, a number of techniques have been used such as alternating directions on the wetted nozzle; this helps to avoid the solder biasing to one side causing the other side to oxidize and de-wet. Another method of combatting this issue is to briefly burst the pump after a solder drop-off. This allows the solder to quickly recoat and re-establish a good wetted flow over all sides. Cam someone explain to me how can i try this?
Oct 21, 2016 | Poor Wetting On The BGA. Looking at your picture I'm not sure you have a wetting problem. Who determined it's not wetted? Are you having functional failures? Is this an isolated incident? What was your TAL? Is the pad on the suspect ball possibly smaller than the others, or connected to a ground plane?
Oct 19, 2016 | Poor Wetting On The BGA. Hi All, Currently im seeing a cold solder/ poor wetting underneath the BGA Ball as i shown in the attachment. From the attachment you also can see one ball with poor wetting and another ball with a good wetting. When i checked with my re-flow profile temperature, the peak temperature of a component was on 253*C. I was in doubt why the one of the ball found poor wetting but another ball beside it has a good wetting? Have anyone have encountered this this before and may i know how you resolved it.
Jul 24, 2015 | You should be fine! best practice for a situation like this would be to run a solder sample, either flux it and run through wave, or screen print, don't place parts and run through reflow. look for proper wetting characteristics if you see de-wetting/non-wetting... don't use them. I always like
Nov 10, 2014 | We have the opportunity to buy a new selective solder machine and are used to using a very old Jade machine with a moving tank and wetted nozzle. I have two process concept questions: Which is better- move the board over the nozzle or move the nozzle under the board? Is a non-wetted nozzle easier to use than a wetted nozzle? Thanks
Jun 27, 2013 | of wetting to the lead, but it is pretty obvious this is a wetted solder joint. Some of the photos in the IPC book make it look as if a fully covered Lead is OK, while stating Fail for Class 1 if there is not evidence of proper wetting. The quoestion is, would this be acceptable seeing how it was a reworked
Mar 23, 2012 | Alternative tin-lead solder pastes to minimize poor wetting on o try Almit Sn62 HM1 RMA V14L ....its the best no clean lead paste for wetting...I sell it and it has solved wetting problems many times when users have used other pastes
May 10, 2011 | Wetting Issues - Humidity Related Do you have pictures and/or cross-sections of the non-wet? Is the HASL SnPb or SN100?
Sep 15, 2010 | BGA non wetting hi All, Here i snap shot previous PCB(HASL) and current PCB(Immersion Silver).Base on the photo it could be PCB oxidize cause the non wetting?
Apr 13, 2010 | Ok, Thanks
Sep 1, 2009 | Is the solder wetting to the pad, and not to the part? If so, and all other things being true (same process, profile, solder), we'd suspect some contamination on the part preventing solder from wetting to the part. This could be tested by attempting to tin the component. If the solder is not wetting to the pad, we'd suspect some level of contamination from the board house that's affecting the wetting. When we had a pad-wetting issue, our board house had us screen a board and reflow without componentes to check the wetting on the boards. cheers ..rob
Aug 3, 2009 | Sounds like the Pin in Paste would be a reflow technique not involving a pot. I'm guessing however the same causes are in play, in that the poorer wetting of the Pb-free allow means it drops out of the joint before it can wet to the terminal. We use similar high current terminals and they require significant pre-heat energy to ensure good wetting. GT
Jul 29, 2009 | Deni, You also need to check if your flux is properly wetting the board. Flux dewetting on the surface can also cause webbing. You can check that with spraying flux on the board surface and watch the wetting behavior. Patrick
Dec 12, 2008 | Greg, I totally agree with you that machine settings are very important in wave soldering and soldering in general. I disagree that lead free alloys can produce wetting like in the attached picture (leaded alloy). Lead free alloys have a much higher resistance to flow and much higher surface tension compared to leaded alloys. Therefore lead free alloys have higher wetting angles and all other associated problems related to poor wetting behavior.
Aug 11, 2008 | What does your top side wetting look like? This is a perfect case where top side wetting will tell you when you have a good joint. Without seeingor knowing your process, I would suggest either more pre-heat or longer dwell in the solder. Either one should yield a better joint. But top side wetting is your indicator here.
Jul 28, 2008 | De-wetting > What could be the main reasons for De-wetting in > reflow process. Can anybody answer Normally it is a contaminated surface finish.
Jul 28, 2008 | De-wetting What could be the main reasons for De-wetting in reflow process. Can anybody answer
Jul 1, 2008 | I would like an interpretation of a solder fillet on a 5 side termination cap. (Ref: IPC-610, sec. 220.127.116.11). My question pertains to the definition of dimension F, and what constitutes the top of the fillet. Does the top of the fillet end at where the wetting stops on the component termination ? Or is dimension F measured from the top of the concave meniscus at the point where the wetting is on the same plane as the component termination? Fig. 8-27 seems to define the top of the wetting as dimension F. I have a dispute with a customer.
May 14, 2008 | Solder wetting to ENIG pads Try running the second side first on a board. If it wets well, it points towards your board house. Run a blank board thru your oven and then try your normal process. If you see issues with the first side now - it definitely points towards your board house.
Apr 28, 2008 | Lead Free De-Wetting... 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.
Dec 3, 2007 | Q: I thought you said that the parts that weren't wetting in reflow were the parts with epoxy. A: Yes you're correct. Q: The question I have is do they wet in wave solder, and if they do, why does it matter what happens to them in reflow? A: Yes, but somebody here don't agree with me that the glued part need help from wave to get the good wetting. Q: Conversely, if they don't wet in wave, reflow isn't your biggest problem. A: Yes you're correct. But somebody here want this non- wetting issue settle at SMT. Q: Just to cover my bases, if you're masking those parts
Dec 3, 2007 | I thought you said that the parts that weren't wetting in reflow were the parts with epoxy. The question I have is do they wet in wave solder, and if they do, why does it matter what happens to them in reflow? Conversely, if they don't wet in wave, reflow isn't your biggest problem. Just
Nov 12, 2007 | QFP wetting Hi, Thanks. Waitng for your reponse. BTW, if I were to perform a test as below will this give me some result to indicate if the component is defective. 1) Print solder paste on plain PCB without copper track. 2) Mount the QFP & reflow 3) If the solder wet on the lead means good component lead 4 ) Solder do not wet on lead means bad plating or oxidize Thanks Rdgs...
Nov 12, 2007 | QFP wetting Hi, ALL I experience some QFP with wetting issue on the heel of the lead. There is no fillet wetting on the heel which causes reject bt the customer, but not all the QFP. Could anyone pls help what is the causes of this problem, it is due to oxidation, insufficient solder or plating issue. Thanks
Oct 22, 2007 | Hi Dave, The solder has tended to wet the component termination of Ag/Pd (chip capacitor) but has not wetted the pads, whereas the solder has wetted both termination & pads when using Ag/Ni/Sn finishes. Thks
Jul 23, 2007 | From NASA document: Conformal coating thickness shall be
determined using a wet film thickness gauge,.......
Wet Thickness Gauges can be obtained:
Wet film Thickness Gauge P/N 790010 Nordson Corp, Amherst, OH
Jan 31, 2007 | Nonwetting Components - why won't components wet to solder? We've had multiple issues with non-wetting components. You say only one part is not wetting? Profile won't be the culprit, if so you would have more part issues. We've used SnPb with lead-free parts for some time now, no issues.
The issues we had with non-wetting was contamination on the leads
Jan 31, 2007 | Nonwetting Components - why won't components wet to solder? We've had multiple issues with non-wetting components. You say only one part is not wetting? Profile won't be the culprit, if so you would have more part issues. We've used SnPb with lead-free parts for some time now, no issues. The issues we had with non-wetting was contamination on the leads
Jan 25, 2007 | Nonwetting Components - why won't components wet to solder? There are several smd components in our factory that don't reliably wet to solder during reflow. Paste and placement are good, but the component won't wet reliably. All of the other components on the boards solder fine, but one of these components will not wet about 10% to 50% of the time. What
Sep 7, 2006 | Non wetting on fine pitch product Did check the coplanarity of the failed lead and found it to be as good as the wetting leads.
Sep 7, 2006 | Non wetting on fine pitch product I have been getting non wets on fine pitch QFP packages on random leads during reflow process. I noticed that every time there is some flux residue left between the non-wet lead and the solder pad. No residue was not observed on the rest of the good leads. Does this indicate that the lead did
Jun 20, 2006 | The minimum vertical hole fill is defined as follows: Class 1: Not specified, with a 270-degree circumferential fillet and wetting on the secondary (solder source side) of lead and barrel, and a 75% coverage of the land area on the secondary side. Class 2: 75% fill, with a 270-degree circumferential fillet and wetting on the secondary (solder source side) of lead and barrel, and a 75% coverage of the land area on the secondary side. Class 3: 75% fill,ith a 330-degree circumferential fillet and wetting on the secondary (solder source side) of lead and barrel, and a 75% coverage of the land
May 25, 2006 | Palladium poor wetting Print a number of pads of the 0603 on to a ceramic substrate. Then place the 0603 on the paste on the ceramic and refow. If the paste shows no wetting onto the component it will prove that there is a problem with the components solderability.
May 23, 2006 | Palladium poor wetting Sorry I misled you. The PCB pads are wetting, but there is no fillet being formed. After reflow, it looks as though no paste was put down on the pads; however the paste print is fine. All other components solder real nice, it's only the Pd-Ag parts that won't solder. Steve
May 23, 2006 | Palladium poor wetting Seems as though the problem is with PCB and not component? "Solder does not wet to pads, wets to component" What is your board finish? Russ
Feb 3, 2006 | the flux in the solder paste should take care of the oxides. if possible print a board and run thru reflow to check for wetting issues......there are some published papers that say that the tarnish layer is too small to create any wetting issues or other assembly problems.
Jan 11, 2006 | MSK As GS told you in an earlier posting, J-STD-002 and IEC 68-2-69 describe methods and equipment for component solderability testing. Go get a copy of either one. The primary component solderability test methods are: * Dip and look method * Wetting balance test The Dip and Look Method is widely used in process QA and reliability monitoring. It is: * Qualitative test process using judgment on whether a sample passes or fails the test. * Based on the physical and visual attributes that the sample exhibits. Wetting balance analyzer suppliers are: * Multicore MUST II Wetting Balance Tester * Robotic Process Systems 6 Sigma Wetting Balance Tester
Jan 9, 2006 | Wet or Dry Wipe When I had that luxury I always used a double pass, first wet then dry, to reduce the amount of wet solvent left on the stencil. That also gives it some time to evaporate. If you've got suction I don't know how you'd ever get any through the apertures unless you're really pouring it on.
Jan 6, 2006 | Wet or Dry Wipe .speedlinetech.com/news_publications/application-notes.aspx?OnId=5 Then go down to MPM and find Solvent Study Released... On Wet/Dry, depends on application. You can do wet to losen material from aperture walls, then dry to final wipe. Its best with a vacuum system though.
Jan 5, 2006 | Wet or Dry Wipe We use dry for everything. There used be be a corroding problem with the fluid for wet wiping, but I'm sure they must have solved that by now.
Jan 4, 2006 | Wet or Dry Wipe Wet wipe could allow solvent through the apps and into the paste. For this reason I never never never use wet wipe.
Jan 4, 2006 | Wet or Dry Wipe What is the preferred method of under stencil wiping? (Wet or Dry wipe)
Dec 1, 2005 | Solder wetting issues Are you sure you're getting enough paste on the pads? It looks like you may not have enough flux to get the solder to wet properly.
Dec 1, 2005 | Solder wetting issues You need to verify if you're getting up to the needed temps. It looks like you're not. I'd say it started to reflow but never reached a long enough time. Nitrogen may help with further wetting.
Nov 9, 2005 | Wetting with lead free at wave is a bit different. You may need to increase your flux parameter to gain top side wetting. May get rid of the voids too.
Sep 8, 2005 | if the problem is wetting change the flux type. have you tried adjusting the temperature of the wave? if your getting 100% wetting id decrease the wave temperature, or try a flux that is less active.
May 31, 2005 | Solder Wetting Problems, Need Referee's can cause dewetting or non-wetting.
May 19, 2005 | have you some GND layer inside the pcb ? see IPC 610 A
May 18, 2005 | Wave Solder Non wetting holes Hi, I am having some PTH non wetting issues. Setup and chronology of events is explained: Set Up; Part: 1 MM pitch connector 378 pins Solder: Kester Ultra Pure 63/37 solder Pot; 250 C pre heat; Peak 94C top side Flux: Qualitek 775, Fluxer: foam Thinner: Alcohol Sp gravity miantained: 0 .85-0.9 Conveyor Speed: 1.1 m/min Events issues: 1- A 0.003" int fit between a 0.020" hole and 0.018" square pin. 2-Non wetting of holes: The leads display good evidence of tinning/solder pick up. 3- Randomly some holes 25-30 per PCb will not wet while the leads are tinned. It appears as if the annular ring did