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Aug 12, 2019 | Paste accumulation on the squeegee side with a 15mils to 5mils Step stencil I've never seen successful printing with a step as deep as you seem to be saying. The keep out would have to be jigundous!!!! SMTnet Technical Library: https://smtnet.com/library/files/upload/Step-Stencils-laserjob.pdf I'd guess * Maximum step is: 2 mil [50um] * Minimum keep out [distance from aperture to the edge of the step]: 25mil [635um] IPC-7525 Stencil Design Guidelines includes stencil step guidelines Our friend Chrys Shea presents "SPECIFYING STENCILS TO OPTIMIZE PRINT PERFORMANCE"
Jan 26, 2018 | Has anyone heard of a no clean paste that can be cleaned in straight DI water ? Sorry to disappoint. No-Clean fluxes are resin-based. They are not soluble in water. Water soluble fluxes are by nature Organic Acid and are soluble in water AND must be cleaned within a short period after reflow as they remain conductive and corrosive. MikeKonrad
May 4, 2017 | Stencil Manufacturer In a previous job we had DEK cut our stencils. If you are not already using the Vector-Guard system it is very nice. It saves $25 (or at least at that time it did) per stencil, but the really nice thing is the space savings. You can store several stencils in the same space as 1 stencil that has
Nov 14, 2011 | Have you tried an ultrasonic water cleaning process? We use an ultrasonic cleaner with tap water and Omega Aqua Clean LPH cleaner (omegasonics.com) then rinse with DI water. However, our cleaning requirements are not as strict as yours are from the sounds of it. Ultrasonic may get under components better. We are cleaning a water soluble flux.
Aug 27, 2011 | What is the best method for cleaning PCBs We assume from the way you wrote the posting that we're talking about bare boards delivered from your fabricator. If that's the case, the best way to clean these boards is to tell your supplier to clean the boards before sending them to you. You should not have to clean boards prior to your
Dec 1, 2010 | Thank you, Patrick and Hege I now more understood about no-clean and RMA. Yes, I agree with Hege the no-clean makes PCB look pretty dirty however the soldering looks good and shinny. To wash out RMA flux, I may need chemicl cleaning, am I right? Currently, we use DI water to clean water soluble
Jul 27, 2010 | lead frame with high temp tape OK to flux clean?? Hi expert, we have one lead frame product proposed to send to flux clean recently. The problem here is the frame is attached with high temp tape. After flux cleaning the frame, the tape turns out deformed in which we think it was due to chemical reaction. Anyone mind to share how to overcome the problem?? since flux clean is unavoidable here. thx.
Jun 30, 2010 | Conformal Coat over No-Clean Tim, try and incorporate an inline wash system. We use one with a surfactant and it cleans the "NO CLEAN" fluxes well. If you dont have an inline system, you can manual clean the boards with an surfactant and IPA. You can also do an ionic contamination test to ensure the cleanliness of the board
Mar 4, 2009 | No Clean and Underfill Good Afternoon Everyone, I have a customer who is inquiring as to the use of a no clean solder paste on their RoHS assembly. We are currently building this with OA, cleaning and then underfilling the QFN, BGA comonents after a sucessful ICT. Does anyone have experience with assembly using no clean
Sep 30, 2008 | No clean and 100 Mbps Fast Ethernet Transceiver Anyone using a No-clean solder paste on a pcb with a 100 Mbps Ethernet chip? Will the residue cause any signal degradation? Any issues with a no-clean solder paste and 1000 Mbps Gigabit Ethernet? Device: National Semiconductor DP83848 10/100 Mbps Ethernet Transceiver (48-LQFP) Paste: AIM NC 254 No-clean solder paste Clock speed: 50MHz
Sep 8, 2008 | Clean vs No-Clean Because of our high volume production, we use no clean flux. We have experienced leakage currents with leadless QFNs. One problem is the part isn't being utilized as it should, but another is the flux residue. There is ionic residue in no-clean flux and if the board is not coated, moisture
Jun 4, 2008 | DEK VectorGuard stencil system. We have been using the the DEK VG system now for 1 yr. Required stencil storage space is greatly reduced and stencil costs are lower. We've had some trouble with stencils not mounting flush in frame, but after a phone conversation with DEK engineering they suggested increasing compressed air to 100 psi which opened up the "jaws" of the frame a little more and allowed the stencil to fully seat in frame. Otherwise were are happy with VG system.
Feb 18, 2008 | no-clean flux vs. impedance A PCBA contains a couple of parts that are not sealed and can't be water washed. We hand solder these with no-clean after everything else is water washed. The designer says the no-clean residue must be completely removed so that it will not affect the circuit impedance. Does this sound accurate , or is he being too carefull? Is there any way to quantitatively argue a case for not cleaning?
Oct 26, 2007 | Cleanning no clean residu We recently changed to an Amtech no clean paste and flux that is washable. So far excellent results. Far superior to the water soluable paste we were using. Fewer solder balls, longer life in printer, boards can be left up to 5 days and still come clean in either our Orbi or Aqueous wash
Dec 15, 2006 | Ionic Cleanliness-No clean residues Hello All, Is Ionic Cleanliness testing using say an Ionograph on No-clean assemblies a valid test? If not, why? I understand factors like PCB cleanliness but is the 1.56ug/in2 IPC criteria valid for no-clean assemblies and can an Ionograph be used to pass that criteria for No-clean?? Thanks
Oct 4, 2006 | Hi, Anyone ever have an issue with stray capacitance when using no clean solder paste. We are having a timing problem on one product. The problem goes away when we clean the assemblies. We use a no clean process normally. These assemblies worked in a no clean lead process but do not now that we
Jul 31, 2006 | I am printing convention leaded paste on onto Immersion Silver board. Board has 16mil fine pitch devices. I am having a problem getting the print to stick to board. Or I am having a problem with the stencil. Never experienced this with jobs before, but this is a new job, new board and a new stencil (and new stencil house!). My question is, do you guys do anything different to your stencils when printing on Imm. Silver? Stencil house is suggesting a different metal foil besides stainless.
May 2, 2006 | Water Soluble vs. No Clean Currently I am using a water soluble solder paste and no clean wire solder. For awhile now I have been pushing to switch to no clean across the board. Can anyone give me an idea of how this will effect production? Switching to no clean will allow me to get rid of my troublesome aqueous cleaner
Feb 27, 2006 | Cleaning PCB assemblies Options are: * Find a low residue flux and conformal coating material that are compatable, so that cleaning is not required. * Use a cleanable low residue flux, clean according to the supplier's recommendations, and then coat boards.
Feb 27, 2006 | Cleaning PCB assemblies We are going to start conformal coating PCB assemblies, and I was wondering about cleaning the boards before coating them. Do I need to clean them and if so, with what? We currently us a no clean solder. I am worried about contamination on the board under the conformal coat. I welcome all and any
Feb 21, 2006 | Stencil past height issue Hi, I am having problem looking through IPC and finding according to ISO spec what should the paste height requirement vs stencil. EXAMPLE: The stencil is 5mils thick and according to the specs we have on paste height measurement the max height to be acceptable is 1.5mils higher than the stencil and the lowest limit is .5mils lower than the stencil. That means if the paste measurement height is reading 6.5mils is acceptable but if it is 7mils then it is too high and fail. What is the industry standard on this issue? Thanks and appreciate any assistance onthis matter.
Feb 13, 2006 | Clean the No-Clean Some low residue [no-clean] flux residues are cleanable, others are not. Talk to your paste supplier for a recommendation of cleanable low residue flux.
Dec 7, 2005 | I have seen problems similar to this caused by too high concentration of cleaning solution used in ultra-sonic cleaning process. If cleaning solution is used, make sure it is compatible with solder process. Also, improper mixing of fluxes and solder or use of the wrong solder/flux (ex. no-clean
Nov 15, 2005 | We are using an inline aqueous washer with saponifier to clean smt assemblies with rosin based no-clean solder paste. Looking for a reliable, cost-effective way to monitor the cleanliness of the assemblies after cleaning. Any recommendations?
Nov 11, 2005 | Manual Stencil Printers http://www.smtprinters.com/printers.html http://www.eliteprinters.com/ http://www.stencilsunlimited.com/stencil_printers.php http://www.manncorp.com/smt_stencil_printers.php I'd say Elite is about the best.
Oct 12, 2005 | Cleaning BGA Hi We have BGA sockets that are soldered on our PCB which required cleaning? Anyone have any solution as for now we just use compress air jet to clean it. We found this is not effective in the long run. Any comment?
Sep 12, 2005 | Cleaning before Conformal Coating Amol, Your problem is already very isolated only one part has the problem (the part that is hand soldered) Manual cleaning is very difficult. Why are you not considering a no-clean cored solder to solder the one part and skip the manual cleaning. Don't forget to check what URL said in his response
Aug 10, 2005 | cleaning of no clean flux Wasn't aware of that. We're using a no-clean with RF pcbs, and that's something to bear in mind for the future - thanks.
Aug 2, 2005 | Cleaning Reworked BGA's. I am looking for a method (Automated preferably) to clean any residue and or debris from a BGA after rework. Is it possible to clean them using an inline wash process, as long as the devices are intact and held correctly. What woudl be the correct method to hold trhem during this process.
Jul 18, 2005 | Possible to water wash no-clean solder paste boards? I have nothing to add technically but we have been washing no-clean for years. Use very clean filtered DI water to avoid the white residue issue and some good detergent or sopanifier and you will get great results.
Jul 14, 2005 | Possible to water wash no-clean solder paste boards? Hi production encountered a problem today. There have been a mix-up of solder paste. We are currently running clean process in one side of board. Unfortunately when PD run the other side process they were able to used a wrong no-clean solder paste... Is it possible to clean these boards? If we do
Jun 7, 2005 | quality of water to cleaning That depends a great deal on what you are cleaning and how clean do you want to get the substrate. We've seen cases where 0.1 uS-cm was insufficiently good and others where 10 uS-cm was more than sufficient.
Apr 11, 2005 | Hi there - I am from the company that owns FinePoint precision cleaning, and we are capable of performing contract cleaning. We would also be happy to help if you need a recommendation on cleaning equipment to purchase. You can call our office at 765-457-8095 for help.
Apr 10, 2005 | DEK underscreen cleaning hi guys, Iam going to run evaluation on DEK 288 underscreen cleaning efficiency. The purpose of this run is to determine the best setting for underscreen cleaning. Could anyone who familiar with DEK 288 share with me you experience on the underscreen efficiency. Thanks
Jan 21, 2005 | no-clean flux removal Hi esoderberg - I was wondering if you had tried altering your soldering profile to try and fully solublize the no clean flux residues and elimate your cleaning dilemma? You can check out my company's website if you want some free reference materials on cleaning and contamination -
Jan 19, 2005 | no-clean flux removal Just curious� Why only localized cleaning? Why not clean the entire board? Localized cleaning by nature is labor intensive. Mike Konrad Aqueous Technologies (909) 944-7771 ext 29 www.aqueoustech.com firstname.lastname@example.org
Dec 15, 2004 | Earth Friendly Cleaning Chemical Here are three VOC free chemistry suppliers. Their chemistries will clean no-clean and RMA flux residues: www.zestron.com www.kyzen.com www.envirosense-inc.com
Dec 14, 2004 | Our paste is no new we have used it before [Cobar no-clean paste]. The solder joints look like they are bursting out salty looking crystals. Maybe the board cleaning is a red herring in that if the boards are clean it stops this crystalisation traveling? Is this possible?
Dec 8, 2004 | CSP No clean residue KS: You're correct. The standoff on a 1.00mm and 1.25mm BGA is high enough to allow cleaning. The standoff on 0.8mm BGA does not allow proper cleaning, even with saponifiers.
Dec 6, 2004 | CSP No clean residue We are currently reviewing a design which has a leadless chip scale package with a solder thermal pad on the underside. The application notes for the device specify use of a no-clean solder paste as the gap under the device will prevent cleaning. Is there any data relating to the long term (15 -20 years) reliability implications of no-clean residues.
Oct 28, 2004 | Stencil Tension What are the defects you see when the stencil is over 50 n/cm? I can't recall ever seeing a (stencil caused) defect that wasn't a dent, ding or some other physical damage, and I would have a very hard time sending back a stencil that is working fine, just because it failed to meet this highly suspect standard. I can see using this test possibly to troubleshoot a print problem but not as a pass/fail test on each stencil. I could be wrong but I think your valuable time could be spent on other projects that would give a lot more bang for the buck.
Aug 26, 2004 | Cleaning Water Soluble Flux After Touch-up Hey, We have introduced a Cleaning Pen from Chemtronics. It removes excess flux after touch up.. This way the operator doesn't have to go everytime to the cleaning room.. Indy
Aug 19, 2004 | We want to get a process running to print paste with a thicker plastic stencil with some room left underneath for preassembled components. I know DEK offers these stencils but since we are using an MPM printer they don't want to sell to us stencils for bump printing, they would only offer the package of printer + technology + stencil. So my questions: are there any other manufacturers of stencils for bump printing? Any informations apreciated. Erhard Hofmann ADOPT Austria email@example.com phone +43-6246-72440
Apr 28, 2004 | bga reflow in water clean solder We can clean the blank out of LARGE BGA. [Cleaning small BGA is a whoooole nuther issue.] But before we get into that, what's the problem and its breadth? Why are you getting poor wetting? What's the story on the components, board, process materials, and process setup?
Apr 13, 2004 | Water Soluble for No Clean BGA Balls Oy. So, what's your thinking on employing a contract cleaning specialist, until you have a proper cleaning system up and running?
Apr 1, 2004 | clean process vs non clean process How high a voltage? TV products use hundreds of volts on the vertical and horizonatal sync circuits. Historically, these consumer products were NOT cleaned. For your situation, contact your paste supplier.
Mar 22, 2004 | PCB post reflow cleaning Just wondering what everyone's ideas are on the best cleaning chemistries for post reflow cleaning. I (like everyone) am looking for the most bang for the buck. Ive tried the big names, just looking for some input on anything else thats out there. Thanks
Mar 18, 2004 | When it comes to re-attaching the BGA onto the PCB, we don't those very nice mini-stencils. They are very nice though. On sources for your rework stencils, try your stencil fabricator will be happy to make those very nice things for you. What's wrong with Circuit Technology Center Flextac stencils? [I mean after you order the correct size and all that.] These stencils self fixture. What could be better? Dreamy: What the hay are you doing in Canada? What happen to Oz?
Feb 11, 2004 | Component stencils Does anybody know if there is such a thing as individual component paste stencils, and who would sell such an item? The reason I am asking is because we have instances when we build prototypes that we don't need a full stencil. We may only need to place one or two components. It would be nice to have a dozen or so standard shape stencils for IC's and other components that aren't real easy to solder by hand. That way a person could hand stencil the paste, hand place the part, and run it through the oven. Steve
May 20, 2003 | Aqueous Board Cleaning First, it is very difficult to properly clean under devices like yours. Second, your ultrasonic cleaner should not be damaging or loosening encapsulated components. It sounds like: * Cleaner is not of the proper type for cleaning electrics. * Cleaner amplitude or sweep are not adjusted properly
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