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May 20, 2019 | Step-up stencil: recommendation thickness Resources are: * IPC-7525A - Stencil Design Guidelines, 3.5.2 Step-Up Stencil This type stencil is useful when it is desirable to print thicker solder paste in a small portion of the stencil. An example would be a ceramic BGA where it is necessary to get 0.2 mm [7.9 mil] paste height because of ball coplanarity but 0.15 mm [5.9 mil] height on all other surface-mount component lands. In this case the stencil foil is stepped up from 0.15 mm [5.9 mil] to 0.2 mm [7.9 mil] in the area of the ceramic BGA. Another example is a through-hole edge connector that requires additional solder paste volume
Feb 1, 2018 | Has anyone heard of a no clean paste that can be cleaned in straight DI water ? Your right, he is "selling it". Or I should say he is not selling no-clean solder paste.
Jan 30, 2018 | Has anyone heard of a no clean paste that can be cleaned in straight DI water ? This is one of the most common questions I get asked. Why clean no-clean flux. It was stated earlier that no-clean residues are benign. This may or may not be accurate. It depends on several factors including the reflow process. In a perfect world, the low-level flux residues are benign. In a less -than-perfect world, they may not be. There may be un-encapaulated flux activators or other ionic residues left behind if the reflow profile was not ideal for the specific flux type and volume. More importantly, when flux residues are not removed, nothing is removed. We should not consider cleaning assemblies a "de
Jan 30, 2018 | Has anyone heard of a no clean paste that can be cleaned in straight DI water ? I believe the correct statement (I've been told) is "the process is no clean". The solder paste is "low residue". As a CM, in the past we had customers that insisted on a wash after soldering. We used DI water with a saponifier which had mixed results. Sometimes you can't convince someone that the low residue flux remnants are benign and do not affect the long term reliability of the product, they still want shiny and clean. If we could go back to the TRI 1,1,1 and liquid Freon cleaning era.....that would be great, oh except for that environmental thing.
Jan 26, 2018 | Has anyone heard of a no clean paste that can be cleaned in straight DI water ? I'm looking for a No Clean SAC 305 Solder Paste that can be run through our inline wash. No chemicals just DI water.
Nov 7, 2017 | If no-clean flux is reflowed correctly, many of the activators are encapsulated within the resin residue left behind after reflow. An ionic contamination test cannot differentiate between ionic residue that was encapsulated (not harmful) and residues that were not encapsulated (harmful). Keep in mind however, when no-clean flux is used and in cases when no-clean flux is actually not cleaned (today more than 50% of no-clean is cleaned), nothing is removed from the assembly. When assemblies are cleaned, it's not just flux that's removed. All process residues are removed (board and component
Nov 3, 2017 | Testing effect of non-clean flux residue on solder joints IPA and DI water are both very common and effective methods of cleaning PCBAs. http://www.zestron.com/sa/cleaning-applications/smt-electronic-cleaning/pcba-cleaning/aqueous-cleaning long time. For cleaning the board is immersed for a few minutes, then allowed to dry. This level of exposure isn't enough to harm the PCB. IPA is a common house hold chemical used in numerous products. Rubbing Alcohol is just IPA with an extra chemical mixed in it to discourage human consumption (at
Aug 23, 2017 | Auto cleaning squeegee hi dear. i'm interest about auto cleaning squeegee and i wanna know , is it really work ? I mean is it possible to clean squeegee with air knife ? thanks .
Aug 13, 2017 | We manufacture low volume, high reliability assemblies (class 3) that are conformal coated. Up until now we have been cleaning after SMT, then after through hole, then immediately prior to coating with test, formal inspection, etc. between cleaning processes. The new philosophy is to eliminate cleaning immediately prior to coating and to "keep it clean" through the various processes after "final" through hole cleaning. This implies the use of nitrile gloves for any handling after the "final" cleaning (we currently do not use gloves at all). The questions are: 1. Is it possible to keep the assemblies clean as they go through their processes assuming the use of gloves? 2. If so, when should gloves be mandated? Only after the final cleaning and how do they know when that is? During bare board handling at SMT? Prior to reflow (consider dexterity for hand placing some larger SMT parts or using
Mar 20, 2017 | Testing effect of non-clean flux residue on solder joints We're currently using no-clean flux (SR-12) in a no-clean manual soldering process. The brownish flux residue impedes direct visual inspection of the solder joints. Therefore, we're forced to clean the residue off. (1) Is there testing we can do (environmental stress chambers) with which we can see the long-term effects of flux residue on solder joints? (2) Has anyone else seen this problem with no-clean flux residue and how do you handle it?
Mar 16, 2017 | Tools For Cleaning PCB after Soldering Hi! I have a very basic question about PCB cleaning. Which is the best way to clean the PCB after soldering? We use a lead free solder wire (3,5% flux inside the core) and after the soldering its a visible wetting,flux around the joint. When using the Flux remover the surface gets clean but it leaves sticky on it (when touch with fingers). Same things occurs when cleaning with IPA.
Feb 15, 2017 | Cleaning PCB After Soldering - How? This video may help answer some questions: http://www.aqueoustech.com/benefits-of-cleaning Mike Konrad Aqueous Technologies
Dec 8, 2016 | Batch cleaner not getting PCBs clean and dry We have a name brand aqueous batch cleaner that uses a chemical and DI water to clean ROL0 flux from our PCBs. It does ok most of the time for SMT boards and we want to include through hole assemblies as well which should be a better cleaning process than our IPA cleaner. The problem is that PCBs with through hole parts (especially connectors and toroid inductors) frequently do not clean entirely and come out not fully dry. I understand that shadowing and crevices can be a significant factor. I want to know if others are having challenges cleaning through hole PCBs in a batch cleaner and what can
Sep 1, 2016 | Is there any field proven spray cleaning technique able to remove flux residues under OSRAM LEDs? Is it possible in principle? The problem is that OSRAM LEDs are low standoff ones and I absolutely have no idea how cleaning agent could get there. More process details: Cleaning machine - spray (clean, rinse, dry) Cleaning agent - Vigon A250 Paste used - KOKI S3X58-A230 OSRAM partnumer - LRTB GRTG Any input would be really appreciated. Regards, Pavel
Dec 22, 2015 | Cleaning The overwhelming technology used in post-reflow cleaning of electronic assemblies is aqueous. Prior to the 1990's, solvents and vapor degreasers dominated the cleaning industry. After the popular solvents were banned via a United Nations treaty, alternative solvents attempted to take their place . Unfortunately, no alternative solvent worked as well as the banned solvents. The industry en-masse switched to aqueous-based cleaning technologies. Today, aqueous-based cleaning technologies has become the conventional wisdom. While there are specific circumstances where aqueous-based technology can not be used
Jun 19, 2015 | Cleaning misprints with no-clean? IPC 7526 details the correct process for cleaning misprinted PCB. Available at the link below. http://www.smartsonic.com/PDFfiles/IPC7526Handbook.pdf
Oct 18, 2013 | You might try testing prior to using the Silicone if possible. Also you might try to qualify your cleaning process rather than the individual board. Clean an unrelated assembly and test it in your Ionagraph. Assuming it passes, Clean your subject assembly, but do not test. Then clean another unrelated assembly and test it. If it passes you could reasonable say that your cleaning process removes ionic contamination, and that the subject board would be free from contaminates. I don't know, however, whether silicone in its cured form can emit or present ionic contamination in and or itself. Just
Apr 3, 2013 | Solder Paste Cleaning Procedure Great Googily Moogily.... For answers to your cleaning questions, please reference IPC-M-108, Assembly Cleaning Guides and Handbooks.
Sep 4, 2012 | Cleaning paste-printed PCB cobhambill is right but depend on how bad the defect, and how good your printer is, you can reprint it one more time. I did sometimes with my equipment with no problem. It's hard to clean NO-CLEAN solder-paste properly, specially with panelized PCB with lots of goldfingers.
Sep 4, 2012 | Cleaning paste-printed PCB The best thing you can do is to clean the board that has a solder paste defect on it. If you don't you probably will have issues after reflow. This could include bridging, raised parts, or any number of issues. You need to remember that if you are reworking something you are applying heat to it numerous times to make things right. The less you heat things the better the solder joints will be the better the part will be. So clean the boards using your favorite cleaning solution and a ultrasonic cleaner if possible. Once cleaned. Make sure that you don't have solder balls in via's or through holes
Aug 31, 2011 | Cleaning My company is reviewing cleaning methods and I read your blog and was left wondering. What is Non-Hermetically Sealed Parts mean exactly. If this is something I need to know moving forward with clean solutions can someone tell me what these types of parts are.
Aug 22, 2011 | Cleaning "No-Clean" in a Non-Aqueous Process I am looking for a methods to clean boards built with a "No-Clean" flux but the boards have non-hermetically sealed parts on them, therefore they cannot be exposed to an semi-aqueous process (what I typically use). These boards will be built in large enough volumes that manual cleaning is out
Aug 4, 2011 | Need to clean no-clean flux? No need to clean unless the sticky residue is an issue for you. If you are working with RF, it could be an issue. You may have probe contact problems as well with ICT and FT fixtures. We use a low residue flux for our wave solder machines (Kester 977).
Jun 22, 2011 | patchwork stencil tTo explain what I mean...sorry for my bad Engilsh... please find short " patchwork stencil" description from EPP Europe. http://www.epp-online.de/europe/-/article/16537487/15944614/Innovators-of-laser-processing-technology /art_co_INSTANCE_0000/maximized/ " A patchwork stencil family The PatchWork version was originally designed in order to solve the issue with quite different solder paste volumes on PCB pads for very different components. "While other
Mar 15, 2011 | cleaning in Ensolv Ionic vapour degreasing solvent Hi, Does anyone have any experience of cleaning lead free solder paste residues off pcbs in a vapour degreasing process using Ensolv Ionic ? Any guide as to the best cleaning cycle would be appreciated. thanks
Jan 14, 2011 | Cleaning a No Clean Contact Zestron. We have cleaned many different solder pastes, including 256, over the years using Zestrons products. They will steer you in the right direction using the equipment you have. N.Ravindran@zestronusa.com
Jan 14, 2011 | Cleaning a No Clean There is a lot of information available about cleaning no-cleans. Takes chemical, mechanical and thermal energy. Find the right chemistry for the flux (not something like IPA that will most likely just smear the residues around and cause problems later.) Then, find a manual or mechanized approach to apply some physical energy and maybe some heat to the chemistry or board to help with cleaning. Regarding the posted suggestion for the definition of quality, 'sum of the customer expectations', I suggest a definition of quality equaling the expectations of the seller. Shean Dalton www.fhpreps.com
Jul 13, 2010 | Clean to No Clean Process Guys, I'm looking for some articles or presentation materials that can convince my customer to convert to a no-clean process. I'm new in this forum i hope anyone can point me to some leads. Thanks. Chris
Feb 24, 2010 | Mixing No-clean and water soluble processes Hi Vince, we don't know, which kind of flux no-clean was used, and which reflow profile also was used (standard or lead free)? Anyway, white residue formation is known to occur after PCAs are cleaned in an aqueous cleaning system where the water temperature is relatively high (> 60° C). Moreover (by IPC standard)... "White residues resulting from no-clean or other processes are acceptable provided the residues from chemistries used have been qualified and documented as benign...". So, use an EDX or IC analysis in order to qualify the final result... XPS analysispcb.com
Feb 23, 2010 | Mixing No-clean and water soluble processes Davef is right on as usual. We are doing exactly what you do. Some smt with no clean paste then the plate through connectors on our selective solder machine using water soluble flux. We then clean with a ultrasonic water process. We do see the residue from the no clean paste turn a milky white color. We have been doing this for over a year, have sold a few hundred modules and have had no issues in regards to the flux and cleaning.
Feb 6, 2010 | Cleaning Copper Surface We do this sort of thing for a living, provide cleaning materials to clean things such as copper. If you'd like we can chat off line.
Nov 21, 2008 | Cleaning in wash baskets Does anyone know of an inexpensive way of holding small parts or boards in place in a wash basket to prevent them from moving during cleaning process.Keep in mind you want the top of the parts/boards to also get clean. Thanks
Sep 30, 2008 | No clean and 100 Mbps Fast Ethernet Transceiver Residues from different no-clean fluxes produce different levels of variation in RF circuits. Some no-clean fluxes work fine. Following this, a no-clean flux can produce different levels of variation in RF circuits depending on the process setup. Often the data sheets for solder paste with no-clean flux aimed at RF applications say, "This material has been utilized on various assemblies with RF designs without cleaning; however, the compatibility of flux residues on RF assemblies is strongly dependent upon circuitry design." The tech sheet from your AIM NC254 No-clean solder paste gives
Sep 8, 2008 | Clean vs No-Clean Here are links to articles on that subject:
Can You Clean a No-Clean Assembly?
Component Cleanliness in a No-Clean World:
Feb 20, 2008 | no-clean flux vs. impedance KRIKIES, a designer insisting on cleaning no-clean residues!
the BLAME-THE-PROCESS bandwagon travels everywhere, me lad!
Feb 20, 2008 | no-clean flux vs. impedance KRIKIES, a designer insisting on cleaning no-clean residues! the BLAME-THE-PROCESS bandwagon travels everywhere, me lad!
Feb 19, 2008 | no-clean flux vs. impedance The low solids flux that is commonly called no-clean can affect some circuits. We are building a PCB that measures pico amps. The customer required that it be cleaned. We would rather used the low solids and eliminate a step. The customer had us build 1 PCB with low solids flux paste . The board gets reflowed and the profile was to the paste manufacturers spec so we were sure that the flux was completely activated. The customer then showed us the measurements this board was capable of and what a cleaned board was capable of. The clean board was more than twice as sensitive. So a test
Feb 15, 2008 | Inspecting a new stencil FYI, Here are the steps in which we take to get approval. The stencil gerber layer needs final approval through our Engineering dept. What they do is send in a gerber layer from the stencil house and lays it over the current solder paste layer and verifies it will match within thier gerber viewer . Once that is proven than the stencil house can manufacturer the stencil and send out. Now as for when it gets into house we dont open the package almost until the job gets ready to run down the line. We have had maybe a handful of stencils in past 5 years that maybe had an issue and we had to due next
Jan 29, 2008 | Cleaning procedure when WS609 flux is used Bruce Barton: We're not intending to suggest that anyone is purposely leaving WS flux residue on the board after cleaning. Fact is, Arun isn't sure if the boards are completely clean. Arun said, "We haven't tested the substrate for cleanliness." Given that the mold is delaminating in the areas with close component spacing, it's possible the boards are not being cleaned well in that area. We suggested a method to determine if the boards were clean and how operators could monitor cleanliness on an on-going basis. What's bogus about that suggestion?
Dec 19, 2007 | Stencil Printing: Single pass vs. Double pass "Any risks associated with double pass stencil printing?" Mostly just too much paste, plus the associated bridging, and your stencil gets dirty quickly. Any gap between the stencil and the board gets filled with paste on the first pass, then migrates laterally during the second pass. In my experience the only reason you should "need" to do it is that something else is wrong with your process, like a bum printer, old paste, worn out stencil, etc. You can probably get away with it for a .050" product, but not with fine pitch unless everything else is in your favor (your stencil is in really good
Nov 12, 2007 | Here are the scenarios: *No-Clean Flux & Foam Fluxer: alcohol is used as a thinner (for titration purposes) if your flux is alcohol-based *No-Clean Flux & Spray Fluxer: alchol is used only as a cleaning agent for your sprayhead.
May 30, 2007 | Small Batch PCBA Cleaning I'm trying to find a solution that will clean our PCBAs that will meet the following criteria: 1. Low cost 2. Enable us to clean 25 - 100 PCBAs per day 3. Leave boards clean, including residue removal 4. Preferably environmental friendly 5. should be able to handle PCBs ~12" max edge width We use RMA flux right now (SN63PB37, rosin core). We've tried cleaning by hand with Vigon EFM and / or RC101. EFM left lots of thin residue on the assembly. RC101 couldn't clean off thick flux deposits. I tried a dual process and the results were better, but I had to spend way to much time cleaning
May 16, 2007 | Board cleaning machine problem Yes cleanness is respect. Our customer require this solution with cleanning board. We've got Teknek SMCM2 What do u mean by anti-stat bars?
Apr 23, 2007 | SMT Cleaning Good afternoon everyone, We have a customer that wants to specify "cleaning processes" on a board that typically has a "no clean process". Normally, I would not care, but I have one component on this board for which I question the cleaning process. There is a leadless surface mount package (attenuator). This package has a center pad, and several leadless pins around the outside of the component. This also sits flush to the board. Our concern is cleaning the area between the pins and the center pad. Is there a specification or can someone point me in the direction of a minimum clearance for a
Apr 13, 2007 | No Clean Flux (Alpha OM5100) low level analog interference Even though this is a "no clean" flux, are you (or the customer) cleaning the boards? If this is truly a low signal level device, there is no way you will get away without cleaning the flux residue. I do a lot of low-level hardware, and we have to clean a number of the assemblies, sometimes even
Mar 29, 2007 | To use a mini stencil, or not to use a mini stencil. Ewwww metal mini stencils? Try http://www.circuitmedic.com/products/stencils.shtml We use their flextac stencils all the time and they work perfect. You can get a couple uses out of each of them if youre
Jul 31, 2006 | Can UP 2000 printer work with R and L justified stencils? You should be able to do it in > TOOLING > OFFSET. The pcb stopper is attached to the camera and a default stop position is calculated from the PCB dimensions. If your stencil image is offset left or right then you can either fiddle the pcb size or input the offset. Offsets front and back can be much more difficult. If the image is too far from the centre to the back then you may have to move the stencil so that it is partially hanging out of the machine - you may have to bybass interlocks etc. If it is too far offset to the front and you can't physically move the stencil far enough
Dec 14, 2005 | Fine Pitch Stencil Design the original question was: Please give me some guidelines on designing Stencils for Fine Pitch. which i did however, 40% fallout for solder shorts this could be caused by many other processes having gone wrong before, i.e. type of solder paste and oven temperature profiles, stencils would be the latter of these things that i would check for faults,,,, or maybe i am just lucky and have a great stencil manufacturer who checks my stencils for problems, how ever small they maybe.... latest problem i have had was heat sync under SMT comp. and too much solder paste resulting in tin balls and weak
Dec 8, 2005 | Thanks Russ. As I was writing the post, it crossed my mind that stencil thickness is probably incorrect. I did not question the thickness because it was something that has been discussed with our stencil fabrication shop. When we were ordering mini stencils, an engineer there said that they make them all the time and that a recommended thickness is 5 or 6 mils. I was very specific that we will be using them for BGA reballing NOT solder paste transfer. The guy reassured me that they have experience with these. Well, so much for experience. I have 3 stencils each being 6mils thick which I stacked. Ball diameter is .028", stencil thickness is .018" - worked well. Basically 1/2 of the ball was inside the aperture of the stencil and that made filling the holes a lot easier. Your suggestion makes a lot of sense. Now all i have to do is find a different company to fabricate the stencils.
Dec 8, 2005 | Fine Pitch Stencil Design Hi, How fine pitch are you going? What kind of stencil printer are you using? We had a manual stencil printer and needed to print 1-mm pitch BGA and needed to go to laster cut and electro polish at 4 thou to get good paste release. We also went 1:1 reduction. However with the DEK being a much better printer, we went back to 5 thou, and don't have problems. Stencil design is really the most important part of your process, apart from perhaps the oven temps. But a bad print will cause most problems. If you have more info on what kind of parts your placing, it might help some suggestions
Sep 9, 2005 | Cleaning before Conformal Coating If the white residue is from a no-clean flux or no- clean solder flux core you can leave it on the board. (Consult with the flux or cored solder manufacturer) Because after being encapsulated with conformal coating the residue is sealed from humidity. I believe the reason for the dewetting after cleaning with xylene is that xylene is water repellent (not soluble in water) and if you use water-borne polyurethane coating the xylene residue will cause dewetting. Why are you using xylene to clean the board? Xylene is a solvent used in epoxy based coatings. Hope this helps Patrick
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