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Apr 9, 2018 | Possible to mix a No-Clean solder and a Clean solder process definitely don't mix clean and No clean. Run No Clean as you decided, but have your flux and paste manufacturers advice, how this flux can be cleaned(if you decide or required to clean). I know for a fact that some of these NC flux residues are almost impossible to get rid of.
Apr 5, 2018 | Possible to mix a No-Clean solder and a Clean solder process We are currently in a Clean solder process (SMT+Wave Solder+Washing). Now our management is planning to convert to a No-Clean process in SMT due to limitations of solder availability and reduction of washing process. Question1: Is it possible to wash with DI water a board with No-clean solder ? Will it impact solder quality? Question2: Can we mix both clean and no clean process? SMT-No clean, Wave solder-clean Thanks hopefully can help me on this issue.
May 9, 2016 | Contamination of the cleaning agent From the SWA data sheet--"SWA is ideally suited for the removal of flux resides and many other cleaning applications that do not contain sensitive metals and substrates. Used for cleaning metals prior to plating operations to provide an extremely clean and slightly roughened surface, allowing excellent bonding of the plated material." From the SWAS data sheet--"SWAS is ideally suited for the removal of very stubborn flux resides and no-clean fluxes, which can be extremely difficult to remove." Based on the data sheet information, it appears you are using a far more aggressive cleaning solution
Oct 26, 2015 | We buy stencils from Stencils Unlimited (stencilsunlimited.com) which is the sister company to PCB unlimited. Stencils Unlimited will be the ones making the stencil if you order the pcbs with PCB Unlimited. We have never ordered pcbs from them so I can not speak to the quality of those. We have gotten good quality stencils and good customer support from Stencils Unlimited.
Jul 26, 2015 | as to its eventual commerical aims (if any). ENIG if your product can justify the cost is by far the best option for PCB finish. It is flat, clean and stores well. Most paste manufacturers will happily send you a pot to try for free. That way you get to put the paste through your process with your products. Nobody else can really tell you what will work best for you. There are several alloys out there for lead free process but by far the most common is SAC305. Most manufacturers will offer this in a no-clean variant. In the UK at least getting non no-clean SAC305 paste is actually often a special order requirement. I wouldn't concern yourself with looking for extreme detail on flux properties. If the paste uses the right alloy and has the cleaning poperties you require the flux will have the properties required because if it didn't it would not be fit for purpose. Instead you should look
Jul 15, 2015 | Cleaning misprints with no-clean? I've read different views on this but the best results i've seen are from when the misprinted PCB is put directly into an automated 'spray-in-air' cleaning machine and cleaned using an appropriate cleaning chemical. Any attempt to manually clean the misprinted solder paste from the PCB usually results in solder paste being trapped in vias and in solder resist channels next to pads. http://www.surfacemountprocess.com/cleaning-a-misprinted-pcb.html
Dec 1, 2014 | stencil Yes nano coating giving the good printing, but the stencil tension is very important for the life, 1st ensure the stencil tension...
Nov 25, 2014 | three areas where I have to focus: a) paste printing - design of stencil, snap-off, understencil cleaning quality, solder paste coalescence parameter (I am not sure how could I check it). b) material impact - solder mask, I heard that roughness and surface tension could also have impact of amount Could be. I am making overprint to achieve proper amount of solder paste inside hole. Now I am trying to reduce maximum overprint and compensate it with step - up stencil. This could reduce effect that some particles of solder paste are not gathering together and occurs randomly on PCB
Nov 4, 2013 | Stencil Life Identification Hi, How can the life of the stencil be decided? As the stencil is used contineously the thickness go on decreasing. How are you all deciding the life of stencil? As visually its dificult to deide the solder paste deposited thickness, is there any tools being used to check the stencil thickness
Jul 30, 2011 | Need to clean no-clean flux? Do we need to clean after hand soldering with no-clean flux solder wire? I am just wondering. The flux is clearly visible. Will there be any long term negative effects on the modules? Is there any IPC requirement on cleaning it? BTW, I talk about normal resin based flux, not the water soluble type (which I think is not no-clean anyway)
Jun 27, 2011 | PCB Washing No Clean I fully agreed do not CLEAN the NON CLEAN process. However, some customer may request to clean the non clean process; and they willing to pay for it. In order to clean the non clean processes (the residual on the board), you need to consider the compatibility of your Non Clean chemical used . The best way were first understand your non clean chemical characteristic, then select some chemical cleaning supplier (you can get a lot of supplier from web search, I do not mentioned here as I am sale person from any of this company and do not tried to put wrong comment of certain cleaning product
Jun 24, 2011 | PCB Washing No Clean I am going to open the flood gates of comments. The purpose of no clean is so you do not have to clean it. Yes I am aware of no cleans that you can clean. If you need to clean the boards use a water soluble paste. If you do not clean, no clean properly you can cause even more contamination on the board. Now back in the day for you old timers cleaning boards was not a big deal with the old style vapor degreasers until we found out it was destroying the ozone layer.
Mar 4, 2011 | 01005 stencils Does anyone have any recomendations on 01005 stencil aperatures? Stencil thickness?
Aug 21, 2010 | Plasma Cleaning / Etching Does anyone have any experience or heard of cleaning fully populated PCBs with plasma cleaning?
Jul 13, 2009 | Stencil Fiducial Repair Here is something I found , I hope it helps : Subject: Re: Repair of fiducial fill material From: Taylor, Royce Reply-To: TechNet E-Mail Forum. Date: Fri, 15 Dec 2000 09:34:59 -0500 Content-Type: text/plain I use a epoxy pen that my stencil house gave me it says: HEAT CURE EPOXY INK AM-33 an ultrasonic stencil cleaners for our stencils. > It' work well, but after some time, we saw a lot of fiducial that the black > epoxy have been partially or totaly remove. I want to know if someone had a > similar problem with a stencil cleaner. Also, we looking for a material to > repair the black epoxy
Feb 18, 2008 | Inspecting a new stencil Most stencil manufacturers use an automated stencil inspection system like our StencilScan AOI that compares the Gerber data directly to the stencil image. We provide the StencilScan AOI system to end users that wish to guarantee stencil / screen and board accuracy and/or cleanliness prior to production. The system can also create Gerber data if the file is lost or damaged. Here is the product info: http://www.smartsonic.com/AOI-StencilScan.pdf Bill Schreiber Smart Sonic Corporation
Dec 20, 2007 | I run a prototype/small-run shop, so I'll include some recommendations too: 1) Don't buy a machine for just what you are doing today. Once you get into this field you will find demand to do more. 2) Don't scrimp on the stencil & machine. You will speed up your production and get better results good job. I've placed 0.5mm pitch parts without grief. Support is also very good. 4) The oven is no less important. What good is pasting & placing well if you don't solder the boards properly? A big part of this equation is the solder paste. I prefer no-clean paste so that I don't have the extra step of cleaning. For SnPb paste I prefer AIM. The oven can easily be your largest power consumption. Be careful with oven specs as some manufacturers do not actually specify max current, but instead specify idle current. There's a big difference. Good luck!
Oct 19, 2007 | Cleanning no clean residu Really, if you start out from the beginning planning to clean the boards, then DON'T use the no-clean flux! The way that stuff is made, it leaves a hard, low-solubility residue that takes a LOT of effort to get clean. If you plan to clean, use a water soluble flux, it will wash off with MUCH less effort. On some specific boards, we have used no-clean flux, but needed to clean just a couple components, and found it to be very hard to get it clean. Jon
Oct 19, 2007 | Cleanning no clean residu Hi Rob, I must take issue with your statement �By definition, no clean solder can be not-cleaned�. All no-clean fluxes can be cleaned. Whether or not one cleans no-clean depends on a variety of factors. More than eighty percent of all post reflow flux residues being cleaned today are no-clean . Although that sounds like a strange irony, there is a logical reason. While many applications do not require cleaning, some do. Many contract assemblers operate a no-clean line and just clean the assemblies that require cleaning due to customer, application, or environmental demands. Rather than running
Oct 19, 2007 | Cleanning no clean residu By definition, no clean solder can be not-cleaned. The solder/flux are formulated to result in low ionic-contamination, hence, no cleaning. I have, however, always had at least one customer that requests their no-clean solder get cleaned. No-clean solder is used post aqueous wash, for parts that are wash incompatible, but the customer wanted no visible residue. If this is your own product, you can prove out the efficiency of not cleaning the no-clean operations by a. conducting ionic contamination testing, and b. conducting accelerated life-cycle testing without cleaning the board
Mar 29, 2007 | To use a mini stencil, or not to use a mini stencil. We always apply solder paste to either the PCB pads or the BGA balls. I have found that only using liquid or tacky flux does not always ensure proper wetting of the pads. Also The BGA sits closer to the PCB making cleaning and endoscopic inspection more difficult. Appying solder paste
Jan 19, 2007 | Affordable, non-flammable cleaning solutions? For flux cleaning after rework try "ProClean" flux remover.
Nov 28, 2006 | J Rose at EMPF says: The introduction of no-clean solder fluxes in electronics manufacturing has given rise to greater levels of solder balling simply because the opportunity to remove them in the wash process does not exist. They are typically caused by any one, or a combination of, the following : * Solder Beading. The result of solder paste squeezing out from under the component body during part placement. The solder trapped under the component body cannot wet to either the lead of the device or the PCB material. This condition can be minimized by changing stencil aperture design to limit paste the individual solder particles initially present in the paste. This condition is usually caused by cold or hot slump, paste deposit thickness and stencil cleanliness. * Solder Splatter. Occurs during reflow and is characterized by finding the solder balls far away from the pads where the paste was deposited
Nov 6, 2006 | production line. A paste�s �abandon time� is defined as the maximum amount of time between two printing cycles that will provide acceptable results without reconditioning or kneading the solder paste or cleaning the stencil. Printer downtime is typically due to placement problems or operator breaks. Solder Checks calendar ...nope not April 1st. -The fresher the paste the better the solder joint. Agreed - My dilema here is upper management wants the two lines to share one stencil printer thus saving the cost of purchasing a second printer. They propose to paste ahead, allow second runner to change stencils, paste their pc's, and so on. Is/are management process engineers savvy in the SMT process?? If so then they must know a little bit on failure analysis. - If shifts end approaches, they offer to store the pasted pc boards in a refridgerator overnight until population the next day. Only if you
Oct 17, 2006 | Cleaning under LCC's Hi Steve, I agree with you that cleaning under LCC's is often difficult but its not impossible. In order to clean the residues, the most important thing to consider is the right compatibility of the fluxes with the cleaning chemistry. There are several companies who manufacturer cleaning agents especially for cleaning under low stand-offs. The high precision cleaning agents provided by companies such as Zestron, Petroferm, Kyzen do have the ability to fulfill your requirements. Since you mentioned that you are involved with Aerospace; it offcourse is much easier to change the chemistry as compared
Oct 2, 2006 | PCB Assy Cleaning Assuming: * Customer board has been designed to provide for cleaning under components. * Cleaning equipment is capable. In meeting J-STD-001, your current cleaning equipment should be able to clean: * Water washable fluxes. * Low residue fluxes, provided the flux is cleanable and you follow the flux manufacturer recommendations. Solvent systems often are used for cleaning rosin-based fluxes in hi-rel, military applications.
Oct 2, 2006 | PCB Assy Cleaning We have a customer enquiry that requires PCB assemblies to be cleaned to J-STD-001 / -004 class 3. We use both water based and no clean process chemistries. No clean flux residues are not permitted and would therefore have to be cleaned. My question is would our spray in air in line water wash or immertion aqueous wash be capable of cleaning to the required level or should we consider investing in a solvent based system.
Aug 24, 2006 | are running at hehe.
These solder balls are at the end of pad, which end? under the part or away from the part.
I believe you may have stencil issue myself, if profile is good.
common causes of balls are:
ramp rate too fast (splattering appearance)
print misaligned (splattering appearance)
bad paste either lot or type. (splattering or formed ball appearance)
bad stencil design (could be single ball or splatter)
poor paste handling and storage - excess moisture in paste
why are you worried anyway? after wash they should be gone since it is water soluble, if they are not gone then you also have a cleaning prob.
So get us the profile data such as max ramp slope, TAL, Max temp, and soak paramaters (how long at what temp)
Hope this helps, solder balls can be controlled we just need to see what you are doing.
( Jul 10, 2006 | Stencil cleaners. The potential to damage stencils by bending the metal of the fine pitch portion of stencils is a concern about spray cleaners.
Jul 10, 2006 | Stencil cleaners. The potential to damage stencils by bending the metal of the fine pitch portion of stencils is a concern about spray cleaners.
Jun 20, 2006 | Hi, Yes, forget Guru, he's a "tosser" who talks "bolloks". Did you ever notice the English have fantastic words for putting people down? Anyway back to the original question. A manual stencil printer might be ok if your not doing anything too tricky on the technology side. However if your doing some 1 mm BGA's or any lead-less stuff, your going to need something better. However we had a manual stencil printer for about a year and it worked great. It was a US brand that had a bearing guide down the side, and we modified it with a metal blade, as it normally had rubber. It worked well. A , but they are a real problem, or expensive when you consider the cost of a good second hand oven. Check it's clean, so you know your not getting a used up junk oven. If it's clean, it should be ok. That should do you. Your doing just over the volume for this to be easy with any kind of equipment, so you do need
Apr 21, 2006 | is very low, here is an alternative: Remove the BGA with hot air. Clean the pads. Purchase a small BGA stencil and squeegee. (google/yahooo for them, I can't remember off the top of my head) Squeegee the paste onto the board. Use your pick and place to put the BGA at the correct location and reflow . You could also remove the BGA with hot air, clean the pads. Apply tack flux, place the BGA by hand and reflow. Leaded BGAs will self-center. You cannot rely on no-lead to self center, though.
Mar 2, 2006 | I recently finished analysis of no-clean fluxes and Ionic contamination and cleaning processes. The results were eye opening. Summary: If you clean a no-clean you better do a good job. Many no-cleans produce a "waxy binder" to encapsulate the troublesome ions. Identical process as in the old RMA days. No difference. If you didn't clean an RMA then why clean a no-clean now? I would: Use BELCORE certified, halogen free materials, verify your thermal process for no-cleans (good profile), control you flux application process (only apply what you need) and not ROSE test for ionics.
Feb 13, 2006 | Clean the No-Clean Cleaning no-clean is the pitts. If cleaning required migrate to water soluble. Can IPC help here? No cleans only need to be removed per IPC if the joint inspection is inhibited...and in general if form-fit-funciton is not achievable. But then there is always that annoying customer who insists it be removed merely on the basis of cosmetics (even though the product is burried in a chassis, kept in a dimly lit dungeon in an Artic region) I will assume this is a customer driven specification. In which I will recommend re-evaluating no-clean solder pastes in addition to new cleaning chemistries
Feb 13, 2006 | Clean the No-Clean Here are some cleaning chemistry companies that have products to clean no-clean flux residues: www.zestron.com www.kyzen.com www.petroferm.com They all have engineers on staff that can assist with setting up a custom cleaning process.
Feb 1, 2006 | Electric Arching on Y-Cap using No Clean Flux Your product may not no-clean compatible. "No Clean" must not be confused with "no need to clean". Your end application, operating environment and circuit operation (form-for-function) will dictate your cleaning requirements.
Dec 15, 2005 | my 2 cents here --- Even though the boards need not be cleaned after SMT when using no clean flux, you will still have to clean them before conformal coating.....and most solvents used to clean boards before coating will take out the no clean flux residues.
Dec 8, 2005 | Questions are: * Is the stencil design proper to provide the correct amount of solder paste? * Is the stencil design proper to provide for release of solder paste? * Is solder paste filling the stencil aperatures, prior to separation? * Are stencil aperatures open / not clogged with dried paste ? * After separtion, is the paste on the board or the stencil?
Sep 11, 2005 | I agree with prior postings, but there is no perfect yes/no answers, right (left)...? Only good questions to be answered. I think it is overkill to have an extra stencil, why do you need it? (That is if you have a proper stencil cleaning equipment). Think about the % of lead (it is not only lead
Aug 22, 2005 | Stencil manufacturer Photo-Stencil or SMT
Aug 10, 2005 | cleaning of no clean flux Comments are: * Sounds like it's necessary to clean "heareous F381, F352 no clean solder paste" in your application. Consider a paste that may be better suited to your application. * If you're cleaning "low residue flux", consider using an organic acid flux? OA fluxes are much easier and cheaper to clean than low res. * Other RF applications have avoided cleaning of low res fluxes. Flux suppliers say things like: -- 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
Jul 14, 2005 | Lead Free Stencil Design Stencil thickness is related to PCB design and is not related to paste type. If you release with a 8 mil stencil then use an 8 mil stencil. Of course there are pastes that release bteer than other and what not but use area and aspect ratios to determine stencil thickness.
Jul 14, 2005 | Possible to water wash no-clean solder paste boards? Here is a link to a specific article about cleaning no-clean assemblies: http://www.residues.com/pdfs/Clean_No_Clean.pdf Our facility does a lot of contract cleaning and cleanliness testing for various companies around the world, and that study should give you a good base synopsis of what to do and what to expect when cleaning a no-clean assembly Sara Gorcos Foresite Inc. www.residues.com
Jul 14, 2005 | Problems with frameless stencils on MPM?? We use the Frame with the frameless stencils, but they seem to not be as tight as the stainless steel frame stencils
May 26, 2005 | how clean is clean? what test methods can be use to verify that the cleaning process for SMAs with water soluble paste is sufficient?
Mar 31, 2005 | I agree with chuck, but would like to add. 2D is a great option and helps to keep your printing process in check, it will measure the x & y coverage on the pad. It will help you determin when your stencil aps become clogged or when the bottom of your stencil needs to be cleaned.... It will also
Mar 7, 2005 | clean rooms/ wire bonding It depends on your product requirements. I have seen aluminium wire bonding operations in as high as class 100K clean rooms. These are the assembly areas for calculators. The best is class 10K clean room for wire bonding. You can go upto fine pitch wire bonding applications in a class 10K clean room. Once you establish class 10K, over time, the clean room condition will improve to about class 5K due to constant circulation of clean air. So you need to balance your product cost / profits with clean room conditions. Maintaining a class 10K or class 100 clean rooms is very expensive.
Jan 20, 2005 | no-clean flux removal esoderberg: So, why do you want to clean your no-clean flux residues?
Sep 14, 2004 | Labeling of SMT solder stencils Perhaps your stencil supplier could laser mark the number on the stencil. This only helps from here on. How about engraving the numbers on the stencils you already have? Engravers are pretty inexpensive and shouldn't damage the stencils.
Jul 28, 2004 | No-Clean Process very difficult to say that all no cleans must be cleaned for reliability. Cleaning in its own right causes many problems i.e leaving wax residues and activators from incorrectly cleaned no clean pastes, terrible to get off. Decent no clean liquid fluxes should completely volatise away so I always recommend if possible not to clean but if visible white powder(weak benign organic acid) is left then process the boards through a reflow oven at glue profile temps and this should volatise all organics off and not interfere with the rosins from the paste. Worth a try and it does work well.
Jun 16, 2004 | Storing non-framed stencils We have a cabinet that holds all of our stencils. It is a homemade cabinet made to fit stencils with about 12 drawers and each drawer holds about 10 stencils. Each drawer is labeled with the stencil# for each stencil. When a new stencil comes in we just make a new label.
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