Beginner's Guide to Soldering Electronics Part 3: Surface Mount Soldering

hi there my name is Bruce Rayne from Breakers creations and this is part three of my beginner's guide to soldering Electronics Series in this video I'll be demonstrating different tips tricks and techniques for surface mount soldering [Music] this video is brought to you by Channel sponsor PCB way but more on that in a moment this is a video I've been planning for quite some time one of the biggest challenges in creating a surface mount soldering video is that there's no single technique for soldering all the different types of surface mount components available I'm going to try and cover as much as I can but I probably won't be able to cover everything if I do miss something I invite you to leave a comment and I will try and cover it in a future video my techniques may vary from the techniques of others and I can only demonstrate what works for me soldering can become more of an art than a science and there are lots of different ways you can achieve the same result I'm about to discuss some of the theoretical stuff but if you want to skip my introduction and head straight for the soldering there are chapters in the description linking directly to all the different soldering techniques in this video there are links in the description for all the tools I use as well as some links to some more budget-friendly Alternatives the first and most obvious thing is a soldering station I would recommend buying a station of reasonable quality with good temperature control I like to use beveled soldering iron tips but this is not essential I'm not a big fan of conical tips but I accept that these are the most common for the record I use a hakko FX 951 soldering station it's also a good idea to have a hot air station I consider a hot air station essential for surface mount rework which I'll cover in my next video but not essential for most surface mount soldering if you buy a hot air station I'd recommend getting a good quality unit but if you don't have a big budget even a cheap one is better than not having one at all I use a quick 861dw hot air station you will also need a good quality tacky flux my flux of preference is the amtec and c559 ASM TF but there are plenty of others available flux is absolutely essential to achieving great results with surface mount soldering when solder melts it immediately starts to oxidize which forms a film on the outside of the molten solder this film prevents the solder from flowing smoothly and makes it Clump up it also makes it cling to your iron and less likely to transfer to the components you're trying to solder I realize there is Ross and flux at the core of the solder itself but that really only works at the moment the solder is melted when working with surface mount components you will often need to work with solder that's already been melted another obvious requirement is solder I use Kester rosin core leaded solder with a 0.5 millimeter diameter I would recommend that for surface mount soldering make sure your solder diameter isn't too thick and make sure you get rosin core I prefer to use leaded solder because of its lower melting temperature but lead free is fine if you prefer you will also need some good quality Precision tweezers and some solder wick for cleaning up any excess solder I also recommend some form of magnification your eyesight might be Sensational and you may not need magnification but I never do any surface mount soldering without my trusty microscope the high magnification really helps me to produce clean and tidy soldering work it also allows me to capture what I'm doing with a camera which is great for videos like this I work with a very hot soldering iron temperature of around 420 degrees C I arrived at this temperature after lots of experimentation and trying lots of different temperatures a high temp like this will not suit everyone and if you're leaving a hot iron like that on a component for too long you risk damaging it I'd recommend starting at around 350 degrees C if you're not getting those results you want try increasing it in 10 degree increments it's also important to remember that some circumstances may require a higher temperature for example you might be working on a part of a printed circuit board that has a big flat copper ground plane that copper can quickly dissipate the heat from the iron when you work on it if this happens you may want to increase your iron temperature to compensate one other thing I recommend is practice don't just launch into a repair of something valuable practice your surface mount soldering skills first work on an old broken VCR or an old worthless computer or you can look at buying one of these little surface mount soldering practice kits they're very cheap and very readily available there are links in the description if you've had a go at surface mount soldering and haven't had much success the thing to remember is that there are three reasons why solder won't stick to something the first is not enough Heat make sure that you are getting the right amount of heat to both surfaces you are soldering before applying the solar the second is oxidization of the solder if the solder has had a chance to form a film on the outside it won't stick to anything and that's when you need to add flux and the third is dirty surfaces if you're trying to solder dirty pads or dirty components the solder just isn't going to stick to them make sure everything is squeaky clean before soldering I should also mention that one method of surface mount soldering is to use a stencil to coat the pads in solder paste place the components then bake the board until the solder paste melts I won't be demonstrating this method I prefer to solder the components individually okay that's enough yakking let's get into it SMD stands for surface mount device and is used to describe these little resistors ceramic capacitors and inductors if you grab virtually any printed circuit board you'll see these everywhere they vary in size from the smallest 0105 package to the 2920 package the package code is basically two numbers put together for example the size code 1206 is 12 for the length and 06 for the width 12 is 0.12 of an inch and o6 is 0.06 of an inch they're a metric equivalents but the inch measurements seem to be the most common my main method for soldering these components is to First apply some solder to the pads then apply some flux hold the component in place with tweezers and then use a hot air station to heat the area my hot air station is set to 430 degrees C once the solder takes hold of the component remove the heat to let the solder Harden then take away the tweezers don't worry if the component position isn't perfect you might want to add a little more flux if there's none left around the component reapply the hot air but make sure the air isn't coming out with too much force or you'll blow it away as the solder melts the surface tension of the solder should pull the component into place with a bit of practice you'll be able to do these steps really quickly these resistors and ceramic capacitors are non-polarized components so it doesn't matter which way around they go if you don't have a hot air station the alternative is to apply some flux put some solder onto the tip of the iron hold the component in place with tweezers then transfer the solder to one side let the solder Harden remove the tweezers and apply some solder to the other side try and work as quickly as possible because if you apply too much heat to a small component like this you will melt the solder on the other side and the component may end up stuck to the end of your iron this little PCB I've been working on was manufactured by PCB way but they don't just do PCB prototyping in production they also offer PCB assembly flexible pcbs smt stencils CNC Machining 3D printing sheet metal fabrication laser cutting and ejection molding they are a real One-Stop shop and if you're looking for some soldering projects to take on why not check out the shared projects page and see the amazing things people are coming up with and try some for yourself I get all of my pcbs produced by PCB way and I hope you'll give them a try too because of the plastic on top of LEDs I prefer not to use hot air instead I put some flux onto the clean pads melt a small amount of solder to the tip of the iron hold the diode in position with tweezers making sure of the correct polarity then transfer the solder from the iron to the first side take the iron away and let the solder Harden before removing the tweezers now that it's held in place you can easily melt some solder onto the other side sot stands for small outline transistor but you do get diodes in this package size as well because they sit a little higher it's very easy to accidentally blow them off the board with a hot air station so I start with clean pads apply some flux put some solder onto the tip of the iron hold the component in place with tweezers then transfer solder to the first pin let the solder Harden remove the tweezers and apply some solder to the other two pins d-pack or Deca watt package is typically used for high power voltage regulators in this instance we have this large area of metal on the underside of the component to solder this I apply a thin layer of solder to the corresponding large flat pad on the board I then apply some flux and put the component in position make sure the pins line up with their respective pads now hold the component down with your tweezers and apply heat from your hot air station we can turn the fan speed up for this because we're holding the component in place once the solder melts the component will lower until it's flush with the board and some solder squeezes out around the edges take away the Heat and allow the solder to re-solidify now apply some solder to the pins soic stands for small outline integrated circuit an sop stands for small outline package both soic and sop can vary based on the number of pins they have they do have some minor differences but I use the same method for both first thing I'll do is apply flux to all of the empty pads I'll then place the component roughly in position paying close attention to the orientation then melt some solder to the end of my iron Now using the tweezers try and get the component as straight as possible be sure to check that all pins are centered in their respective pads now I apply solder to only one pin in one of the corners now I stop and inspect to see if the component is still in the correct position if it's moved it's quite easy to just melt the solder of that one pin to shift it around a little now I solder one pin on the opposing Corner if you need to you can twist the component a small amount to reposition not too much though as we don't want to tear off the soldered pad melt some solder onto the end of the iron then solder the PIN now that I have two pins soldered have one final check that it's in the correct position now I solder one more pin in one of the other Corners it doesn't matter which one now go to the row of pins with only one pin soldered make sure there is plenty of flux if there isn't add a little more with the solder in one hand and the iron in the other gently melt and slide up and down the pins this is a process called drag soldering some people will frown on this method but once you perfect it it'll save you lots of time if you have the perfect amount of flux and solder you'll end up with all the pins soldered and looking clean and consistent if some pins haven't soldered properly you may need to add a little more solder if the solder isn't spreading well or the pins are bridging you need to add more flux if you accidentally add too much solder remove the excess with some solder Wick this is probably the one I get asked about the most micro USB connectors like this can get accidentally yanked off pcbs and assuming there's been no pad or Trace damage it's a pretty simple job to reattach it USB connectors typically have these anchors on the side to secure them to the board then the pins at the back for the power and data start by applying plenty of flux to the pads this will also help to keep the connectors steady while working now position the connector in place looking carefully at the position of the pins relative to the pads put some solder onto the tip of your iron and then hold the connector in the correct position take your time and when you're happy with it solder down one of the anchors it doesn't matter which one carefully inspect the pins to see if the position is still correct if you need to move it apply heat to the soldered pad and move the connector as required when you're happy with the location melt solder to the opposite anchor this PCB also has two pads at the back for extra mounting strength I'll apply solder to these as well these anchors are what holds the connector to the board and micro USB connectors can often get yanked around a bit so make sure you apply plenty of solder but also be careful that you don't get any of that solder on the inside of the connector or you might block the plug from fitting in there now put some solder on the tip of your iron but only a little we really don't need much for these tiny little pins it's easier to add more solder later than to try and remove too much hold the board so that you get a good view of the pins make sure there's plenty of flux if not add some more poke the tip of the iron into the pins one at a time when they get hot the flux will help to transfer the solder onto the pins and pads gently do each pin one at a time once complete check that all pins are soldered and there is no bridging between pins it's also a good idea to double check that there's no solder on the inside of the connector micro SD card sockets can be quite tricky they're not all the same and some of them have their pins under the socket itself which can present a soldering challenge there are two anchors at the front of the socket two at the back and eight pins in the middle start by applying plenty of flux to the pads place the connector and position it very carefully make sure the anchors are over their respective pads and the pins are neatly centered in their pads melt some solder onto your iron hold the connector in place and transfer the solder to the first anchor if your socket is a little crooked you can swivel it slightly before soldering the next pin when soldering the anchor on the other side it may be tempting to come at it from this angle but don't do that if you solder it from the opening of the socket you run the risk of getting a blob of solder on the inside which may block the card from sliding in easily instead put some solder on the tip of your iron and then solder the second anchor from the outside now we'll swivel the board 180 degrees and solder the other two anchors make sure there is plenty of flux on the pins if there isn't add a little more my soldering iron tip is too thick to fit into the slot we could come in from the top down but I'm going to do something else I'm going to swap my soldering iron tip for this bent conical tip this one is long and thin enough to fit into the slot feeding the solder through the top and the iron in through the side I slowly solder each of the pins the thin tip takes a little longer to get the pins hot so I hold it there a bit longer until the solder flows well now I'll look through the slot opening to make sure that all pins appear soldered properly it's also a good idea to make sure you haven't got any Blobs of solder blocking the slot opening surface mount electrolytic capacitors are polarized so their orientation is important they have a stripe on the negative side and the plastic base is beveled on the positive side because the base is plastic we need to try and solder quickly so as not to melt it melting doesn't really do any harm it just doesn't look very nice surface mount electrolytic capacitors can vary greatly in size start by applying some flux to the pads place the capacitor making sure the polarity is correct put some solder onto the tip of the iron hold the capacitor in place with tweezers then apply solder to one side let the solder solidify remove the tweezers then add some solder to the other side tantalum capacitors and diodes are both polarized so their orientation is important tantalum capacitors have a stripe on the positive side and diodes have a stripe on the side of the cathode both components can vary greatly in size surface mount diodes are usually black and tantalum capacitors are usually black or orange start by applying some flux to the pads place the capacitor making sure the polarity is correct melt some solder onto the tip of your iron hold the capacitor in place with tweezers then apply solder to one side if you're not happy with the positioning melt the solder and move the capacitor as required let the solder solidify remove the tweezers then add some solar to the other side follow exactly the same steps for a diode the qfp or quad flat package is probably one of the more challenging components to solder because it has very small delicate leads or pins so you need to be super careful when handling them you can buy tools specifically designed for picking up components like this using suction rather than trying to handle them with your hands or tweezers the first thing I need to do is apply flux to all the pads then very carefully place the component paying close attention to the orientation one of the challenges I have with this component is that it's too big to fit in my microscope field of view so I need to check the component position one corner at a time this is probably the trickiest part of the process put some solder onto the tip of your iron then very gently and carefully solder one single pin in the corner if the component moves apply heat to the soldered pin and reposition it gently now go to the diagonally opposite corner the position of this corner is still good but if you need to twist it slightly to fix the position you can put some solder onto the tip of your iron and carefully solder the one pin at this point the component Is Anchored in position and soldering the remaining pins is pretty straightforward start on one of the adjacent rows that doesn't have a soldered pin make sure there is plenty of flux if not add some more that was probably too much with solder in one hand and your iron in the other gently drag solder the pins being very careful so as not to bend any go very sparingly on the solder so you don't Bridge any of the pins Now flip around to the row of pins on the opposite side add some more flux if needed repeat the process of gently drag soldering the row of pins now I do the remaining two rows in the same way I accidentally put too much solder on this row so I'll use some solder Wick to remove the excess now take a good close-up look at all the pins check for any that aren't soldered check for Bridges between pins and check for bent or damaged pins and that is your finished qfp qfn or quad flat no lead are probably my least favorite components to solder as the name suggests they have no leads or pins and they soldered directly to the PCB I'll start by applying lots of flux onto the whole area I want to create a small mound of solder on each and every pad apart from the large Center pad we'll do that next with solar in one hand and your iron in the other gently melts solder onto the pads if the Mounds aren't forming well add more flux now we need to add a thin layer of solder to the center pad this Center pad is instrumental in getting the position of the qfn right add more flux to the center pad the qfn component has a small dot in one of the corners this is pin one the PCB has an arrow in the pin one location so place the component so that the dot is in the correct corner try and get the component as close to Center as possible hold the component with tweezers and apply hot air my hot air station is set to 430 degrees C and the air is on Full once the center solder has melted it will adhere to the underside of the qfn and hold it in position you can see that when I move the component around with the hot air it keeps getting pulled back into the center position by the solder underneath now take the hot air away and allow the solder to harden we have the centering correct now we need to get the component flush on the board place your tweezers on the top of the qfn and gently push down reapply hot air and once the solder melts the qfn will lower until it's flush with the board and any excess solder will squeeze out the side take away the hot air and wait for the solder to harden now we need to clean up the solder around the edges my soldering iron tip is a little large for this so I'm going to swap for a smaller bevel tip though a chisel tip can work quite well for this too apply some more flux and drag your iron tip along each side of the qfn to ensure that each of the side pins have a good connection to the pad and all of that excess solder has been redistributed to the pads if you have too much solder remove it with some solder Wick inspect each side very carefully to make sure all the pins are soldered plcc or plastic leader chip carriers are very common in older technology but not so common these days one notable characteristic of the plcc is that it can be soldered directly to a PCB or it can be placed into a socket the first thing I'll do is apply flux to all the pads now I'll place the component plcc chips have a small dot on the beveled Edge side this dot indicates pin one and needs to line up with the corresponding dot on the PCB get the component lined up with the pads by checking each opposing corner put some solder onto the tip of your iron hold the component in place and carefully solder one pin in the corner because the plcc pins curl under the component I poke the soldering iron tip into the gap between the pin and the PCB like this now move to the opposing corner if it doesn't quite line up you can twist the component a little until it's in the correct position put some more solder onto the iron and solder one pin from this corner at this point the component Is Anchored in position now to solder the remaining pins start on one of the adjacent rows that doesn't have a soldered pin make sure there is plenty of flux with solder in one hand and your iron in the other gently drag solder the pins plccs can gobble up quite a bit of solder so you may need to use a lot we'll check for Bridges when we're done Now flip around to the row of pins on the opposite side add some more flux if needed repeat the process of gently drag soldering the row of pins now do the remaining two rows in the same way take a good look at all four sides from an angle and check for any pins that aren't soldered or any bridged pins I have a couple of bridges here I can add a bit of flux to try and spread the solder around or Graves from solder Wick to remove any excess one thing I'm sure you've noticed is how much flux I use when surface mount soldering and this will leave you with a PCB covered in flux even though this flux is referred to as no clean it can trap moisture under it and cause corrosion so it's still essential to clean off any excess personally I use an ultrasonic cleaner I have two ultrasonic cleaners a small 10 liter model and a larger 30 liter model if you want to know more about ultrasonic cleaners or watch my review of the Vivo 30 liter cleaner there are links in the description but if you don't have an ultrasonic cleaner buy yourself some 99 isopropyl alcohol I buy it in 5 liter bottles like this and it's remarkably cheap I buy these bottles from a local chemical supplier for 24 each get a plastic container that's a bit bigger than the board you're cleaning pour some ISO alcohol into the bottom drop the board in and give it a gentle scrub with a soft toothbrush until all the flux is gone this flux has a UV Tracer in it so when I shine a UV light the flux glows this helps me see when the flux has been washed away take the board out let it drain and then dry it in the sun be sure not to use it until it's completely dry one notable emission from this video is BGA or ball grid array components that's because I'll be doing a separate video on BGA soldering and rework at a later date this will include soldering removing and re-balling BGA chips I do hope this video has been of benefit please feel free to leave any questions or comments you might have I regularly do repair live streams on YouTube and I always welcome soldering questions in the chat I'm also happy to do live demonstrations of different soldering techniques so please subscribe to the channel and turn on notifications so you can see when I'm doing a live stream please press the thumbs up if you enjoyed this video and thanks for watching

Channel: Branchus Creations

Views: 38,884

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Id: o8UmA6oC_tU

Length: 35min 2sec (2102 seconds)

Published: Mon Aug 28 2023