Hi Have you ever wondered how a PCB is manufactured? one of these standard double-sided PCBs that you take for granted these days. In this case, this is a PCB panel which contains ten individual PCBs But if you wondered how they actually manufacture these at the factory, what equipments use, what processes are used in things like that, now you can actually make your own PCBs at home. It's not that hard, but they're not going to be anything like the quality you can get from a professional PCB manufacturer. They're so cheap these days, it's almost pointless making your own ones at home unless you absolutely need them in like one hour.

Because you're not going to get the plated through holes. You're not going to get the solder Marchia, Not going to get the silkscreen component overlay, You're not going to get the nice gold flash pads and everything else. You're not going to get the V scoring, the routing, and everything fantastic that you take for granted on one of these. PCBs that you can get for five dollars at one of these prototyping services if you wait long enough.

But they're so cheap these days. There's actually a lot of steps which goes into manufacturing a professional quality. PCB Like this one, so we'll take a look at it thanks to Richard Brady from PCBs Own Net for this video of manufacturing. in this case, an old version of my microcurrent.

The video you're going to see is that quite a few years old I've had it in my archives for a long time. I've only just got around to editing this footage now PCBs Own have actually upgraded their factory and their processes and technology since this video was taken, but this video will be a typical example of how sort of you know your traditional PCB manufacturing process works. and before you watch this video, it's important to realize that this PCB only has one plated through-hole on all these other holes here are not plated through and that's important as you'll see in the video. In this case, it's actually a good example this panel because it combines the routing paths like this with the V scoring which is on the edges.

like that you can see that and I've done a video on actually our PCB design for manufacture and it's one of my most popular videos. It's almost approaching half a mil in views now, so click here if you want to have a look at that one. I Highly recommend it. Anyway, let's get on with the show.

Now, the first step here is to actually process the Gerber and drill files that you give them and there's various ways that they do this depending on what software they use, what machines they have, and everything else. So I don't have any video on that so we'll just leave that and we'll go straight to generating the film. Now what you see here is the film printing machine. I'm not sure what model this puppy is and this is the film for all the photo image oral processes.

So the copper layers top and bottom so you'll have a different film there. you'll have top and bottom silkscreen as well. If you've got a photo image above silk screen, you may not. The manufacturer may actually use an ink jet type silkscreen.

silkscreen is an old terminology when they actually used to use a silk screening process I don't think anyone uses that anymore. Ink Jets are very proper popular now so it can direct print onto PCBs So we're actually going to see a photo image Abul silkscreen or component overlay here today. It's a much better process than the inkjet one. You can get much higher resolution, but it's you know it's an additional cost and additional steps involved in here.

And then of course we're going to have films for the top and bottom a solder mask as well. so we're going to end up with that. Six different films here for this one double sided PCB But having said that, Circuit Labs don't use this technique anymore and this is a somewhat older one, but lots of places still doesn't generate films. Don't get me wrong, they've got a newer laser direct imaging machine where they use a laser to scan directly and expose directly the both like the copper master.

Soleil All those photo image Abul processes all directly done and with the laser and you can do a way of the film. it's great. So just for completeness, I'll show you this video I found on YouTube from the Alba PCB group. So I credit to them and this is a Nouveau Go 800 direct imaging machine.

So they take a blank double sided PCB that is already got the photo image of all surface on it, they clean it with an anti-static out roller just so there's no charge on there and then they put it in the Machine and line it all up and boom. It closes and then it takes your own twenty thirty ten to thirty seconds. There you go to actually use the laser to scan over it and actually image the thing. So this does away with the film and here they are just doing the other side.

So this does away with your traditional film process, putting the film over the top, lining it up, and then exposing it to ultraviolet light. in this case, exposing it to a presumably an ultraviolet laser, doing basically the same thing but direct with laser so you don't have to muck around with film. And the UV exposure coating that they've got on the PCB is called dry film. so this would be like it typically called a dry film process and they'll show you the stats here on the resolution they can get.

It's pretty amazing, but we're getting way ahead of ourselves are we don't actually expose the board yet. We actually drill the plated through holes. So this is a excellent brand machine. One of your traditional machines CNC machines to drill these holes.

in fact a the Exelon file format. A lot of PCB manufacturers will specify that it just means the drill file whatever before whatever our brand Cnc machine they use and you'll notice here it is. It's picking up the tool that picks up the different size drill bits. You'll notice that there's multiple panels in there stack I'm not sure how many maybe you know 10 or something like that stacked in and I know maybe 5 or something like that and they tape them down like that and then they're drilling them all at once.

It's just more efficient to drill multiple boards all at once and they would have that state those down as well. And the reason why you would dance, steak, or are pin them all together is so that those boards don't a slip in there and I get misaligned when they're being drilled like that and we'll see that shortly. Here we go, we'll see that they're taking them off and then they're removing it. and then we can see them actually punching out the pins in this thing.

And then of course they're just going to do a little bit of manual deburring of the Holls there, no worries. And then they're going to put it into an electrolysis bath where they do the plated holes. so you'll notice that this panel doesn't have many holes in it. That's because I microcurrent just happens to not have many plated through holes on.

It's just a one major one for the ground connection. That's why you only saw one. There's only like ten major holes on this thing that there actually are plating. You know your average board would have most of the holes drilled at this point.

You know all the vias and everything else they'd all be I get played at this point. so they basically pass a very large current through this and I won't go into the electrolysis technique but there we go. All three point two volts 94 amps. There you go, thank you very much.

But basically what it's doing is just are coating the inside of the hole with our copper so it then it can connect at the top and bottom layers and after a set amount of time they take it out and bingo we have played it through holes. Beautiful! Next up we have our dry film process. You'll notice that they took them out of a baking oven there and they put them through these rollers where they've got this UV sensitive dry film it. this back in the old days was done as like a wet a wet process that actually you know get a squeegee out and roll it on.

But this modern dry film is art. much better than this. So they put it through there and Bingo! We've got a dry film applied to the both the top and bottom. so now we can expose our board to UV light and get our pattern on there.

So now we take our photo resist coated board and then we accurately align our film on top of this thing and we do that for both sides and in this particular case they're doing two different panels, two different sides at the same time. That'll just be an efficiency thing. So this is our UV exposure machine. The cold light is it and give it a bit of a wiper dive and we'll expose this sucker and you'll notice that a lot of this video has like a yellowy tinge to it or some sort of tinge to it.

That's because the lights at this stage because these boards of UV sensitive. They would have special lights in the manufacturing facility that would not expose these by and she goes into the machine. it'll expose it. You can see the light coming on and you don't need to expose it long at all.

it'll come out any second. I'm sure because these are real high intensity UV lamp. So I can remember doing this some G's a long time ago we use like a big arc UV arc flash lamp I can't remember like two big things came together and and it was a pretty horrible process. This is much more controlled than that, but there you go.

You don't expose a mark for long if you're exposing your own boards at home like you might put them out in the full Sun for 15 minutes for example. But now this you know, much more higher intensity. Now they take the film off, you can see that the photoresist on there now has that exposed. This is a negative up photoresist so it generates a negative image from the positive film there.

Next up, we peel our dry film off. There we go and we're going to whack this into the developer machine. This is a big thing with our rollers and it's got your developer eye chemicals in there and will eventually pop out the other side. This takes a bit, it goes through and it develops that then probably washes it and all that sort of jazz.

Now you can see the size of the machine here and it's quite large. It'll eventually pop out of the developer and now this one's interesting. Not all manufacturers will do it like this. I Believe this is actually a negative photoresist as you can see so it's got the exposed pads in the copper.

Now if you put this, if you're used to etching your boards at home, if you put usually after the exposure like they should whack it directly into the etchant. But in this case look, we've got the exposed copper. It's a negative so it wouldn't have you just eat away or your circuit and you'd end up with a negative image board. So what they do now is they put it back into another I'm not sure why they're putting it back into another copper electrolysis machine here, but they will.

Then they'll do that and then another step and then they will actually tin plate it. So interestingly all of the copper traces in your copper pads and everything else your actual circuit layout will be all tin plated and then it goes into the etchant which it's a way the copper. So yeah, this process to be like a total opposite to what you'd do at home. So here after they've given it a wash, they will whack it into the tin plate in electrolysis bath here and and that will coat all of the exposed copper their top and bottom with 10 so that tin won't be eaten away in the etchant and Bingo! Look at that! Our beautifully tin plated board? Awesome! And of course you've got to wash it.

Next up it goes into our stripper solution and that strips off all of our photoresist so that we're just left with our tin plate and copper. And of course we whack it into our agent. There we go. Look you can see, oh look is this blue everywhere? You can see that's a ammonia solution.

so that'll be ammonia Arpa sulfate and it's just coated everything. I Don't think there's any avoiding this. It looks horrible. but that's what happens.

Manufacturing processes are messy and here we have it. our beautifully fully etched PCB and with just the tin plate left isn't that fantastic. And as I mentioned, our older processes might have done this a bit differently. They would have just used that positive photoresist and etched away the copper there and then done a roll tin plating process over.

But roll tin plate is pretty hard and there's our completed boards with our plate of through-hole You see the art. large plated through-hole there. you might be able to see it, but there's all our traces out top and bottom. and now it's time to apply our photo image.

Abul solder mask. And you know how we talked about dry film last time and how you could have a wet process with the squeegee? Well the photo image will solder mask in this case is a wet process like this. So yeah, they just squeegee that across and in your color of your choice as well. I Chose a red solder bus so they'll do that for top and bottom side of the board and isn't it pretty? Look at that.

Bobby Dazzler And now we have to expose our photo image will solder bus. You guessed it with UV again and you guessed it. We've got the film again so they have to carefully align that on there good alignment marks and our holes for these things. So it's not as how you're doing as it looks and they do that.

They will do that for our top and bottom of the board and then they'll put it back in that UV exposure box and Bob's your uncle and out she pops or nicely XUV expose Thank you very much! And of course our solder mask is covering all of our tin plated copper traces and pads. So we've now UV expose it. So now we put it into the developer machine and if you're paying attention before you would have noticed that it was a positive film that we are put over this and bingo that's what we get out. It removes the solder mask from the places that we don't want it ie.

the pads because well, components won't stick down to solder mask. That's a whole idea of it. It's to stop the solder bridge in between all the pins and next up is our component overlay or what's often called a silkscreen. Although this is not a silk screening process, Once again, this is a photo, image or ball art process Just like we had before.

it's a wet process. So we get our where, we put our board in and then we get our squeegee and then we put the coating of our once again photo image of all our component overlay material onto the board. In this case, I've chosen a white overlay but you can choose other colors and you'll notice that basically this is the third identical time we've done this. We apply, we expose and then we develop in the first case, we did the copper layers and then we did the solder mask and now we're doing the component overlay.

The only difference between these was that the copper ones used a dry film technique, but you can also use our dry film for the solder mask and for the component overlay as well. They just happen to use a wet process here. So basically three identical step processes like that for the three different components of a PCB, the copper, the solder mask, and the component overlay. And once again, we apply our film on here, top and bottom component, or silkscreen overlay if you've got if you specify both top and bottom.

Once again, they need to align those accurately now. I Mentioned before that you can actually do the component overlay as a like, like an injector inject printing machine and that's common unlike low-cost prototype boards and stuff like that, but it's not nearly as good a quality, not nearly as accurate as a photo image Abul process. So if you're really after high quality silkscreen that looks fantastic and has a lot of detail in it then and is accurately aligned, then you definitely want a photo image will overlay process like that's used here. and once again, we're going to expose that to the UV light and quite frankly, getting a bit sick of exposing all these different layers.

But hey, this is how what it takes to manufacture a PCB And you guessed it, once we've exposed our component I overlay. Yep, we're going to develop it and we couldn't actually see the developer jets inside the other our processes, but they've given us a good look inside. Here you can see those jets going down. that could be water at the end actually rather than any way it would go through our multiple steps where it would add they would spray the developer on and then it would out of course spray water on to clean it out because you want them to come out clean, ready to handle and pass on to the next process.

But here it is is the beautiful photo developed and exposed photo image able solder mask and it's fantastic and super accurate. Much better than that inkjet stuff, but we're not done yet. No, this interesting look in the vertical machine is actually a flying probe tester and this is the electrical test part. A lot of this might be optional extra or it might be standard in your own process.

When you get your board manufactured you might be part of the cost and you can see they've got two separate probes there and they go on there jumping all around the place and passing the current through to see if there's continuity and basically test every trace. It takes your Gerber file and it knows that this traces. This pad is supposed to connect to this pad down here and it goes and hunt. That's what's called a hundred percent electrical testing.

Usually they do it to 100% You know you can. What's the point doing ten percent. So they go through and and test every single trace like that. And yeah, it takes time I'm Often if you really want to save cost on the board, you can say don't do the electrical test and we'll take the chances that they're You know that they've got a break in the trace and their Foley or whatever like that and and the manufacture will happily, you know, wipe their hands off and say okay, your responsibility.

We didn't 100% test. you chose to save a bit of money because time is money and they have to put each board through this particular each panel through this process. So that cost money and you can see that they're doing 150 million air power continuity test there. but they also do an isolation test in this case out 64 volts.

you can specify it I Don't know what standard that is or whether or not that's just their own in-house thing, but I'm sure it could do higher and can certainly do lower than that. But they test the isolation between adjacent traces and you thought our board was finished, didn't you? Well, nope. we've got another process. This is the V grooving or V scoring.

You'll notice that there's two blades in there, so they're actually doing two V grooves at the same time. There we go and they just yep, they're making sure it's lined up and then they push it all the way through like that. And this is why typically a manufacturer will tell you. Oh, we can only V groove the entire length of the ball because to sort of stop a bit of the way in.

that's not very accurate. So typically they'll go. Yep, we just V groove the whole thing and this is why. So there's our blades on both sides of the board there, so it creates a V on the top of the V on the bottom and it just leaves a little our web in between.

And this is how you can snap off your boards. This is how they penalize them. Typically, this is like a cheaper, easier process and and faster than routing which we'll see in a minute. Because we're not done yet.

we go back to our good old CNC machine because you remember we've only drilled the one of the Joe walk. just the plated through holes. What? If you've got holes in your panel which you typically might have to Lin holes or other holes that are unplanted, Well, they do these at the final step, otherwise they would have gone through the electrolysis bath and they we've got plated. So here we go.

We're punching out all of our non plated holes and that in the case of my microcurrent here that's for all my switches and you'll notice that to save time. Once again they've stacked multiple our panels together up to well. whatever your drill and your drill bits are capable of the the bigger the stacks then the more you're going to wear out your drill bits, etc. They'd be a like a high-speed tungsten carbide drill that bits on them but they go through drill bits.

This is why you'll actually pay more for the more holes you get and you might have encountered this on a prototype service. They might say our maximum of 300 holes or a thousand holes or something like that over that. hey you need a you know a better quote and though factory not only the time to drill these things because as you saw it's not particularly quick but also because the drill bits are very expensive and they break them in you know, with monotonous regularity or they just you know these wear out. they have to change them all the time.

So really it you know it's an expensive and slow process so you'll pay per hole and you might have heard the change in the noise there. Well it's changed to now a routing bit and now it's doing the routes in there which I've specified in my on the mechanical layer of my PCB a typical route in bit size two point four millimeters. so my micro count board is actually a good example here cuz you can see the V score in the V grooving on there combined with the route in the path like that. So I've got nice clean edges on the side.

That's the advantage of routing is that it provides really nice clean sharp edges whereas V scoring when you snap those things off, you're going to get a rough as guts edge with fiberglass hanging out, etc. So but I didn't want any to use any what's called mouse bites and I've done videos on this on how to penalize this. one of my more popular videos I'll link in it down below. So there's various techniques for holding a piece to be inside a panel.

So I've decided to mix V groove and rout in here and what it's doing here now is actually routing out the final panel which I specified. so there is like that wasted space all around the outside. They do that for right handling and alignment purposes. They've got alignment holes in as we saw before, they have to stack the multiple panels and they need something.

the holes which aren't in your panel they will add that so they you will specify a particular panel size and that's what's being routed out here. but they need additional material handling material on the outside of that. So if they had a de predefined panel size you couldn't make your panel that big. They'd go warm.

you probably could, but it would be a special case where they go. all we have to add these are manual tooling holes and stuff like that. And there's actually one process which we didn't see in this video because this board and process in particular did not have it. And that's the gold plating on the pads which are often either specify especially if you're doing our BGA's and high density stuff like that.

you really want really controlled flat surface pads and Goldie's excellent for that or you might have gold fingers or you know something like that on a card edge and they actually you might think that they do a up another plating process for that electroplating process. but it uses what's called an electrolysis ie. it doesn't use an electrolysis process hence the name electroless and it's gold over nickel. So the nickel are played at first and then they'll put the gold over the top and he's a Euro.

Circuits are video that explains that. so full credit to them and of course our gold is expensive. It adds up and so you wouldn't coat your entire board like that. So you'll do the solder mask out process first and then you'll plate the gold just on the pads because otherwise it cost a lot.

Gold's not cheap. The copper component pads and holes have been left clear of solder mask. Now we apply a soldier able surface finish to protect the copper until the components are soldered onto the board. On this line, we chemically deposit first nickel onto the copper and then a thin coating of gold over the nickel.

This is a chemical process needing no electrical connections. The line is fully automated, moving the panels through a series of tanks which clean and sense the copper surface and then deposit about five microns of nickel and a tenth of a micron of gold. So I Hope you enjoy that and thank you very much to Richer Brady for shooting our this video as my microcurrent panel went through their old factory. They do have a much newer one with Nuit technology now, so head on over to our PCB Zone dotnet to check them out.

They're manufactured in New Zealand Hi to all my New Zealand viewers! And if you're wondering how a multi-layer PCB has made one with our four six eight up to like 20 layers or whatever, it's basically the same as manufacturing a double sided PCB except they call these a prepreg and they're much much thinner and then they manufacture them as double sided PCBs Like this, but they leave off the solder mask and everything else and then they just sandwich them and glue them together as multiple layers. so two four six eight. so they just manufacture them separately and then stack them up and then they do the final whilst solder mask and that silkscreen on the outside, but it's basically the same way, just lots and lots of more steps. So I hope you liked that video and appreciate what goes into that super ridiculously low cost double sided PCB that you're getting from what our these are modern prototype PCB Manufacturers very basically bugger all cost.

It almost cost more to post them these days and it cost to make it. There is a lot of steps and it doesn't get any easier than that. all those different processes, they still have to go through that. but of course the prototype assembly are places have optimized their processes for you know, getting the best throughput and margin on multiple designs and nuts stuff like that.

But anyway, I hope you found that video interesting. If you did, please give it a big thumbs up and comments and all that sort of jazz down below. Catch you next time hi Previously I've done a video on design for manufacturing your circuit board ie. how to mount it in a panel such as this for production and I'll link that in down below.

it's been incredibly popular one so this is a kind of a follow up to that in how to add some automated test functionality to your particular panel to help in testing your final product. This is something that I worked on a few years back and you'll see that on the edge of the product here, which is actually hidden normally hidden to the user by way of you know, a mounting rail.