Hi Welcome to the Eev blog an Electronics Engineering Video blog of interest to anyone involved in electronics design. I'm your host Dave Jones Hi Now I Know a lot of you out there like designing your own products and that's fantastic. Now let's say you've come up with this great new design. Okay, you've got this oneoff you've built.

It works great. You've debugged it Fantastic. And you want to make 50 of them. 100 500 a th000 think big 10,000 100,000 What do you do? How do you take your project from a oneoff through to volume production? Well, I'm glad you asked.

What I'm going to do today is take you step by step through the processes both thought and design processes you need to do to take a one-off project through to volume manufacturer. Let's go. What I'm going to concentrate on today is just the board level stuff. Okay, so I'm not going to get into to housings and you know, designing the overall look and feel of the product that requires a whole separate blog.

So this will just be the board level. how you can design and manufacture a high volume. PCB Now let's start by taking a look at something like this. Okay, it's a through hole board, traditional through hole.

Okay. green solder mask. You know, pretty basic traditional board. Now is this suitable for high volume manufacturer? Well, yeah, you can get it done, but it's not going to be very cost effective and for high volume manufacturer, that's what it all comes down to.

manufacturing, cost, and complexity. Now, if you've got a through hole board like this, it's just not going to cut it these days. Okay, too expensive to manufacture. Sure you can.

Labor's still a bit cheap in China but trust me, it's not going to be as cheap as surface mount. So the first thing you want to look at is converting your through hoold design like this into something more like this. Which mostly in almost the goal is to go entirely surface mount because as you'll see, that'll save you the most amount of cost, it'll reduce your assembly time and everything will be sweet. So look at converting every component in your design into, uh, surface mount.

Now I Know this can be almost a total redesign and that's why I've mentioned this before in the blog during your entire design process. even if you're doing a one-off prototype. if you think there's even a remote possibility of making this into a volume product in the future, you need to put a lot of thought into what components you choose for your board. But trust me, even if you do have to re totally redesign your entire board from through, hold through the surface mount, or just change half the components on there to lower the cost.

Whatever. as you'll see, it'll be worth it. So go to the extra effort up front. If you're going to make more than say 50 boards or something, it's worth putting the effort in to redesign it properly.

Now the difference between Through hole and surface mount is pretty obvious. Here's some video of a Um A through hole assembly line and as you can see the workers sit there. they manually install the components and well, that takes time, effort, and labor and you want to avoid that if at all possible. Whereas here is a modern pick and place machine, placing your component from reels and tubes of components onto the board automatically and this can churn out boards much much quicker with less effort.

You set it up once and you push the button and it's all automatic and your boards magically spit out the other end. That's the ultimate goal for high volume manufacturer as little labor as possible. One of the first things you do is go through every component in your bill of materials in your design and you look at it. is that component uh, easily manufacturable by the supplier.

I'm going to choose to assemble my board cuz not all assembly houses are the same. They have different requirements, they have different pick and place machines with different capabilities, and not all of them can do what you want. So basically you want to stick if you can stick to uh, large, common components cuz that means every assembler out there will be able to do it. and uh, do it cheaply.

Now that might mean okay. Oh, 402 size resistors and capacitors for example. There are some assembly houses out there that don't have the new machines that can handle components that's small. So think about 0603 instead of 042.

think about quad flat pack uh packages instead of BGA or something like that. BGA is going to be a little bit more touchy, harder to inspect, yields not going to be as high more critical pad Dimensions all that sort of stuff. So stick with the common package which is I say 0603 and up. 0402 is okay.

Um, you know, stick with .5 mm pin pitch or larger on your Um S so type packages and your quad flat packs and stuff like that and you'll be fine with high volume manufacture. You're going to have to spend a bit more money on components than you anticipate. If you're making say 100 boards, Well, you can't just go to Digi Key and buy 100 resistors loose on the tape like that. The the uh assemblers are going to hate you for it.

Trust me because they may not say so. Okay, but they're going to charge you more because then they have to manually put these onto what's called reels. Okay, this is what you need to buy for all of your components. Uh, all of your SMD components.

Now reels come in different types. This one might have 5,000 resistors, but they're very cheap so this reel might only cost you 5 or 10 bucks or something like that. You can get little mini reels like that or they come in huge reels like this. Okay, or uh, when you're talking about Ic's you might.

They might come in tubes like this and these automatically slip into the pick and place machine and the chips shoot out like that. Okay, you don't just want to buy them loose in your little digp packet like that that. Otherwise, if you do that, they'll have to hand sold of them. The efficiency is going to drop.

They're going to charge you more. They're going to take longer to assemble them. It's hopeless. So you want all your components? Um, now.

chips need to be in either tubes or they need to be uh on. You can get chips on reels as well or they need to be in what's called trays. Now here's a photo of the trays. Trays generally aren't as good cuz a lot of uh machines can't support trays so they'll want everything on reels or tubes.

So just be careful there. Let's do a search on Digi key for a part to see if we can get it in uh, reel, or partial reel or something like that. See what our options are? Now let's take take an example of the ZX ct19 and let's still search for that and as you can see, three options here are popped up. We want the So 23 version which is here okay but look it's got three line.

It's got three different rows there. It's got three options for the same part. Check out the quantity over here. 114,000 Parts they've got in stock, so that's fantastic.

Okay, but as you can see, they're all the same. uh, quantity? um available. So that tells you it's exactly the same part. Exactly the same stock, but three different procurement options.

Now the SEC the second row here. as you can see just here it says it's available in Cut tape. Now that's the version you will typically get. Um, it says minimum quantity over here of one.

Okay, now that's the one you typically get when you buy prototypes. Okay, you only want five parts for a prototype. so you buy five. They cost you a do and N sets each.

You know and you pay five bucks. and and that's it. Okay, nice and cheap for Prii, but we want. Let's say we want to manufacture a 100 boards.

Okay, you wouldn't buy, you wouldn't buy that cut tape. Uh, version. You wouldn't buy that part number because it comes on the cut tape. It doesn't come with a reel and it doesn't come with the leader tape attach which the manufacturer your assembly house needs to put that into the pick and place machine so that's pretty use usess to your manufacturer.

Now if you look at the top row up here as you can see minimum quantity of 3,000 so that's obviously it that says tape and reel. Okay, so that is one reel of Parts but you've got to buy five 3,000 of them minimum to get that one reel and they're 43 cents each. Let's go look at that, uh, price? sorry, 40 cents each at 3,000 but that's $1,209 So you'd have to spend $ 1,2 $29 there just to get your 100 parts needed for your 100 boards so that the assembler can assemble them. Now that's just crazy.

Okay, so what you want is this third option down here. Now this isn't available for all parts. So really, this is, uh, you have to choose your parts that go into your design carefully if they have these options. If you're only going to make a hundred of them, or or even you know, 500 and you want them on a reel, they offer what's called a digial option.

Now that is the same as the cut tape. As you can see, you can only buy you can buy just one of them, but they will actually charge you a fee and they'll put it on a reel for you with the leader tape. Exactly what the manufacturer needs. but you can order any quantity you want.

So let's go in there and calculate that price. And let's say we only wanted to build our 100 boards. So we go down here. we type in 100 and we go calculate and instead of paying the over $1,000 we had before, our total extended price is $84 Uh, plus, um, plus here it says a $7 reeling F fee will apply to each real ordered, but that's cheaper.

Okay, you're still only paying less than $100 for your 100 Parts as opposed to over $1,000 for the 3,000 minimum. So uh, just be careful when you're designing your uh product. Make sure these not only are the parts in stock, but they're available in suitable uh quantities either reels or tubes or or um, partial trays or something like that for your particular design. It's very important so you can spend a lot of time just mucking around on Digi key finding or Mouser or it's the same on Mouser and Element 14 and the others.

they all have the same service. Um, you can spend ages just doing this to optimize. Uh, the manufacturing for your little board. For your 100 or 500 boards, it's crazy.

So yes, if you're going to make 100 boards, you might have to buy 500 Ic's You might have to buy 5,000 resistors something like that. That is the price you pay uh for going to high volume manufacturer. essentially. So if you want to get 100 boards made up front, then you need to do the costing based on your entire reels of components.

just assuming you're only going to make 100. if you're going to make another th000 down the track Great. You'll have most of the reels components on the re left over, but you have to, uh, amortise that cost in to your 100 boards. Now the other important thing to remember is that uh, the pick and place machines can only support a certain number of these at any one time.

so a machine might only be able to support 20 reels or 30 reels. That means you can only have uh, 20 or 30 different components on your board. If you have to do more than that, then they need a second machine either in line with it and the board goes through the first machine on a conveyor through to the second machine. Not many houses will have that setup, the smaller houses won't have that, so they'll have to put your board through a second time, reset up the machine.

So if you're manufacturing 100 or 1,000 boards, they put it all through once and when they're finished, they rip off all the reels, they change them over. They have to put your boards all the way through again and that cost you money. Try and avoid that. So go through your design component by component and see if you can consolidate the number of components.

Do you really need a 15K pull-up resistor? If you've got a 10K resistor somewhere else on your board, use a 10K for the pull-up Consolidate those values If you need a 20K resistor on the board, it might be better to put two 10K resistors in series in your circuit because you're already using that component 20 times Elsewhere on the board. So just look at consolidating your components. It's very important. Also, think about pads sizes.

There's no point designing a fantastic board. if you find that your manufacturer and their process cannot successfully load your component on the board. they short together because the the solder maskers to um, you haven't got sufficient solder mask between the pins of an IC for example, and they put too much paste on it, shorts out or a resistor tombstones because you don't have thermal reliefs on one pad. I.E You've got one pad connected this pad over here of your resistor connected to a big Solid Ground plane which sucks all the heat away and the other one just going off to a 5 track.

then well, that resistor can Tombstone Look at things like that, Sometimes manufacturers will have their own preferred pad Styles but usually um, if you say stick to the manufacturer's recommended footprint or you use the IPC standard Footprints uh, you'll generally do okay. but uh, you also have to think about the size of the p pads. so um, uh. the IPC footprints for example come in three sizes nominal, least, and most uh so they'll put an N, L or an M on the end of the footprint name in your library.

and what that means is the just the amount of um P The pad size uh, L is the least amount of pad size so the smallest. So if You' got a very high density board with all the components stuffed together then uh, you want to use the least size pad the the small P you can get but then you might find oh then you can't uh, probe them or you can't so to rework them by hand if you have to or something like that. So you've got to think about those sort of things. Normally you'd stick to the nominal size footprint, but if you want something, the flying test probes to come down which is another aspect of your design.

you got to think about testing, testing and programming. Your board can be a big thing. Now if you've got a microcontroller on there for example and you've got to program it well, how do you do that? Okay, it was fine in your design. You might have used a socket for a dip chip but if You' got surface mount now well you can program uh, the chip before you put it on there before you give it to the manufacturer, but that's hard and difficult.

It's much better to actually, um, solder your microcontroller for example onto the board and then provide an in circuit programming header so you've got to make sure that is design into the board. You've got to make sure it's accessible where you can program it. and if you design a little bed of nails which comes down, here's a photo of a typical bed of nails for a board, then you bring It down, and you want to be able to get those Pogo pins onto those test pads or onto that in circuit programming uh, header. So you got to think about that sort of stuff when you're designing the board up front.

and we haven't even gotten to panelization in the high volume manufacturer yet. One of the most useful things you can do when you're designing a high volume product is to to get a spreadsheet of all the components, your entire bill of materials into a spreadsheet. Put them in the uh, the descriptions, the footprints, the quantities, and the manufacturer's part number, and then the supplier part number. and usually an alternate supplier part number.

So you might put in the digi key part number, the Mousa, the element 14, uh, part number or something like that as your supplier and then you'll have it might have another column. Uh, based on, um, how many comp components are on a reel. For example, there's 5,000 per reel. So if you go to the effort and and cost as well, you put the item cost.

you can total them all up. see what it's going to cost you to manufacture 100 boards, even though you've got to buy 5,000 resistors in all these reels. So a spreadsheet is Handy Putting the effort in upfront pays dividends in the long run. trust me.

Okay, so you've done all the hard work you've got your board. You've gone through all The processes I just mentioned and it's all ready to go. Well, no, sorry, it's not. If you just try and get one individual board like this or aund or a thousand of these manufactured just on its own like that, it's not very economical.

Why? The reason it's not economical to get just one board like this uh manufactured individually is because well, it goes through the machine, the pick and place just does that one board and it spits it out and there's all sorts of handling issues with the board as well as it goes through the machine and stuff like that. So what you want to do is what's called panelize it and that's take your one design and step and repeat it onto a PCB panel such as this. Now there are certain uh panel sizes which will go into, but basically you just want to step and repeat it like that. So in this case, we've got 12 boards on the one panel.

So they set up the machine, the board goes in and Bingo! They can assemble 12 boards at once. Well, components have to be Place one by one, but it just means it's much more efficient. You can just churn multiple boards through the process much quicker and that adds up to real savings in high volume manufacturer. Now there's a conflicting requirement with panels.

because your Barebo PCB manufacturer they will have standard panel sizes now. It's very tempting to fit as many of your designs as you can onto that maximum size panel that they do. but you have to be cautious doing that because you have to ask. can my PCB assembler actually physically handle a board that big? Their machine.

Their particular machines they use might have a limit on the maximum size of the board and it might be a lot smaller than the maximum panel size the PCB manufacturer can supply. Now a typical bare board PCB panel might be 18 in x 24 in or 450x 600 mm. Now a lot of assemblers might not be able to handle that size board now. I Generally stick with like an A4 size uh panel because I I I Find You know pretty much everyone can handle an A4 size but ask your manufacturer what they can uh handle because you don't want to get your boards manufactured and then find oops, it's 10 mm too big for the machine.

Uh, you're screwed. You got to go to a more expensive manufacturer. Watch out for it. Let's take a look at a typical panel.

I've got one here now. Uh, there's many different ways to do a panel which we'll go into, but a panel will have these basic requirements. It will have what's called a tooling strip top and bottom. This is this bit down here.

Now What that does is allows the uh pick and place machine to actually grab hold of it. Can either sit in rails like this and it can go physically be uh, automatically moved through the machine like that. Now what? The tooling strip must have? Um, it. By the way, it should be about 10 10 mm wide top and bottom like that.

If it's any smaller than that, then the machine may not be able to automatically handle the board. The other thing you will have in these tooling strips are the tooling holes. Now you typically have four of them like this, a minimum of four and they're typically a 4 mm diameter hole. and they're used.

um to get, uh, little um, there's little uh, sprigs cogs in there that physically move the board along the panel so it should have tooling holes. The size isn't that critical. Um, but 4 mm is a bit of an industry standard tooling hole and it must have fiducials as well fiducials marks as well. Uh, which we'll go into in more detail later.

and a panel must also have a way to break the boards out. so it must either have uh rou in which is like this one with breakout tabs or Vroo and we'll go into those. but they're the basic requirements of a panel. Now even if you've got a huge design like this one, this one's almost A4 uh size.

And really, as you can see, only one of them fits on a panel. Now we can manufacture this as just an individual board or what's called a loose uh board or a fully routed board without any tooling strips. but uh, then um you. There's limits to how close your com components can come to the edge of the board because it needs to physically hold it.

So even with a board like this that's large, you would still put tooling strips top and bottom and a way to break the board out. And here's an example of a more advanced panel that has uh, three extra features which I'll show you. uh, one of them is a bad board marker. Now if you take a look here as you can see, it's um, it.

it's just on the it's in the part of the Dead uh part of the panel. but it's a marker that uh, the assembler can actually Mark that indicat in when they do an automated test that this particular board is bad out of. you know, if you got 20 boards on there, that can be really important so you know, don't bother using that board. it's failed.

Now another uh item it's it's got is what's called an impedance test strip because this is a controlled impedance PCB So um in the tooling strip Here we've added uh, an impedance test coupon it's called and what that does is just allows you. When the be boards manufactured, it allows you to um, test that the controlled impedance is exactly what you want it to be. The third item this board has is what's called a test stack. Now what this does is it brings the internal copper layers cuz this is an eight layer board I Think it is.

It brings the copper to the edge. Now this could be tricky to try and get on camera here, but as you can see, the copper is right on the edge Now you would probably need a microscope to look at that. But what just allows you to inspect the Uh individual layers on that board after it's been manufactured? So that and and there different lengths. There's many different ways to do this, but that's just an example of how you can inspect the board um, after it's manufactured.

Now a lot of Um companies when they be board manufacturers. When they assemble your panel, they will provide you with a uh, what's called a core sample and they will actually cut off a part of one of your boards and they'll give it to you. Um, so you can actually inspect that under a microscope yourself. but this just allows you to do that just in case they don't provide you with that core sample.

There's another important thing I Forgot to mention not only for the individual bear board, but um, it relies it It uh has the same thing on panels as well. Now when you um when you lay out your board, you should add what's called pullback to The Copper Now as you, can see, the copper doesn't go all the way to the edge and that includes those internal layers as well. If you've got an eight layer board, don't bring your copper all the way to the edge because it can short out and cause all sorts of problems. So have have say 1 mm pullback or something like that.

At least allow something so the copper doesn't go right to the edge. There's one other thing you can do with panels as well. If you've got a lot of boards like this, it's a fairly unique requirement. Uh, everyone won't need it, but I'll just mention it.

It allows you to actually see these little breakouts in the corner here. Okay, you can actually route out out. Um, you can actually route out, uh, tracks out of there and bring the tracks out of each panel. So you might want to bring out, uh, test tracks out of each panel like this.

and you might have a test connector on one side of your board or some interface for some sort of test jig. and you might want to test all of your boards in situ in the one panel. Um, it's it. it.

It's not a common requirement, but you can actually do that. Now, let's get into how you break the boards out. How do you get them out of the panel after they're assembled? This has got four individual boards in it. Okay, quite complex.

how do you break it out? Now there's two different Uh methods to do it. One is called V grooving which I'll show you up close and the other is called uh routing and uh breakouts with tab breakouts. Now this is an example of a V Groved board. As you can see, it's got these score marks or what's called a V Gr I'll show them up close later but along like this and both vertical and horizontal.

Now here's another Uh board which is another example of VG Groving as well. Okay, now this works really well on completely Square boards. If your board is completely square and you don't have any components overhanging the end, which can often be a problem. Uh, because when you get this board, um, after it's assembled, they have to break these out.

Now normally what they do is they run along with a little wheel along there which actually top and bottom which then does a nice clean cut on it. Um, but if you've got components overhanging the edge for example, like like like you have a connector or something like that overhang in the board. Well, you can't actually get in there to break it off so you might have to break it off by hand. But what a VG Grove allows is it allows you to easily just snap the board off and I'll show you here it is Bo See, but what you get? Okay once you do that is you.

you I probably can't show that on camera, but you get a pretty rough, pretty rough. Edge it gets hairs. it get gets uh little little fiberglass hairs on it and it's It's just not a very clean way to actually uh, do a board but you can just snap them off even if they got component overhangs. you can sort of Wiggle them a bit and they'll come apart really easily.

That's VG Groving. Now it's pretty hard to get in there and actually show you what a VG Grove looks like. But what it basically involves is if your board is like this: the drill actually drills down into your board like that that's the top of the board and this is the bottom of the board and it goes like that. they drill it top and bottom okay and it leaves just a little bit of uh, fiberglass actually connecting in the middle like that and that allows you to just snap the boards off really easily and that's VG Groving.

Now you can actually specify the angle of the actual Groove in there like that if you want to get fancy and all you know, if you're someone like Apple and you're really designing, you know, a million or a billion of these things, then all that sort of stuff might actually matter. But um, generally you just say I want VG grooving please and they'll just do VG grooving now I Mentioned uh, copper pullback before now because a VG Grove actually has a distance between it which can be a bit, uh, variable. Then you have to be very careful to actually pull back your copper so that it's not exposed when they do the Vgr. So if you have continuous, uh, copper going across like this and you take it right to the edge of your board, then well, you're just going to get exposed.

uh, copper when they go in and they drill it for the VG Grove Just be careful of that. Now the other type of panelization is what's called rou. In with these tab, that's a tab breakout. Okay, now you just specify the routing path around your board.

This is really good for odd shaped boards which I'll show you in a minute. But um, basically there's St industry standard tooling sizes for these routes. Now 2.4 mm is a standard routing tool. WID So you just specify that as an outline and they will do it.

You can't actually tell them to do it, but it's better to specify it yourself so you know exactly what you're going to get. But these tab breakouts, these can be a bit tricky. These can be an art in itself. Now this is this board is hard to actually push out by hand.

Um, sometimes you can break the board and especially when it's loaded with components, You don't want to do that. so you might get in there with a pair of Uh side Cutters for example, side Cutters Like that and actually cut the board out. Now you have to um design these Tad cutouts in such a way that it allows the board to be held in there fairly firmly. Okay, cuz um, you can't.

If you've got a very large board like this which I'll go into, you can't just have one on the corner over here one on here because the damn thing will warp so you have to have. You might have to have multiple Um tab multiple breakout tabs along the edge of your board depending on how big it is and you have to make them so that they when you cut them out. they don't have any burs as well. Here's an example of of a very wide Uh breakout Tad that supports a very large board such as this.

and it has multiple holes spread in an arc like that, which allows you to actually break it out. so you put these unplated uh holes around there in an arc and it breaks out and it leaves just like a little indent um in your board when you break it out. Here's a good example of a panel with an odd shaped board. As you can see, we've got the tooling holes the fiducials over here, but it's got, um, it's routed out.

Okay, it's routed out around here now and all the way around like that. Now this is a good example because it has a combination of VG groving and routing. So if you've gotten um, you can see that the board has a weird shape on the on the bottom here and the top, so you route out the weird shaped ones. but it's straight on the edges.

so you do VG grooving on the edges like that. so that allows you to snap easily, snap out that board while giving you, um, the uh, giving you the advantages of the odd shaped board with the routing and there. This is just a fairly simple example. Actually, there's much more, uh, convoluted ways you can actually do this and it's almost an art actually.

uh, figuring out how to snap a board out of a panel? What combination of VG groving? you use? What combination of routing as well? One very important thing to remember is how stiff is the board cuz often it will only be supported along the Uh along the top and bottom edge here by the machine and the pick and place machine comes in and it places the component down and you don't want this to happen? Look at this board. Okay, and granted, this is a 0.8 mm board. It's half the size of a standard 1.6 mm board, but look at how much that board warps. Okay, Fantastic.

That's normal Fr4 I Kid, you not? Okay, but that's 0.4 mm. that can make you seasick. Almost Really okay. So you've got to take that.

Uh, you've got to take the rigidity of your board into account when you're actually designing a panel. And here's an example of a panel that just has a V groving along the top and bottom Edge and vertical routing like that. Once again, you could have done that as a VG Grove but in this case, we wanted to get a really nice Edge cuz this is what. V This is what routing gives you.

Routing gives you a beautifully clean and smooth edge on your board with no burs whatsoever, whereas a VG groved Edge will be. um, it'll be uh, sharp, it'll be. It won't be completely flat. and it it's just.

you know it's not a clean Edge at all. Um, you may even have to file it down afterwards. So uh, from that point of view, routing is preferred. But here's an example of a board that because there's no Central support in here.

okay, it's routed all the way from top to bottom like that. Okay, this can actually this can, uh, warp. As you can see when you place the components in the middle, that board can actually warp like that. So cuz there's no rigid support in the middle to actually cross brace it.

So this board doesn't have components in the middle so you didn't have to worry about it. They're only on the top and bottom, but if you start putting it in the middle, it. can Flex a lot and that can be a problem. And here's yet another board where it's fully routed around and it's got tab brakes like that.

but in this case, it's got the tab brake in the in the middle as well, so that helps form a rigid structure for the board. so it's not going to, uh, warp nearly as much as that other board that didn't have any Central support in it. Here's an example of a panel that has many different designs in it, and generally this is okay for prototyping, but for production, uh, it's generally frowned on. You don't want to have to load, uh, multiple individual designs onto the one panel.

It just confuses things. You can exceed the number of reels you've got and stuff like that. So really, you want to stick to one design per panel. Now that little thing there on the panel is what's called a fiducial mark.

Now, these are very important to not only put on your panel, but on your actual board as well. Now, as you can see, this board will actually have um, actually, four fiducials on the panel itself. Now, typically you only need two, you put them in opposite corners of the panel. Now, the reason these are important is because when the board's manufactured, it's dimensional tolerance.

I.E From a reference point over here to over here, maybe slightly out. Now that's not a problem when they assemble a board. Uh, they take a reference point, which will be this fiducial mark down here. What it does is a camera comes over and it looks at it, looks at that fiducial.

Mark Now, a fiducial mark is typically 1 mm in diameter or a couple of millim in diameter. It's copper with the Um solder mask pulled back. Now, it's very important to have the solder mask pulled back, so there's a lot of contrast between the Um copper color on there and the surrounding solder mask. But the reason you have two is they they align it down here like this at this point and then the camera goes over there and gets the other fiducial and it knows from the files you've given it how far that Dimension and that Dimension is and it actually can, uh, rescale the board to um, uh, take into account any minor dire directional tolerances on the bear board manufacturer.

If you've got fine pitch components like this. BGA For example, as you can see, what you do is, you put what's called a local fiducial into here. So you see there's a little fiducial there, and there's a little fiducial at opposite corners of this High pin count device. So if you look at, if you look at that device, there's the little tiny.

there's the little fiducial there. There it is and on the opposite side. so you want to put those on very high density devices like BGA Typically for So packages and everything else, you just don't bother. you just rely on the two fiducials on the panel.

But local fiducials can be important to get extra dimension in tolerance in that particular area of the board. And one very important thing not to forget: if you're loading components on the top and the bottom of the board, make sure you add the fiducial marks on the bottom as well, otherwise they won't be able to Su They may not be able to successfully load that side of the board. so make sure you do fiducials on both now. I Know what you're thinking: Why is this board gold? Why is everything goldplated, all the pads and everything thing? Well, not only does it look funky, you know, nice gold highlights around the edge, but uh, gold can be made extremely extremely flat surface.

So when you got a high pin count BGA device like this, um, it's It's very important. In fact, it's vital to use gold because if you use uh, um, solder or uh, tin coated board, sure they can air level them. um which is what's called hot air leveling on uh on a copper on a tinned finish, it's going to be nowhere near as flat as this. so it's very important for solder mask layering and for Um for the tolerances when the balls go on there and it and the uh solder reflows.

so I'd recommend even for simple boards, gold plate doesn't cost that much extra. I'd recommend you get gold plate I use them on all my personal boards as well. Cost a few cents extra. Now there are going to be times when well, you just can't uh, panelize your board.

One example of this is my microw watch uh board which because it it sits on your wrist and the board's exposed, you can actually see it I I Wanted really nice, cleanly routed edges I didn't want to have to vgr it and then file them off to get a nice Edge that sucks. So I got them individually routed. so this is what's called supplied loose or individually routed from the PCB supplier and that's great if you want beautifully uh, milled and machined edges and that's okay. If you have to just do an individual board like this, it's it's fine they can.

What the uh PB assemblers can do they'll charge you for it though is they'll make up a custom little carrier module that's uh, you know, routed to the shape of your board and they will actually Mount them in that there'll be an extra tooling cost, but it might be worth it if you want a beautifully routed board now I'm sure everyone recognizes this. it's the Arduino Now did the Arduino guys actually, um, get these assembled as individual boards? Or did they actually panelize it and snap it out later? Well, there's a couple of telltale signs. All you got to do is run your finger along there and you can tell it's as rough as guts. That means it's been VG groved and snapped out on all four sides.

And if you actually get in there and take a look at it, it might be hard to see it, but it's actually a V. It's It's actually a V shaped Edge on it. you can see where it's been VG groved and snapped out. But this bit over here has been routed.

Check it out. That's smooth as a baby's butt in there. but it's rough up here. so they routed out that little bit Vgr everywhere else there you go.

Okay, now let's actually take a look at a board. now. assume this is your design. Okay, and you've got it finished and you're proud of it.

And it's lovely and looks looks great in 3D mode. Check it out. There we go. It does everything you want now.

Uh, what you have to look for is that A We talked about this before you've pulled back the uh the Copper from the edges of the board. Okay, very important. Uh for when you do VG Groving cuz we're going to VG Grove this design because it's a nice uh Square uh board. So and we don't need uh, fully routed, nice clean edges, we're to just Vgr it.

Okay, so what we do is we flip it over to our panel And we do a separate. This will usually be a separate uh PCB and you've duplicated this board multiple times now. This is Alim designer. It'll automatically uh, do this for you.

You can actually Place multiple designs but as you can see, we've created a panel size here. We've created uh tooling strips top and uh bottom and we have actually uh, put in the tooling holes. There it is. It's a 3.2 mm hole.

As you can see, we've created the fiducial here like this which is basically just a pad um with a uh, this one has fiducials top and bottom but it's a pad um that just has the solder mask expanded on it. So if you go into 3D mode here, let's check it out. It all looks really groovy and you can see that the uh copper had doesn't touch between boards like that. So there's enough room to actually do the uh, the VG groving in there.

and you can actually see that the fiducial looks like a real fairium fiducial. It's got the gold um plated pad in there with the solder mask expansion so that will provide nice high contrast. There's the uh tool in holes up there and it all looks very good and penalized. Now if we go back to 2D mode, what you do is you actually create Um, you actually create a separate uh well I I call it Fab noes but you can call it anything you like a separate layer that just has uh, the particular tooling information you want.

In this case, you just put a line in there that shows I want VG grooving all the way down there and I want VG grooving across the middle like that and it's easy and the manufacturer will just interpret that. it's not actually um, part of your board layer, but it'll appear on the Gerber files and that gives them the information they need to manufacture this panel with VG Groving now of an overlooked Uh aspect of board design. It's not just Uh panel based, but for any board, but particularly when you're going to manufacture is you want good solder mask expansion around your pads. Now this is a standard uh, quad flat pack 44 pin micro controller um with a reasonable pin pitch.

But let's go to 3D View here and what you want, There's the Chip And You want the solder mask expansion between these pads you want? You don't want this solder mask in here. This little Slither of solder mask to be so thin that it actually disappears when they go to manufacture it. there's a minimum width it needs to be and that's probably about four or five Uh th before it starts becoming unusable and it breaks. If you don't have solder masks between your pins, you end up.

You can get shorts easily on your pins so you want a reasonable distance. A solder mask. It's very important to check this before you send your boards out to be manufactured and then loaded. Now, as you can see here, we've actually got an expansion of 1.5 thou on or 1.5 mil as it's called 1.5 th on the solder mask.

uh, expansion and that's what we get here. Now we can actually go in there and actually, uh, measure that distance between the uh, measure that solder mask width in there. and as you can see, it's 5.5 mil. So this one is more than adequate to be manufactured.

That will be no problems at all. We get good, um, solder mask between our individual pins and we shouldn't get shorts. Um, there's a very low likelihood of getting shorts on those pins. That's what you want.

So now you finished your panel design. It's all fantastic. You got your tooling strips, your duals, and la la you got it all. What do you do? Well, you got to supply the correct file to not only the Bebo manufacturer, but to the PCB assembler as well.

Let's take a quick look at that. Okay, so we've created our PCB panel. Now let's generate the Gerbers Now as you can see, I'm going to generate this is only a two layer board so I've got the top overlay, I've got the top paste uh mask which will go to the assembler. Won't you don't have to send that to the PCB manufacturer? They don't care about the paste uh you got the top solder mask, top layer, bottom layer, bottom solder mask, bottom paste, bottom overl lay If you've got an overlay on the bottom of your board, I uh actually create a separate uh mechanical layer for the PCB boundary.

that's just the outline, the outer outline of the board, and I've got the Fab notes. As I said before, now, the Fab notes can include all sorts of stuff about the detailer board like it's 1.6 mm fr4 and you want gold plate and yada, yada, yada and tented vas and all that sort of stuff. but this uh Fab notes only just has the VG Grove information cuz I'll supplyer Tech file with all that other information separately. so we'll just generate some Gerbers there and bingo, it's done.

Here it is and there is. There's our Gerber information so it's got. these are all supplied as separate layers. So here we go.

It's generated all of the layers. This shows them all overlaid, but as you can see, it will do it separately. There's that separate Vroo thing I showed you before. Here's the origin marker down the bottom.

that's the reference origin and these are the different layers. There's my board outline, there's my uh PCB um, that's the top sorry, the bottom solder mask, and and that's the paste file. but that goes to the assembler and there's the uh overlay and there's the top solder mask and the bottom layer and so forth. So as you can see, it just generates um a information for the panel so that the manufacturer knows what to do.

They know you want VG groving all through that board and it's the same thing if you do routing. Now there's one other thing that you have to supply to the PCB manufacturer. We've done the Gerber files, but you need to supply the NC drill files. Now let's just generate those and bingo they're done and there they are.

There's all our different holes used in our design as you can see, some of them are actually uh, slot there but um, others are these are supposed to be square? they it doesn't render properly but um that generates a a industry standard NC drill file which goes along with yogas and that Um provides all the information the manufacturer needs in terms of Uh drill sizes, how many drills, and Where to drill them. And of course there's one vital thing which the assembly house is going to need and that is the Uh pick and Place files to know exactly where to put what component. So we can generate uh, pick and place files here. Let's do it as a text file and here's the pick and place file which is generated.

This is a text one, it can be a CSV or other formats as well. Manufacturers will can pretty much accept anything you give them. Here's the Uh Designator down in this column down here and then we've got the footprint. and then we've got uh, the actual location of the component relative to a particular reference point which is usually the bottom left hand corner, but it doesn't always have to be.

And this is the file that the manufacturer needs to feed into their pick and place machine to assemble your board. And of course you would also give the Uh assembler the overlay diagram as well, showing where all the parts go with the Uh reference designators. And also an important thing to also give them is uh, a physical sample of the board exactly how you want it built cuz they aren't mine readers. usually they do a pretty darn good job.

They do know what they're doing, but um, nothing beats them actually having a real physical sample in their hands that they can actually uh, compare the board when it comes off the machine, or when they're loading and setting up their machine. and after having gone through all that information, you can just say well, I don't want to do that. Just give your board and the just the Gerbers for the individual board, bill of materials, everything else to the assembly house and some assembly houses will'll do all that panelization and everything else of the fiducials, the tooling and the Uh pick and place and all that for you. it's called a turnkey uh solution.

They will take just your individual board and you don't even have to send them the components. You don't have to worry about the reels and all that sort of stuff getting them in tubes, trays, and quantities. You just say I want a th000 of these? please? And they'll go. Yes sir, no problem.

but they'll charge you a lot more money for it and you also don't keep individual control. like when you do your own panel and you do everything yourself, you supply the parts. They might get the parts from the gray Market who knows. So just something to watch out for.

You can get the assembly houses to do the whole shebang, but whether or not you want to I don't know, it's up to you. So there you go. That's a pretty much a quick overview of how to design your product for high volume manufacturer and there's more that goes into it as well. There's more smaller little uh things which are applicable to Niche designs and stuff like that.

but the golden rule is talk to your PCB assembler first before you go and design your panel and everything else because you might put all the money buying your components, designing your board and then find oh, might find it hard to get an assembler or the assembler you like to do your board so just be careful and uh, you will probably have to do a Second Spin as well or a third spin of the board It's not uncommon whatsoever, so just budget that in you're not always going to get it. Even the professionals don't always get it right the first time. Catch you next time.