- Hey everybody. Thanks for tuning into Altium Academy. I'm Zach Peterson. I'm a technical consultant with Altium, and today we're gonna be
talking about something that I think new designers
might struggle with, which is how to compare
manufacturing services for your circuit board. So what should you be looking for when you start talking to a manufacturer? And should you just focus on fabrication or just on assembly? Should you try and assemble it yourself? Let's get into it and talk
about some of the stuff you should think about
before you start working with a manufacturer. (upbeat music) If you're like me and you design PCBs and you make that known publicly, sometimes what you will start getting is a lot of spam from manufacturers. So here's some of the
stuff that I tend to get. Someone offering to sell me a
bunch of capacitors, I guess. But here's kind of the
thing I'm talking about, where it's, like, hard to really
tell all these folks apart. You know, they all do HDI via-in-pad, multilayer PCB up to 30 layers. Again, that's a bit high. Here you can see, okay, you know, they're listing their lead times
for different layer counts. Again, the stuff that they can produce. And so just, you know,
looking at all of these, and by the way, you
can see the dates here. It's, like, the 26th, the 27th, here's another one, the
very next day, 28th, again, 24 layer, FR-4, aluminum, you know, all the really common stuff
that you would expect to see any PCB manufacturer tell you in an email. So, I mean, how do you pick between all these different things? I don't know why these guys
feel the need to spam me, but I swear I get, like, 10 emails a day on all my different email addresses trying to get me to go
with some manufacturer that I've never heard of. And I get it. You know, they got to find
customers and make an income, so I'm not knocking 'em too hard, but I will say this, when you start to get 10
different emails a day asking you to fabricate
your 48 layer board with some random overseas
manufacturer, you start to wonder, how do you actually
compare all of these guys? Who should you select to
manufacture your next PCB? It's kind of a golden question, and there's a lot of different
things to think about when you're selecting a PCB manufacturer. I think what a lot of hobbyists do is they just focus on price. And if you're just building
something that's really simple, you're gonna assemble it yourself, you're maybe not so
worried about lead time, you don't have to worry about any specific industry standards, maybe you're not designing to class two or class three under IPC, then you can usually go overseas, find somebody who's gonna
fabricate your board for, like, you know, five or 10 bucks a board, and they'll ship 'em back to you. You can assemble it yourself and everything's gonna be all good. Is that gonna be right for every project? Probably not. There are some projects that
need really fine capabilities. We've talked about this in terms of HDI and just in terms of
trace impedance generally, so some manufacturers
need very tight clearances and very fine capabilities
in order to be able to fabricate that stuff. Some manufacturers, they might
need to fabricate something with a really high layer count. Maybe you need controlled impedance, so you need a specific stackup. These are all different
things to think about. One of the places where I like
to start really is lead time. So this is one of the things
that is more important for me and the stuff that I work on because generally the clients I work with have very important deadlines
that they might need to meet. So I don't want to go overseas and have them take four
weeks to fabricate the board, and then another two weeks to do assembly. We might need something
that is fabbed in a week, assembled the next week,
delivered overnight, and we're under three weeks
for the entire project. Sometimes that happens. So lead time is usually
for me the biggest driver of who I'm gonna select. Some companies will have
different lead times for different projects. Some companies are a lot better at actually standardizing
their quoting process, and you can actually go online and you'll be able to get
prices for different lead times in order to figure out which is gonna be the best option for you. Now, sometimes the lead time
also varies with capability, and sometimes for different
capabilities that are needed, you actually need to get a custom quote, and it may not just be
a standard lead time. You know, it may be, like,
a five day or an eight day or even a 14 day fab time,
followed by, you know, a one week or two week assembly time. So lead time can be very important if you do this professionally. Maybe you work for, like, a manufacturer and they have to outsource something to an external fab house. Lead time is always important. So in general, if your
lead time goes down, meaning you want the board faster, what's gonna happen to cost? Well, cost is gonna go up, and sometimes it can go way up. So the difference between,
like, an eight day and a five day lead time
is not gonna be so big as the difference between, like, a five day and a two day lead time. So why is that? The reason is that there's
actually a lot of NRE or nonrecurring engineering costs that go in to the front
end of your project in order to set your board up so that it can be
fabricated in their process. So one of the things that they have to do is they have to make stencils. They have to do some
programming on their equipment. So these are the two big ones, is they have to do some of this, and then sometimes they
have to order materials and they just pass all this stuff onto you as the customer, okay? So there's some NRE costs involved. That takes a little bit of time. When you go to shorter
lead time, cost goes up because they gotta do
all this stuff faster. They're gonna push off other projects or they're gonna have to have people working overtime to do this, so that's where the costs come in. Lead time is the biggest thing for me. It might not be the biggest thing for you. After lead time, people
generally start looking at something like capabilities. So clearances are a big one. So, stuff like trace
to trace, trace to pad, pad to pad, and so on and so forth, so just on down the line. There are all sorts of
different clearances. So most fabricators should
be able to reliably handle something in the neighborhood
of, like, you know, three to maybe six mil capability limits on a lot of different stuff. There's also, so this
was under clearances, but there's also something like what's the minimum trace width that they can fabricate reliably? So if you have a board and you've proposed a layer stack that requires
three mil trace widths, you're not gonna be able to take that to every single fabricator. You may have to go to a
very specialized fabricator that can do less than
five mil trace widths. Most fabricators can handle down to five mil really reliably, so if you go down to
five mil as your limit, you're gonna be safe most of the time. But again, this stuff like
clearances, trace width, that's gonna be stuff
that a good fabricator will put on their website, so make sure to check their
website for their capabilities. And a lot of places, again,
if they're really good, they want your business,
they're gonna have a link right at the top of the
homepage that says capabilities. Click on that, go read through it. So as far as costs involved with this, some manufacturers will
have multiple processes, and what I mean by that is
that they will charge you or quote you at different rates depending on the size of trace or the clearances that you need, okay? So in general, as you
get these values smaller, what happens to your cost? Cost is gonna go up. So don't be surprised
when you send in a board that has very small trace widths, and you don't actually
tell them on a quote form what the trace widths are, and you get an idea of cost in your head, and then they email you back and they say, oh, it's actually this
cost, which is much higher, and it's because you
might not have accounted for stuff like trace widths. Now, in terms of clearances, sometimes if you violate these clearances, your board will actually receive what's called no bid status, so meaning they don't want to bid on it because they know that
whatever you've given them will not make it through their process. Now, if they are actually
a good manufacturer and they want your business, what they'll do is they will call out, hey, specifically these
particular issues in your board are what are causing us to
give you a no bid status, and they'll tell you, you know, hey, increase your pad to pad
distance by a certain level, or a really common one
that I've even, you know, mistaken before or that a client has essentially asked me to
violate before is via to via. So what I mean by this is not necessarily the pad to pad per via. It's actually the drill hole to drill hole in copper pour. So drill the drill distance is important because drill has some wander, and they want to make
sure that if you say, hey, I need these two vias spaced by, you know, five mils, let's say, that they can actually
fabricate that reliably. Five mils is really small for via to via, so just keep that in mind
because you're most likely not gonna be able to do that
with mechanical drilling. Okay, so next is quantity, and in general, it's the quantity that you
need at the desired lead time. Not all manufacturers can crank out 10 million boards in a week. They would have to stagger that because there's finite production
capacity in any factory. If you need, like, a short run, maybe it's just one panel of 10 boards, and they're gonna do it
at a certain lead time, they're gonna quote you one cost, obviously as your quantity goes up, the cost will go up, as well. If you double quantity, so
let's say I go to, you know, 2X quantity, I actually
don't get 2X the cost. So this does not necessarily happen, and that's because of those NRE charges. So the NRE charges go into
all the tooling that's needed to be able to fabricate the board, and then the same thing
kind of goes with assembly. So there's these upfront costs. However, that's just the cost to produce a single panel worth of boards. So if I double the number
of panels that I want, essentially the only
added cost is machine time and then the additional laminate materials and any other chemicals involved that are used to produce the board. So those NRE costs get amortized across all of the panels
that you want to produce. So just because you double the quantity doesn't necessarily mean
that you double the cost. So if you have a big budget and you want to get a few extra boards and you're already producing
at a reasonable volume, you can always order an extra
panel and get it assembled, and then you've got some extra boards just in case if you need 'em. Same thing here with
quantity at lead time. If I then decrease the lead time, as well as increase the quantity, you could actually get to a situation where you double the cost
or more than double the cost if you want to get
really short lead times. So again, these are all
important aspects to think about when you are going out and
getting quotes for your project. So I always say this to newer designers because I want to tell
them, don't be surprised when you start seeing how
some of these numbers change. You might wonder, hey, I can
produce, you know, five boards for the same cost as I can
produce 15 bare boards. Well, the reason is
that you didn't actually double the quantity. When you're on a quote form,
you're talking about the number of bare boards you want
fabricated and assembled. However, fabricators produce panels. They don't produce individual boards. If they want to produce one board that's maybe a three by three inch board, or they want to produce eight of those that are three by three inch boards, what they're gonna do is
they're gonna line those up in a panel and they're gonna
produce the entire panel. So the panel is what determines the cost and not necessarily the
individual number of boards. And even then, doubling
the quantity of panels does not just automatically double the total cost of the project. So, so far I've been talking
about bare board fabrication, but the same kind of ideas
go into assembly costs. So if we're talking about assembly, we also have to deal with
quantity at lead time, and again, don't be surprised if you have to decrease
your lead time a little bit. You do see a slight increase in cost. However, just like with
fabrication, if I go from, let's say, a five day lead
time on bare board fabrication to a 48 hour lead time, I'm
gonna see a bigger increase than if I go from, you
know, 10 day to five days. Assembly also comes
with its own NRE costs. So assemblers will be programming
some automated machines. They're gonna program
their pick and place, they're gonna program their SMT line. They're probably also going to program any automated inspection
equipment that they use, so they're gonna have some
upfront costs that they incur and they pass those onto
you as part of your project. So just like with bare board fabrication, those NRE costs get amortized over the entire quantity of
boards that you want to produce. Same thing goes with assembly. So if you're just gonna
assemble, you know, five boards, if I multiply my number of
boards I want to assemble by 10, it's not necessarily the
case that my assembly cost is gonna multiply by 10. Maybe it multiplies by three or four, but it's not necessarily
gonna multiply by 10. Just keep that in mind,
because as you scale, you start to take advantage of
some of those cost reductions as you get to higher and higher tiers. Okay, so the next thing
that I want to bring up that goes into your manufacturing costs and also your lead time and everything are some of the little
extras that are needed when you're looking through
manufacturing services. So what do I mean by little extras? Well, generally you can add on services like electrical testing. So you can get continuity
testing added onto your board at a, usually a pretty small fee. At the most basic level, this is gonna check for opens and shorts where they expect to
find opens and shorts. So what they'll do is
they'll look at your netlist. They'll be able to see, hey,
I need to have continuity between these two nodes in the netlist, and then they can actually see, oh yes, with the electrical
test, we have continuity, meaning a short, and
then they can also see where they don't have shorts or where they have open circuits, just like you would expect
from looking at the netlist. Another important test that's
done is controlled impedance. So if you are producing a
board that has a high frequency or high speed signaling on it and you aren't sure of the impedance, or if the impedance that
you've designed is correct, they can actually do a test, a controlled impedance test
on the stackup and make sure that what you've designed
will actually hit their spec. Now, ideally you should contact them early and get the stackup that they are going to build your board on so that way you will have
much greater assurance that the board that you
design with their stackup and with their required trace width and materials and dielectric
constant and everything is gonna hit the impedance
target that you need. Now, this is just an additional test. If you have controlled
impedance lines on your board, you don't have to do a
controlled impedance test. This is more for your assurance. This is so you can sleep at night. Some other important points,
IPC inspection level. So IPC classes have their
specific inspection levels that go into them, and if
you go to IPC class three, you will pay quite a
bit more for inspection. However, this is required for very high reliability products like you will find in the
defense and aerospace industry, so this is another little add-on. And there are other
add-ons that you can get. You can get UL markings, so you can have UL testing added on. The big one, if you're
ever gonna go to market at high volume with a new
product, is Underwriters Labs, so the UL testing is very important. Now, these are the four big ones that you need to think about
if you're gonna go to market or if you're working in
a specialized industry that has high reliability requirements. UL also carries some
requirements on power products, so if you're going to market
with any kind of power products that has any sort of safety issues that might be associated with it, good to get UL certification
if it's required. Some other points to look out for if you happen to need them
from your manufacturer, castellated edges. Castellated modules, what are those? So if you've ever bought one of those little ESP I
think 8266 is the number, those little ESP modules,
they come with an array of, like, half cut holes along
the edge of the board. There are a number of other modules that come packaged like that, too. That's what they're talking about, is if your board needs to
have castellated edges. Some companies can do that for you. They may do it at a nominal fee that you have to add on to your fab order. Plated edges, meaning the
entire side of the board is plated up with copper, and then that is overlayed or plated with an additional plating material, ENIG, ENEPIG, immersion
silver, one of these. The plating material as
well influences the cost. So this is another important one because most boards that
are just basic boards will go with tin lead,
SNPB, so tin lead plating. But if you're doing
anything like class two or if you need to go to, like, RF and you need to work at
very high frequencies, you may need an alternative plating. So we talked a little bit about this when we looked at what happens
with controlled impedance microstrips near ground poor. We actually saw that
the plating influences the losses in those channels when you're at very high frequency. So alternative platings, I'll
just write a couple of 'em. ENIG, immersion silver,
sometimes written ImAG, but immersion silver. And your manufacturer will have a list of the different platings that you might need for your board. We actually have a blog article that's linked in the description
that describes and compares the different platings
that are used in PCBs. If you're not familiar with
all the plating options, go check that out. Okay, the last one I'm gonna go over is via fill or sometimes called via plug. It basically means the same thing. So do you need to have
all your vias filled in with either conductive
or non-conductive epoxy? So these are more for
specialty applications. In terms of via fill
for, like, a dense board, what you might actually
have is via in pad, and in that case, you do
want to fill up those vias so that we have a nice flat surface where assembly can then reliably solder your components onto those pads. So via fill/via plug needed
in high density stuff. Some specialized applications
might need it, too, so if you need that, just make sure your manufacturer can do it. All right, everybody, so
this is a list of stuff that you should think about
when you're going to compare and choose a PCB manufacturing service. Obviously look on the quote form, look at their capabilities. Just make sure that they can
do the minimum that you need, and if they can go above
and provide some extras, definitely worth considering. Go ahead and hit that like button, hit that subscribe button. If you have questions, leave
'em in the comments section 'cause we love to get your questions. This is definitely one of those times where you can't forget
to call your fabricator. (dramatic music)
