Dan Maloney
It also helps to remember that not everything gets soldered.
The gold protects the vias from oxidation.
Any tips for that "low-oxygen low-humidity environment"? How about a ziplock bag and a tiny desiccant pack? Are the better (but affordable in volume) methods to keep a PCB as usable as possible for 4 year shelf life?
I forgot the unused pads.. I usually tent vias to put silkscreen over it
@Paul Stoffregen Really, I'd recommend moving to "just-in-time" ordering if possible. A PCB that sits around for four years is going to absorb all sorts of environmental contaminants that are going to make soldering difficult.
@guido.giunchi That's good practice -- but not 100% successful. Moisture and whatnot can still creap through.
@Paul Stoffregen if you have any type of vacuum sealer, thats your best bet. This is how we keep our stock boards (with a desiccant also placed inside
@Mark J Hughes @Elijah which finish is most commonly used on the boards you build? Do most of the boards come out of your shop with ENIG finish?
In our fab, we have a rule that a PCB may only be left for one year in our stores. After that, it gets thrown out. People who are responsible for buying PCBs acknowledge this and plan ordering according to statistical plans.
has some info on via filling at the 1398s mark.
https://www.youtube.com/watch?v=efi9IzFJ4W4&t=1398s
@Evan Juras i would say HASL finish due to the fact that we specialize in quick turn-proto type orders. Most quick-turn / prototype orders are focused on saving as much money as possible
@MS-BOSS correct, we use the same practice. 1 year storage, then we toss the boards.
@Evan Juras But it's not that much more expensive to upgrade. And it can save a bunch of hassle at Assembly.
I'm surprised to hear you say HASL. I would have thought that was too rough for most SMT.
@Audi McAvoy The SMT issue comes down largely to stencil gasketing.
If you have a solder-paste printer, it doesn't matter what the coplanarity of your pads is.
@Audi McAvoy I would say the margin is much higher. If i were to take a walk through the shop right now, I would have to keep a close count.
Guess who's got two thumbs and a solder-paste printer?
@Mark J Hughes Ah, I have to keep remembering that not everyone is using stencils.
@Audi McAvoy You can't use stencils in a quick-turn shop.
Sadly, solder printer is too slow. Since we are making hundreds of boards daily in our own assembly line, using a printer instead of stencil is a no-go. So, for large production, you are left with stencils.
We routinely assembly boards in 6-8 hours for many of our high-tier clients.
That's from when we get the design files to when we push them out the door in our shipping department. And that includes ordering & receiving parts!
If you need to make a stencil adjustment -- a little more paste here, a little less here, you just can't do it.
Versus throwing the board in a solder-paste printer and hitting the "enter" key and letting the machine vision do the rest.
Nice.
I mean, there's a little more to it than that, but not much.
I do recall someone mentioning time factor. Each shop will be different, but it comes down to what processes the shop has in-house vs what they will have to have done at another shop. Anything we cant do in our own shop is a quick drive away.
Yeah -- we have our own teams assigned at the major distributors. They pull parts just for us.
@MS-BOSS -- yeah -- we specialize in prototype / MOQ 1 orders. You sound like you do large-volume. There stencils still are king.
Does finish get applied to the inside of plated vias? If so, how? How do you get the finish in those tiny holes? :)
Since ENIG and HASL are our main choices... we have them both in house and ready to go! I know that Silver is one of our outsourced finishes, but we can have it sent out and returned in just a few hours.
@Mark J Hughes Yes, we do large volumes, but only for our internal needs. We have two or three SMT assembly lines and one solder wave machine for THTs. Not sure if we do have selective solder wave tough.
@MS-BOSS -- where are you located? The States? Somewhere else?
@Evan Juras Yes, the finish is also applied inside of all plated holes that are exposed (non-tented with soldermask). We are able to plate most hole sizes in our standard tanks... but for those smaller holes (or holes above 10/1 aspect ratio) we have custom pulse plating tanks.
@Mark J Hughes Czech Republic, but our company has development centers and production fabs ins everal other places on the globe, too.
@MS-BOSS Very cool. Well we are very happy to have a friend across the globe :)
http://listen.shoutcast.com/zeelradio.m3u
Are there any other questions we've missed due to scrolling?
I'd also like to again plug our 100% FREE webcourse that starts at the end of the month. 50 lucky participants will get their designs fabbed / assembled / shipped for free!
For your basic maker in his basement using a stencil. the best finish would be ENIG?
Yes -- Enig
I don't have a basement - still ENIG?
Oh -- and KeySight is giving away oscilloscopes in the course!
As price is probably more of concern for a hobby maker than perfection, maybe OSP could be OK, however not every fab lists this finish as their standard ability...
@Christoph -- you really should get a basement. Or perhaps a root-cellar for ENIG.
Awesome - more chances NOT to win - grumble...
@MS-BOSS makes a good point -- but OSP is pretty fragile -- you can damage it if you don't handle the board carefully -- also very short service life.
Is there anything in particular we should look for when inspecting finish on newly ordered PCBs?
Apologies to all, I didn't want to shame you because i have a basement.
@Dan Maloney Why can't you win?
'cause other people want to sign up?
Does good use of flux overcome the OSP issues in re-work sort of way?
When making PCBs in our makerspace which is located in basement of college dormitories in the "real hobby style", we usually make them using the photoprocess, then coat them in immersion silver to make them solderable for longer periods of time (it stays OK for months). Vias are then made after cleaning the boards using rivets. But that is really just for "hobby" things.
@Andy Geppert it might. And for a maker-style project, it might not matter. But the idea is to keep the oxides from forming in the first place. Damaged OSP allows oxygen in. Flux might fix that, and it might not. I'd lean towards not. But it might not matter.
@Mark J Hughes - Luck o' the Irish, I suppose - been entering Keysight's Wave contests for three years and still nothing. It's almost like the statistics are against me or something ;-)
@MS-BOSS -- oh look at MS-BOSS with his fancy basement ;)
maybe off topic - but how can a hobbyist get on an 8- or even 10-layer panel?
$
that's cheating
same as everyone else :)
@Christoph Not at home, unless you are a fanatic.
@Dan Maloney I've entered those too! Well you can enter my contest -- I'm in charge of the giveaway. Odds should be better than 1 in 100.
OK, official time is up. Mark and Elijah probably both have to get back to work, so let's just say thanks for the chat. I'll post a transcript soon.
Excellent chat. Super thank you!
@Christoph You want the whole panel?
@Evan Juras yes, @Christoph posted a great example of a very rough finish at the beginning of our chat. The finish looked like it had very deep grooves.... this is cause for poor solderability. Discolored spotting in the finish can also be a sign of a bad plating tank, but this should be caught by the QC department and never shipped out.You just want it to look flat, smooth and shaped well (meaning a square should be a square/ a circle should be a circle)
Thanks Mark and Elijah!
Awesome, thank you Mark and Elijah! Very informative chat.
no not a whole panel just a few 10 cm²
Just order a panel through us. Unless you need it crazy fast, the costs are pretty reasonable.
+1 : Thanks Mark and Elijah!
Royal lists custom Solder mask colors in their capabilities... How custom are they and can I say "mix X for me". I'm guessing the chemistry is more complicated but what can you do?
Thank you @Elijah and @Mark J Hughes for your time and information.
If anyone who is interested in microwave-grade PCBs wants to know more about why nickel is not your goodfriend and why that makes ENIG and ENEPIG not that good as you might think, look here at one of my logs:
https://hackaday.io/project/169808-microwave-stuff-what-to-do-and-what-to-avoid/log/173571-so-you-were-told-to-use-gold-finish-on-your-microwave-projects
Next week we switch gears and talk about amateur radio homebrewing:
@Christoph just reach out -- maybe we can pair it with another customers panel.
https://hackaday.io/event/169987-amateur-radio-homebrewing-hack-chat
Thanks everyone, it's been fun!
@Mark J Hughes that would be awesome!
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