[sdiy] Board manufacturing questions

[Tom Bugs]

Hi Aaron

Well, I've liked PCBCart - they're actually not *too* bad prices for 
proto-typing -- sometimes it may be worth getting, say, 10 units of a 
protoboard - slightly wasteful if something drastic is wrong, but then 
better value if you've got everything correct.

Answers to your particular points:

i) 0.063" is absolutely standard & recommended. I use the thickest 
0.126" for front-panels, but normal boards are fine with the regular 
setting.

ii) Well, I use RoHS Lead Free - I was using the lead-free hot-air 
choice, but recently had some very strange behaviour where some boards 
would solder really badly (maybe 5% of boards) - even with mailing to 
PCBCart we didn't discover what the issue here was. Since then I've gone 
with the gold-plated option (next down from lead-free-leveling) - may be 
a bit more expensive, but has been working very nicely.

iii) 2oz may be better (I've heard people recommend this) - 1oz works 
ok, but if you need to desolder things you run the risk of lifting 
pads/traces off the PCB.

iv) I've pretty much kept the standard settings for those items -- it is 
important, though, to check using:
-- DesignRuleCheck (DRC, bottom left corner) - set your preferences and 
check for errors - VERY useful tool
-- and you can run ULP (top middle) called StatisticsBRD which seems 
useful (I haven't used it much, but it does look useful)

One further thing to note -- one quite good aspect of PCBCart is that 
you can easily re-order at a later stage (if you don't need to change 
anything) and at that stage you can change settings like finishing type 
/ solder-mask colour / copper weight --- so perhaps begin with a really 
plain green, 1oz, etc board and then when it comes time to re-order 
(well, if you're looking to do that) you can upgrade to better settings 
without incuring the initial setup costs. (basically, I think the 
initial setup costs increase if you choose settings like thicker boards etc)

Hope that is some help.
Good luck!
Tom / BugBrand

Aaron Lanterman wrote:
> Howdy y'all,
>
> So, I've got board layouts ready to go for the timbre circuit, the 
> LPG, the envelop generator, and the balanced modulator of the Music 
> Easel. (I've got four other boards almost ready to go, but I figured I 
> should actually order and build and test some before working more on 
> the layouts.) I've actually had these done last January, and am just 
> now getting around to seriously look into getting them fabbed.
>
> I like the idea of trying PCBCART since they take Eagle files 
> straight-up, without having to export Gerber files (and worry about if 
> I'm doing the export right, including all the files, etc.)
>
> PCBCART kind of sucks for prototyping because if the "one-time tooling 
> fee," but after that it looks pretty cheap (in case I happen to luck 
> out and say a board actually works...)
>
> Some questions:
>
> 1) The web interface defaults to a 0.063 thick board. Should I go 
> thicker/thinner? What's cheapest?
>
> 2) The web interface defaults to "hot air solder leveling," but 
> there's other more exotic versions available. Any compelling reason to 
> go with a different technique?
>
> 3) It asks about copper weight, and defaults to "1 oz" but 2, 3, and 4 
> oz are available. Thoughts?
>
> 4) It asks for minimum tracing/spacing, minimum annular ring, smallest 
> holes, and number of holes. How do I ask Eagle to tell me what these 
> are for my different layouts? (I know I can set a design rule check to 
> check if a minimum of something is exceeded, but it may be that I 
> naturally didn't go anywhere that minimum and hence there's no reason 
> to pay for a more detailed process.)
>
> #4 is my main concern.
>
> - Aaron
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