PCB prototype vs small production run

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i got a quote for 1 pcb prototype for $657 (1day), $525 (3day) $289 (1
week), a run of 25 (the amount I need) for $416 (1 week), tempting to
skip the prototype eh?


Re: PCB prototype vs small production run


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i got a quote for 1 pcb prototype for $657 (1day), $525 (3day) $289 (1
week), a run of 25 (the amount I need) for $416 (1 week), tempting to
skip the prototype eh?
<<
You'd better read the fine print. There's often a tooling NRE charge
tacked on to the production run.


Bob


Re: PCB prototype vs small production run


it includes the NRE for production ($99)


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Yep - interesting economics.  What are your board specs, and what PCB house?

Richard

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What is the size/spec of the board?. For this sort of money, you should be
able to get something about half the size of a PC motherboard, in four
layer from one of the PC pooling companies. For a board this
large/complex, going without the prototype is not a practical option.

Best Wishes



Re: PCB prototype vs small production run


you missed the point, if I have an error it simply means I will reorder
the production boards and toss the bad ones at a extra cost of $416
(total $832), there is a "prototype", in this case it also happens to
be the first production run (because of the low cost)

Even with a double production order it is still less then my normal 3
day proto + 1 week production $525 + $416 = $941

In the first case (without prototype) if no errors , then my total cost
is only $416. I also get the final boards earlier (1 week vs 10 days),
if there are errors then the final boards arrive a few days later  as
compared to the proto + production order(2 weeks vs 10 days).

just thought for small production runs, the option to eliminate the
prototype makes some sense, of course there are many variables,  if you
routinely need 10 prototypes to get the thing working then the 3 day
(or 1 day) prototype makes more sense to get a reasonable delivery
time.


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(snip)

I think *you* may have missed Roger's point.  At the prices you indicate, it's
presumably a fairly complex board.  The chances of it coming in OK first time
are arguably not enormously high as a result of that (assumed) complexity.  What
you are proposing is trading off that extra error-finding cycle for the possible
$$ saving.  I guess you have the best picture of how complex the board and how
likely it is that the first run will be problem-free.

I did this once on a small mixed thru-hole/SMD job with about 50 components.
There was a lot of extra time spent checking before signing off.  It did have
ONE error that slipped through, but fortunately that only required a hand reflow
of solder across two adjacent through-hole pins.  You may be that fortunate.  Of
course you may not.

Re: PCB prototype vs small production run


"I guess you have the best picture of how complex the board and how
likely it is that the first run will be problem-free. "

Again, my main point was that two production runs were the same price
(or lower in my example) as one prototype plus production...


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Skipping the prototype ? This means you're
going to repair the 25 for each error that
slipped your attention.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

Re: PCB prototype vs small production run


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no, it means if there is an error I simply will reorder the boards and
toss the bad ones at a cost of $416 (total $832)

Even with this double order it is still less then my normal 3 day proto
+ 1 week production $525 + $416 = $941

In the first case (without prototype) if no errors , then my total cost
is only $416. I also get the final boards earlier (1 week vs 10 days),
if there are errors then the final boards arrive a few days later  as
compared to the proto + production order(2 weeks vs 10 days).

My point was the small production runs are just slightly more then a
single prototype, (for whatever reasons I don't understand, I assume
its due to the labor overhead), and its tempting just to skip the
"offical prototype" ...


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Mainly beacause the supplier has to use a whole sheet of PCB material to
make one/two units and then has to pay for disposal of the rest OR he makes
the prototypes up "by hand".

PS: I have used http://www.pcbpool.com/ with luck before for that kind of
thing.



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www.sparkfun.com offer a service at $5/square inch for
double-sided, plated-thru, solder mask and nomenclature
screen on both sides. They electronically combine your
Gerber files with others' (and their own) to make up full
panels. No minimum, but it happens on their schedule, so
no guarantee of delivery date, etc. But $5/in is pretty good
for that quality.

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Re: PCB prototype vs small production run


Sparkfun is great for small 1x2 inch boards, its less then anyone I've
seen. but my board is 12x12 inces so at $5/square inch that $720, that
is by far the highest price yet, especially with no delivery dates.


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Yeah, they specialize in tiny stuff.


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but aren't even large blank 2 layer pcb sheets dirt cheap (<$5)?


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Or, if you're going to populate the board and test in under a week,
and think you can get it right first go, save $100-$200, and get 24 PCBs
free.

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Entirely typical in fact, going back to my experience in the 1970's
sending out taped mylar.

Sometimes you can save a few bucks on the prototype by not having
legends and solder masks.  Of course then you'll discover when you buy
the production lot that the legends are on the wrong sides and the
solder mask is upside down!

Tim.


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yep, I can see that happening, I always spec my prototype identical to
my production specs... unless its an early experimental
no-way-its-going-to- production board, then I will let up on the
soldermask,silk, gold fingers, cutouts etc requirements


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What board house gave you that quote?

Try these two companies below for dirt cheap prices.
I've only done 2-layer pcbs with them and do a nice work.

http://www.custompcb.com/index.html

https://www.barebonespcb.com /!BB1.asp




Re: PCB prototype vs small production run


the board is fairly big >100 square inches

so

http://www.custompcb.com/index.html

can't handle anything greater then 8x11, so thats out

https://www.barebonespcb.com /!BB1.asp

can easily handle the size, but no soldermask, no silk, no cutouts, no
thanks. but their regular service handles all these, lets see  $393
proto (1 unit) not too bad, but production is $1802/25 units, thats 4
times my quote, you can have them.


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