[time-nuts] Parts Selection

[Bob Camp]

Hi

I don't see a way to reasonably ship a solder mask with each board. I agree
it would be neat, but it would cost ...

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Bob Bownes
Sent: Friday, March 25, 2011 1:25 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Parts Selection

Here are my answers:

Done it before? - yes.

Done it in the basement / last 2 years? - Yes. In last 24 hours actually.

Set up to do it in the basement? - Yes. Can do by hand, hot air rework
tools, or reflow oven.

Would I buy one? - done that before. Likely would again. (counts as a yes).

Would actually do it in a reasonable amount of time? - Yes, other
projects pending of course.

And a +1 on the solder paste mask. 7-15x microscope makes it easy.

Bob



On Fri, Mar 25, 2011 at 1:19 PM, David C. Partridge
<david.partridge at perdrix.co.uk> wrote:
> Well, if you ship a paste mask with the PCB I've no problem at all, but
that's not likely to happen, so it's down to hand work.  I've done that
before now and while it's not the easiest job, it's quite doable with a
microscope or the eyes of an eagle.
>
> Dave
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Bob Camp
> Sent: 25 March 2011 17:08
> To: 'Discussion of precise time and frequency measurement'
> Subject: [time-nuts] Parts Selection
>
> Hi
>
>
>
> Just a show of hands sort of thing. It comes up each time we talk about
projects and never really gets answered. Rather than trying to work it out
as a part of a project, let's see if it can be addressed by it's self.
>
>
>
> How many people are willing to solder up a project with multiple 0.5mm
spacing >=144 pin package IC's on it? There's a typical package drawing at
the end of:
>
>
>
> http://www.national.com/ds/DP/DP83816EX.pdf
>
>
>
> I'm sure it's a "what's in it for me?" sort of question. Let's assume it's
just neat piece of bench gear rather than a home grown cesium standard for
$100.
>
>
>
> I don't think this part really matters, but it might to some people. Say
each chip is well below $100, but above $20 each. There might be only one
part like this on some projects, but for the sake of this poll, let's say
there are two or three of them. Net is roughly 250 to 500 pins like this to
solder, on some number of packages. It's part of a project that will cost
you $250 to $500.
>
>
>
> I'm not talking about opinions on weather it can or can't be done. It
certainly can be done and is done every day. What I'm asking is - would you
buy a bag with the parts all in it? If you do are you going to put it
together in a reasonable amount of time?  Reasonable time might mean
different things to different people. For the sake of completeness, yes you
also need to get it working after you assemble it.
>
>
>
> Next layer (you knew there had to be more) - have you done it before
(anywhere)? / done it in the last 2 years (at home)? / are you set up to do
it today (at home)?
>
>
>
> I'm not trying to get into "how would you do it / what would you need /
could you farm it out". Those are also neat questions, but not part of this.
>
>
>
>
> I'll start off the voting (and yes the answers are out of order):
>
>
>
> Done it in the before - yes.
>
>
>
> Done it in the basement / last 2 years - no.
>
>
>
> Set up to do it in the basement - yes, but not set up well.
>
>
>
> Would I buy one - done that before. Likely would again. (counts as a yes).
>
>
>
> Would actually do it in a reasonable amount of time - unlikely.  (That
counts as a no).
>
>
>
> Any more votes?
>
>
>
>
>
> Bob
>
>
>
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>

_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.