Steve,
If you're looking for some bare-bones paste measurement, check out
this system at Start International. I have used it previously and it really
works.
http://www.startinternational.com/pdf_files/microscopes_specialty.pdf
Mike McMonagle
PCA Process Engineering Supervisor
K*Tec Electronics
1111 Gillingham Lane
Sugar Land, TX 77478
(281) 243-5639 Phone
(281) 243-5539 Fax
[log in to unmask]
> -----Original Message-----
> From: Stephen R. Gregory [SMTP:[log in to unmask]]
> Sent: Monday, October 25, 1999 3:55 PM
> To: [log in to unmask]
> Subject: [TN] SPC programs, how make the best use of the efforts..
>
> Hi All,
>
> I'd like to ask any input or opinions on how to implement a SPC program
> that
> will really be meaningful. I don't want to waste time and effort on
> something
> if all it's going to produce is "window dressing"...
>
> Our business is very high-mix/low volume stuff. From boards that are very
> straight forward, standard 50-mil pitch stuff, to those that have every
> part
> on the board (SOIC's, CQFP's) cut and formed, pre-tinned, and then placed
> and
> reflowed. A big run for us is 100-boards, most of the time it's 50 and
> under.
> I guess what I'm saying is that there are TONS of variables with a lot of
> the
> products we build here.
>
> We do a lot of hi-rel stuff here, very custom, almost hand built boards.
> We
> also hand place a lot of components here...for example the resistors on a
> lot
> of the boards come to us in little 2" X 2" matrix trays that can't be
> machine
> placed. Any design problems that cause defects on the boards most of the
> time
> won't be corrected because the document trail that has be completed is so
> daunting that our customers tell us to not ask for changes because it
> won't
> happen, and our time is best spent figuring out a way how to deal with it.
>
> So what I'm wondering in a situation like this, what good is SPC going to
> do?
> I think the time spent trying to correctly identify all the variables and
> gather meaningful data would be better spent in training and working with
> our
> operators to learn all the little nuances with the product we build so we
> can
> deal with them. What was proposed to me for example in screen printing,
> was
> to create a simple attribute chart for example;
>
> 1. Is the paste coverage complete? Yes/No
> 2. Is it registered on the pads? Yes/No
> 3. Is the paste smeared? Yes/No
>
> or such simple attributes such as that, and then plot them on a chart. To
> me
> it'll be a waste of time. We don't have anything to quantify any
> measurements...no paste height measuring equipment, or X/Y measuring
> equipment, everything will be done by the ol' Mark-I / MOD-I eyeball with
> all
> it's subjectivity...but I am still being asked
> to establish an SPC program in SMT.
>
> Am I fighting this too much? Or is there some means that will be
> worthwhile
> to make this happen? Oh yeah, it's gotta be cheap (next to nothing) too...
>
> Thanks in advance!
>
> -Steve Gregory-
>
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