Philip Poling wrote:

> Greetings TechNetters,
>
> I'm trying to justify changing some of our circuit assemblies from THT to SMT.
> They go into a 40 Ton vehicle, so saving weight or space isn't enough
> justification.  I need to be able to show that, at least in some cases, you can
> reduce the cost of a circuit assembly by converting it to SMT.  For my
> justification, I need to find some examples of how other companies have actually
> reduced the cost of a circuit assembly by converting it to SMT.
>
> Have any of you gone through this process and actually reduced the cost of a
> circuit assembly?  Was the savings significant?  Have any of you written any
> articles or reports that you could share?  Or, has anyone read any articles or
> books on the subject?
>
> I'd appreciate receiving any information and examples you have.  Exact figures
> are not required, just ballpark estimates of cost savings would be very helpful.
>
> Thanks,
>
> Phil Poling
> United Defense
> 4800 East River Road
> Fridley, MN 55421-1498
> 612-572-6533
> [log in to unmask]

Hi Phillip,
                I can't give you actual figures, becuase I'm not the one who usually
has to worry about the costiong. However, There are several areas of imediate cost
reduction in converting to SMT. First reduction of board size, Obviously regardless of
wether or not space is a requirement the board will be physically smaller assuming
similar component count. With good board design, you will find less holes (both through
hole and Vias) reducing the amount of drilling. I'm assuming you will be automating the
placement, which will lead to another reduction in costs due to increased speed of
manufacture. Several of the boards that where redesigned for SMA, though the same size
due to having too fit into subracks are now assembled in less than half the time. Also
becuase of the automation there is a marked increase in placement acuracy, leading to
less error and of course less rework. If your putting Surface mount assemblies into
vehicles however, be careful to do your vibration research. There is no reason if SMAs
are designed for this enviroment that you will have problems, but beware that they
really don't like high G bumps. From my experiance, watch for PWB rigidity, and solder
quantity. These seem in my experiance to cause the most problems and faults for SMAs in
high vibration areas.

                P. Tremewen

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