In message  <14405333201304@toastmaster.com> lilel@toastmaster.com writes:
> One of you's guys wrote:
> >If you're designing with PICS,  your board has to cost less than a
> >meal at McDonald's
>
[snips]
>
> One of the arguments against surface mount goes like this:  Surface
> mount layouts require at least a double sided board.  Laying out
> surface mount on a single sided board is a fool's errand because it
> is difficult to jump across traces using a resistor.  You need that
> second layer of copper in order to get the thing to route.  Two layer
> boards are more expensive than single layer boards, ERGO surface
> mount would have to be WAY cheaper than through hole to really be
> cheaper.
>
> So my question is this:  What to you folks think - is surface mount
> cheaper than through hole?  Does surface mount require a two sided
> board in order to route?
>
>

Lawrence,

The answer to your question depends on the complexity of your circuit,
but I have some observations to make:

  - I find sm passives are easier to solder in place. There is no need
    to bend the leads, solder then crop. The board can stay on the
    bench an not be picked up and turned over etc. The sm ICs are more
    fiddly by hand, but if you ensure the pads are wider than that
    recommended it is easy enough.

    Just to clarify this, there are three phases in our projects in which
    we use PCBs:

    1) Prototype. The designer would solder the bits in.
    2) Pre-production. These would be in batches of 10 or 20. We have
       some outworkers who will do this for use. They prefer sm too.

    3) Full production. This is done by a contract company. They
       set up pick and place machines for the sm parts. Again, this
       is their preferred method.


  - I have laid out 2 projects now, 100 percent sm using only the
    component side of the PCB. There are no holes (I didn't need
    mounting holes), so the whole drilling process is removed with
    considerable cost savings. The circuits were small eg 16C71,
    max232 and associated caps, serial FRAM, 5 transistors, 3
    connectors and a bunch of Rs and Cs. The routing took some
    time, but I got there in the end.

  - This is subjective, but I think that sm looks the part. When I
    compare the sm boards to the old boards we used, there is no
    comparison - the sm boards look much better. Our customers get
    to see the boards from time to time, so it is important.


Regards,

Mike Watson