Hi Derk!
....mmmmmmmmmmmmm , well, first let me say that your thought process is so powerful, I will have to assume that I fatally missed something in your rational.
I'll respond briefly on this in hopes I'll get to better understand the merits of your suggestions.
In prima fasia, this would be a complete disaster. Placing the SMDs in a "random" fashion, would seriously violate essential physical and electronic associations that the components function provides.
Example: With the very high speed microchips we use today, very heavy use of decoupling and bypass capacitors must be used and must present themselves IMMEDIATELY (asigned placement) on the IC pins they afford their function to.
"Random placement" of these components would folly at best.
--- In Homebrew_PCBs@yahoogroups.com, Derk Steggewentz <derks@...> wrote:
>
> Richard,
> I am following the thread. because I like the creative
> approach.Regarding accurate placement: Why don't you just place the
> components arbitrarily and after potting and peeling of the tape you
> scan the side with the exposed pins. With a piece of software (to be
> written) the user then can interactively identify the components on the
> image. With this information and the schematic the software has all the
> information to do the rest, including printing.
> Although I can see a few problems with the general approach I think it's
> worth following.
> Derk
>
>
> Richard wrote:
> >
> > Hi gnuv!
> >
> > On a blank 8.5"x11"x1/4" Corian@ substrate, print out your component
> > layout screen (lets say that's a 2.5"x3.5" finished module size) in
> > the center of this substrate.
> >
> > Apply double sided (releasable) "micro-adhesive" tape/film over your
> > printed screen (its "micro thin" and "see through").
> >
> > Apply SMDs with a vacuum assisted "pick and place" probe.
> >
> > When finished, stack on top your substrate the 8.5"x11"x1/4" Corian@
> > potting mold (with the 2.5"x3.5" square hole in the middle).
> >
> > Epoxy Pot to top of mold. When cured, release potting mold from
> > substrate, potting mold is then flipped over, and run through the
> > modified printer for conductive and insulative inkjeting.
> >
> > --- In Homebrew_PCBs@yahoogroups.com
> > <mailto:Homebrew_PCBs%40yahoogroups.com>, "gnuvvekaavaali"
> > <gnuvvekaavaali@> wrote:
> > >
> > > --- In Homebrew_PCBs@yahoogroups.com
> > <mailto:Homebrew_PCBs%40yahoogroups.com>, "Richard"
> > <richard.liberatoscioli@> wrote:
> > > Something else I realized tonight, since the SMDs are "picked and
> > placed" onto the "micro adhesive only"(no soldering) the SMDs can be
> > placed "end to end" or "side to side" depending on the design of your
> > schematic.
> > > > >
> > > > > For instance, 3 legs from my 64 pin QFN IC go to 6 capacitors,
> > each leg going to two capacitors, then all caps go to vdd-.
> > > > >
> > > > > This normally would take 16 PCB tracks just to do this. By
> > > > joining the SMDs "physically", soldered end to end without
> > > > wires, from the top surface, I have now reduced my "printed
> > > > wiring" down to just 4 connections. Similar printed wiring
> > > > reductions are reflected throughout the entire assembly.
> > >
> > > Wow - very creative effort, indeed.
> > > How do you ensure the accuracy of the SMD placement on the tape?
> > >
> >
> >
>