..... an example of the conductive traces "reduction" ratio:
64 pin leadless QFN RFID GEN2 UHF Reader IC with all required SMDs connected (res,caps,inductors,x-tal,etc.)
Conventional multi-layer "PCB" verses "Flip n' Print"
16 traces reduced to 4
5 traces reduced to 2
5 traces reduced to 2
14 traces reduced to 3
5 traces reduced to 2
23 traces reduced to 10
7 traces reduced to 4
5 traces reduced to 2
6 traces reduced to 3
8 traces reduced to 3
5 traces reduced to 2
6 traces reduced to 3
5 traces reduced to 2
Totals:
110 traces reduced to 41
Instead of a 5 or 6 layer conventional "PCB" (1.5" by 3/4") only 2 or 3 "printed layers" are needed.
By placing the SMDs "end to end" and "side by side" in combinations, for these connections, you afford essentially a zero "resistive loss",zero "stray inductance and capacitance" and highly conductive soldered connections.
With the now greatly reduced physical length of the "inkjetted conductive traces"(most are only 1/8" to 1/16" long), the higher resistance of the conductive inks now becomes negligible.
In essence, this assembly method uses the SMDs themselves as the majorty of the "wire traces" required.
--- In Homebrew_PCBs@yahoogroups.com, "Richard" <richard.liberatoscioli@...> wrote:
>
>
> Hello Homebrew Printed Circuit Group!
>
> I have successfully modded my Epson Artisan 50 printer Epson Printer
> Mod
> <http://groups.yahoo.com/group/Inkjet_PCB_Construction/photos/album/1664\
> 97487/pic/list> to make PCB boards. I did this, as I'm sure as all in
> this forum, want to quickly build working devices from all the many
> awesome microchips out there (ie: MCU, RFID,WIFI,GSP, etc.)
>
> In my current project, I need to fabricate a "system-in-package" (SIP)
> module containing an RFID reader chip (QFN), MCU chip and WIFI
> chip(QFN) on two PCB's (1 1/4" x 3/4") including the required discrete
> SMD's (resistors, capacitors, inductors, x-tal, etc).
>
> This project requires very small SMD's and a very small and dense
> multi-layer PCB with micro vias for fabrication.
>
> This project well exceeds my existing "Homebrew" equipment capability to
> fabricate this module.
>
> In assessing the demands for the size and scope of this project (for a
> "homebrew" solution) the "show stopper" was all in the fabrication of
> the PCB itself.
>
> Here I began my quest for a different "homebrew" solution.
>
> Could I build this module without the complex multi-layer PCB?
>
> Could I interconnect all SMD's (IC's and discrete's) without soldering?
>
>
>
> Concept proposal:
>
> Start with a blank substrate (metal, glass, FR4,ceramic,etc) in place of
> a conventional PCB.
>
> Apply double sided releasable 3M "micro adhesive" tape covering the top
> surface of the substrate.
>
> "Pick and Place" all SMD's onto the top surface of the substrate. Note:
> with no PCB traces or vias to contend with, a 50% reduction in SMD
> spacing is obtained.
>
> "Epoxy Pot" the top surface embedding all the SMD's.
>
> Flip over the substrate (now working from the bottom side) and release
> the tape and substrate from the potted assembly. Clean off any residual
> adhesive.
>
> At this point, you should see only the exposed metal contacts of all the
> SMD's.
>
> Using the modified Epson Artisan 50 printer (set head height to pass the
> 1/8" thick epoxy pot assembly depth) and print with special UV curable
> conductive ink (Metalon®)
>
> UV cure (need to build a "homebrew" UV source for curing the conductive
> ink). The commercial version does it in 3 or 4 seconds.
>
> Subsequent conductive traces (emulating the multi-layers of a
> conventional PCB) are first "masked out" by printing with a different
> inkjet of NON-conducting ink at the conductive trace crossovers.
>
> DONE! : )
>
>
>
> [Non-text portions of this message have been removed]
>