Concept example pics are now here:
http://groups.yahoo.com/group/Homebrew_PCBs/photos/album/2086759579/pic/listAssembly update method:
After drilling the micro-vias, I have found that just a standard sewing needle works great to imprint the inward "dimple" to roll in smooth the copper to protect the mag wire from chaffing.
--- In Homebrew_PCBs@yahoogroups.com, "Richard" <richard.liberatoscioli@...> wrote:
>
> In my quest for the "quintessential" SMD prototyping method for the "Homebrewer" to easily fabricate complex, micro-sized, multi-chip electronic circuitry of today Â….. this concept assembly suggests an extremely fast and high quality solution.
>
> GENERAL FEATURES:
>
> This process targets the small sized and mobile ultra-low powered MCU and RF designs.
>
> Easily replicate the recommended highly engineered manufactures PCB reference designs for this components layout.
>
> PCB interconnections to extremely fine pitch 64 pin QFN and discrete micro-sized 0402 resistors/capacitors/inductors is quick and easy.
>
> Affords both high and low current wiring requirements with "self-stripping" and "solderable" solid copper magnet wire (traces).
>
> Provides a full board solid copper bottom layer for high speed MCU and RF designs requiring very low ground impedance including RF coplanar transmission lines.
>
> Any size conventional PCB SMD densities with multiple board layer designs are easily equaled with just one standard, single sided, FR4 board.
>
> There is absolutely no "etching or printing" of conductive traces in this process.
>
> All IC pins and discretes terminating to ground (VDD-) is always less than 1/16 inch to the copper ground plane below (providing a very fast ground).
>
> Bottom side of special ICs requiring a "ground bonding plate" is easily addressed.
>
> With components in hand and CAD work done, even highly dense and complex PCBs can be completed and working in one day.
>
>
> MINIMUM FABRICATION EQUIPMENT REQUIRED:
>
> Simple CD tray PCB printer adapter or other modified PCB printer.
> http://www.fullspectrumengineering.com/pcbinkjet.html
> http://groups.yahoo.com/group/Inkjet_PCB_Construction/photos/album/1664\
> 97487/pic/list
>
> Dremel high speed drill and drill press stand
> Powerful "hands-free" magnifier glass.
> Micro-point soldering pencil.
> Micro-needle syringe solder paste dispenser.
> Micro-syringe epoxy adhesive dispenser.
> SMD "pick and place" aids (ie: fine tweezers or vacuum pic).
> Exacto knife.
>
>
> ASSEMBLY PROCCES:
>
> In your favorite PCB CAD software you "drag and drop" place your descrete SMDs (RCL) in what I refer to as independent "Hybrid SMD Assemblies". A very simple example of this would be, lets say on pin 22 of your IC, is first connected a resister, then this resistor is series connected to a capacitor, from this capacitor, series connected to another resistor and this resistor is then connected to ground (VDD-). In CAD, you join all three SMD package outlines with NO interconnections between them (the SMDs are top surface layer "butt end" connected (and later top soldered) by their own contacts. At both unconnected ends of this RCR series'ed combination, you designate a via to bottom layer (the via should be right next to the end SMD component, but not obscured by its foot print. Placement of the SMDs in this fashion forms a newly created "Hybrid Assembly" This method results in a 50% reduction in SMD component spacing and 50 to 80% reduction in bottom layer conductive wiring. The ground end of this hybrid is established by soldering magnet wire from its contact to the copper ground plane immediately below it through its via. The other end of this hybrid (high side) is connected down through its via then back up through the via on pin 22 of the IC. This "hybrid assembly process" is repeated throughout the entire circuitry.
>
> Basically, when you have finished your cad work, you print your component layout screen onto the bare (no copper) top layer of your FR4. Mount all SMDs with an epoxy "Micro-dot" adhesive under all your smds. Then let the entire board cure.
>
> Drill out all via holes (via hole size representing the wire gauge of the magnet wire)
> With a drill press mounted "micro-cone shaped tip" (drill remains un-powered) slightly impress a inward rounding over "dimple" to the copper hole edge (protects magnet wire from chaffing). All routing wires remain close to PCB in point to point and point to multi-point fashion. The finished top layer terminal connections (being as short as the components they connect to) are almost invisible to the naked eye.
>
> The Via-Mag process affords its very easy fabrication of interconnections due to the vias being placed immediately where the connections are to terminate. Micro-manipulation of the wire ends "locks" the ends perfectly in place for quick and easy "hands-free" soldering even on the smallest micro-sized SMDs.
>
>
> This concept wiring example can be viewed at:
>
> http://lowermerioncivic.blogsite.org:5080/openmeetings
> Log on as: Guest Password: Guest
> Enter conference room: VIA-MAG PCB Assembly
> Note: The board shown was used for concept creation only, because of its many existing vias able to illustrate just the two magnet wiring examples.
>
> Or in the "VIA-MAG" photo folders section here
> (currently an empty folderÂ… until an upload problem is resolved)
>