Richard wrote:
thinking of using the scan to e.g correct component placement in the
input file of the Router, using maybe a router produced Gerber and
slightly shifting components, modifying/extending Kicad etc. etc. There
are many approaches thinkable and they don't seem insurmountable to me.
you ever try to manually place something onto something adhesive? When I
do, it's usually always a tiny little bit off. And then there is no
pushing around anymore and cursing won't help either, as soon as one
corner touches the adhesive surface, that's it. Well, I guess some
mechanical and optical (think parallax) help can be constructed. I'd
rather write some code, trying to take human failure out of the equation.
again, this time printing the "inverted version" of the component
screen'. Good thought. But I have difficulties to think of how that
would work in the real world. What is if there is a conductive layer in
between, e.g. a ground plane, which I can imagine you want considering
all this tight spacing and possibilities of capacitive coupling etc? Or,
if no layer, what if a trace crosses just there and you are poking your
needle through possibly more then one of them? It doesn't seem practical.
have tried and succeeded to "solder wick" out a defective IC before,
more then once. O.k. not a 128 pin QFN, but regular SOPs etc.. The
majority of SMT components ain't 128 pin QFN's anyway. Regular solder
station and a fine tip is all you need. I want to be able to do that
with my prototypes where an IC (your quote) 'cost on average $3 to $5'.
PRINT OUT A NEW ONE (your quote) and throwing away maybe 10 of the other
chips in the circuit worth $3 to $5 apiece does not sound like a great
option to me.
'hybrid' is as far away from a a 'real' sized PCB as it gets.
The advantage of real prototype PCBs are also that I can put my finger
onto components or traces, introducing capacitance and changing circuit
behaviour, take a soldering iron and quickly add a cap, change an R etc
etc (with my cheap soldering iron), until i am ready for the next
iteration of the prototype pcb.That would possibly save substantially on
the number of iterations. Each iteration with your technique, even the
smallest, requires a complete redo. I can change an R in a minute while
you have a 4 hr turn around.
Derk
>No, I don't want to reinvent and reimplement existing router apps. I am
>
>
> Excellent and very powerful PCB CAD software already
> exists(KICAD,Eagle,etc.)for FREE! Do you really want to start your
> project with trying to first write your own routing software?? I don't
> think the "homebrewer" has on staff a seasoned team of code writers at
> their disposal : (
>
thinking of using the scan to e.g correct component placement in the
input file of the Router, using maybe a router produced Gerber and
slightly shifting components, modifying/extending Kicad etc. etc. There
are many approaches thinkable and they don't seem insurmountable to me.
> Well, yes it does! The CAD software un-forgivenly demands this. ItThat problem is exactly what I tried to solve with my suggestion. Did
> expects what you place in its "virtual design board" to be absolutely
> representative of the real world "outside physical placement" of the
> actual components location. When I have you print the component layout
> screen to the substrate, the CAD software later makes reference to
> this fine placement when you flip the module upside down and now needs
> to print micro thin conductive traces. Think about a 128 pin QFN IC
> with lets say 50 0404 SMDs. Your SMDs better be right on the money!
>
you ever try to manually place something onto something adhesive? When I
do, it's usually always a tiny little bit off. And then there is no
pushing around anymore and cursing won't help either, as soon as one
corner touches the adhesive surface, that's it. Well, I guess some
mechanical and optical (think parallax) help can be constructed. I'd
rather write some code, trying to take human failure out of the equation.
> In re of "probing" .... your wrong! All the SMDs remainI like your idea of 'running your finished module through the printer
> 100%accessible, even the connections "inside" of the constructed
> "micro-hybrids". Yes, they are covered by the insulating mask, simply
> run your finished module through the printer again, this time printing
> the "inverted version" of the component screen. With a micro-sized
> drill or sharp needle point probe, slightly tag the surface to pass
> through to the conductive layer underneat
>
again, this time printing the "inverted version" of the component
screen'. Good thought. But I have difficulties to think of how that
would work in the real world. What is if there is a conductive layer in
between, e.g. a ground plane, which I can imagine you want considering
all this tight spacing and possibilities of capacitive coupling etc? Or,
if no layer, what if a trace crosses just there and you are poking your
needle through possibly more then one of them? It doesn't seem practical.
>Yes, I hand solder surface mount components quite frequently. And yes, I
> That's very true! But think about it. Is the "homebrewer" equipped
> with special and very expensive "solder re-work stations" that allows
> changing out a 128 pin QFN or 0404 SMDs??? Your talking about ICs that
> cost on average $3 to $5 and descretes around 20 cents a piece.
> Have you ever tried to "solder wick" out a defective IC before?
> Chances are you'll lift every "pad" right of the board!
> My point is .... for the cost and time involved,if you have a
> defective module...PRINT OUT A NEW ONE!! In about 4 hours, your back
> up and running.
>
have tried and succeeded to "solder wick" out a defective IC before,
more then once. O.k. not a 128 pin QFN, but regular SOPs etc.. The
majority of SMT components ain't 128 pin QFN's anyway. Regular solder
station and a fine tip is all you need. I want to be able to do that
with my prototypes where an IC (your quote) 'cost on average $3 to $5'.
PRINT OUT A NEW ONE (your quote) and throwing away maybe 10 of the other
chips in the circuit worth $3 to $5 apiece does not sound like a great
option to me.
> Manufacturers today must commit their prototypes to the fabracation ofVery true. But that's not what you are doing with your technique. Your
> "real" sized PCBs to even develop the circuitry through many ite
> ations of the "true sized" PCBs.
>
'hybrid' is as far away from a a 'real' sized PCB as it gets.
The advantage of real prototype PCBs are also that I can put my finger
onto components or traces, introducing capacitance and changing circuit
behaviour, take a soldering iron and quickly add a cap, change an R etc
etc (with my cheap soldering iron), until i am ready for the next
iteration of the prototype pcb.That would possibly save substantially on
the number of iterations. Each iteration with your technique, even the
smallest, requires a complete redo. I can change an R in a minute while
you have a 4 hr turn around.
Derk