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Re: [Homebrew_PCBs] maxim samples

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  • Stefan Trethan
    Hi all.. Want just write that a bunch of very expensive maxim samples did just arrive, from the initial order with - in the company field. so it seems they
    Message 1 of 76 , Apr 1, 2004
      Hi all..

      Want just write that a bunch of very expensive maxim samples
      did just arrive, from the initial order with "-" in the company field.

      so it seems they do send to individuals without any trouble.

      I used the standard web input, filled all 8 positions, with expensive
      parts like the max038, and in the "which product" field i placed "battery
      chargers"
      because some parts are for this.

      however, they did not obey my wishes concerning the packages in most cases.
      (i was bold enough selecting cerdip but got only pdip)


      it came from maxim Germany.


      ST
    • Adam Seychell
      Hi Jeremy, The FLASH COPPER product seems like a general purpose alkaline type copper plating solution, but with the added benefit of not containing cyanide.
      Message 76 of 76 , Apr 3, 2004
        Hi Jeremy,

        The FLASH COPPER product seems like a general purpose alkaline type copper
        plating solution, but with the added benefit of not containing cyanide. The
        question as to what type of plating solution is best for plating inside
        carbon coated holes (coated methods of either graphite loaded inks or
        deposited carbon black) is probably only going to be answered with lots of
        experimentation. Getting holes coated in copper is the last stage that
        needs to more worked on. I would agree that organics can also play a big
        role in platability of copper over carbon. Trying to describe the exact
        mechanism behind the function of organics responsible for improving plating
        performance would be next to impossible. The experts don't understand
        what's fully going on at the substrate surface layer. Plating additives are
        derived empirically, and is why the companies who develop them hold the
        ingredients a closly guarded secret.

        For an overview of the different processed of making holes conductive:
        see http://www.epa.gov/dfe/pubs/pwb/ctsa/ch2/ch2-1.pdf
        Blackhole process does not involve any electroless plating, it doesn't even
        have a "flash plate" or "pre-plating" step. Note: the Carbon method
        described in the above EPA document describes Blackhole II which has since
        been replaced by Blackhole SP. The latter process only has one carbon dip
        cycle, instead of two.

        Adam.


        Jeremy Taylor wrote:

        > I think it really has to do with the balancing chemistries. , or the
        > organics. The Flash I'm using has no cyanide, I was under the impression
        > that the blackhole method was purley an electroless process , including the
        > copper flash.
        >
        > ** Big side note here ... I'm not a chemist, and I cant get in to many
        > details beyond the basics, or what I have specific instructions for.
        > I was under the impresion that the balncers were most attracted to the areas
        > with the greates potential for conductivity. And thus the higher thier
        > consentration in the solution, the more profound the hole plating vs the
        > foil~ would be. as the foil surface en mass is of higher potential. I have
        > noted that I start to see color change in the holes before the foil begins
        > to pinken. < is that a word? So I'm assumin I happen to have enough organic
        > content to effectivley hamper the plating on the urface of the foil until
        > after the hole walls bein to fall in to balance with the foil surface.
        > I've also seen that I do not need to flip and rotate the board 1/2 thru
        > plating for uniformity like I did with the acid copper. But this may be due
        > to anode placement. vs board size, so to many variable to state that as
        > fact. Caswell sataes it like this:
        >
        > "
        > FLASH COPPER produces a fine grained. smooth. dense and ductile copper
        > deposit. which is nonporus and has excellent bonding properties. The
        > throwing and covering power of the non-cyanide process is superior to
        > cyanide processes. This is especially evident in barrel plating. It has
        > uniform low current density distribution with excellent micro-throw
        > The grain is smaller than cyanide copper. which increases the density of the
        > deposit. This density provides excellent heat treat stop off and masking
        > properties. The fine-grained FLASH COPPER deposit under nickel chrome
        > improves the overall corrosion resistance and helps to throw the nickel
        > farther into the low current density areas.
        > FLASH COPPER produces a softer and more ductile deposit than cyanide or acid
        > copper. The soft deposit imparts improved adhesion and corrosion resistance
        > and greatly improved resistance to thermal shock.
        > It has a high deposit purity and hence no out-gassing with subsequeut
        > brazing. soldering or vacuum operations.
        > FLASH COPPER is simple and inexpensive to use because it replenishes the
        > copper in solution by dissolving the copper anode and here again it is a
        > unique product with only one maintenance additive.
        > "
        >
        >
        > After speaking with Ron at TnT , he sugested that alot of customers who use
        > thier process skip the flash step, and go directly to pattern plating with
        > thier Acid copper product, I'd asume they have acid worked out well enough
        > to market it with the ink , or we'd be seeing a change in procedure. But
        > with that siad, Caswells flash is performing very well and for a complete
        > kit setup cost under $200 I'd like to see more people try this method to
        > verify my results. Caswell sells a product called "silvaspray" made for
        > plating plastics and works very well with the flash copper product, I'd
        > suspect - it to could be used for hole plating. I'll probably try it out
        > when I start running out of the TnT ink.
        >
        > ... thoughts to promote either a solid tin / SnPb plate, or acid copper
        > plate over the flash. I'm tempted to try a few boards without eitther to see
        > if it holds up , If the solder from the assembly process would cover it. I'm
        > preparing a plot for a negative I'll run tonigh, In the morning I'll see how
        > it deveolps, and if this film can tent well enough I'll give it a go
        >
        > JT
        >
        >
        > ----- Original Message -----
        > From: "Adam Seychell" <adam_seychell@...>
        > To: <Homebrew_PCBs@yahoogroups.com>
        > Sent: Friday, April 02, 2004 6:36 PM
        > Subject: Re: [Homebrew_PCBs] Plating Holes (was: plated tin as the etch
        > resist)
        >
        >
        >
        >>Ok, thanks for your response. I thought you might have had made a grand
        >>discovery in getting through holes to place reliably over carbon coated
        >>holes. As I said earlier, I'm using carbon black to coat the holes and I
        >
        > am
        >
        >>experiencing the same problems as many did in who tried to make
        >>carbon/graphite process commercially viable, such as MacDermid. The
        >
        > current
        >
        >>process by MacDermid is called BLACKHOLE SP, and is well established in
        >>industry. They claim BLACKHOLE SP to be suitable for even the most high
        >>tech PCBs, 16+ layers, 0.1 mm hole diameters, et. The early attempts by
        >>these companies had problems getting the copper to plate on relatively
        >
        > thin
        >
        >>layer of carbon/graphite. From my experiments of plating carbon coated
        >>holes, I've found the chemistry of the plating solution to play a huge
        >
        > part
        >
        >>in obtaining successful copper coverage. For example, I found acid sulfate
        >>bright tin bath plates the holes much more reliable than acid copper bath.
        >>I also found small amounts of chloride in the acid copper bath have a
        >>detrimental effect, with > 300ppm of Cl- will completely inhibit any hole
        >>wall plating. I am wondering if the alkaline bath you use is the answer to
        >>getting the holes plated with good reliability. I'm not up to speed with
        >
        > my
        >
        >>electrochemistry but I believe the reason holes are difficult to plate in
        >>is that the carbon has a higher overpotential for deposition of copper
        >
        > than
        >
        >>copper on copper does. In other words you need higher cell voltage to
        >
        > plate
        >
        >>on carbon than on copper. Overpotentials depend on many things and pH is
        >>one of them. The carbon surface resistively is relatively high (about
        >
        > 10e+6
        >
        >>times more resistance of a unit square) compared to the copper foil
        >
        > surface
        >
        >>resistively. During plating a voltage drop develops at the boundary were
        >>copper meets the carbon. The result is a forward growth of copper over the
        >>carbon surface during the plating cycle. The copper growth emanates at the
        >>hole ends and eventually meets half way inside the hole completing the
        >>coverage. Its the rate of this copper growth front the determines how good
        >>the process is running. If the growth rate is too slow (or nonexistent)
        >>then too much copper will be deposited on copper cladding, and not enough
        >>inside the holes. Worse still is the voiding inside the holes due to
        >>patches of extremely thin coatings of carbon. This is the fundamental
        >
        > problem.
        >
        >>There a number of alkaline copper plating chemistries that could be
        >
        > tested.
        >
        >>The good news is we don't need high speed, smooth bright finishes, since
        >>the aim is to "flash plate". The acid copper bath will take care of the
        >>remaining copper. Industrial alkaline copper uses cyanide , which I prefer
        >>not to use. Another possibility is copper sulfate + ammonia hydroxide +
        >>ammonium sulfate with around pH 8 so it doesn't smell.
        >>
        >>Like you, I am doing this as a hobby so I don't get the time needed to do
        >>thorough experiments. I did most of my carbon hole work when I had a part
        >>time job in which I had the time to built a home lab just to explore this
        >>process. I've had a about 1 year break from it now, but these discussions
        >>have got me thinking about it again. It might be time to dust out the lab.
        >>
        >>Adam
        >>
        >>
        >>
        >>
        >>Jeremy Taylor wrote:
        >>
        >>>Hard to say - and subjective at best. but IMO yes.
        >>>We can discuss this more tomorrow, I've been trying to take some pics ,
        >
        > but
        >
        >>>man is it difficult to even get the holes...
        >>
        >>
        >>
        >>
        >>
        >>
        >>
        >>>
        >>>
        >>>http://www.soundclick.com/jtsound
        >>>----- Original Message -----
        >>>From: "Adam Seychell" <adam_seychell@...>
        >>>To: <Homebrew_PCBs@yahoogroups.com>
        >>>Sent: Thursday, April 01, 2004 11:09 PM
        >>>Subject: Re: [Homebrew_PCBs] plated tin as the etch resist
        >>>
        >>>
        >>>
        >>>
        >>>>Jeremy Taylor wrote:
        >>>>
        >>>>
        >>>>>My last post must been sent just prior to yours.
        >>>>>
        >>>>>I actually ended up completely closing up some holes with the acid
        >>>
        >>>copper.
        >>>
        >>>
        >>>>Does that mean the alkaline plate was more capable of completely
        >>>>covering the holes walls with copper than compared to acid copper
        >>>>plating ? Which bath was better ?
        >>>>
        >>>>
        >>>>
        >>>>
        >>>>>It' definitely a more aggressive plate.
        >>>>
        >>>>yes, the acid copper is fast, almost 100% coulombetric
        >>>>efficient, good throwing power and easy to maintain and setup.
        >>>>This is why I suspect you have chosen alkaline plating because it
        >>>>performed better when plating on the ink surface.
        >>>>
        >>>>Regards,
        >>>>
        >>>>Adam
        >>>>
        >>>>
        >>>>
        >>>>Be sure to visit the group home and check for new Bookmarks and files:
        >>>>http://groups.yahoo.com/group/Homebrew_PCBs
        >>>>Yahoo! Groups Links
        >>>>
        >>>>
        >>>>
        >>>>
        >>>>
        >>>
        >>>
        >>>
        >>>
        >>>
        >>>Be sure to visit the group home and check for new Bookmarks and files:
        >>>http://groups.yahoo.com/group/Homebrew_PCBs
        >>>Yahoo! Groups Links
        >>>
        >>>
        >>>
        >>>
        >>>
        >>
        >>
        >>
        >>
        >>Be sure to visit the group home and check for new Bookmarks and files:
        >>http://groups.yahoo.com/group/Homebrew_PCBs
        >>Yahoo! Groups Links
        >>
        >>
        >>
        >>
        >>
        >
        >
        >
        >
        >
        > Be sure to visit the group home and check for new Bookmarks and files:
        > http://groups.yahoo.com/group/Homebrew_PCBs
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
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