i have seen them also. (neil's)
these cylinders look like pop rivets, but thinner wall (and of course no shaft).
you simply apply them by tining one side of the board, then using a homebrew soldering iron tip (which
has a narrow tip and after a mm from the tip or so a broader shaft).
you put the rivet on the soldering iron (flanged end back) and put it in. press a second and the tinned
surface of the board solders the flange to this side so only soldering in bottom is necessary. (to this
i also read they conducted thests with NOT AT ALL soldering the flange at the top side, only placing it
in cold and soldering bottom (no, the top wasn't tinned so that the tin meltet when soldering bottom)
and they had no single connection (of i don't know how much) which had no contact. but i won't trust
this (oxidation).
my personal idea of placing them is to put a number of them on a piece of hard wire with the right
diameter and go with this from hole to hole, the rivets sliding down. after that simply press on the top
with dry flat soldering iron tip. this should be faster and doesn't require a special tip for holding
them.
the version i described is the one of solid copper, which is really a pipe and not filled.
i believe the version neil has heard of is the following:
think of soldering tin, it has the diameter of the hole but slightly thinner.
then put a layer of copper on the outer surface.
then cut it to small pieces of pcb with (but maybe don't cut through to keep it as a bar and not tiny
pieces). then insert a piece in a pcb and mechanically "rivet" it in like they did (do) with rivets in
bridges or boats, from both sides with a hammer or press.
then melt the tin out and put your lead in.
this leaves the small copper walling very similar to electroplated but dry.
i heard this has the disadvantage that you should have cleaned the drill holes with strong acid (to make
the fibers stick out and remove the "smeared" epoxy (which can melt).
therefore it that tool neil described, and a mecanical pen can be used. you insert such a piece and then
brake the rest off and go to the next.
a pen can't be used with the upper rivets because the flange would jam it.
a third version (which i don't like) is the following:
there are sold small pieces of copper, each a bit longer than the pcb.
these are conic shaped, a tipped end is inserted in the hole and the thicker end gets stuck at a certain
point and holds it there.
they are also put together on a rod one after the other for easier handling.
you simply put in, break, put in, break. at the end solder both sides.
there is no possibility for putting a wire of a component through with this method.
the first riveting method may be improoved by riveting them really in, pressing a flange on the bottom
after inserting. but this needs good riveting tool in a press, i have no lathe which would be a help in
experimenting and making this tool. but it also isn't needed at all. works fine so.
this are all non-chemical through holing methods i know (without "take a wire and a iron and solder on
both sides")
regards
stefan
10.05.2003 02:06:18, Neil <cobra_neil@...> wrote:
>There is one other method I've heard of, which is to use small "eyelets" that
>look like little open cylinders with flanged ends. There is a special tool
>that's used to insert this in the holes of the PCB, to connect the sides, and
>a component lead can be placed right thru it. I've even heard mention of
>being able to use a mechanical pencil instead of the tool. However, I've not
>been able to find a local source for this. Heard a recent mention of LPKF as
>a possible source, but didn't find it on their site.
>
>Cheers,
>-Neil.
>
>
>
>On Friday 09 May 2003 18:37, Markus Zingg scribbled:
>> How this is done depends on a number of factors. The easiest way is to
>> just put some wire through the holes and solder it on the top and
>> bottom layer. Aside of the obvious advantage of simpleness and
>> cheapness, this method is having some disadvantages like:
>>
>> - much work
>> - restrictions on where such vias can reside (i.e. you can't put them
>> under an SMD part etc.
>>
>> Variants of the above method exist in that you can have finished wires
>> (don't know the exact english term for this) which you can insert with
>> a tool, but the soldering and the placement restrictions are the same.
>>
>> Real through hole plating must be done using a through hole plating
>> station which consist of several tanks holding chemicals. The PCB then
>> must be delved into them, moved within them back an forth (so as the
>> fluids can flow through the holes). The last step is then a copper
>> bath where an electrolytic process is applied.
>>
>> I'm right now in the process of building my own through plating
>> station - it's an ugly whole lot of work, but I too got sick of either
>> waiting for others to make my PCB's for my money or having
>> restricitons mentioned with the above method.
>>
>> One of the bigger obstacles when it comes to through hole plating
>> (IMHO of course) is getting the right chemicals. There is much
>> experience in there and the companies who produce such chemicals of
>> course treate them as a big secret. I too had to bit the bullet and
>> buy finished mixtures. I bought them from Bungard which is a germany
>> based firm. In the end I will have my own through hole plating station
>> with 5 tanks which puts me in the position of creating even multilayer
>> boards.
>>
>> If the people on this list are interested I will post a link once the
>> station is finished so as others may can use it as a starting point
>> for their own constrtuction. I'm pretty far already, that is if all
>> goes well I may even finish it this weekend.
>>
>> HTH
>>
>> Markus
>>
>> >Hi everyone,
>> >
>> >I?m new here, I?ve been working with PCB?s for a while and now I want to
>> >start making my own boards for a great number of reasons.
>> >I found enought info on the net and in this group archive files to know
>> > how to make them double sided with many details.
>> >But I couldn?t find almost a thing about how to make the component holes
>> >conductive (metalized holes).
>> >Can anyone give me a help with this?
>> >
>> >Thank you
>> >
>> >Nuno T.
>> >
>> >
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