Self-fluxing Enameled Wire?

I just saw this item on Instructables:

[www.instructables.com]

I'd never heard of self-fluxing enameled wire. Neat idea. I can see this being used with a RepRap wiring head (wrap, solder, cut). If you place chips onto your build plastic dead-bug style (pins pointed up), a wiring head could do the point-to point connections.

Hi Steve,

... it's the 'stone-old' principle of Wire-Wrap - long before you could by bread-boards and PCB-prototyping and -making was really easy there was this kind of prototyping (and sometimes for small series too).

You could then buy isolated wire-coils, IC's with special longer pin-legs, pin-grids, plastic-combs for organizing the wires and other stuff for this job.

The main tool was a sort of wire-gun with the wire on a coil feeded through a manually, or in better guns motorized, rotary-head, which could wind the wire with some force around the sharp-edged pins breaking the wire-isolation, so you got firm contact with some windings (for better contacts there would be soldering too).

I had similar thoughts for a PCB-wire-head, where the board would be extruded with plastic, with holes for the IC's and components and some embedded wire-feeding-edges and then a wire-head would 'draw' the connections with isolated wire.

But it's a very complex job to connect properly and cut the wire in the right positions, so it's not such a good point yet ...

Viktor

Actually it is not wire-wrap in this instructable, its more like "solder-wrap". It was a technique in which you use coat copper wire and solder in at certain places, creating lots of toxic hazardous fume which we all used to love. I used this in the dark ages trying to put together some 74SL244 and alike to make an I/O device for my Sinclair ZX81. You could back then actually buy a kit with wire-on-a-roll pen and some plastic pieces that would fit in a breadboard and with a "comb" kinda thingy that you could roll the thread around. (Hmm without a picture this is not so easy to explain ;-).

I must say I prefered working with wire-wrap, as long as you documented your work it was dead easy to make a change in the construction at the last minute. I have never seen one but I think there where wire-wrap robots used industrially somewhere in the medieval times. Solder-wrap was a lot cheaper though. Wire wrap sockets are dead elegant things but unaffordable for a teenage computer nut, unless obtain via a surplus outlet...

In the instructable however I think it's gonna be tough not to solder some already present wire into another by accident. In the old days we used plastic channels that all wires where ran on the side of the components!

Hi mimarob,

... i soldered my wire-wraps sometimes too, so it's not so a big difference for me.

When home, i'll look around if i can find some examples of wire-wrap without and with soldering ...

Why not trying to reprap some test-boards with integrated combs and for wire-separation and better organizing again rats-nests?

This could be a sort of revival for the wire-wraps

Viktor

Steve,
I built some of the eletronics for my machine using that techinque: [hydraraptor.blogspot.com] the picture at the bottom shows the back of the board.

It is a bit fiddly for a robot to do but may be possible.

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[www.hydraraptor.blogspot.com]

Many decades of moons ago I worked for company that made all their computers using wire wrap systems because the volume was so low and each system very customized. But they used a system much like RepRap to build each board. Very fast and very accurate. So recreating history should not be a problem. Especially when we really need to create 1 off versions of a board. (ie. I being 1 of a thousand people who will build a copy of the board). I read somewhere that history does repeat its self and here we go again.

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Bob Teeter
"What Box?"

or maybe since we are reproducing a known construction it might be possible to solder the rats nest in the "right" order so no shorts are created by aftercoming soldering.

Sounds like a tricky place-and-route algorithm with a really large computational complexity...

or... since we have the plastic extruder... just put a drop of plastic on each wire for each bend, thus avoiding wires to cross future solder points..


we would need a solder tool of some kind, a roll of wire with a cutter and an extruder head!!

25 years ago the name of the wire product in the U.S.A. was just wrap.
It came on spools that mounted on a manual wrapping tool. Pack rat that I am I still have some. I have no idea where to find something like it today.

Similarly There were 2 low volume automated prototyping systems that used Cartesian mechanisms
The first was called stitch weld. It used closed end barrel pins pressed into a piece of fiberglass board. The head was positioned over a pin, pressed a coated wire onto the head of the barrel pin applied an electric current and the wire was spot welded to the pin. The head was repositioned trailing wire behind it and repeated the operation. When a route was completed the operator cut the wire and started a new route.
The second was a system called Multiwire. The principle was similar, but the system required a board with etched plated through holes wires were welded to the pads around the holes the wires were routed on a rectilinear grid (Manhattan routing) and embedded in a thermoplastic. This allowed for very high routing densities and fast board turnaround. The boards were pricey as I recall.

The automated wrap systems that I remember did not require that any soldering be done. You can still buy the sockets to this day. The wire wrap that was used made contact because the pin/post was square and when the wire wrap was wound around the ping the edge of the square pin cut the insulation on the wire and made contact. It also had an automatic wire cutter built in so that there was NO human interaction beyond setting a board with sockets soldered in place by soldering opposite corner pin to the board to hold them in place. Each board was 18 inches by 17 inches and covered with sockets. Those system lasted 20 years or better. So can this be done on a reprap. Absolutely.......

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Bob Teeter
"What Box?"

... but noone can afford the wire-wrap sockets...

Quick check on Google for wirewrap sockets let to this.

[www.jameco.com]

Sockets from $.82 tin to $5.75 for gold.

Yes they are not $.14 each as they were in the hay day of wirewrap but they are not that expensive for 1 off designs.

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Bob Teeter
"What Box?"