There are three possibilities, as I see it:
1. (more likely) the Ag plating (immersion, nor electrolytic, probably)
was wiped without a proper DI rinse bath. IMHO, this is inexcusable.
2. I'm assuming that the outer insulation is PTFE, as well the inner. Is
it possible that the PTFE had some fluorethylene monomer in it at the
time of sintering?
3. The PTFE is porous (after all, it is sintered, not moulded) and some
nasties have wicked in due to inappropriate storage conditions.
Brian
Graham Collins wrote:
> Hey Steve
> Cool pictures.
>
> Looks like braided rope, the manufacturers put in one cluster of strands
> with a different color to give it a pattern... So you can tell your
> sailing crew to pull on the "green fleck" rope.
>
> As for your wire, I'd interpret picture 3 as one cluster of strands in
> the braiding has bad plating and/or something nasty contaminating it,
> making it corrode. Since these are new, and they aren't going to
> improve with time, I'd reject them... bad batch of wire!
>
> regards,
> - Graham
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
> Sent: Tuesday, June 09, 2009 10:35 AM
> To: [log in to unmask]
> Subject: [TN] Green Junk in Wire
>
> Good Morning!
>
> We've just had something come-up that really has a few of us scratching
> our heads around here.
>
> To preface this; we have a mechanical assembly building where we put
> cabinents and boxes together plus do some cable and harness assembly.
> Yesterday one of engineers called me and said that they were seeing some
> green stuff on some of the cables that we've built and said that I
> should come and take a look at it. While I was walking over to the other
> building it was thinking to myself; "I hope that somebody didn't get a
> hold of the wrong flux or something...".
>
> When I got there, I was really suprised at what I saw:
>
> http://stevezeva.homestead.com/files/Green_Junk_1.jpg
>
> http://stevezeva.homestead.com/files/Green_Junk_2.jpg
>
> http://stevezeva.homestead.com/files/Green_Junk_3.jpg
>
> http://stevezeva.homestead.com/files/Green_Junk_Close.jpg
>
> The photos that you see come from a cable assembly that is about 3-feet
> long, and we're seeing it on cable assemblies that are longer. The wire
> in the assembly is a PTFE insulated single conductor shielded and
> jacketed cable. The conductor and shield is silver plated OFHC copper.
> The photos are taken from a section in the middle of the wire well away
> from any area that soldering has been done. The shields of all the wires
> in the bundle get soldered together at each end using a ORL0 wire solder
> and flux. The green substance appears throughout the wires. In "Green
> Junk 3", you can see how the green is with a group of the strands of the
> braided shield and how it spirals around the wire.
>
> It goes without saying that I'm contacting the wire manufacturer, and
> I'm sending out a cable assembly for analysis. But have any of you ever
> seen this before?
>
> Steve
>
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