You just named the problem with Multiwire--wire is sequentially applied to a thermoplastic substrate.
Whatever other advantages or problems it may have, it is a
*prototyping* process, not a mass production process. It is to PCB production as e-beam is to photolithography.
Tin Whiskers:-
For those who though leaded solder was best. Here is the problem with lead free solder.
Colin
And in the meantime whilst smaller manufacturers who don't have the resources of the big boys to research this crap in sufficient detail to find the 'correct' process to replace the previously utterly reliable and simple leaded soldering that they were using, cartloads of electronic equipment are failing as a result of the bad joints that the experimentation or 'best fit' replacement alloys are causing.
I wonder what qualifies you to make that remark at the beginning of your post, telling people not to look to this group for 'factual' information on lead-free ? When I tell you that I work day in day out with equipment from major manufacturers that uses the stuff, and that since they have been using it, I have seen the incidence of bad joints in places that would never previously have suffered, skyrocket, do you consider that to not be 'factual' ? Am I lying perhaps ? There are many good engineers that contribute to this group, and most have reported seeing an increase in such bad joints. Are they all being less than 'factual' ?
When push comes to shove, this is an electronic repair group, frequented by, amongst others, repair professionals who have to deal with the effects of legislation such as RoHS, and its implications, at the sharp end, which is more than the manufacturers and political activists / pseudo scientists responsible for creating these situations, do. As such, I feel that it is therefore rather presumptuous of you to suggest that opinions voiced on this group, are not based in fact, and thus not valid.
Arfa
If the water tables around an outdoor shooting range had any higher levels of lead leeched into them, the whole world would know about it, and that is what we call NEWS.
FACT is that there is no such lead level increase in such areas, and they dump TONS of lead into the ground at popular ranges.
FACT is that I have been touching, rubbing, etc. lead alloy soldered circuit card assemblies (as well as the solder itself) my entire adult life, and my lead levels are lower than the doc had previously seen for someone my age, the last time I had that test taken ( about four years ago).
If you believe that to be a possibility, are you not concerned about the additional carbon based fuels used to heat these lead free solders to the higher temperatures that they require?
Leonard
energy
Fully operating incinerators are sprinkled all over this country. There was even some twit on TV the other day claiming that their placement was racist.
stack if
Do you know the rate that pure Lead oxidizes? Do you know the rate at which 63/37 Tin Lead Solder oxidizes at?
Bullets are still being found in old US Civil War battle fields, and they are practically pristine balls. No crust whatsoever.
What actually happens with pure Lead is that it's first few mils of depth become "tempered", similar to aluminum anodization.
So it becomes harder, and would oxidize even less.
And lead free utilization does exactly what against these elements and compounds?
There are SEVERAL HDTV set top tuners out there that will pipe the finished signal into a standard TV. What is nice about digital broadcasts is that when you have the signal, you have it all. No snow, No herringbone patterns. Crisp and clean, with no caffeine.
Except when it breaks up.
Graham
That's what cost Napoleon dearly in Russia. He lost his armies to exposure due to their uniforms literally falling off their bodies.
All Tin buttons, even on their boots.
There have been polymer based conductive circuit assembly adhesives around for several years now.
NOT cheap.
The answer will be Rhodium alloy solders for safety and mission critical applications... perhaps.
Most VME backplanes utilize a press fit pin, directly into a clad hole, and it is gas tight in the connection regions and there is no solder involved. Lasts for years and years.
That's worrying ...
Arfa
As are most other products that are *not* subject to excessive amounts of vibration.
Arfa
Good one.
Nope. If you tune the signal, you get ALL of the data. You must exceed more than ten percent bit error rate for a dropout to occur, and it is bit error rate that matters most for a "tuned" channel.
Yes, a good write-up of the problems, and why leaded solder didn't suffer from them.
Arfa
I have a cable TV set top box. There's no tuning involved. It still breaks up occasionally.
Graham
tin
Oh, I recall it now.
It seems that the Open University has studied this issue and has indeed found tin pest in 'cheap' lead-free solders that are 99%+ tin. These are in commercial use too !
The question next should be whether the popular SAC alloys are affected.
Graham
IT tunes itself, dipshit.
Do you actually think I meant that you had a knob to turn?
Get your head out of your twenty year behind the digitally tuned receiver world ass.
OK... I'll spell it out for you.
If it ACQUIRES the signal, and locks it in, it gets ALL packets from the HEAVILY FEC coded stream, and can handle up to a 10% bit error rate before the "tuning" starts to lose, and not be able to repair with the FEC, data packets. When that happens, one starts to lose audio and or video or could see some video artifacts. It usually results in short term. low frame count dropouts.
So it isn't "breaking up". That is an analog expression. In digital broadcast streams, the term is "dropout".
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