If it is not one of those exotic OSP, E-Sn etc.etc. for HASL or plated,
you can do steam aging upon receiving. I use to do following: steam
aging for solderability, (unless you qualify the vendor OK... You know
they are good all the time), wirebonding for the gold after aging at
elevated temp (depend upon what kind of gold... I am picky)....Again,
qualification of your vendor is the key. You really can not change
someone's process without a lot of work (if they are willing).... If you
do not do your "home work" to select and qualify a vendor, monitoring is
a very very very costly game (and a very very risky game... If you spot
something of "reject", you normally do not have time to find a
replacement without impact schedules .... All the JIT game play...too
bad, you just have to live with it...unless you are large enough to
operate using 2nd vendor... Nowadays, with the MBA on the top looking
for every penny, I guess very few operate using 2 vendors system...
Stupid to hang your self on one tree...but, looks good on books... The
additional operation cost is normally in a different line of business
cost, not on BOM cost)....
Jk (2 cents prior to dew)
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis
>Sent: Sunday, May 11, 2003 4:27 AM
>To: [log in to unmask]
>Subject: Re: [TN] Wetting Balance Testing
>
>
>Gaby
>
>Many decades ago, in another life, we used to test PCBS we
>were manufacturing with special test coupons at the rate of
>one per hour. This does not answer your question. For
>components, I think I'd sample 5, using the toughest
>conditions, on receipt and again before using them, if there
>were a considerable time lapse.
>
>Brian
>
>gaby wrote:
>> Brian.
>> Could you please tell me what sample size is usually used for
>> production approval (dip test) after storage more than 1/2
>year after
>> the first test at incoming inspection? Maybe there should be another
>> approach- in production test of a certain number of mounted circuits
>> and full visual inspection -even X-ray-afterwards? Of
>course. I think
>> that no supplier would receive failed components after 1/2
>year back.
>> and if desperately needed and there is no chance of receiving new
>> components soon. there must be found a solution to use them-hand
>> soldering, coating renewal, or else.... Thank you very much, I as
>> usually appreciate your answers very much. Gaby
>> ----- Original Message -----
>> From: "Brian Ellis" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Sunday, May 11, 2003 8:37 AM
>> Subject: Re: [TN] Wetting Balance Testing
>>
>>
>>
>>>I disagree entirely with this view. You may let pass some components
>>>with marginal solderability which will have deteriorated to
>>>unsolderable before they even reach the production line, and it does
>>>not allow for tolerances in the flux composition and activity. You
>>>must have something that demonstrates the worst case
>scenario. Believe
>>>me, this is the voice of experience.
>>>
>>>Brian
>>>
>>>Reuven ROKAH wrote:
>>>
>>>>Hi Dave,
>>>>I think that testing with "no clean flux" that is uses in production
>>>
>> line
>>
>>>>is more practical than "R" type rosin. Its more
>aggressive, so if it
>>>
>> fail,
>>
>>>>it will represent the future results in the real life in production.
>>>>
>>>>Best Regards
>>>>
>>>>ROKAH Reuven
>>>>
>>>>e mail: [log in to unmask]
>>>>
>>>>
>>>>
>>>> Dave Hillman
>>>> <ddhillma@ROCKWELLC To:
>>>
>> [log in to unmask]
>>
>>>> OLLINS.COM> cc:
>>>> Sent by: TechNet Subject: Re: [TN]
>>>
>> Wetting Balance Testing
>>
>>>> <[log in to unmask]>
>>>>
>>>>
>>>> 09/05/03 03:23 PM
>>>> Please respond to
>>>> "TechNet E-Mail
>>>> Forum."; Please
>>>> respond to ddhillma
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>Hi folks! Just an FYI but one of the major changes in the recently
>>>
>> released
>>
>>>>JSTD-002B specification is a revision of the flux chemistry for
>>>>solderability testing. The committee spent an enormous amount of
>>>
>> resources
>>
>>>>on investigating the flux chemistry change. The new flux
>chemistry is
>>>>a standardized, specified, activated flux formulation which
>replaces
>>>>the
>>>
>> old
>>
>>>>"R" flux chemistry. The flux chemistry change was the result of
>>>>industry feedback - with the advent of new component
>surface finishes
>>>>and solder alloys the use of an "R" flux chemistry was resulting in
>>>>false negative solderability responses. Additionally, the
>use of "R"
>>>>flux was one contributor of testing variation and the new
>>>>standardized flux
>>>
>> formulation
>>
>>>>contributes to less test variation without unduly influencing the
>>>>test results. Jack Crawford at the IPC Office has a Flux
>>>>Justification Memo which explains the committee's efforts
>and has the
>>>>committee test
>>>
>> results -
>>
>>>>I recommend anyone who is conducting solderability testing to get a
>>>
>> copy.
>>
>>>>Dave Hillman
>>>>JSTD-002 Committee Chair
>>>>[log in to unmask]
>>>>
>>>>
>>>>
>>>>
>>>> Brian Ellis
>>>> <b_ellis@PROTONIQ To:
>[log in to unmask]
>>>> UE.COM> cc:
>>>> Sent by: TechNet Subject: Re: [TN]
>>>
>> Wetting
>>
>>>>Balance Testing
>>>> <[log in to unmask]>
>>>>
>>>>
>>>> 05/09/2003 02:05
>>>> AM
>>>> Please respond to
>>>> "TechNet E-Mail
>>>> Forum."; Please
>>>> respond to Brian
>>>> Ellis
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>Except for when you are doing flux comparisons, wetting
>balance tests
>>>>are used for determining the solderability. To obtain consistent
>>>>results you should always use the least active flux so as to reveal
>>>>all the faults. If something solders well with this, it will solder
>>>>with any flux. Therefore it is normal to use a pure, unactivated WW
>>>>rosin flux (usually 25%w/w). That way, you can get reproducible
>>>>conditions with your suppliers and/or other plants.
>>>>
>>>>Brian
>>>>
>>>>Braddock, Iain wrote:
>>>>
>>>>
>>>>>Why # 1, why would you not want to test with the flux you
>are using
>>>>>on
>>>>
>>>>your
>>>>
>>>>
>>>>>production?
>>>>>
>>>>>Iain.
>>>>>
>>>>>-----Original Message-----
>>>>>From: Munie, Gregory [mailto:[log in to unmask]]
>>>>>Sent: 08 May 2003 15:11
>>>>>To: [log in to unmask]
>>>>>Subject: Re: [TN] Wetting Balance Testing
>>>>>
>>>>>
>>>>>
>>>>> *** WARNING ***
>>>>>
>>>>>
>>>>>
>>>>>This mail has originated outside your organization,
>>>>>
>>>>>either from an external partner or the Global Internet.
>>>>>
>>>>> Keep this in mind if you answer this message.
>>>>>Neil
>>>>>
>>>>>I've done a lot of wetting balance but I have to add a few
> comments
>>>>>on
>>>>
>>>>the
>>>>
>>>>
>>>>>"dip and look." (I agree with all Bev's other comments and
>>>>>suggestions.)
>>>>>
>>>>>The dip and look as it's traditionally done does deserve
>to die. But
>>>>>if
>>>>
>>>>done
>>>>
>>>>
>>>>>correctly it can tell you almost as much as wetting balance.
>>>>>
>>>>>And I define correctly as:
>>>>>
>>>>>1) Use ONLY water white rosin flux. NEVER use any activators in the
>>>>
>> flux.
>>
>>>>>2) Control your immersion (wetting balance is good for this :-)
>>>>>
>>>>>3) Coverage criteria means nothing if you don't see active
>wetting,
>>>>>i.e. solder rises ABOVE the surface of the bath to wick UP
>the part
>>>>>lead.
>>>>>
>>>>># 3 is absolutely critical: in a real world soldering
>situation that
>>>>>is exactly what you want to happen for either wave or reflow
>>>>>soldering.
>>>>
>> It's
>>
>>>>>what happens to the section of the lead that's NOT in
>direct contact
>>>>
>> with
>>
>>>>>the solder that tells you whether the part is solderable.
>>>>>
>>>>>Greg Munie
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>Original Message-----
>>>>>From: Bev Christian [mailto:[log in to unmask]]
>>>>>Sent: Thursday, May 08, 2003 4:25 AM
>>>>>To: [log in to unmask]
>>>>>Subject: Re: [TN] Wetting Balance Testing
>>>>>
>>>>>
>>>>>
>>>>>Neil,
>>>>>
>>>>>You also need to consider what alloy you are using. Dr. Lee of
>>>>>Indium
>>>>
>>>>has
>>>>
>>>>
>>>>>shown that 62/36/2 Sn/Pb/Ag gives significantly different
>results.
>>>>>And
>>>>
>>>>then
>>>>
>>>>
>>>>>there is the work Chris Hunt et al of the British NPL have done on
>>>>>lead
>>>>
>>>>free
>>>>
>>>>
>>>>>solders. And then are you using a solder globule or solder bath?
>>>>>Don't forget temperature, atmosphere (most likely air, unless like
>>>>>Chris you
>>>>
>>>>can
>>>>
>>>>
>>>>>afford a dry box) and preheat (or is that what you mean by hang
>>>>>time?).
>>>>
>>>>If
>>>>
>>>>
>>>>>you are using a globule block we have also found that how centered
>>>>>your component lead is over the solder globule affects
>your results
>>>>>as well.
>>>>>
>>>>>I would say it is not so much the length of the lead
>(unless you are
>>>>
>>>>talking
>>>>
>>>>
>>>>>about something obscenely long - no comments please), but rather
>>>>>what
>>>>
>> the
>>
>>>>>lead is connected to - like an internal heat sink. And, yes, we
>>>>>have
>>>>
>> had
>>
>>>>>ONE problem with the heat sinking ability of a component affecting
>>>>>the results. I gave a short presentation to the J-STD-002
>committee
>>>>>at
>>>>
>> APEX.
>>
>>>>I
>>>>
>>>>
>>>>>will send you a copy. It will not show up for other TechNetters,
>>>>>unfortunately. In essence, we found that wrapping the wetting
>>>>>balance
>>>>
>>>>clip
>>>>
>>>>
>>>>>in polyimide tape allowed the component in question to pass
>>>>
>> solderability
>>
>>>>>testing!
>>>>>
>>>>>All said, we have had excellent results using a wetting
>balance and
>>>>>much prefer it to the dinosaur "dip and look" test, which I would
>>>>>like to see
>>>>
>>>>DIE
>>>>
>>>>
>>>>>for SMT components. Now if we can just agree on what pass/fail
>>>>>criteria will be....
>>>>>
>>>>>regards,
>>>>>Bev Christian
>>>>>Research in Motion
>>>>>
>>>>>-----Original Message-----
>>>>>From: Neil Flatter [mailto:[log in to unmask]]
>>>>>Sent: May 8, 2003 1:17 AM
>>>>>To: [log in to unmask]
>>>>>Subject: [TN] Wetting Balance Testing
>>>>>
>>>>>
>>>>>For those of you doing solderability testing, what sorts of
>>>>>parameters should we be concerned about for reliable results? Our
>>>>>tester already allows inputs for lead perimeter, cross sectional
>>>>>area, and hang time.
>>>>
>>>>My
>>>>
>>>>
>>>>>company's testing also specifies immersion angle, depth, and speed
>>>>>as
>>>>
>>>>well
>>>>
>>>>
>>>>>as the type of flux. By controlling these factors, can I expect
>>>>
>>>>repeatable
>>>>
>>>>
>>>>>results?
>>>>>
>>>>>It has been suggested that we also need to limit the length of the
>>>>>leads
>>>>
>>>>for
>>>>
>>>>
>>>>>our testing as wall as installing a thermal break between the lead
>>>>>and
>>>>
>>>>the
>>>>
>>>>
>>>>>hanger. Both have been blamed for failing test results.
>Has anyone
>>>>>experienced changes in test results from these variables?
>>>>>
>>>>>Neil Flatter
>>>>>TRW-Automotive
>>>>>Process Quality
>>>>>
>>>>>---------------------------------------------------
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>>>>
>>>>
>>>>>Please visit IPC web site http://www.ipc.org/html/forum.htm for
>>>>
>>>>additional
>>>>
>>>>
>>>>>information, or contact Keach Sasamori at [log in to unmask] or
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