Lieber Herr Jeremias,
Ich stimme Ihnen zu.
Weil vielleicht die Goldversprödung keinen Funktionsausfall bei Durchlöchern herbeiführt, kann es doch zu einem Totalbruch führen.
Ich würde dem Zulieferer vorschreiben auch bei kleineren Goldschichtdicken als 2,5 µm zu entgolden.
Hinsichtlich der Normen, wenn man etwas darin finden will, muss man sich daran beteiligen um es durchzudrücken.
Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com
-----Original Message-----
From: Jeremias, Michael <[log in to unmask]>
To: [log in to unmask]
Cc: [log in to unmask]
Sent: Tue, Aug 4, 2009 12:14 pm
Subject: WG: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT
Lieber Herr Engelmaier,
In der J-STD-001 steht:
3.9.3 Gold Removal Gold shall13 be removed:
• From at least 95% of the surface to be soldered of the through-hole component leads with 2.5 μm [0.0984 mil] or more of gold.
• From 95% of all surfaces of surface mount components to be soldered regardless of gold thickness.
• From the surface of solder terminals plated with 2.5 μm [0.0984 mil] or more of gold.
A double tinning process or dynamic solder wave may be used f
or gold removal.
Electroless nickel immersion gold (ENIG) finishes on PCBs are exempt from this requirement.
These requirements may be eliminated if there is documented objective evidence available for review that there
are no gold related solder embrittlement problems associated with the soldering process being used.
(13) Class 1-Not Est
Class 2-Proc Ind
Class 3-Defect
Das heisst ein Zulieferer, der nach J-STD-001 liefert darf auf den Entgoldungsprozess verzichten, wenn bei through hole componenten die Goldschichtstärke unter 2,5 µm z, B 2,4 µm beträgt. Ist das wirklich so zulässig?
Oder sollen wir unserem Zulieferer vorschreiben auch bei kleineren Goldschichtdicken als 2,5 µm zu entgolden. Sie schreiben doch, dass selbst bei bei viel kleineren Durchschnittsgrössen als 3wt% Goldversprödung vorkommen kann. Und mit 2,5 µm Goldschichtstärke lässt sich das in einem engen PTH nicht erreichen, da die Lofüllung nicht ausreicht.
Sie schreiben auch, dass die Gefahr besteht, dass das Gold nicht gleichmässig verteilt sein kann. Das wirkt sich natürlich bei Feinpitch BAuelemneten umso mehr aus. Dann sollte das auch in den Normen so stehen.
Sincerly
Michael Jeremias
Industrial Engineering (OPPI41)
Electronics Production
((( Defence Electronics
EADS Deutsc
hland GmbH
89077 Ulm
Tel.: +49 (0) 7 31.3 92-5533
Fax: +49 (0) 7 31.3 92-73 15
E-Fax: +49 (0) 7 31.3 92-20 5533
-----Ursprüngliche Nachricht-----
Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Werner Engelmaier /*
Gesendet: Dienstag, 4. August 2009 13:44
An: [log in to unmask]
Betreff: Re: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT
Lieber Herr Jeremias,
1. Es ist nicht leicht ein IEC Dukument zu ändern.
2. Die meistens Länder haben eine Vertretung bei der IEC die für solche Anfragen zuständig sind.
Wie ich schon früher gesagt habe, sind diese Goldgrenzen von 1,6 vol% oder 3 wt% sehr grobe Daumenanpeilungen, und Goldversprödung kann bei viel kleineren Durchschnittsgrössen vorkommen, da in den meisten Fällen das Gold nicht gleichmässig verteilt ist.
Ausserdem, ist diese Goldversprödung nicht eine Ja/NeinSache sondern brigt eine absteigende Gefügeschwächung.
Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com
-----Original Message-----
From: Jeremias, Michael <[log in to unmask]>
To: [log in to unmask]
Sent: Tue, Aug 4, 2009 4:09 am
Subject: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN
A SOLDER JOINT
Unfortunately, the discussion about the matter is not so serious as the problem.
Proceedings in technological quality are not available by (hundreds!) of mails with ridiculous content but by hard work.
1, Who knows the responsible at IEC or TC91, who is able to change it?
2. Who is able to make thebchange request?
Sincerly
Michael Jeremias
Industrial Engineering (OPPI41)
Electronics Production
((( Defence Electronics
EADS D
eutschland GmbH
89077 Ulm
Tel.: +49 (0) 7 31.3 92-5533
Fax: +49 (0) 7 31.3 92-73 15
E-Fax: +49 (0) 7 31.3 92-20 5533
P Before printing, think about the environment !
mailto: [log in to unmask]
EADS Deutschland GmbH
Registered Office: Ottobrunn
District Court of Munich HRB 107 648
Chairman of the Supervisory Board: Dr. Thomas Enders
Managing Directors: Dr. Stefan Zoller (chairman), Michael Hecht
This E-mail and any attachment(s) to it are for the addressee's use only.
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0
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-----Ursprüngliche Nachricht-----
Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Joyce Koo
Gesendet: Freitag, 31. Juli 2009 19:06
An: [log in to unmask]
Betreff: Re: [TN] AW: [TN] AW: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A
SOLDER JOINT
Who ever made doc and approved it should get shot at... seriously. Not a Friday
joke.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jeremias, Michael
Sent: Friday, July 31, 2009 12:17 PM
To: [log in to unmask]
Subject: [TN] AW: [TN] AW: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A
SOLDER JOINT
Unfortunately it is not (!)=2
0a typo from me . The document DIN EN 61191-1
contains this value 2,5 µm . But I am not confident, that this is low
enough for any process cases so we use for PTH the same rule as above as
mentioned below
Sincerely
Michael Jeremias
-----Ursprüngliche Nachricht-----
Von: TechNet [mailto:[log in to unmask]] Im Auftrag von Joyce Koo
Gesendet: Donnerstag, 30. Juli 2009 12:22
An: [log in to unmask]
Betreff: Re: [TN] AW: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER
JOINT
Must be a typo. Should be 0.25 micron? 10 micro-inches?
---------------
-----------
Sent using BlackBerry
----- Original Message -----
From: TechNet <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Sent: Thu Jul 30 04:26:14 2009
Subject: [TN] AW: [TN] FORMULA FOR DETERMINING GOLD PERCENTAGE IN A SOLDER JOINT
IEC 61191-1
chapter 6.2.2 contains the rules
< 1,4% Volume Au, < 3% Wt Au in the final solder interconnection
< 2,5 µm for PTH Wave soldering (I am not confident, that this is low enough
for any process cases so we use for PTH the same rule as above)
You have to take into consideration solder paste volume(stencil-thickness),
wetted Au-surface, wetted Au thickness
Own investigations show, that Au brittelness may occure from 1,6% Vol and
really will occure from 2,3% Vol.
Sincerly
Michael Jeremias
Industrial Engineering (OPPI41)
Electronics Production
((( Defence Electronics
EADS Deutschland GmbH
89077 Ulm
Tel.: +49 (0) 7 31.3 92-5
533
Fax: +49 (0) 7 31.3 92-73 15
E-Fax: +49 (0) 7 31.3 92-20 5533
P Before printing, think about the environment !
mailto: [log in to unmask]
EADS Deutschland GmbH
Registered Office: Ottobrunn
District Court of Munich HRB 107 648
Chairman of the Supervisory Board: Dr. Thomas Enders Managing Directors: Dr.
Stefan Zoller (chairman), Michael Hecht This E-m
ail and any attachment(s) to it
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