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Date: | Thu, 26 Aug 2004 10:37:22 +0200 |
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Guenter,
12 microns of copper dissolved by solder ???
I just took a look into IPC 6012A electroplated copper thickness in holes :
minimum thickness allowed in through holes 18-20 microns . In low aspect
ratio blind vias 10-12 microns allowed. So maybe SMD device will be still
attached to the surface, but what about holes ???
There is something wrong.
Edward
Edward Szpruch
Eltek Ltd
P.O.Box 159 ; 49101 Petah Tikva Israel
Tel ++972 3 9395050 , Fax ++972 3 9309581
e-mail [log in to unmask]
> -----Original Message-----
> From: Guenter Grossmann [SMTP:[log in to unmask]]
> Sent: Thu August 26 2004 9:14
> To: [log in to unmask]
> Subject: [TN] Antw: [TN] LF Solder Pot
>
> Victor
>
> Lead free solder in a wave solder machine does solve a lot of copper from
> a PCB. Trials that where done at ERSA with a solder pot temperature of
> 275°C and a conveyor speed of 1m/min showed that approx. 12um of copper
> have been eaten away from a SMD pad. The only way to avoid this is to
> lower the temperature as far as possible. The lowest wave temperature we
> where able to solder through hole on a 4 layer FR4 with 2 fully metallised
> inner layers was 245°C; 1m/min with SnAgCu. However, this is was the
> lowest limit. We settled now on 250- 255°C for a pilot production.
>
> Best regards
>
> Guenter
>
> EMPA
> Swiss Federal Laboratories for Materials Testing and Research
> Centre for Reliability
> Guenter Grossmann, Senior Engineer
>
> 8600 Duebendorf
> Switzerland
>
> Phone: xx41 1 823 4279
> Fax : xx41 1 823 4054
> mail: [log in to unmask]
>
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