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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