Grant

Looking at the postings made, I think the point to be made relates to the
presence of flux residues rather than the condition of the solder.

It would seem that you are leaving too much flux residue which is then
"curing" to form a residue that is too hard to easily penetrate in test.

As you are not cleaning, you should refer to J-STD-001B Section 8.3.5 Flux
Residues: I quote:

"Assemblies shall be tested in accordance with IPC-TM-650, test method
2.3.27 and shall comply with the following requirements for the maximum
allowable level of flux residues:

Class 1 assemblies less than 200 micrograms/ sq. cm
Class 2 assemblies less than 100
Class 3 assemblies less than 40

Maybe you have too much residue in the first place?

Regards,
Graham Naisbitt

[log in to unmask]

WEB: http://www.concoat.co.uk

CONCOAT Ltd
Alasan House, Albany Park
CAMBERLEY GU15 2PL UK

Tel: +44 (0) 1276 691100  Fax: +44 (0) 1276 691227
----- Original Message -----
From: Grant Emandien <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, August 19, 1999 3:18 PM
Subject: [TN] Solder joint curing


> Hi all out there,
>
> What is the average period for a solder joint (reflow and wave) to 'cure'?
I
> also state that I don't quite know what cure means in this instant - but
the
> general problem we have is the minimum period (if there is such a thing!)
> required for a solder joint to cure before introducing it to ICT under
> reasonable conditions of stability.
>
> Our test guys are complaining that the assemblies reach there machines too
> late (hours later), resulting in hardened flux which the test pins have
> difficulty in penetrating, causing damaged pins, retesting and hence
> unnecessary wear of the test fixtures and reduction in throughput.
> Introducing the assemblies too early while the joints are still in
> 'transition' may also result in retesting (true or false?).
>
> As you may have guessed, we don't clean boards as a norm however, this may
> be the way to go in future as will be experimenting with a cleaner
shortly.
>
> Cheers
> Grant
>
> ##############################################################
> TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
> ##############################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
following text in
> the body:
> To subscribe:   SUBSCRIBE TECHNET <your full name>
> To unsubscribe:   SIGNOFF TECHNET
> ##############################################################
> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
> information.
> If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
> 847-509-9700 ext.5365
> ##############################################################
>

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################