Forwarding for Bob Willis ([log in to unmask])
-------------------------------------------------
The only solder levelled boards used in the hands on event was
tin/copper/nickel solder levelled for me by CEMCO at their contract
service
in Scotland. The boards were produced by Merlin Circuits and we used
tin/silver/copper paste.
When the sections are available I will expand on the story. Please
remember
the aim of this event was to let people get their hands dirty, try
lead-free
processes for real and see what happens with convection and VPS. Also
the
joint on different PCB finishes and to demystify the process.
Again if its missing please circulate and I will ask the IPC team to
confirm
if as you say the responses are going on line or not.
Bob Willis
2 Fourth Ave, Chelmsford, Essex, CM1 4HA
Tel: 01245 351502
Fax: 01245 496123
Mobile: 07860 775858
Email: [log in to unmask]
Web: www.leadfreesoldering.com
Web: www.bobwillis.co.uk
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]]On Behalf Of MA/NY
DDave
Sent: 21 August 2003 02:04
To: [log in to unmask]
Subject: Re: [LF] PCB finishing type for lead free solution with CSP,
BGA & press-fit connector
Hi Bob, and IPC-LF Listservers,
Note: Bob sent a note to me and to this list responding to my
previous note, yet for some reason it doesn't appear. I have
pasted below only a bit of Bob's message that I wanted to furthur
discuss and added one other question under this subject tread.
<--- BobW's note snipped --->
<Well I think I can comment.
<
<The NPL report which is available from the NPL web site on Lead Free
<Reliability with Mixed Alloy Rework concludes that there were few
<issues. I have said the team should, in my opinion, have included
<reliability testing of rework joints as another reference.
<I currently work with the NPL team, but Chris Hunt may like to
<discuss the issue further on the forum.
<----------------------
When I first read that you were allowing mixing of alloys I thought
of all the LF alloys I have seen discussed. Now I am guessing that
you probably meant a range within the SnAgCu family, yet I could
be wrong. Please comment or maybe Chris can??
Would you mix all the way from SnAg25Cu07 to SnAg47Cu17
and also SnAg25Cu07Sb05 into the mix??
It seems a bit messy to me and tough for a Reliability person.
Next Question:
When you did your LeadFree HAL (Hot Air Leveling) or HASL
which alloy did you use? Did you also HASL with different
alloys to experiment with that processing/material facet??
YiEngr, MA/NY DDave
On Mon, 11 Aug 2003 15:49:08 +0100, Bob Willis <[log in to unmask]>
wrote:
>Following the comment from Peter we used solder levelled boards on the
>Lead Free Experience I was running six weeks back in Brighton the
>process, equipment, finishes and components we were running at outlined
> in the story. http://www.smartgroup.org/ev_leadfree3.asp
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