Eric

I agree with Werner, that from the standpoint of performance VPR has a large 
number of advantages. We both have experience going back into the 70's with 
this process. The bad news is the potential environmental risk. This is what 
eventually brought the process to a standstill and as far as I am aware the 
issue is still unresolved. My guess is that it will be sometime before 
anyone develops the equipment to overcome the threat.

Best regards
Lee
JLP Consultants LLC
804 779 3389


----- Original Message ----- 
From: "Werner Engelmaier /*" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 16, 2008 3:28 PM
Subject: Re: [TN] Vapor Phase Soldering - The way Forward?


Hi Eric,
This is another example of the environmentally unfriendly nature of the 
Pb-ban part of RoHS.
Because of the temperatures reqired for SAC, SnAgXx and SnCuYy solders, 
assemblies of higher complexity in terms of larger components and/or thicker 
PCBs, almost invariably will require VPS to assure good wetting and joining 
up of solder volumes [balls & paste, lead 'tinning' & paste, etc.].
The biggest advantage of VPS is the asymptotic heating to the sump 
temperature—it just cannot get any higher than that.

Werner







-----Original Message-----
From: Eric CHRISTISON <[log in to unmask]>
To: [log in to unmask]
Sent: Thu, 16 Oct 2008 8:57 am
Subject: [TN] Vapor Phase Soldering - The way Forward?









Subject

Re: [TN] FW: [LF] Vapor Phase Soldering







" I should also opine that when soldering RoHS-compliant assemblies using

lead-free solder paste, you will probably get a much better yield with

VPS than you ever will with convection. Especially in the case of SAC

solders. "



Richard's statement prompts me to ask a related question.


The subject of vapour phase soldering came up in a review that I
attended this morning on the qualification of a new semiconductor
package. It was stated that VP soldering would become a lot more popular
in the future because of a number of advantages it has over hot air when
using it on lead free components.


What is the opinion of Technet20on this? I'm particularily interested on
predictions of it's usage for the manufacture of high volume PWB assys
for consumer electronics.


Thanks,


-- 
Eric Christison Msc

Mechanical Engineer

Consumer & Micro group

Imaging Division


STMicroelectronics (R&D) Ltd

33 Pinkhill

Edinburgh EH12 7BF

United Kingdom


Tel:    +44 (0)131 336 6165

Fax:    + 44 (0)131 336 6001


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