Ioan, 
For all our sakes, I hope you are right. However, Klein Wassink retired a long time ago, and remember, these are some of the same folks that gave us RoHS.
Werner

 

 

-----Original Message-----
From: Ioan Tempea <[log in to unmask]>
To: [log in to unmask]
Sent: Sun, Nov 22, 2009 9:03 pm
Subject: Re: [TN] NTC Large Hadron Collider Restarts


Esteemed colleagues,

I have always considered the knowledge of Technet as my supreme source and I 
have learned a lot!

But should we even think the people soldering the hadron had no idea what they 
were doing? Honestly, I am not worried a bit that just anybody got this task. I 
bet big scientists were involved, even if we don't know them. Let's not forget 
the soldering bible has been written by a Dutch...

Regards,

Ioan Tempea, ing.
Ingénieur Principal de Fabrication / Senior Manufacturing Engineer
T | 450.967.7100 ext.244
E | [log in to unmask] 
W | www.digico.cc

N'imprimer que si nécessaire - Print only if you must

-----Message d'origine-----
De : Steven Creswick [mailto:[log in to unmask]] 
Envoyé : Sunday, November 22, 2009 7:46 PM
À : [log in to unmask]
Objet : Re: [TN] NTC Large Hadron Collider Restarts

Steve,

I admit that I should have taken more than a quick glance at the process
document which you presented, however, if the both parts of the joint have
been pre-tinned, AND the JOINT to be soldered is indeed brought up to 230C+,
why shouldn't the joint be reasonable?

My recollection is that the Sn96.5/Ag3.5 is a eutectic solder, melting at
221C, so the 230C is certainly a whole lot closer than I would prefer to run
with, but it should indeed have melted and bonded with the pre-tinned
surfaces.

Subsequent posts have discussed tin pest, etc.

My greatest apprehension is in regard to the stresses imposed in the joint
[any joint material] when transitioning from room temp to cryogenic and back
again.  I hope there is some serious stress/strain relief built into the
joint structure!

Werner, since you have had the opportunity to see the instrument to some
degree, can you provide insight as to the physical size and potential delta
length which may be involved in the soldered joint?

What are the physical sizes of the 'leads'.  Are they too large to join them
with a high-power ultrasonic welder, and do away with solder altogether?? 

Steve C

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