Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 20th May 2008, 09:51 AM   #1
zoolu is offline zoolu  Israel
diyAudio Member
 
Join Date: May 2008
Default Hand assembly cosmetics

What are the main changes associated with lead-free hand assembly cosmetics?
  Reply With Quote
Old 21st May 2008, 01:59 PM   #2
diyAudio Member
 
Join Date: Feb 2005
Location: S.England
Have you tried using lead free solder yet? It is HORRIBLE. You also need higher temperatures...

This RoHs is VERY wierd though but I agree with most of it: 'lead' free is a euthamisim, it is not just about lead content. It has taken us the best part of 2 years to get to lead free on our products.... products that rely on heavy LEAD acid batteries...

Andy
  Reply With Quote
Old 22nd May 2008, 10:11 AM   #3
diyAudio Member
 
Join Date: May 2008
Lead-free solders flow a little slower than 63/37 using the same activation levels for the fluxes.
The contact angles are slightly larger and feathering out of the solder is therefore less
pronounced. The solder joints tend to be less reflective than 63/37 solder. Some re-training is
required prior to a full transition to lead-free is done.
In some cases certain shrinkage effects as described in Section 5 of the IPC-STD-610D occur.
The IPC-610 classifies these as soldering anomalies and not necessarily defects.
As mentioned on page 5-22 of the above document, it is not a defect for Class 1, 2 and 3 if the
tear bottom is visible and the shrink hole does not contact the lead, land or barrel wall. See the
photos below for examples taken from the Kester laboratory.
What is the best soldering tip temperature for lead-free SAC and SnCu?
The temperature of the tip or contact temperature is very important to ease the lead-free handsoldering
operation. When using 63/37 solders temperatures as low as 650:F have been used
but with lead-free 700-800:F is best. The higher temperature does compensate for the slower
wetting exhibited with these lead-free alloys.
Above 800:F issues of board and component damage may arise; at lower temperatures cold
solder joints and flagging are the normal complaints.
Higher temperatures and longer contacts with the parts to be soldered may also increase the
intermetallic bond layer. So avoiding prolonged contact and repeated rework is not
recommended. The above diagram shows what happens as the bond layer increases in
thickness a higher risk of embrittlement occurs.
The risk of de-wetting also increases with higher temperatures.
I think it will help you out.
__________________
http://swpc.co.il/
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
want dead counterpoint SA100 SA-100 in good cosmetics jlw Tubes / Valves 0 4th October 2007 08:52 PM
cone cosmetics el`Ol Full Range 4 27th June 2005 03:21 PM
A little hand 4 amp_man Polimorph Solid State 2 15th June 2004 01:18 AM
Second hand oscilloscopes in the UK trwh Equipment & Tools 10 17th November 2003 05:57 PM


New To Site? Need Help?

All times are GMT. The time now is 02:39 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2