Steve,
     
     You stepped on a "hot button" issue at Hitachi.  What we have been 
     doing is maintaining a controlled list of humidity sensitive parts and 
     performing a baking cycle on all of these parts prior to assembly.  In 
     some cases, we keep a tight control (i.e. # of hrs) on exposure to 
     humid conditions and store the parts in a dry box.  We have wanted to 
     eliminate this process for some time but have only managed to remove a 
     small number of parts from "the list".  We are not willing to change 
     the environmental conditions in the plant due to ESD concerns.
     
     This baking requirement places other limitations on our parts such as 
     requiring heat resistant trays and tubes (so no repackaging is 
     required for baking).  It is a "royal pain".  Also, our designers 
     rarely pick parts that are not sensitive or are even concerned about 
     the packaging issues for manufacturing (another sore spot for us 
     component engineers).
     
     The real reason for our problems is that our Receiving Dept. insists 
     on opening all packages to perform a parts count prior to transfer to 
     Incoming Test (ah, beaurocracy at its best).  We have worked with them 
     to properly seal the packages after counting so that we can stop doing 
     a majority of our baking.  Also, we are using more dock-to-stock and 
     instructing Receiving to go by the outside labelling instead of 
     openning the packages.  This also limits the problem considerably 
     (small wonder why we can't seem to get any REAL work done around 
     here).
     
     My suggestion for you is to keep track of the unsealed time on your 
     parts and if it exceeds 2~5 days (your choice) then bake them for 12 ~ 
     24 hours (also your choice) and then restart the clock.  That way you 
     perform an extra process ONLY when necessary.
     
     Regards,
     
     Roger Held
     Manager of Electrical Component Eng.
     Hitachi Computer Products (America), Inc.
     [log in to unmask] com


______________________________ Reply Separator _________________________________
Subject: Humidity Sensitive parts
Author:  [log in to unmask] at Internet-HICAM-OK
Date:    5/9/96 3:18 PM


Hello out there.
     
        We are looking into the handling of our humidity sensitive parts.
We currently keep them in their sealed bags, and reseal unused parts 
immediately after a build(we build very low volumes of boards per day).  We 
are considering controlling the environment in the room where we build, and 
keeping the humidity under 30% to eliminate any moisture build up in the 
parts.  Do I run into other problems, such as ESD issues, and how can I deal 
with those?  Are there health concerns from running in too dry an 
environment?  Any comments would be appreciated.
        Thanks.
     
Steve Quinn
Heurikon Corp