Jim,
I echo my colleague's remarks.
In my former life, we identified parts for heat, moisture, and ESD
sensitivity on the parts lists, drawings, and manufacturing planning (shop
routing sheets). Where there was doubt, we always sided on the most
sensitive.
For example, with moisture and ESD sensitivity, we found that most
manufacturers did label their hardware but did not know if the hardware
would survive specific environments. When we implemented aqueous cleaning,
we discovered that specific resistors were damaged by the cleaning process,
while the supplier insisted that their hardware would survive the process.
Through materials and failure analysis, we discovered that the resistor not
only would be damaged with aqueous cleaning but also with vapor degreasing.
We could only clean these parts via Isopropyl Alcohol (IPA) and a hand brush
after soldering.
Another horror story had components that were "ESD Class 1" certified by the
vendor. We discovered that the components were actually "ESD Class 0" after
circuit boards started failing at test and in one instance at the customer.
The vendor, and our Engineering department, did not know until failure
analysis was performed and it was determined that these devices were
classified "Class 0" by our internal QA organization.
Caveat Emptor: Let the buyer beware.
Hope this helps.
Good Luck.
Lee Whiteman
Senior Manufacturing Engineer
E-Mail: [log in to unmask] <mailto:[log in to unmask]>
Ph: (610) 362-1200 x208
Fax: (610) 362-1290
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of Jim Jenkins
> Sent: Wednesday, September 18, 2002 2:03 PM
> To: [log in to unmask]
> Subject: [TN] Moisture sensitive parts
>
>
> Hi everybody,
>
> Lately we have had a few problems with moisture sensitive part
> precautions.
> During the design phase, a part is identified as moisture sensitive. The
> purchase orders are then modified to include packaging/labeling notices
> identifying the moisture requirements. Then, when the parts are received,
> some are properly packaged and labeled and some are not. In all cases when
> we contact the supplier we are told that the part in question is no longer
> sensitive [component assembly processes were changed, etc] or we
> have parts
> come identified as sensitive which were not when we created the design. So
> the $1000 QUESTION is, do you try to identify moisture sensitive parts on
> your design documentation or do you rely on your supplier to properly
> identify and package sensitive parts and just handle them accordingly when
> you receive them???
>
> We have had a number of discrepancies, and I was wondering what everyone
> else does to avoid this kind of thing. As always, thank you in
> advance for
> any help you can provide.
>
> Have fun,
>
> Jim Jenkins
>
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