Siegmund,
We use a label and place it in a 0.30 X 0.90 inch opening in the solder
mask.It contains all of the standard marking data required,as well as an USN
in alpanumeric human readable characters and machine readable code( bar code
3 of 9,128 and 2 D data matrix).It is readable and permanent, whether
Conformally coated or not.
These labels are for Aerospace applications and all of the "due diligence"
has been completed to establish the acceptability for use in that
environment.
The USN is the TEI(text element identifier)for the 5 digit CAGE Code of the
Manufacture and the true permanent serial number assigned to that
entity.This is in compliance with ATA Spec 2000 requirements.
Dewey

> -----Original Message-----
> From: Zweigart, Siegmund [SMTP:[log in to unmask]]
> Sent: Friday, May 09, 2003 3:59 AM
> To:   [log in to unmask]
> Subject:      [TN] laser marking systems
>
> Hello all
>
> For a new customer we are looking into laser marking systems.
> It should be able to mark bar code and 2D data matrix codes in the solder
> mask.
> We had some discussions with customer and some potential suppliers.
> Some questions came up:
> -       What is better: Nd-YAG or CO2 laser (in the Nd-YAG process the
> solder mask is removed down to the bare copper,         with CO2 only the
> color is changed).
> -       Do you have any experience with readability of the barcode after
> the
> product was exposed to Air / humidity / soldering       processes?
>
>
> All input welcome
>
> Siggi
>
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