I'd say you're way ahead of average Anil ; just contemplating the options .
I don't fancy labels as well ; so far the best I managed on part No.s and
Revisions is a grid of mini (gold) pads ; which are on each dispensing
program filled (marked) with paste ; so when it goes through reflow , the ID
is "printed" in solder .
Did try to train Gemini into serial thinking ; so far still battle with it ;
as you can imagine your 1-400x first ; 401-800x second ; etc.....: panel ID
sequencing is not fun on programming . Still didn't give up ; must be
possible one way or other ( 7 segment[pad/dot] digit ) ; just the
programming time is bit on the far side .

I can do it on laser marker flying on XY ; but that is one of my "lunch
time" projects ; the expense and return validation is tedious , not too fast
on this one .
There is also printer , as you said ; but with all sorts of available
landings on panel configurations this would have to be on XY as well , + Z
extra on rotation as comparing with laser diode marker . Nice auto project
if you have time to play .
Handheld  indenting (forget the ink pain if you can) serial counters should
be everywhere ; or easily tooled up ; within 1" space .
I used to use them heated on plastic parts . The prefix was manual ; the
serial advanced each trigger click (say Z 0001) .

Check pro's like : http://cmslaser.com/html/systemphotos.html
<http://cmslaser.com/html/systemphotos.html>  ;
if it won't click on you ;
go via dogpile to "laser marker" .
They have for example specifically pcb marker , and application support .
If you'd mark on the white silk screen flags ; you get good definition for
bar coding as well (if you have enough time in cycle to burn) .
The PC SPC link of Serial with date and say profile of the moment record
should be than relatively "easy" .

Have a fun ; keep in touch if you'll be winning faster than me .
paul



-----Original Message-----
From: Anil Kher [mailto:[log in to unmask]]
Sent: Tuesday, 17 August 1999 14:14
To: [log in to unmask]
Subject: [TN] Indelible Marking on Finished PCBs


I am surprised that no one is marking finished PCBs. Are we still sticking
BBT OK stickers which get into post assembly wash and clean  etc.- or are
you using bar coding ?? I must be truly living in the stone age then.

My problem is that I process PCBs in a 40 to 400 panel Up. The panels have
traceability upto singulation. Post singulation there is no way we can
impart traceability except by marking them as they pass thru inspection. I
wish I had one of these hand held labelling machines kind of that will allow
me to print on each PCB " BBT OK, SNo XXXXX" next one " BBT Ok, SNo XXXX1"
and so on. Since the nos. would be small we need a digital printer -
preferable hooked up to our PCs so that we can keep track of the cards sent
with every Invoice.( and keep a record of the singulated card no. to the
production panel no.) The printer could be desktop or hand held. Latter
preferable. The ink should be quick drying with UV ?? I know the wishing
season is far away so help me G O D.

Anil

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