> > anybody have suggestions for fast / easy / clean way of removing
> > part numbers / id info from IC's, a couple hundred to do at a time

> I use a small belt sander with 100 grit belt. You hardly need to apply
> any pressure and you can hand-hold the chip quite safely (better for
> that little bit of tactile feedback anyway)


I'm surprised at all these useful answers (not just the above from my
esteemed co-Westie) with nary a comment on advisability.
What you WANT to do is what Hewlett Packard used to do before they were
seduced by the dark side and became like everyone else (and worse).

-    Identify ALL components clearly
-    Provide detailed circuit diagrams with component lists
-    Provide detailed descriptions of circuit operation including what goes
on inside any special chips.
-    Publish free glossy technical journals describing in detail your
leading edge discoveries and research.
-    Sell at a price that seems high at first but is unbeatable by anyone
wanting to achieve equivalent functionality and quality.

Presumably, if you are de-identifying your ICs, it is to protect users from
unscrupulous repairers who would rip them off.
Presumably it is not to keep out honest competition.
- Presumably you will always be there for them, will always support your
product, will never decide it is too old to be worth servicing, will always
offer a reasonable turn around time and price for repairs.
- Presumably you will hand out full circuits and circuit descriptions fro
free if you decide to no longer do any of the above.

In my experience, ground off part numbers, like encryption schemes and
indeed locks etc, only keep out and inconvenience honest people. It is very
seldom that a competent person cannot deduce what an IC is by its pinout and
functionality.
Harder - yes.
Annoying - yes.
Stops copying - not at all.
Makes life hard for repair people when equipment has been abandoned by the
supplier or the supplier has vanished - you bet.

If you must do it, boiling for an extended period in concentrated red fuming
nitric acid seems to work well :-)




      Russell McMahon
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