Regarding this, it all depends upon what the changes are.
If for instance there is an alteration to the circuit by the addition or
changing of components then I would agree on the revision change.
Any boards that have left the factory of this issue could when returned
for replacement etc be instantly identified as being different by their
revision number.

If for instance a components lead diameters have changed and the
drilling details of the board need altering to suit, and the pads on
the board are suitable to provide adequate land for a different drill
size, then only the NC drill data & drill drawing need altering.
This should not need an increase in revision unless you are going to run
both the old & new boards alongside each other, as a direct replacement
for the previous board (which is now populated OK) why increase the
revision?

The cost of this change is usually limited to half a days work in
altering & re-issuing the drilling detail drawings and whatever it costs
for the
PCB manufacturers re-tooling.

At my employers over here in the UK the changes to a board have never
costed as much as 25-250k even after $/£ conversion.
As we are talking about modifications and not starting from scratch, I
generally find that most MOD's take about
1-2 days for schematic & PCB changes.
1/2 day to create Gerber files and check them.
1/2 day ensuring that all drawings etc are printed & issued to the
correct departments.

Also 1 week to get the approval from the engineer/manager responsible
(only joking on this bit, but it does take a while !).

So this would cost about 3 days labour plus the retooling costs from the
PCB manufacturers (typically £100 for me).

Now we may not be doing the same sort of large scale production that
some of you do but a PCB is a PCB and the same sort of
things apply to all boards simple or complex, with times & cost
increasing depending upon the complexity, layer count & modifications
involved. 






T.T.F.N

Matthew Lamkin
Printed Circuit Board Draughtsman
Protec Fire Detection PLC
Churchill Way,
Nelson, Lancs
BB9 6RT.
Tel 01282 717393
Fax 01282 717273
Email = [log in to unmask]

Company Web Site = http://www.protec-fire-detection.plc.uk


>-----Original Message-----
>From:  [log in to unmask] [SMTP:[log in to unmask]]
>Sent:  Friday, April 30, 1999 1:34 AM
>To:    [log in to unmask]
>Subject:       [TN] Revision change costs
>
>     I am interested to find out how much it cost to change a revision on a
>     PCB.  Here is the situation:  A PCB is in use on a product already in
>     production.  Say an item on the fab drawing needs to be changed - one
>     that does not affect form, fit, function.  Some here believe that any
>     drawing that has left the building needs a rev change.  I'd heard once
>     in a seminar that to change artwork on a board in production could
>     cost from 25K - 250K.  Is this so?
>     Any input is appreciated.
>
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