> At my new company we are using vendors who can't 
> plot their own film, and we have to modem the data
> over to a photoplotting vendor. This implies that
> NO up-front engineering type CAM work is being done,
> and most of these boards are impedance controlled
> RF designs. Am I confused in thinking maybe we should
> look for more modernized vendors, or did I just get 
> spoiled by cream-of-the-crop high-tech excellence? 
> (Also, its probably worth noting that the previous 
> employer's concern was high-quality prototypes FAST 
> TURN no matter the cost. Whereas here, money is a big 
> issue and these low-tech places are CHEAP!) 
> Not trying to start any wars here, but I'm curious
> how many vendors these days just work from someone 
> else's film?
************************************************

Jack,
Can only reply to our earlier processes.  I'm sure somebody else does it
somewhat different. 

The only time we used to put targets on the artwork was when we laid
out boards by hand.  The targets were used for reduction of 4/1
artworks.

Then we started photoplotting artworks at 1/1.  We never used targets,
but we DID plot on 7 mil film.  It's more stable than the 3 mil that was
being used, and once the temperature stabilized after shipping to the
board vendor, who in turn made their copies, we never heard of any
problems.

Our vendors can plot their own originals so now we just send the
gerber file, no artworks.

I guess the only thing I'm unsure of in your process is if you supply x-y
drill listings to your vendor.  It wasn't mentioned.  I would think that if
they were having any problems with film shifting or
expansion/reduction,  they would then have problems meeting annular
ring of the holes and would be calling you.  If they're bombsighting, the
problem would be possibly the wrong size board, track too close to the
edge or exposed, or the tracks are smaller than designed.  

Hope this helps somewhat.

Larry Campbell
BFGoodrich, Avionics Systems
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