it really isn't that simple, at least for us
we can almost never let the bd shop panelize because it just won't come
out the way we want

in the case of a repeated rectangular array of bds with nothing hanging
over the edges, sure maybe

assuming we are talking about a 'panel' that can ride thru the wave
solder and/or reflow oven then the features and dimensions of such an
assembly panel are very different from a 'fab' panel

we often have a 'panel' of interrelated bds which make a 'set' for a
given unit
the bds have no particular dimensional commonality and often have big
parts reaching into each other's space which have to be carefully

also the breakaway details can rarely be left to the fab house unless it
is a very simple situation
even then you have to allow extra room for the traces near the
breakaways so they don't tear

many of our bds have BNCs sticking out well over an inch past the bd
we usually provide a big pc of bd material under those that breaks away
it adds a lot of sq inches and cost but beats the cost of hand soldering

one time we had a big bd with a large cutout in the corner
trying to save work we put a big note in the corner instructing to leave
material there and provide some tabs to break it away
on the first spin a good shop missed it and the corner was fully cutout
we called
on the next spin they provided the material and tabs but they were too
flimsy for our needs
on the third spin they got it right
we moved the board to another shop and it came with a big cutout

from now on we will draw all the tab features

these kind of details make it tough
Dennis Saputelli

Bob Wolfe wrote:
> Abdulrahman wrote
> > The bottom line is that the photoplot people can panelize in seconds,
> > literally. They do it all day, every day. If you must control the panel,
> > then give them a dimiensioned drawing (which can be on a mech layer on
> your
> > original PCB file) and then tell them to step and repeat the other layers
> > accordingly. If you make changes to your board, you don't have to change
> > anything else....
> Absolutely the way to go. A fab vendor is panalizing every board you do
> anyway, even if you
> only want separate boards delivered, they break them out of the panel they
> created.
> The fab house could not make any money if they did one ups on a 12x18 panel,
> or your
> boards would be pretty expensive. They do this like Abdulrahman said every
> day all day.
> All you need to do is provide the geometry of you panel to the fab vendor if
> it needs to be
> controlled for panelized assembly and test. We just added a sheet to the fab
> dwg that defined
> this panel. Also like Abdulrahman stated the only time you will need to
> touch this panel
> dwg again is if the board outline itself changes. This seems to me a whole
> lot easier than dealing with
> trying to merge whole design databases together. If you must be a little
> more contolling yourself
> the CAM software will step and repeat each file too just like the fab house
> does but again why put
> yourself through all that trouble, you will need to do this every time you
> make a simple change to
> the board.
> Let the fab do what they are going to be doing anyway just supply them with
> the
> dimensions you want.
> Robert M. Wolfe, C.I.D.

___________________________________________________________________________            Integrated Controls, Inc.    
   tel: 415-647-0480                        2851 21st Street          
      fax: 415-647-3003                        San Francisco, CA 94110

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