Carl Denk <cdenk <at> alltel.net> writes:

> 
> This sounds reasonable and appears to be the case. On one side (face) 
> there are traces concentrated toward the right, and toward the left are 
> a mess of the squares, mostly arranged in an array. It appears  that the 
> original order and the later order came out of different shops,the green 
> and opacity are different shades.

The squares thing may be applied only to certain materials. I don't know which.
Google does not seem to have a term for this. Here is a nice glossary of terms
wrt. PCB:

  http://www.ami.ac.uk/courses/topics/0100_gls/pdf/edrmt005_v2.pdf
 
> Is there a way to specify this copper balancing not be done?

Don't know. You have to talk to them first ;-) Afaik the patterns are used for
wave soldering and for IR ovens for large areas, only for SMD and mixed boards.
It depends on the process.

> I had been trying to keep all the traces on the bottom of the board, 
> sounds like I should try to balance the top and bottom copper? From a 
> hand soldering view, and knowing that (shouldn't happen but once in a 
> great while does) a trace may become loose, and it's easier to fix if 
> the trace is on the bottom.

It is not your concern, it is theirs. You only need to deal with this if you
have to work with production to avoid warping boards from 'tossing' SMD parts or
causing large bulky components (like large SMD chips) to be become unseated. The
squares were certainly not put there to 'help' your design, and they almost
surely help with chemical consumption (etchant and manuf. speed) and someone
else's more stringent design (if it was panelized with that).
 
> Really appreciate this explanation, I try very hard to be equitable with 
> everyone, but I can't excuse PCBFABEXPRESS from not replying promptly. 
> Likely will go ahead and use the boards. :)

You have no reason not to use them. Only some boards with HV clearance or RF or
low capacitance requirements are affected by this.

Peter P.


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