MikeR,
        sit down have a coffee, clear your mind a little, chant some mantras
or something. I will try to re-explain the comments about removing the mask
from selected areas. Seems that point is still confusing you.

        Soldermask layers are considered to be negative feature layers.
(i.e. where there is a detail drawn or displayed, this is actually where
soldermask does not appear. Just like power planes.) For a pad, the
soldermask must be cleared, right? In your display for the soldermask layer,
everywhere there is a pad you will see the shape and size of that pad (+/-
any expansion amount). Remember that that pad shape you observe is where
soldermask will not remain when the board is processed.
        Now for your heatsink problem. Assuming the heatsink is rectangular
shaped, I would place (on the appropriate soldermask layer, top/bottom) a
fill of the appropriate proportions. Remember that like the pads, this fill
is a positive feature on your display of the soldermask layer, however it is
processed during fabrication as a negative process so there will be an
opening (void) in your soldermask which corresponds to the fill that was
placed on the soldermask layer.
        If your heatsink is a complex or non-rectangular shape, you can use
the same method using a complex polygon shape on the soldermask layer.

Hope this explanation helps you Mike. It is not complex but for some reason
you seem to be having a mental block over this. I've been there too, some
preconception is probably clouding your perception of what others or myself
have tried to explain to you.

Brad Velander,
Lead PCB Designer,
Norsat International Inc.,
#300 - 4401 Still Creek Dr.,
Burnaby, B.C., V5C 6G9.
Tel. (604) 292-9089 direct
Fax (604) 292-9010
website www.norsat.com


> -----Original Message-----
> From: Robison Michael R CNIN [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, September 19, 2001 5:16 AM
> To: 'Protel EDA Forum'
> Subject: Re: [PEDA] eliminating solder mask ??
> 
> 
> thanks to all who responded.  i've absorbed some of it and i'm still 
> chewing on the rest.
<SNIP>
> 
> there was also talk about just deleting the mask where the heat sink
> goes, and a polygon "pour" or "fill" was suggested here.  i have never
> done this before.  i'll have to dig into the documentation 
> and find out how
> thats done.
> 
> again, thanks to everyone for helping.
> 
> miker

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