> When I do my home etched
>=20
> boards I always have the 'Fill Pads' switched on anyway.
>=20
>=20
>=20
> For home made boards, I use a small pad hole in the etch as a center=20
> mark to start the drill. Prevents the drill from walking, and if you are=
=20
> slightly off in your positioning of the drill, it helps the drill to=20
> walk to center. :)

Yes, I used to do that before also. I used GCPrevue and a special aperture =
file=20
where all D-codes for holes was set for a small diameter and all D-codes fo=
r=20
lines was off. A copper layer with this aperture in xor mode (complement?)=
=20
could then be placed over the normal copper layer to create a small hole in=
 the=20
pad.

I havn't come around to do this yet since I started to use designspark. I j=
ust=20
did a couple of boards today where it was a good thing that pads were fille=
d=20
since the top and bottom copper did get a bit displaced. By drilling slight=
ly=20
off center in the pad I could still get an acceptable result for most of th=
e=20
pads on both sides. The hole in small pads could otherwise end up in the=20
clearing between the pad and the groundplane on the top side when drilled f=
rom=20
the bottom side.

This board has a PIC24FJ256GB106, a 64 pin TQFP with a pitch of 0.5mm=20
(19.7mils), and I wasn't sure if it was doable on a home a etched board. I =
used=20
vias with 1mm (39mils) pad diameter and 0.5mm holes (20mils). I try to use =
as=20
thick tracks as I can and on this board the thinnest is 9mils. The minimum=
=20
clearing is 8mils (between the pads for the TQFP). The etching did go well =
and=20
I also seems to have succeded in hand soldering the TQFP.

/Ruben

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124
200 39 Malm=F6 Sweden
Tel +46 40142078
ruben@rjjournal.net
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

--=20
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