With a library part meant for PTH a hole might have a 8 or 10 mil ring
around it. If you want a structurally sound pad i would use about 1mm
ring around the hole minimum (this is about 40 mil). This greatly
depends on the component and a lot of other things.
For components with 100mil pitch this obviously means oblong pads,
round or square ones won't cut it for me.
It is a big no-no to put any lifting force on a pad anyway because
each component must sit flush against the other side or use some form
of standoff or special bend. But despite this pads still often
experience lifting forces and must be properly large for strength. In
a PTH board the plating forms sort of a rivet with the two pads and
solder, which is reasonably strong on it's own.
ST
On Feb 17, 2008 10:18 PM, Chuck Kelsey <wb2edv@...> wrote:
> Give some examples of what you guys believe to be good pad sizes for various
> applications.
>
> Thanks,
> Chuck
> WB2EDV
>
>
>
> ----- Original Message -----
> From: "Stefan Trethan" <stefan_trethan@...>
> To: <Homebrew_PCBs@yahoogroups.com>
>
> Sent: Sunday, February 17, 2008 4:08 PM
> Subject: Re: [Homebrew_PCBs] Re: DipTrace
>
>
> > It's not just an issue with toner transfer. Most PCB packages come
> > with component libraries meant for professionally made PTH boards. The
> > pads are far too small for single sided boards and beginners wonder
> > why their boards come out crappy and unreliable. The ones that aren't
> > lazy will do what you did and get good results, the others, well,
> > let's hope they'll learn eventually.
> >
> > At least all decent PCB packages allow to change pad size after the
> > fact when the part is placed. Eagle does not, of course, i hate it.
> >
> > ST
> >
> > On Feb 17, 2008 9:51 PM, Myc Holmes <mycroft2152y@...> wrote:
> >> When using the Toner Transfer method, it is helpful to have oversized
> >> pads,
> >> to prevent liftoff while soldering.
> >>
> >> I created an entire library of Toner Transfer friendly pads as well as
> >> adding many new compnents for my own use.
> >>
> >> Myc
> >>
>
>
>
>
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