He could have just said one ounce per square inch. (Close enough!) Seems
easier to remember than 4.65 g/cm2. But eventually you're going to end up
doing some arithmetic, either way.
Tim Reeves

-----Original Message-----
From: Eric Christison [mailto:[log in to unmask]]
Sent: Monday, July 23, 2001 8:44 AM
Subject: Re: Component Mass / Pad Geometries


Nice to see some consistent units - g/in^2 here. Haven't seen this mix since
I came across a stress quoted in N/in^2 ;-).....





> Hi Steve!
>
> The formula that has been floating around for a while is that you get
> 30-grams of surface tension for every square inch of pad surface....
>
> -Steve Gregory-
>
>
> > Question?
> >
> > There is a formula somewhere which I can use to calculate the maximum
> > allowable mass of a component in relation to the pad lands. Basically
>  I
> > want to make sure our designers do not put components on the underside
> > of the PCB which are going to fall off during doublesided reflow.
> >
> > I would like to point out that this is a design for manufacturability
> > question, not an attack on the tentative grasp on reality some card
> > designers have.
> >
> > Steve.
> >
>
>
>


Eric Christison

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