Ground Loops / Multiple Net Pours / Grounding vias

ThomsCircuit said:

Like when the components pad is covered by the component so a paste is applied then it is heated from underneath to melt the solder.

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Example. I do like this guy

Tell me if I'm wrong but (referring to link) it looks like the pad on top and bottom are ground layers with a small area of the soldermask removed underneath and not a signal net.

The top pad is to allow the IC heatsink pad to be soldered.

As you say, the underside having no resist is to allow soldering, but only as the board is being hand-assembled; if it were being machine assembled all components would be fitted then the whole thing reflowed.

Note that there are both VIAs arrays underneath the IC and in the connected copper areas above and below, to provide better heat transfer to the underside ground plane.

rjenkinsgb said:

Note that there are both VIAs arrays underneath the IC and in the connected copper areas above and below, to provide better heat transfer to the underside ground plane.

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I noticed. It really explains not so much the calculations but the methods and how to apply this on my pcb boards with the design spark software.. All the feedback has explained a great deal. I am grateful for this group your input.