Hi all,

I am looking at IPC-2222 9.1.2 regarding thermal relief pads. It provides a
formula for
the web width based on the minimum pad size.

I can use this method with my current software, which allows me to create a
thermal
relief for each pad. But, I also use a system that only allows me to specify
thermal
relief pads for 'non-vias' in a particular plane.

My questions are, what are you guys using to calculate your thermal relief
pads?
Do you calculate the web size for each pad used, Or do you have some other
method of calculating the web width.

Any advice, rules of thumb etc. would be most appreciated.

Just one more thing, could anyone confirm what is meant by "Standard
Manufacturing Allowance"
in IPC-2222 Figure 9-1. Is this the same as IPC-2221 table 9-3 "Minimum Hole
Location Tolerance, dtp"?

Regards.

Mark

Mark Holmes PCB Designer
Helvar Merca Ltd.
Hawley Mill
Hawley Road
Dartford
Kent DA2 7SY
Tel: 01322 222211
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