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what does thermal relief mean?

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ayeong

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what is thermal relief ?

I have been going through the PowerPCB Concepts document and came across several times on the term "thermal relief".

What is "thermal relief" all about ? It seems to be associated with VIAs and through holes.

Thanks

Best Regards
 

Rayengine

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Thermal Relief

When you consider through hole component, it is very difficult to desolder the leads which connected to Ground (A large plan of copper). Thermal Relief is to add some bridges instead of the large plan connected to Ground or other signal carried the same nature. Heat won't absorb rapidly --- so called Heat Relief.
 

yingyang

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thermal relief

:wink:
Anybody have any idea of computing the thermal relief or modeling method???
 

cyberrat

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Computing it? no its not that complicated.

The pad has a cutout in the copper around with 4 bits of copper in a cross fashion from the copper to the pad, you just ensure that those 4 are of sufficient width to handle the current etc.

I.E. for a standard 1/4w resistor hole a thickness of approx 20-30 thou with a clearance of 20-30 thou should suffice, AFAIKR its not rocket science.
Just creating enough relief to allow the pad to heat up to accept the solder
without all the cooling produced by attaching it to groundplane.

Roland.
 

amjad

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Re: what is thermal relief ?

A shape has circle having spokes used for connections in negative planes.
 

Ice-Tea

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Re: what is thermal relief ?

Another reason to have thermal relieve pads instead of the entire surface of a large (read: capable of holding lots of heat) is that when you have wave of reflow soldering of your board, the component may 'drain' so much of the heat that your solder won't heat up enough and produce bad solder joints.
 

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