Author Topic: PCB copper weight (thickness) and thermal relief  (Read 1385 times)

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Online SiliconWizardTopic starter

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PCB copper weight (thickness) and thermal relief
« on: September 19, 2018, 08:42:16 pm »
Do you typically adjust your thermal relief parameters when designing a PCB with a greater copper weight than standard (eg. 2 oz instead of 1 oz)?

My latest board has 2 oz copper weight and I didn't think of changing anything regarding thermal relief. Pads that are connected to a copper plane (with thermal relief) are *very* hard to solder onto compared to what I'm used to. I even managed to "tombstone" one cap while hand-soldering it, something that has very rarely happened to me. :-DD
 

Offline KL27x

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Re: PCB copper weight (thickness) and thermal relief
« Reply #1 on: September 19, 2018, 08:51:32 pm »
i havent found a a good way to do that in Eagle.

What i have done thus far is to remove the thermal and route a trace into the ground plane, then rename the net of the stub trace to ground. it js a pain to rework, so I try to leave this to the end. honestly i k ow i am missing a step here but i cant remember how i disconnect the pad from the plane.
« Last Edit: September 19, 2018, 08:53:12 pm by KL27x »
 

Offline ConKbot

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Re: PCB copper weight (thickness) and thermal relief
« Reply #2 on: September 20, 2018, 06:06:10 pm »
Yep. You need software that supports rule based definition of thermal reliefs, rather than one generic one for a pour/plane and all the components on it.  I.e. with 2 Oz copper you can set 0402's to have a 6 mil wide connection, 0805s can have wider, MOSFETs that youre trying to sink the the plane can be no relief.  The copper pour gets generated appropriately and no having muck around with manually adding traces. 
 


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