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From: "Richard Rasker (rasker AT linetec DOT nl) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
Subject: [geda-user] Thermals: size problem, SMD
Message-ID: <9f527cf8-d7c0-2b6a-641f-23efb3663ff2@linetec.nl>
Date: Thu, 12 Jul 2018 22:03:53 +0200
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Reply-To: geda-user AT delorie DOT com

Hello,

Some questions with regard to thermals.

1: When I create small vias with a thermal, e.g. 0.3 mm drill width, 
0.15 mm annulus width and 0.15 mm clearing, the resulting four thermal 
connections to the surrounding copper plane get so narrow (just below 
0.125 mm), that my PCB manufacturer flags a warning.
Also, the PCB is placed in a higher (and rather more expensive) 
technology class.
The only way to make these thermal connections wider, is to increase the 
clearance in polygons, but that isn't always desirable, as it eats away 
at the conducting area of any unconnected copper planes.
Or is there another way to increase the width of those thermal connections?


2: SMD thermals, or the lack thereof. If I really need thermals, I 
create tiny rectangles without clearance (S key) to connect pads to the 
surrounding copper planes.


The other, 'lazy' solution is to simply set the clearance of the pad so 
low (with Shift+K) that the pad is completely engulfed in the copper plane.
However, I understand that this may cause problems, not just in the case 
that I manually want to remove the component, but also in the actual 
reflow process ('tombstoning'). So is it better to always use home-made 
thermals? Because that is a bit of a hassle.


Thanks for any thoughts on this.


Best regards,

Richard Rasker