I never saw that article (post a link to it if you find it) but it is more likely that it is the plating in the holes that dissipates the heat. For example, if you drilled unplated holes to get air flow, I would bet you a lunch the net effect would be HOTTER at the component in question unless you have forced air flow, because you removed material. but by plating the holes, you added a thermally conductive path that is about 1000 times better than fiberglass at conducting heat. very common practice... hope I'm not steering you wrong, Jack On Thu, Oct 29, 2009 at 1:39 PM, SUBSCRIBE DesignerCouncil wheels < [log in to unmask]> wrote: > Guys, > > A EE there had convinced us to take small pours that connect to a tabs of a > SOT-223 and add vias to the pour. Mind you that the pour were not gnd and > had no reason to connect to a opposite side pour. The claim was that having > holes in the board would help dissipate heat by air flow. I thought he was > crazy. Then I saw an article that supported his claim. I can seem to find > it > now. Anyone remember seeing it. I think it was publish this year. > > > John > > --------------------------------------------------------------------------------- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL) Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ---------------------------------------------------------------------------------