X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f X-Recipient: geda-user AT delorie DOT com X-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tfsoft.org.ua; s=mail; t=1518219020; bh=8E5KvXgktrR0ZrxKD49VOaIaGwKbd1AOtyTYbloQ9iw=; h=To:Subject:Date:From:In-Reply-To:References; b=B7pmh7fGALoS8td71RI7fOUpqNCBsAV3ykV5WJe8XVhENlSy7GYWs8nscTi6DBAau 5RNVoXfCCb66v5U5iuhON3ir9Bgz1PpYQCJfzrccGbmLuiBf82fabaQMkOdrYuL+eC niL+JXcnvyuis/GumeMSWUdwWbEAIYroK0VUjnuw= To: geda-user AT delorie DOT com Subject: Re: [geda-user] tented vias in center pad of QFN? X-PHP-Originating-Script: 0:rcube.php MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Sat, 10 Feb 2018 01:30:20 +0200 From: "Anton Dubniak (twister AT tfsoft DOT org DOT ua) [via geda-user AT delorie DOT com]" Organization: TFSoft In-Reply-To: References: Message-ID: X-Sender: twister AT tfsoft DOT org DOT ua User-Agent: Roundcube Webmail/1.2-beta Reply-To: geda-user AT delorie DOT com Errors-To: nobody AT delorie DOT com X-Mailing-List: geda-user AT delorie DOT com X-Unsubscribes-To: listserv AT delorie DOT com Precedence: bulk John Griessen (john AT ecosensory DOT com) [via geda-user AT delorie DOT com] wrote 2018-02-10 00:57: > Hi, Does a via in the soldered area of a center pad of a QFN work > well with solder mask on the back covering the holes? > Or, do they need to be open? They should not be tented, as the trapped air will prevent the tension forces to do its job and solder will not be sucked inside the vias, which, in turn, will not result in a good thermal contact. Once I forgot about solder mask check in a similar situation, but the manufacturer's CAM operator was kind enough to fix this issue in place (by editing the gerbers) and notified me about it. -- Best regards, Anton Dubniak (twister AT tfsoft DOT org DOT ua)