PCB Libraries Forum : BGA Chamfer https://www.PCBLibraries.com/forum/ Mon, 06 Apr 2026 21:57:57 +0000 Mon, 03 Dec 2012 15:12:05 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=727 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[BGA Chamfer : The BGA, CGA is an exception...]]> https://www.PCBLibraries.com/forum/bga-chamfer_topic727_post2522.html#2522 Author: Tom H
Subject: 727
Posted: 03 Dec 2012 at 3:12pm

The BGA, CGA is an exception because the plastic package is lifted off the board surface by the Balls or Columns.
 
We didn't have to chamfer the BGA silkscreen and just left two lines. The absense of silkscreen is popular for all "Bottom Only" terminal packages.
 
But you can see the BGA silkscreen chamfer by tilting the PCB to look under the BGA.
 
When you look straight down on a BGA you cannot see the chamfer but you do immediately notice lines that do not form a crop mark (like the other 3 corners).
 
]]> Mon, 03 Dec 2012 15:12:05 +0000 https://www.PCBLibraries.com/forum/bga-chamfer_topic727_post2522.html#2522 <![CDATA[BGA Chamfer : When component dimensions are...]]> https://www.PCBLibraries.com/forum/bga-chamfer_topic727_post2521.html#2521 Author: AGONZ67
Subject: 727
Posted: 03 Dec 2012 at 3:05pm

When component dimensions are entered for a BGA package and the output created. The silkscreen chamfer will fall under the part as created if the physical part does not have a chamfer. All BGA packages do not physically have a corner chamfer so this silkscreen will sometimes be under the component and not visible after assembly. This violates the basic rule, "no silkscreen under the component" and "all silkscreen outlines visible after assembly". Maybe the chamfer can be eliminated and the remaining silkscreen without the chamfer would serve as the pin one indicator? I know there was discussion before on this, & there was a post showing the corner with a line extending from it on the silkscreen.

]]> Mon, 03 Dec 2012 15:05:29 +0000 https://www.PCBLibraries.com/forum/bga-chamfer_topic727_post2521.html#2521