Minimum Annular Ring

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

I set the "Minimum Alowable[sic] Annular Ring" setting to 0.70mm.  However, no through-hole parts that I calculate using the Through Hole calculator honor this setting.  Is this setting for FP generated footprints only?  It would be nice if this applied to all through hole components as some of my parts are approaching my PCB vendor's minimum annular ring spec. 
Also, it seems like over the years the PCB Libraries through hole proportional pad stacks keep getting smaller (smaller annular rings, hole over lead down to 0.20mm from 0.25mm, etc.) for the same lead size.  Why do these keep changing?  

Also, we were previously using IPC-7251 "A" levels.  When published, will IPC-7351C provide a recommended proportional padstack?  If so, will they be comparable to any of the previous "A", "B", or "C" levels (based on your default settings I'm assuming that IPC-7351C proportional padstacks are similar to IPC 7251 Level B settings, though proportional in some calculations instead of fixed)?

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
plinder Members Profile Send Private Message Find Members Posts Add to Buddy List Advanced User Joined: 13 Apr 2012 Location: Vermont Status: Offline Points: 141	Post Options Post Reply Quote plinder Report Post Thanks(0) Quote Reply Topic: Minimum Annular Ring Posted: 18 May 2015 at 12:20pm
	I set the "Minimum Alowable[sic] Annular Ring" setting to 0.70mm. However, no through-hole parts that I calculate using the Through Hole calculator honor this setting. Is this setting for FP generated footprints only? It would be nice if this applied to all through hole components as some of my parts are approaching my PCB vendor's minimum annular ring spec. Also, it seems like over the years the PCB Libraries through hole proportional pad stacks keep getting smaller (smaller annular rings, hole over lead down to 0.20mm from 0.25mm, etc.) for the same lead size. Why do these keep changing? Also, we were previously using IPC-7251 "A" levels. When published, will IPC-7351C provide a recommended proportional padstack? If so, will they be comparable to any of the previous "A", "B", or "C" levels (based on your default settings I'm assuming that IPC-7351C proportional padstacks are similar to IPC 7251 Level B settings, though proportional in some calculations instead of fixed)?



Tom H Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5719	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 18 May 2015 at 1:18pm
	Sorry that we did not link the Minimum Annular Ring to the Calculator. It was a last minute feature addition that was not fully tested. It will be fixed in the next V2015.13 pre-release later today. The typo was fixed in the current .13 pre-release. As far as the changes to the Proportional Pad Stack math goes, we have finally found a good algorithm that works, but the "Minimum Annular Ring" feature overrides the hole to pad size multiplier. The current Multiplier = Hole X 1.50 mm but you can change the 1.50 multiplier to whatever you want. C4hange it to 1.6 or 1.75 and see the difference. Here is the latest PTH Reference Calculator - PCB_Library_Expert_PTH_Reference_Calculator.zip Here is how the PTH Reference Calculator and Library Expert PTH calculations are made. Look for the next release of V2015.13 pre-release and everything will be fixed.
	Stay connected - follow us! X - LinkedIn

Tom H Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5719	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 18 May 2015 at 3:17pm
	The Minimum Annular Ring is now working in the V2015.13 pre-release - www.pcblibraries.com/downloads
	Stay connected - follow us! X - LinkedIn