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Generic Footprints for CAPC and RESC

Printed From: PCB Libraries Forum
Category: PCB Footprint Expert
Forum Name: Questions & Answers
Forum Description: issues and technical support
URL: https://www.PCBLibraries.com/forum/forum_posts.asp?TID=2628
Printed Date: 07 Oct 2024 at 1:24am


Topic: Generic Footprints for CAPC and RESC
Posted By: bfrantz04
Subject: Generic Footprints for CAPC and RESC
Date Posted: 07 May 2020 at 12:42pm
I would like to create generic footprints for standard component sizes.  

For instance from EIA 0201 to 1210 for capacitors and EIA 0201 to 1210 for resistors.  

Having only a few verified footprints will help keep our library maintenance down to a manageable number.

Are variations between manufacturers consistent enough to do this?  

Do I just pick a representative manufacturer and go with that?


Replies:
Posted By: Tom H
Date Posted: 07 May 2020 at 12:50pm
The package sizes are fairly stable. It's the tolerances that are all over the map. 

Build your discrete library using the same package dimensions and tolerances. 

Different mfr.'s with have different package and terminal lead tolerances and these tolerances are used to create the pad stack length and width. 

Use reasonable tolerances that the majority of your suppliers use. Find common tolerances. 



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Posted By: bfrantz04
Date Posted: 07 May 2020 at 5:47pm
Ok, once I have all of these tolerances put together how do I use these with the Solder Joint Goal Tables to calculate dimensions?  

Do we use maximal or least material or some combination of both?

Also it looks like the rules are the same for capacitors and resistors now?

Posted By: Tom H
Date Posted: 07 May 2020 at 6:27pm
There are 3-tiers for the Rectangular End Cap packages. 

The solder Joint Goal values are all user definable. 

IPC-7351 is now a Guideline and has a basic starting point. 

The smaller the package the slighter the solder joint goal variance. 

Here are the current Solder Joint Goal tables -  uploads/3/Library_Expert_Solder_Joint_Goal_Tables.zip" rel="nofollow - uploads/3/Library_Expert_Solder_Joint_Goal_Tables.zip

Note: there are different solder joint goals for every Chip Package size. 



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