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Proper Handling of Holes for Through Hole Headers

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=669
Printed Date: 19 Nov 2024 at 9:35am


Topic: Proper Handling of Holes for Through Hole Headers
Posted By: DaveCowl
Subject: Proper Handling of Holes for Through Hole Headers
Date Posted: 08 Nov 2012 at 12:03pm

I just generated a 4x2 shrouded header and I have questions regarding the output.

1) The hole size is shown as 1.08mm (based on .62mm square pin) - should I round to 1.1 or 1.05 in preference to specifying a 'non-standard' hole size?

2) If I do run with 1.1mm hole, I am guessing that I should also update all of the pad sizes to match the hole size?

3) Is there a way to have the hole size automatically select the closest standard hole size?

4) I note that none of the hole parameters (Thermal pad, hole size, antipad) appear in the ASCII HKP padstack output for this part.

Thanks!


Replies:
Posted By: DaveCowl
Date Posted: 08 Nov 2012 at 12:21pm

5) What tolerance should we set on holes? 0.05mm? Or does it scale with hole size?

Posted By: Tom H
Date Posted: 08 Nov 2012 at 2:09pm
Since, the PCB Footprint is 100% mathematical calculations there is no way to set a "Hole Size" round-off. Rather we could, but people could get into trouble. The FPE does have a "Pad Size" rounding feature in the "User Preferences > Terminals > Through-hole > Settings > Pad Size Round-off".
You can also make adjustments in the "User Preferences > Terminals > Through-hole > Environment > Min Annular Ring or Min. Fab. Tol.
 
In the PCB Footprint Editor you insert the Maximum lead size and it auot-calculates the hole size.
 
The fabrication drawing drill chart should have a +/-0.003" (+/-0.075 mm) hole tolerance for plated holes and +/-0.002" (+/-0.05 mm) toleramce for Non-plated holes and +/-0.005" (0.12 mm) for slotted holes.
 


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