Proper Handling of Holes for Through Hole Headers

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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!

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DaveCowl Members Profile Send Private Message Find Members Posts Add to Buddy List Advanced User Joined: 18 Oct 2012 Location: Santa Clara, CA Status: Offline Points: 161	Post Options Post Reply Quote DaveCowl Report Post Thanks(0) Quote Reply Topic: Proper Handling of Holes for Through Hole Headers 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!



DaveCowl Members Profile Send Private Message Find Members Posts Add to Buddy List Advanced User Joined: 18 Oct 2012 Location: Santa Clara, CA Status: Offline Points: 161	Post Options Post Reply Quote DaveCowl Report Post Thanks(0) Quote Reply Posted: 08 Nov 2012 at 12:21pm
	5) What tolerance should we set on holes? 0.05mm? Or does it scale with hole size?

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: 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.