Hole size for through hole compoent

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

   I am using a power module that has 1.02mm diameter round pins.In Footprint Expert I specified a through hole header with 1.02mm round pins.
The resulting hole size is 1.20mm.
I found this IPC information:

Minimum Hole Size = Maximum Lead Diameter + 0.20mm (for Level B of IPC-2222)

Being the manufacturer of the power module does not specify a tolerance I figure I should at least add a few mils to the diameter. Also through hole drill usually has a tolerance of +/- 3 mils. So going by IPC recommendation I am figuring 1.02mm + 0.127mm for tolerances + 0.2mm = 1.347mm.

Does this make sense?

Thanks

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
jnbrown Members Profile Send Private Message Find Members Posts Add to Buddy List Active User Joined: 13 Jan 2020 Status: Offline Points: 40	Post Options Post Reply Quote jnbrown Report Post Thanks(0) Quote Reply Topic: Hole size for through hole compoent Posted: 16 Dec 2021 at 11:58am
	I am using a power module that has 1.02mm diameter round pins. In Footprint Expert I specified a through hole header with 1.02mm round pins. The resulting hole size is 1.20mm. I found this IPC information: Minimum Hole Size = Maximum Lead Diameter + 0.20mm (for Level B of IPC-2222) Being the manufacturer of the power module does not specify a tolerance I figure I should at least add a few mils to the diameter. Also through hole drill usually has a tolerance of +/- 3 mils. So going by IPC recommendation I am figuring 1.02mm + 0.127mm for tolerances + 0.2mm = 1.347mm. Does this make sense? Thanks



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: 5716	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 16 Dec 2021 at 12:07pm
	Makes perfect sense, but in every through-hole calculator in V2021 Footprint Expert the user must enter the minimum and maximum lead diameter. i.e.: the tolerance is built into the calculator. A maximum lead diameter of 1.02 should produce a 1.22 hole, but it totally depends on your Hole Size Round-off is in Tools > Options > Terminals > Through-hole > Hole Size Round-off > 0.05 (will round-off to the nearest 0.05 mm value).
	Stay connected - follow us! X - LinkedIn

jnbrown Members Profile Send Private Message Find Members Posts Add to Buddy List Active User Joined: 13 Jan 2020 Status: Offline Points: 40	Post Options Post Reply Quote jnbrown Report Post Thanks(0) Quote Reply Posted: 16 Dec 2021 at 12:35pm
	I did not have the Min/Max button selected. Now I entered 1.02 +/- 0.05mm for the lead size and I am getting 1.25mm for the hole size. Where is the +/-3 mil drilled hole tolerance taken into account in the calculator?

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: 5716	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 16 Dec 2021 at 1:27pm
	In Tools > Options > Terminals > Through-hole There is a setting for "Minimum Annular Ring" In the 60-year history of PCB design, the PCB designer should know what the minimum annular ring needs to be to compensate for the +/- 3 mil drill hole tolerance.
	Stay connected - follow us! X - LinkedIn

jnbrown Members Profile Send Private Message Find Members Posts Add to Buddy List Active User Joined: 13 Jan 2020 Status: Offline Points: 40	Post Options Post Reply Quote jnbrown Report Post Thanks(0) Quote Reply Posted: 16 Dec 2021 at 1:49pm
	I am not asking about pad size or annular ring. I am asking about drilled hole size. The IPC recommendation says Minimum hole size.