No.
--
George Patrick
Tektronix, Inc.
Central Engineering, PCB Design Group
P.O. Box 500, M/S 39-512
Beaverton, OR 97077-0001
Phone: 503-627-5272 Fax: 503-627-5587
http://www.tektronix.com <http://www.tektronix.com>
http://www.pcb-designer.com
It's my opinion, not Tektronix'
-----Original Message-----
From: Steve Smith [mailto:[log in to unmask]]
Sent: Thursday, June 26, 2003 12:21 PM
To: (Designers Council Forum); Patrick, George H
Subject: RE: [DC] Thermal Relief Calculations
George,
Did you mean:
((Thermal ID + Thermal OD) * .2)/4 (rounded to the nearest mil.)
Regards,
Steve Smith
Product Engineer
Staco Energy Products Co.
Web Site: www.stacoenergy.com
-----Original Message-----
From: [log in to unmask]
[mailto:[log in to unmask]]
Sent: Thursday, June 26, 2003 3:17 PM
To: [log in to unmask]
Subject: Re: [DC] Thermal Relief Calculations
Our gap formula is (Thermal ID + Thermal OD) * .2 (rounded to the nearest
mil.)
--
George Patrick
Tektronix, Inc.
Central Engineering, PCB Design Group
P.O. Box 500, M/S 39-512
Beaverton, OR 97077-0001
Phone: 503-627-5272 Fax: 503-627-5587
http://www.tektronix.com <http://www.tektronix.com>
http://www.pcb-designer.com
It's my opinion, not Tektronix'
-----Original Message-----
From: Mark Holmes [mailto:[log in to unmask]]
Sent: Wednesday, June 25, 2003 1:49 AM
To: [log in to unmask]
Subject: [DC] Thermal Relief Calculations
Hi all,
I am looking at IPC-2222 9.1.2 regarding thermal relief pads. It provides a
formula for the web width based on the minimum pad size.
I can use this method with my current software, which allows me to create a
thermal relief for each pad. But, I also use a system that only allows me to
specify thermal relief pads for 'non-vias' in a particular plane.
My questions are, what are you guys using to calculate your thermal relief
pads? Do you calculate the web size for each pad used, Or do you have some
other method of calculating the web width.
Any advice, rules of thumb etc. would be most appreciated.
Just one more thing, could anyone confirm what is meant by "Standard
Manufacturing Allowance" in IPC-2222 Figure 9-1. Is this the same as
IPC-2221 table 9-3 "Minimum Hole Location Tolerance, dtp"?
Regards.
Mark
Mark Holmes PCB Designer
Helvar Merca Ltd.
Hawley Mill
Hawley Road
Dartford
Kent DA2 7SY
Tel: 01322 222211
mailto:[log in to unmask]
Visit our NEW updated website at:
http://www.helvar.co.uk
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