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Reply To: | TechNet E-Mail Forum. |
Date: | Fri, 11 May 2001 11:15:01 -0700 |
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FYI, from a practical manufacturing point of view, I normally will ask that the clearance be
at least 15 mils, ID to OD of thermal relief. Anything less than 5 mils has a good chance of
turning into a direct connect.
kb
Ted Tontis wrote:
> I am still fairly new to PCB design and I am studying for the IPC
> design cert. I cam across IPC -2222 9.1.2 Thermal relief in conductor planes
> which states the relationship between the hole size, land and web area is
> critical. Typically, divided 60% of the minimum land area diameter by the
> number of webs desired to obtain the width of each web in accordance with
> the following example:
> I understand this with no problem but where does it state the air
> gap or expansion size? Is it the same value all the way around the land
> area? or does the current control the distance?
>
> Thank you,
>
> Ted Tontis
> Engage Networks Inc.
> [log in to unmask]
> PH 414.273.7600 Ext. 7607 <http://www.engagenet.com>
>
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Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
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