[SI-LIST] Re: Advantages & Disadvantages of Flooding Vias??
- From: "Stefan Milnor" <stefan.milnor@xxxxxxxxxxxxxx>
- To: "Jack Olson" <pcbjack@xxxxxxxxx>, <ManatoshGBaidya@xxxxxxxxx>
- Date: Mon, 2 Mar 2009 08:45:17 -0800
I agree with the advice given by Jack below.
Regarding not being able to "see" the vias in the Gerbers, I usually overlay
the drill drawing on the Gerbers to make sure the plane connection vias are
showing up where I think they should be, and do a spot check.
________________________________
From: si-list-bounce@xxxxxxxxxxxxx on behalf of Jack Olson
Sent: Mon 3/2/2009 7:28 AM
To: ManatoshGBaidya@xxxxxxxxx
Cc: eric@xxxxxxxxxxxxxxx; istvan.novak@xxxxxxx; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Advantages & Disadvantages of Flooding Vias??
You don't have anything to worry about.
The only reason for thermal relief is to reduce the amount of heat needed
for soldering/desoldering.
Vias aren't considered soldered connections, and many designers flood them
One of the only reasons for not flooding them is that the spoked connections
are easier to see in
plots and gerber data (flooded connections are difficult to "see").
Lamination and Soldering temperatures are much higher than your normal
operating temperature
(or else you have a bad design!) so any bow and twist will happen at the
extremes, not during normal operation. In other words, you'll see it before
it ever gets used in the field.
If it doesn't warp during assembly, it won't warp later on.
Heat will flow through your planes regardless, and nothing about vias
contributes to bow and twist.
As a matter of fact, getting more heat onto the planes will REDUCE your via
barrel stress
Jack
.
On Sun, Mar 1, 2009 at 11:25 PM, <ManatoshGBaidya@xxxxxxxxx> wrote:
> Hi Gentleman,
>
> Good Morning.
> I am working on a dense Aerospace Cockpit Control Board and I want to
> Flood all of my Vias as Vias Connecting to the Respective planes (Power
> & Gnd) is not having good connectivity through the Thermal Spokes.
> Flooding vias will help me gaining the required copper area for the
> Circuit.
> Via size used is .015 Inch Drill\.025 Inch Pad.
> Will this create any problem in the Component Assembling Process as some
> of the heat may pass through the planes and thus PCB may undergo Bow &
> Twist or expansion of the PCB.
>
> Please put your expertise thoughts on it.
>
> Thank you,
> Regards,
> Manatosh
>
>
>
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