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thermal relief and copper pour

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mlkcampion

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thermal relief

Hey
I use orcad layout for my PCB designs. In one particular design i have used a
copper pour as a ground plane, and in the process i have attached it to ground pins using the net attach. In orcad it places this ground net attach as spokes to the copper pour, however the lines are extremely thin (not manufacturable). I want to increase the width of these spokes. How should i do this?

Thanks
Mike
 

FvM

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orcad thermal relief

All PCB tools I've been working with had parameters for it, I'm pretty sure that's also the case with Orcad. The setting may be either global or more likely individual for each copper pour object.
 

mlkcampion

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thermal relief orcad

Thanks
Yes i have found the Thermal relief settings, in this dialog box there are settings for
Small Thermall Releif and Large Thermal Relief. Bit lost on why there is 2 settings.
The options you are given are:
Annular Overdrill
Isolation Width
Spoke Width


Firstly iam not sure which iam working with small or large because when i was doing the copper pour and did the net attach I didn't intend the attachment to be a "thermal relief" but it seems there is an obvious connection between the two operations. I dont know if this is the case in all EDA tools.

I have tried changing some of the settings in the dialog box and the spokes did get larger but the settings have gone back to a default setting in the dialog box however the spokes have remained large, so again confusion as to the link between the dialog box and what i am seeing on the layout?

Thanks

Added after 1 hours 13 minutes:

Ok so Spoke width is definately the setting required, i increased the size again and it worked after i did a redraw/refresh, but it won't let me make the spokes smaller? This seems to be an orcad issue.
 

FvM

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copper pour

With other tools, there is typically also an option to disable thermal isolation for individual pads and for the copper pour as a whole.
 

rinj

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orcad copper pour isolation

In OrCAD 10.5 to disable thermal isolation for individual pads and for the copper pour as a whole, select the vias from the spreadshet, go to prpperties/edit padstack, enable the option Flood planes/pours.

regards,
rinj
 

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