OrCAD PCB Editor 16.3: Thermal Relief, Antipad

[hobbss]

I am using OrCAD PCB Editor 16.3. My problem/question is partly software specific, and partly PCB layout in general.

I am attempting to create the footprint for a connector that will be carrying significant current loads (i.e., I ~ 16.5A). The connector is through hole, and has an odd pin with two "feet" (i.e., two drilled holes for each pin). For reference, the part number is: 42820-2212 (a Molex part, the data sheet and footprint can be referenced on Digikey's website).

So far, I have attempted to create a pad with two holes in it (rectangular for pin 1, and oblong for pin 2). I have created an antipad the same shape as the pad, with an additional 25mils all around.

My question pertains to the thermal relief: I have done some calculations, and determined that I need trace widths greater than an inch on internal layers to minimize temperature rise. Therefore, I would like to have no thermal relief on this component (given a hole dimension of 1/8", the thermal "relief" would actually just flood the pin). I am not worried about damaging the component, and my soldering iron can get hot enough to ensure a good solder joint even if the pins are flooded in an internal plane. However, PCB Editor complains that if a pad has an antipad defined, it MUST have a thermal relief shape defined as well. Is there any way around this? Or, is there a compelling reason why I really do need thermal relief? If so, how do I ensure that the "spokes" are sufficient to carry my required current?

---------- Post added at 10:43 ---------- Previous post was at 09:45 ----------

Follow up: Is there a way to change the spoke width for a thermal relief on only one component? I have attempted to edit the properties of the dynamic plane shape (use oversize spoke), but that updates it for all of the pads that touch this plane. I.e., a +5V power plane, with a bunch of IC's plugged in and one power connector. I would like to have large spokes on the power connector, and small spokes on the IC's.

 

[NIKHILRAJ]

I believe if you are going for manual soldering.thermal relief is NOT a must. Since you can heat the component untill it get proper soldering. ( machine soldering thermal relief may require for proper soldering , or special care shold be taken, they may complain heat is spreading to plane and it is not getting prper soldering ).

Is your Orcad demanding thermal for plane layers only? or if you define all the layers as routing, and put some copper pour there. will orcad agree with out thermals?

 

[hobbss]

I know that from a physical standpoint the thermal relief is not necessary. I am more concerned with the the software, specifically a DRC report with errors in it (difficult to justify in terms of long term documentation). OrCAD is demanding a thermal for all layers.

 

[hobbss]

Rephrasing a question from above:

I need to edit the thermal relief properties of a particular dynamic shape (i.e., a heat spreader beneath a TO-220 package). I would like to change it so that a through hole pad will be flooded by the shape (the tab on my footprint is technically a through hole pad), but all other shapes will still have normal (orthogonal) thermal relief. I managed to do this once, so I know it is possible, but I am having difficulty repeating this step on another heat spreader. Somehow, before, I managed to pull up a single dynamic shape property window (not the standard "edit property" window), but now, all I can seem to find now is the "edit global dynamic shape parameters," when I only want to edit a single shape parameter.

Can anyone help point me in the right direction?