Creating a complex pad shape that includes arcs?


#1

Hello all,

Long-time Kicad user, new poster here. I’m designing a complex power board for an electric racecar, and am making a footprint for the Tamura EPM1510SJ DC/DC module: http://www.tamura-ss.co.jp/en/electronics/pdf/EPM1510SJ_1208AE.pdf

The pads are mostly circular with a little bit “cut off” on parallel sides. How should I go about making these pads? Can I import a DXF as a pad shape?

Right now, I’m planning on using rectangular pads of the correct size instead.
Thanks for any pointers here.

Will


#2

You could create a complex pad. But realistically, you would be better off with either ovals or rounded rectangles for this.


#3

HI,

I fail to see the benefit of the rounded end pads. Overall it looks to me like they want to maximize the pad area (I thing is a good thing).

but, the round pads with the sides cut off look like what they used when they designed PCB with actual tape and stick-ons pad arrays… Our company had some really old designs that we wanted to convert to CAD designs. Those designs looked like the recommended foot print your link showed.

I would use rectangular pads where the pins are close and either round or rectangular for the others.


#4

As above, just use rounded rectangles, they will be more than close enough.
The clearance between pads looks to be the important detail, and I often make the pads ‘beefier’ than the specs, which here would become longer than that 3.5mm.

On some connectors, we have made the copper larger than the solder mask, to get full benefit of adhesion, and prevent anemic pads lifting if exposed to stress, but save on solder consumed…

On very high current parts, with some mass, we also avoid taking current on the non-solder side, if possible.
Where we really have to ‘other side’ high current pins of mass, we use an array of vias, so you do not rely on a single plating ring


#5

Thanks for all the suggestions; I ended up just using rectangular pads for the critical clearances between pads, and circular pads for the two others:


#6

I do not understand why the shape mentioned would need complex pads, and It’s already resolved.

As addition, anyone stumbling into this thread and wanting “complex pads with arcs”, have a look at:

/usr/share/kicad/demos/custom_pads_test

image

Edit:
24 days after the text above I accidentally bumped into a simple method to create complex footprint pads in KiCad V5.0.2 as in the screenshot above.
You can draw lines, arcs and polygons on any layer, then drag a selection box around it , press Right Mouse Button and select: “Create pad from Seleced Shapes” in the popup menu.