Wednesday, 25 March 2015

pcb design - Defining a circular cutout in a pad in Altium


I'm creating the footprint for a Wurth inductor, 744043100. The recommended land pattern is below.



744043100 recommended land pattern


They use a radius 1.8 mm circle in the middle of the component to define a void in the pad. I'm trying to create the same shape in Altium, but am running into some trouble with it. In the screenshot below, I've tried two methods.


Altium footprint implementation.


Pad 2 uses a region with six vertices and an arc to define the curved region, which works but seems prone to some round-off errors. It's not a big deal, but I can measure my radius to be ~1.76 mm at y = 0 mm. It also requires some math to find the vertices and arc angle, and no one likes that.


Pad 1 shows what I'd like to be able to do. My preference here would be to define a rectangular fill, define a circle of radius 1.8 mm, and use the circle as a cutout to modify the fill. Is it possible to do this from within the PCB library editor? Is there another way to define this shape that I've missed?


I'm using Altium 18.1.7.



Answer



I would do this by defining the outline and then creating a solid region from the outline. Eg. Snap grid set to 0.025mm. Set at 0,0 for center so that the center arc can be used to snap to the ends of the lines (do them first). Takes just a few seconds to draw this.


enter image description here


Then Tools->Convert->Create Region from Selected Primitives



enter image description here


And then add a pad to the region etc.


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