PCB spirals

Making PCB Layouts, Manual routing, Auto-routing, Copper pouring, Updating from Schematic, Manufacturing Output
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Tomg
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Joined: 20 Jun 2015, 07:39

PCB spirals

#1 Post by Tomg » 29 Mar 2023, 15:31

There have been previous posts with questions about making copper spirals on a PCB without using an external MCAD program. While browsing the internet for easy ways to accomplish this task, it did not take long to find several videos showing differing methods for creating a reasonable facsimile of a spiral. So, for those who might be interested, here is one such method adapted to make use of the PCB Layout editor's drawing tools...

1) Draw a small, 180-degree arc to represent the inner-most element. This arc's diameter will determine the spacing between line centers, so make sure it is well-defined. It will help to set the grid spacing to a value equal to half the first arc's diameter, and the Arc Mode (main menu > Objects > Place Shape > Arc Mode) to "Start - End - Middle Point".
2) Draw a second 180-degree arc that is 2x the diameter of the original arc, making sure to snap its starting point to one leg of the first arc.
3) Draw a third 180-degree arc that is 3x the diameter of the original arc, making sure to snap its starting point to the free leg of the second arc.
4) Draw a fourth 180-degree arc that is 4x the diameter of the original arc, making sure to snap its starting point to the free leg of the third arc.
5) Draw a fifth 180-degree arc that is 5x the diameter of the original arc, making sure to snap its starting point to the free leg of the fourth arc.
6) Draw a sixth 180-degree arc that is 6x the diameter of the original arc, making sure to snap its starting point to the free leg of the fifth arc.
7) Etc, etc, etc...
spiral_1.png
spiral_1.png (57.44 KiB) Viewed 1203 times
Notice that all odd-numbered arcs shown in the example above have their midpoints horizontally-aligned with the midpoint of the first arc. However, all even-numbered arcs have their midpoints horizontally-aligned with the free end of the first arc.

All copper arcs will have to be connected to the same pre-existing net in order to avoid initial DRC gap errors caused by adjoining elements of the spiral.

Setting the line width of all arcs to a value equal to half the diameter of the first arc yields an equivalent gap between all lines...
slw2.png
slw2.png (7.64 KiB) Viewed 1177 times
Tom

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