Single Droplet Pads

A feature added to the Edge Rasterizer at the request of one of our customers is to use a single droplet on round pads that are below a user specified diameter.

This feature was implemented because normally the edge rasterizer treats each pad as if it were a boundary -- and pads that are the same size or slightly larger than the droplet diameter might either be ignored (too small to fill) or improperly filled.

The Test File

We start with a simple Gerber test file that contains a number of round pads of varying diameters: 100, 90, 80, 70, 60, 50, 40 and 30 um.

single droplet test file

Normal Operation

If we rasterize this normally (5080 DPI, 30 um droplet diameter, 15 um pitch) we get the following droplet pattern:

normal raster settings

Notice that the droplets of 50um, 40um and 30um diameter are "dropped" from the output because they are too small to fill using the edge rasterizers boundary based algorithms. This is what we would like to avoid -- dropped data.

Single Droplet Mode ON

So now we will set the Single Droplet parameter on, and set the threshold to 51 um. Any droplet of diameter less than 51 um will be filled using a single droplet.

single droplet mode on with threshold = 51 um

You can see that the three round pads whose diameter is less than 51 um are "filled" using a single droplet.

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