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exatech
Netherlands
18 Posts |
 Posted - 05 Aug 2009 : 09:13:21
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I cannot seem to get good results plotting a solder paste stencil with undersized pads. First of all, while the design units are millimeters, the undersize unit appears to be 10 inches:
pad = 0.25mm, undersize = 0.002, result 0.15mm.
pad = 0.25mm, undersize = 0.004, result 0.05mm.
Apart from this, I would much rather undersize by a certain percentage, so that small pads remain big enough, but bigger pads get reduced sufficiently. Is there a way to achieve this?
Thanks,
Henk |
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DavidM
United Kingdom
458 Posts |
Posted - 05 Aug 2009 : 12:51:47
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There are two ways to undersize to produce paste masks. The first - which is presumably what you are using - is on the Plotting dialog, where you can specify an absolute amount (in whatever units are shown on that dialog).
The other method, which allows more control and is probably what you need, is to add a specific paste layer to your design using a Paste layer type. On that layer type you can specify the undersize value, either absolute or as a percentage of the pad width.
When using the second method, if you find you need specific sizes on the paste layer for particular pads, you can add an 'exception' for that padstyle on the paste layer to make it a specific size, then it won't have the standard undersize applied.
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exatech
Netherlands
18 Posts |
Posted - 05 Aug 2009 : 14:41:18
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| thanks David, I did know about the layer undersize option, but didn't know that it would work in percentages as well. Going to try this out asap. |
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Solder paste stencils