To remove solder paste from a specific pad in Altium, clear the "Paste Mask Expansion" checkbox in the Pad Properties panel for that pad. This disables the paste generation for the selected pad(s).
Here's a more detailed explanation:
Steps to Remove Paste from an Altium Pad:
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Select the Pad: In your Altium PCB document, select the specific pad(s) you want to modify.
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Open the Properties Panel: If the Pad Properties panel isn't already visible, double-click on the selected pad, or go to View > Panels > Properties.
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Locate the Paste Mask Expansion Region: Within the Pad Properties panel, find the section related to "Paste Mask Expansion." This section controls the generation of the paste mask for the pad.
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Clear the "Paste Mask Expansion" Checkbox: You'll find a checkbox labeled "Paste Mask Expansion". Uncheck this box. This will effectively disable the paste mask generation for that specific pad only. If a value is present next to the checkbox for a specific expansion, this will no longer be applied to the paste mask generation for the pad.
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Verify the Change: Regenerate or update your paste mask layer to confirm that the paste has been removed from the pad. You might need to refresh the view or rebuild the paste mask layer.
Additional Considerations:
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Global Paste Mask Expansion: Note that Altium also offers a global paste mask expansion setting. Modifying the setting described above affects only the selected pad(s). To manage the default expansion applied to all pads, access the "Paste" settings within the PCB design rules.
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Design Rules: Be aware that design rules might override manual settings. If you've defined design rules that automatically add paste to pads based on certain criteria, you may need to adjust those rules as well.
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Pad Stacks: If dealing with complex pad stacks, ensure that the paste mask settings are properly configured within the pad stack definition.
By following these steps, you can effectively remove solder paste from specific pads in your Altium PCB designs, allowing you to customize your assembly process as needed.
