Working with the Paste Mask Expansion Design Rule on a PCB in Altium Designer

Rule category: Mask

Rule classification: Unary

Summary

The shape that is created on the paste mask layer at each pad site is the pad shape, expanded or contracted radially by the amount specified by this rule.

Constraints

Default constraints for the Paste Mask Expansion rule.

• Expansion - the value applied to the initial pad shape to obtain the final shape on the paste mask layer. Enter a positive value to expand the initial pad shape, enter a negative value to contract it.

How Duplicate Rule Contentions are Resolved

All rules are resolved by the priority setting. The system goes through the rules from highest to lowest priority and picks the first one whose scope expression matches the object(s) being checked.

Rule Application

During output generation.

Tips

1. The paste mask expansion can be defined for pads on an individual basis. While browsing properties for a selected pad through the Properties panel, options are available to follow the expansion defined in the applicable design rule, or to override the rule and apply a specified expansion directly to the individual pad in question.
2. Paste mask expansion can also be defined at the individual level for the following objects (through the Properties panel, when browsing the properties of a selected object): Track, Region, Fill, Arc. Options are available to follow the expansion defined in the applicable design rule, to override the rule and apply a specified expansion directly to the individual object in question, or to have no mask at all.