Working with the Board Outline Clearance Design Rule on a PCB in Altium Designer
Rule category: Manufacturing
Rule classification: Unary
Summary
This rule defines the minimum clearance allowed from design objects that are fabricated, to edges of the board. Either a single clearance value can be specified for all object-to-edge possibilities, or different clearances for different pairings can be defined, through the use of a dedicated Minimum Clearance Matrix. The terms Board Outline and Board Edge are general names used interchangeably to describe the outer edge of the board. The term edge is defined in the table below the image. The Board Outline Clearance design rule checks object-to-edge clearances on the electrical and overlay (silkscreen) layers.
Constraints
Default constraints for the Board Outline Clearance rule.
| Edge Type | Definition |
|---|---|
| Outline Edge | The outer-most (exterior) edge of the board |
| Cavity Edge | The edge of a user-defined cavity |
| Cutout Edge | The edge of a user-defined cutout |
| Split Barrier | When a Split Line defines the edge of the board on this layer, this edge is referred to as a Split Line Barrier |
| Split Continuation | When this layer continues beyond a Split Line, this edge is referred to as a Split Line Continuation (a permeable boundary). To allow an object-kind to cross a Split Continuation, set the clearance value to zero. Zero indicates that for these object-kinds, this is a continuation layer, and the objects are allowed to violate (pass over) the split line. Use this technique to allow routed tracks, for example, to travel across from one Layer Stack Region to another. |
- Minimum Clearance - the value for the minimum clearance required. A value entered here will be replicated across all cells in the Minimum Clearance Matrix. Conversely, when a different clearance value is entered for one or more object pairings in the matrix, the Minimum Clearance constraint will change to N/A, to reflect that a single clearance value is not being applied across the board.
- Minimum Clearance Matrix - provides the ability to fine tune clearances between the various object-to-edge clearance combinations in the design.
Working with the Clearance Matrix
Definition of clearance values in the matrix can be performed in the following ways:
- Single cell editing - to change the minimum clearance for a specific object pairing.
- Multi-cell editing - to change the minimum clearance for multiple object pairings:
- Use Ctrl+Click, Shift+Click, and Click+Drag to select multiple cells in a column.
- Use Shift+Click, and Click+Drag to select multiple contiguous cells in a row.
- Use Click+Drag to select multiple contiguous cells across multiple rows and columns
- Click on a row header to quickly select all cells in that row.
- Click on a column header to quickly select all cells in that column.
With the required selection made (either a single cell or multiple cells), making a change to the current value is simply a case of typing the new value required. To submit the newly entered value, either click away on another call, or press Enter. All cells in the selection will be updated with the new value.
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
Online DRC, Batch DRC, interactive routing, and autorouting.