Isolation Routing

Isolation Routing creates a Geometry object with toolpaths that cut around the copper features of a Gerber object. The toolpaths cut the gap next to each copper feature, so the copper is isolated from the rest of the copper. Use it to route the traces of a PCB.

Where to find it

• Plugins menu: select Isolation (shortcut Alt+I).
• Plugin Toolbar: click Isolation.
• The plugin panel opens in a new tab of the side panel. The tab shows the plugin name. Select a Gerber object in the Project tab, or choose it in the Source Object combo box.

Screenshot placeholder: images/Isolation-Routing-1.png - the whole Isolation panel, with the Tools Table, the parameters of one tool and the Common Parameters visible.

Quick start

1. Load a Gerber file with Importing Files.
2. Select the Gerber object in the Source Object combo box.
3. Enter the cut width in Tool Dia (mm, or inch in an inch project). The default is 0.1.
4. Click Search and Add. The tool appears in the Tools Table.
5. Select the tool row. Set Passes and Overlap for this tool.
6. Keep Isolation Type set to Full for a complete isolation.
7. Click Generate Geometry. A new Geometry object appears in the Project tab.
8. Check the toolpaths on the canvas. Then mill them with Milling or the Milling button.

Screenshot placeholder: images/Isolation-Routing-2.png - the Tools Table with one tool row selected and the result Geometry object on the canvas.

Parameters

Source

Parameter	Description	Default
Source Object (combo box)	The Gerber object to isolate.	-
Selected objects	When checked, every Gerber object selected in the Project tab is isolated with the same tools. Each result is a new object.	Off (tools_iso_multi_objects)

Tools Table

The table holds the tools that the algorithm uses. The columns are described in Tool table columns.

Parameter	Description	Default
Tools Table	The tool pool. Only the tools in this table are used.	-
Tool order (combo box)	The order in which the tools are used. Default: the order of the table. Forward: from the smallest to the biggest diameter. Reverse: from the biggest to the smallest diameter.	Reverse
Tool Dia	The diameter of a new tool. Used by Search and Add, Optimal and Pick from DB.	0.1
Optimal	Finds a tool diameter that gives a complete isolation.	-
Search and Add	Adds a tool with the diameter of Tool Dia. A background search in the Tools Database looks for a matching tool. If nothing is found, a default tool is added.	-
Pick from DB	Opens the Tools Database and adds the tool you select.	-
Delete (trash icon)	Deletes the selected tools in the table. Select a row first.	-

Drag a row to change the position of a tool in the table.

Parameters for the selected tool

These controls hold the values of the selected tool. Each tool keeps its own set of values.

Parameter	Description	Default
Shape (combo box)	The tool shape. The choices are listed below this table.	C1
V-Tip Dia	The tip diameter of a V-shape tool. Shown only when Shape is V.	0.1
V-Tip Angle	The tip angle of a V-shape tool, in degrees (1 to 180). Shown only when Shape is V.	30
Cut Z	The cutting depth, as a negative value, below the copper surface. For a V tool, it also sets the effective diameter.	-0.07
Passes	The number of isolation passes. Each pass is one tool width further from the copper. Integer from 1 to 9999.	1
Pad Passes	The number of extra passes for pads only. Each one adds one tool width. Integer from 0 to 999.	0
Overlap	How much (percentage) of the tool width each pass overlaps the previous pass.	10 %
Milling Type	Climb: best for precision milling and to reduce tool usage. Conventional: useful when there is no backlash compensation.	Climb
Isolation Type	Full: complete isolation of the polygons. Ext: isolates only on the outside. Int: isolates only on the inside. Interior isolation needs an opening inside the polygon, such as a doughnut shape.	Full
Apply parameters to all tools (button)	Copies the values in the form to all the tools in the table.	-

Shape choices:

• C1 to C4: a circular tool with 1 to 4 flutes.
• B: a ball tip milling tool.
• V: a V-shape milling tool. The V-Tip Dia, V-Tip Angle and Cut Z fields appear.
• L: a laser.

Common Parameters

These values apply to all the tools.

Parameter	Description	Default
Rest Machining	When checked, the copper is processed from the biggest selected tool. What the tool cannot process goes to the next bigger tool. The Tool order is then set to Reverse and cannot be changed.	Off
Forced Rest	When checked, the isolation is done with the current tool even if the interiors of a polygon could not be isolated. Works with Rest Machining.	On
Combine	Combines all passes into one object.	On
Clear leftovers	Clears strips and triangles of copper left between passes. Adds one more path along each of them. Works for full isolation with combined passes, not with Rest Machining.	Off
Check validity	When checked, the tool diameters are checked. The check shows if the tools give a complete isolation.	Off
Simplify	When checked, the paths are simplified. Points stay within the tolerance distance of the original geometry.	On
Simplify tolerance (field)	The tolerance of the simplification, in mm, or inch in an inch project.	0.001
Except	When checked, the area of an object is subtracted from the isolation geometry.	Off
Object type (Geometry or Gerber)	The type of the object used for Except. It sets the kind of objects in the object combo box below.	Geometry
Object combo box (under Except)	The object whose area is removed from the isolation geometry.	-
Selection (combo box)	The isolation scope. All: isolate all the polygons. Area Selection: isolate the polygons inside a selection area. Polygon Selection: isolate a selection of polygons. Reference Object: process the area of another object.	All
Type (combo box, for Reference Object)	The type of the reference object: Gerber, Excellon or Geometry.	Gerber
Reference object combo box	The object whose area is processed. Shown for Reference Object.	-
Shape (for Area Selection)	Square: a rectangle. Polygon: a polygon drawn with clicks.	Square
Interiors	When checked, the interiors (holes) of a polygon can be selected. Shown for Polygon Selection.	Off
Select All / Deselect All	Selects or clears all the polygons. Shown for Polygon Selection.	-
Boundary	When checked, the isolation is limited to the area inside the outline of an object. The paths outside the outline are cut off.	Off
Object type (Geometry or Gerber) for Boundary	The type of the boundary object.	Geometry
Boundary object combo box	The object whose outline limits the isolation, such as the board outline.	-
Trace the boundary	When checked, one path is also cut along the boundary outline.	Off

Buttons

Parameter	Description	Default
Generate Geometry	Creates the Geometry object with the toolpaths.	-
Milling button (icon)	Opens Milling for the Geometry.	-
Buffer Solid Geometry	Shown only when the Gerber file was loaded without buffering. Creates the buffered geometry that isolation needs.	-
Reset Tool	Resets the parameters of the selected tool.	-

Advanced

Tool table columns

The Tools Table works the same way in Isolation Routing, Non-Copper Clearing and Paint. In this plugin the table has two columns. Non-Copper Clearing and Paint also show a Shape column.

Column	Meaning
#	The tool number. With the order Reverse, the algorithm starts with the biggest diameter.
Diameter	The cut width in the material, in mm, or inch in an inch project.
Shape	Not a column here. Set the shape in the Shape combo box of the parameters.

Only the tools that create isolation geometry stay in the result.

Shape and the V tool

For a V tool, the effective diameter is:

diameter = V-Tip Dia + 2 x |Cut Z| x tan(V-Tip Angle / 2)

Example: V-Tip Dia 0.1, V-Tip Angle 30 degrees, Cut Z -0.07 gives a diameter of about 0.1375 mm. The Tool Dia of the V tool follows this value.

How the passes are placed

The offset of pass n from the copper edge is:

offset = tool diameter x (2n + 1) / 2 - n x overlap x tool diameter

The overlap is a fraction, so 10 % is 0.1. The first pass (n = 0) is at half a tool width from the copper. Each further pass moves outwards by one tool width minus the overlap.

Rest Machining

With Rest Machining, each tool processes only what the bigger tool did not reach. Use it with a set of tools of different sizes. The tool order is forced to Reverse.

Limits

• The values of the tools are limited by the ranges in the form, for example Passes from 1 to 9999.
• The Isolation Type Int works only when the polygon has an opening inside.

Beginner Mode

Beginner Mode hides these controls: the Add from DB section, Milling Type, Isolation Type, Apply parameters to all tools, Rest Machining, Forced Rest, Except, Selection, Selected objects, the reference object controls, Interiors, and the table context menu. Switch the mode with the level button at the top of the panel, or in Preferences.

Tcl

The Tcl command is isolate. See Tcl Command Reference.

See also

• Non-Copper Clearing - removes the copper outside the traces.
• Paint - paints the copper pattern.
• Follow - cuts along the centre line of the traces.
• Cutout - cuts out the PCB outline.
• Optimal - finds the tool diameter for a complete isolation.
• Tools Database - the tools for Search and Add and Pick from DB.
• Gerber Object - the input object.
• Geometry Object - the output object.
• Milling - turns the Geometry into G-Code.
• Preprocessors - the G-Code formats for the machine.
• Keyboard Shortcuts