There are two methods of tabbing in Router-CIM.  You can use either 2D or 3D tabs.  The differences are described below.

2D Tabs

These tabs are very square, and cause the cutter to stop and lift up in Z to the height of the tab, then move over by the length of the tab and then back down in Z to the normal cut depth.

3D Tabs

3D tabs are usually faster, but leave a varied amount of material.  The tool lifts up as it is cutting to the tab height in Z, while the X and/or Y are still moving.  Because the tool does not stop and lift up in Z then move over and then move back down in Z in 3 separate moves, the machine will cut these faster.

Changing from 3D Tabs to 2D Tabs

3D tabs are the default in Router-CIM.  You can change from 2D tabs to 3D tabs by unchecking the 'Use 3D Tabs' option.

3D Tabs Enabled:

3D Tabs Disabled:

If 3D tabs are enabled, you can adjust the 3D Tab Ramp Amount. The value needs to be numeric to enable the change. The smallest numeric value allowed is 0.01. The default for this field is AUTO

Note: The 3D Tab Ramp Amount only affects the UP movement of the 3D tab. The ramp down movement will be defined by the tab length.