If your design has an irregular shape, then tab routing may be required. DEX will add a gap, equal to the router cut width, between the boards to allow the router bit to pass between them. Small tabs of material will remain to hold the boards in place. To make separation easier, you can add small non-plated holes to the tabs called 'mouse bites to perforate the tab. If you desire a smooth edge on your PCBs, these areas will need to be sanded after the boards are removed from the array.
Because tab routed arrays are inherently less sturdy than scored arrays,You should add tooling rails to all 4 sides of the array. This will give your array of PCBs more support during handling and assembly processes.
Single PCB with routed break-apart tabs on 4 sides
Magnified View of break-apart tab with mouse-bites