Tab routing is the best way to set up parts relative to the PCB Layout tooling process. 

 In addition, the client should remit instructions that details which parts need to be delivered as a panel, and delta comments that show where tabs can’t be placed. By doing these two things, you eliminate unneeded changes to the mechanical drawings. The client must provide the dimensions of the parts’ datums of the assembly if their panel location is critical to the design. 

 A tab-routed panelized part will use the parameters stated below for set up: ◾Place and locate the tabs at least 9 mm (0.35 inches) from all board corners.
 ▪ Locate tabs at least 9 mm (0.35 inches) from the datum holes or directly on center.
 ▪ A 3.175 mm (0.125 inch) cutter should be used unless the design specifies another type of tool. Every path of cutting that are not between the boards should be 3.175 mm (0.125 inch) wide. The preferred spacing between boards should be at least 6.35 mm (0.25 inch), 3.8 mm (0.15 inch).
 ▪ Locate the tabs a distance of 75 mm ±12 mm (3.00 inches ±0.50 inches) apart from one another.
 ▪ Ensure the tabs are placed in a straight line with an X – Y axis when possible.
 ▪ To avoid fracturing of the traces or hole-walls, do not tab the component holes or traces that are near the edge of the board.
 ▪ The width of the tab should be 3 mm ±0.25 mm (0.118 inch ±0.010 inch).
 ▪ The dimension of the tab location should be ±0.5 mm (±0.020 inch).
 ▪ Tabs should be dimensioned to the center on a 0.5 mm (0.020 inch) grid.
 ▪ Locate tabs at least ±6 mm (±0.236 inch) from any radius on the outside board edge.