what is the suitable definition of contact interaction between two deformable 2D part instances in abaqus ?

Hi

In modeling of orthigonal machining. it is necessary to define the contact between tool surface and the workpiece. but the region of contact during the simulation change . the tool and workpicece has been simulated as 2D deformable parts.  the problem is that what conditions must be considerd to define the suitable contact interaction between two deformable 2D part instances in abaqus? what kindes of surfaces must be define for tool and workpiece? node based, element based or geometry base surface? and how diefine conditions in initial increments to prevent the errors that cause the simulation terminate!?