[lammps-users] how to move my tool to a certain direction?

Dear lammps-users:
I am doing nanometric cutting simulation recently, and i want to study to tool wear in the cutting process. I encounter a problem, if i set the cutting tool to be rigid and turn off the force and torque, then the tool could move smoothly in a certain velocity, but there would not have tool wear phenomenon, but if i set the cutting tool as normal workpiece without setting rigid, when the tool gets near the workpiece, the interaction between the tool and the workpiece would make the tool leave its original moving direction and cutting process could not carry out.
I wonder whether there is a way that the tool could move in a certain direction without using rigid?
Waiting eagerly for the reply, thank you very much!

I suppose you could define some subset of atoms in the interior
of the "tool" to move in a prescribed way (e.g. the fix move command
is simpler than fix rigid). That would allow the atoms
on the exterior to wear away.