Tool force magnitude and orientation (TFMO) is a set of drilling parameters that influence the performance of a particular drill bit. The tool force is a measurement of the amount of lateral or vertical force acting at or near the bit, while the orientation describes the overall tool angle or toolface.
The tool force magnitude and orientation, and other tool force components are usually determined in real time by fuzzy logic controllers. This controllable parameter is utilized in trenchless construction to ensure that the actual drill path remains as close as possible to the intended drill path.
The TFMO are affected by several external factors including:
- Soil/rock properties
- Drill bit properties
- Rotation speed
- External forces acting on the drill bit
- Underground obstructions.