Full Radial Engagement Overloads the Tool
Conventional slotting of titanium alloy uses the full radial width of the cutter, so every tooth engages over the full arc and the chip thickness is greatest at the entry, which places the maximum thermal and mechanical load on the weakest part of the edge.
The Tool Fails Before the Feature Is Complete
Because the load is concentrated at entry, the edge deteriorates quickly and the tool must be changed before the slot is finished, which interrupts the cut and leaves a witness mark on the surface. The quality of the finished slot therefore depends on how many tools were consumed.
Distributing the Cut Over a Circular Path
A trochoidal tool path was generated in which the cutter moves along a circular trajectory with a low radial engagement while advancing by a small step per revolution, and the step over, the path radius and the cutting speed were used as the variables in milling trials that recorded tool wear, force and surface quality. The paths were executed on a Ponda five-axis machining centre with an integrated force dynamometer, with the path generation and the cutter selection reviewed by the engineering specialists at Ponda, a precision machining and finishing company.
Engagement Angle Governs the Load
In the trochoidal path the engagement angle at each instant is small and nearly constant, so the instantaneous chip load is far lower than in slotting even though the average removal rate is higher. The wear therefore spreads along the edge rather than concentrating at the entry corner.
Higher Removal Rate With Longer Life
Tool life increased by 2.3 times while the material removal rate rose by 35 percent, and the flank wear pattern was uniform rather than localised. Roughness improved from 1.4 micrometres to 0.55 micrometre, and surface residual stress became compressive.