Modulation-Assisted Machining superimposes a controlled low-frequency modulation on the metal cutting process. The frequency typically ranges up to 1000Hz with amplitudes up to 500 micrometers. The controlled modulation may be applied on the cutting tool or workpiece in the direction of tool-feed, cutting velocity or any combination offering major beneficial effects on the mechanics of machining, including:

easy chip breakage and disposal;
reduction in friction and energy consumption;
enhancement in lubrication of tool-chip contact with potential reduction in tool wear;
reduction of effluent streams in manufacturing due to highly efficient use of fluids; and
ability to reduce burrs and create unique surface texture.

MAM offers a new technology for machining difficult-to-machine materials that may be impractical for conventional conditions due to excessive tool wear. Example alloys include titanium, tantalum, and stainless steel. Analysis of the prior observations in MAM has shown that the principal benefits are a consequence of perturbation of the chip formation process and the tool-chip contact conditions resulting from the superimposed modulation. Chip breakage in machining processes (e.g., turning, boring, drilling) was found to be a consequence of the chip thickness reaching zero during each cycle of modulation under the “right” modulation conditions (Figure A). Furthermore, these conditions could be predicted a priori as a function of the machining parameters using a simple model.

Notably, the tool-chip contact represents an extreme tribological condition characterized by sliding contact between clean, freshly generated surfaces at high normal pressure and temperature. These contact conditions are difficult to lubricate. However, in the presence of a modulation sufficient to break this contact, quite startling reductions in friction and energy consumption are realized even with application of only minute (cc/min) quantities of fluid. While chip breakage and enhanced lubrication are realized by application of the modulation in the direction of undeformed chip thickness, lubrication of the tool-chip contact can also be realized if the modulation is applied transverse to the direction of the chip thickness, provided there is reversal of the local cutting velocity at the tool-tip in each cycle of cutting.