The fabrication of high precision miniaturized components in micro- and nano-technologies requires a deep understanding of the physical mechanisms governing the nanomachining process. To aid with this need, the current article employs molecular dynamics to investigate the thermo-mechanical aspects of orthogonal nanometric machining in a copper workpiece. We study the evolution of the material removal process, the effects of machining velocity on the predicted MD response and the variation of the temperature within the chip for different machining velocities and machined thicknesses. As expected, the chip temperature rises with increasing machining velocity but it only noticeably decreases with growing machined thickness for machining velocities >= 50 m/s. The chip temperature indicates the isothermal nature of the machining process for low cutting speeds (<= 10 m/s for copper) and the non-isothermal evolution of the process for high cutting speeds (>= 50 m/s for copper).