Manufacturing sector faces the challenge of harnessing digital industry. Responding to this challenge, the present work shows different machining processes, as turning, grinding and milling, that have been optimized following Industry 4.0 paradigm. In all cases, this optimization objective has been reached using data platforms where process variables coming from numerical control or sensors are stored, and where optimization algorithms are ran. These improvements are diverse and specific for each process: quality control, cutting tool life improvement, or defect prevention.