How can we do our best, in manufacturing processes?

The paper presents synthetically the main methodologies for production systems optimization. There are presented: Six Sigma, Theory of Constraints, Toyota Production System, Lean Manufacturing, Agile Manufacturing and Smart manufacturing. The comparative study analyzes the goal, the main focus, the observed problems, the methodology, the desired outcome, the primary, but also the secondary effects and some critics for each methodology. Based on such an analysis, managers can choose the optimization methodology that best suits the organization's strategic goals, technological level, and organizational culture.