## 1 Introduction
The authors of Reference [14] consider that \"companies that remain out of this revolution could disappear, as they would remain technologically obsolete with respect to their competitors\". The new production strategy for global competition must integrate, as a vital component, flexible manufacturing, being able to respond technically and economically efficiently to variable conditions and rapid and continuous changes in manufacturing, which often cannot be anticipated [15]. Within this framework, the new advanced manufacturing systems will have to constantly adapt their hardware and software components to the industrial and informational environment. On the one hand, the current manufacturing systems must meet certain manufacturing requirements in the Industry 4.0 environment such as system integration from the perspective of manufacturing leadership; interconnecting material and informational resources; automation and digitalization; flexibility and adaptability to market demands; last but not least, integration of new management concepts. On the other hand, over the past decades, the Lean management system has proven to comprise the most efficient methods and techniques of manufacturing organizations, with wide and successful applicability [16], especially in companies producing goods and services and in the processing and automotive industries. Current studies and research [17; 18; 19] assess \"synergy\", the connection between the two large concepts (i.e., Industry 4.0 and Lean management), and the possibility of correlating the demands imposed on modern manufacturing and integrating new management models. [PERSON] et al. (2022) [20] holistically approached the development of production organizations from the perspective of integrating organizational management into Industry 4.0, making contributions through the integrated conceptual framework and simulation model, with applicability in increasing the performance of production systems. The research undertaken by the authors focused on developing the current production systems in Industry 4.0. The research study performed an analysis of Lean tools and Industry 4.0 technologies to identify possibilities for correlating principles into an integration framework model, useful and applicable in streamlining advanced production systems. The present paper has the following structure: Section 1 (Introduction) provides a description of the context of the occurrence of the two concepts: Lean Management and Industry 4.0. Section 2 includes a summary of some current state-of-the-art best practices for implementing Lean and Industry 4.0 as well as the current view on the possibility of interconnecting them in an industrial environment dominated by digitalization. In Section 3, based on the analysis of the key elements of the two current production strategies, through a conceptual approach a Lean management--Industry 4.0 integration framework is presented, highlighting the favorable effects on production in the industrial environment. Section 4 represents the applicative character of the paper through a case study carrying out the implementation of Lean in the field of flexible manufacturing and improving the process by integrating the techniques of Industry 4.0, digital twin, and simulation. Section 5 is intended to validate the results and discussions. Section 6 presents the conclusions and future research avenues.