## 1 Introduction  
The manufacturing industry has changed considerably over the past 30 years, leading to significant changes in management practices and product and process technologies, as well as customer expectations [1]. Today's economic landscape is increasingly characterized by dynamic economic changes (such as in costs, resources, productivity, and the complexity of products), social elements (including discerning customers, changing markets, and evolving organizational cultures), and environmental considerations (such as energy efficiency, waste reduction, and the impacts of climate change) [2, 3, 4]. Manufacturing industries also face challenges such as geopolitical crises, raw material shortages, and sustainability regulations, and growth is constrained by the economic worries, skills shortages, and supply chain problems that were still present in 2023 [5, 6]. To remain competitive in this ever-changing environment, new approaches must be found to ensure sustainable competitiveness and adaptability [7]. The continuous adaptation and improvement of manufacturing processes is essential in this regard, helping companies to meet the demands of internal and external stakeholders and thus remain competitive [8]. Efforts therefore continue to focus on optimizing costs, improving quality, reducing waste, streamlining production processes, and increasing the production throughput. To keep pace with continuous change, continuous improvement (CI), a key lean principle, needs to be in place, which aims to achieve consistent operational progress while involving and empowering all employees of the organization [1]. Various studies have argued that approaches such as the use of digital technologies [9; 10; 11; 12; 13], as well as a comprehensive lean approach [14; 15; 16; 17; 18; 19; 20], are necessary for operational progress. A combination of these approaches is increasingly seen as an answer to operational challenges in retaining competitiveness, especially in high-cost countries [21; 22; 23; 24]. The question of effective influences and challenges in the combination of digitalization and lean practices is well recognized and widely discussed [9; 16; 22; 25; 26; 27; 28; 29; 30; 31; 32]. The implementation and connection with lean practices is still very theoretical [27]. The research to date has largely focused on the theoretical aspects of this issue, while the practical interactions between the two areas are not yet fully understood and lack empirical evidence. However, research on the combined topic of lean practices and I4.0 has gained increased momentum since 2019 [27]. [PERSON] et al. [27] identified several benefits of integrating lean practices and I4.0 in previous research. These include efficient communication, better decision-making, increased flexibility, productivity, quality, and reliability, as well as reduced inventory, and overall performance improvements. Yet, [PERSON] et al. [27] found that more research is needed to show how I4.0 tools and lean approaches affect performance, as this area has not been explored in sufficient detail. They found that there was a significant research gap due to the lack of case studies in this area. In particular, the role of I4.0 and CI as a key lean principle is neglected widely and needs further investigation [27]. Our goal is to bridge the gap between the insights and perspectives of academics and practitioners through empirical research by analyzing the topic with relevant use cases from different manufacturers. The focus of our work is to explore how I4.0 technologies can reinforce the CI process as a key lean management approach. We focus on CI, as we argue that this area can benefit from the implementation of I4.0 technologies, significantly increasing production effectiveness and efficiency. The overall equipment effectiveness (OEE) is a central key performance indicator (KPI) that evaluates a machine's performance, availability, and quality.