In recent years, Industry 4.0 (I4.0) has been a recurrent theme in the literature on Lean Six Sigma (LSS), given the synergies that can arise from their combination. However, their joint implementation presents several challenges. In this article, a systematic literature review (SLR) of research on I4.0 and LSS integration was performed. This review involved five database platforms and included seventy-four articles providing state-of-the-art knowledge on the topic, focusing on the barriers to and enablers of integration. As a result, 20 integration barriers were identified, highlighting the high implementation cost, long learning curve, and technology incompatibility as the main barriers. Seventeen enablers were found to facilitate and guarantee implementation success, highlighting investment in IT infrastructure and employee training, stakeholder involvement, and top management support. In addition, the article discusses actions to facilitate I4.0 and LSS integration in practice, determined by connecting the identified enablers to their corresponding barriers. Finally, the SLR identifies several avenues for future research.

The Lean Six Sigma (LSS) philosophy and sustainability have become topics of interest since the 1990s; they have generally been analyzed together since 2012. Numerous professionals, managers, and researchers have sought methodologies by which to assess their impact and know their effectiveness within companies. During the past decade, the application of partial least squares structural equation modeling (PLS-SEM) has been widely accepted in various modeling, prediction, or multivariate analyses as a way to measure the impact of LSS on sustainability. This study conducts a literature review to identify the use of PLS-SEM in measuring the impact of LSS on sustainability. A systematic review methodology has been employed, applying five search criteria to three scientific database platforms. This approach has been helpful to identify PLS-SEM as a valuable methodology for measuring the impact of LSS on sustainability. One of the research findings is that LSS practices positively impact 83% of economic indicators, 78% of environmental indicators, and 70% of social indicators. This article creates a theoretical foundation for future research on these issues, outlining research opportunities to generate future studies. It also allows researchers and managers who are interested in improving sustainability indicators to access valuable knowledge regarding what types of LSS tools could be used.

The company under study is mainly dedicated to the manufacture of dairy products, both liquid and powder, in different functionalities or profiles: whole, skimmed and deslactosed. For production planning, the company has a traditional process, which projects a weekly production plan with the objective of satisfying the demand while looking to maintain an inventory and control production costs according to a pre-defined policy. The company has two major challenges: the first is to maintain a balance between the consumption of a regular volume of milk and the efficient use of surplus fat, while satisfying the demand. The second challenge is to ensure the correct use of factory assets by controlling the levels of stocks and production lots. The company currently does not have an adequate tool to fulfill these purposes. This study seeks to design a mathematical model that helps to develop a manufacturing master plan that allows to meet projected demand, keep inventory at the appropriate levels and comply with production considering capacity constraints.

Improvement was developed in the production process in the Traditional Cakes area of the Dulcería-Café company (SMS) through the current evaluation of the productive processes, with the purpose of identifying the activities that did not contribute any value to it. It was applied the Value Stream Mapping (VSM) value stream modeling tool to make a comparison between the current processes and the changes necessary for the continuous improvement of the company.

The company of the present study is an importer and marketer of medical supplies and equipment that contributes to the improvement of health care in the country, located in the city of Guayaquil where its distribution center is located to serve its customers nationwide. The company, did not have a tool that allows to plan the dispatch routes efficiently. The construction of routes was performed empirically considering the distances and time variables from one client to another, considering that most of the clients are public and private hospitals, clinics, as well as, medical centers, laboratories and health centers with different hours of service to suppliers. In this study, time windows were considered as vehicle routing variables, in which different clients can be attended, as well as traffic levels that were presented in certain sectors and at certain times. In addition, emphasis was placed on the analysis of the routing system that existed and an improved vehicle routing system was developed. The best solution that was adapted to the problem was the Vehicle Routing Problem (VRP) model with time windows applying the Clarke & Wright algorithm to minimize costs, distances, improve service quality and be more competitive.