# Industry 4.0 and Lean Six Sigma Integration: A Systematic Review of Barriers and Enablers  
[PERSON]  
1 Institute for Manufacturing, Department of Engineering, University of Cambridge, 17 Charles Babbage Road, Cambridge CB3 0 PS, UK 12 Facultad de Ingenieria en Mecanica y Ciencias de la Produccion, Escuela Superior Politecnica del Litoral, ESPOL, Campus Gustavo Galindo, Km 30.5 Via Perimetral, P.O. Box 13 09-01-5863, Guayaqui 090902, Ecuador 2  
[PERSON]  
2 Facultad de Ingenieria en Mecanica y Ciencias de la Produccion, Escuela Superior Politecnica del Litoral, ESPOL, Campus Gustavo Galindo, Km 30.5 Via Perimetral, P.O. Box 13 09-01-5863, Guayaqui 090902, Ecuador 2  
[PERSON]  
2 Facultad de Ingenieria en Mecanica y Ciencias de la Produccion, Escuela Superior Politecnica del Litoral, ESPOL, Campus Gustavo Galindo, Km 30.5 Via Perimetral, P.O. Box 13 09-01-5863, Guayaqui 090902, Ecuador 2  
[PERSON]  
1 Institute for Manufacturing, Department of Engineering, University of Cambridge, 17 Charles Babbage Road, Cambridge CB3 0 PS, UK 1  
Footnote 1: email: [EMAIL_ADDRESS]. I4.0 and LSS are approaches that help companies be competitive and respond quickly to changing market demands [11]. Moreover, I4.0 has gradually developed into a topic of significant interest for practitioners and academics interested in L and LSS. As shown in Figure 1, the number of publications investigating the relationship between I4.0 and these methodologies has grown significantly in recent years. However, most studies have only focused on the relationship between I4.0 and L [10]. The literature has indicated the need for more studies addressing the integration between I4.0 and LSS [12]. Despite the growing interest in integrating I4.0 and LSS, only a few studies have attempted to synthesise and assess the related body of knowledge using standalone literature reviews [10; 13; 14; 15; 16]. For example, in [16], a systematic literature review (SLR) was performed to identify the contact points (CPs) between I4.0 and LSS. They identified 13 CPs in total and their corresponding technical requirements. More recently, in [10], a scoping review (SR) based on a combination of bibliometric and qualitative content analysis was conducted to encapsulate the literature on the combination of I4.0 and LSS and orient future research. In particular, they identified the synergies emerging from this combination, some success factors for implementation, and KPIs that may experience an improvement. While these reviews provide significant value to the field, their focus has mainly been on assessing the relationships and synergies between I4.0, L, and LSS, identifying technologies and techniques involved in integration, and highlighting possible effects on performance. However, some critical aspects of the integration process still need to be comprehensively reviewed, synthesised, and assessed. In fact, one of the 'gaps' is related to the conditions that facilitate or hinder the integration process between I4.0 and LSS in companies. In this regard, the first research question (RQ1) to be addressed by this study is as follows: What are the main barriers and enablers when integrating I4.0 and LSS? Another aspect that requires attention in the literature is how the enablers of integration can be deployed independently (or together) to address the obstacles to integration. Consequently, the second research question (RQ2) to be addressed is: What are the possible approaches to facilitate the integration of I4.0 with LSS? Finally, although  
Figure 1: Journal articles on I4.0 and LSS integration per year. several authors have conducted case studies showing the Industry 4.0 technologies used in conjunction with LSS, a systematic review of these, which would allow for identifying the most used technologies in the context of integration, is lacking. Therefore, this article will address this gap by answering the following question (RQ3): What I4.0 technologies and LSS techniques/tools are commonly involved in integration? The remainder of this paper is organised as follows.