# Industry 4.0 and Lean Six Sigma Integration: A Systematic Review of Barriers and Enablers
## 4 Review and Discussion
### Integration Barriers  
Three barriers to integration were identified as the most recurrent in the literature: high implementation costs [32; 44; 45; 82], technological incompatibility [36; 83; 84; 85], and extended learning curves [75; 86; 87; 88]. Other relevant barriers were identified and are listed in Table 5. The identified barriers were organised into the four major categories discussed below. **Cultural suitability--**The literature highlights several barriers related to organisational culture, namely resistance to change [48; 76; 81], insufficient management support [61; 87; 88], and short-term vision [86; 89]. Usually, the resistance to change during the integration process comes from the fact that an increase in automation is sometimes perceived as a threat to job stability [90]. In addition, changing the company KPIs in connection with the new data collected by I4.0 technologies is not always well received by staff [23]. As for the other two barriers in this category, their importance comes from the fact that, for the effective implementation of I4.0, a long-term vision, clear plans, and objectives must be set early on in the process [89], hence requiring significant management attention. \begin{table}
\begin{tabular}{l l l} \hline \hline \multicolumn{1}{c}{**I4.0 Enabling Technologies**} & \multicolumn{1}{c}{**(\%)**} \\ \hline Big Data & & 51\% \\ Internet of Things (IoT) & & 43\% \\ Cloud Computing Systems & & 35\% \\ Radio-Frequency Identification (RFID) & & 35\% \\ Digital twin/Simulation/CAD/BIM & & 27\% \\ Robots/Automation & & 19\% \\ Enterprise Resource Planning (ERP) & & 19\% \\ Augmented Reality (AR) & & 18\% \\ Digital Automation/Sensors & & 15\% \\ Artificial Intelligence (AI) & & 9\% \\ Virtual Reality (VR) & & 7\% \\ Blockchain & & 1\% \\ Wireless Sensor Networks (WSNs) & & 1\% \\ \hline \hline \end{tabular}
\end{table} 
Table 4: List of technologies enabling I4.0 and LSS integration. \begin{table}
\begin{tabular}{l l l} \hline \hline \multicolumn{1}{c}{**Category**} & \multicolumn{1}{c}{**Integration Barriers**} & \multicolumn{1}{c}{**Articles Considering the Enabler (\%)**} \\ \hline \multirow{4}{*}{Cultural suitability} & Resistance to change & 8\% \\  & Insufficient management support & 5\% \\  & Short-term vision of company goals & 4\% \\  & Insufficient organisational communication & 1\% \\  & Low employee involvement & 1\% \\ \hline \multirow{2}{*}{Financial plausibility} & High implementation costs & 28\% \\  & Lack of awareness of potential benefits & 4\% \\  & Long implementation time & 4\% \\ \hline \multirow{4}{*}{Operational viability} & Long learning curve & 16\% \\  & Poorly structured, non-standardised processes & 8\% \\  & Insufficient data privacy/security & 8\% \\  & Data loss issues & 8\% \\  & Low level of experience and skills in LSS/I4.0 & 7\% \\  & Significant changes in production processes & 4\% \\  & Workforce instability & 1\% \\ \hline \multirow{4}{*}{Technological feasibility} & Technology incompatibility & 18\% \\  & Insufficient IT design and infrastructure & 9\% \\ \cline{1-1}  & Matching and integration between different data sources & 8\% \\ \cline{1-1}  & Massive volume of data to be managed & 3\% \\ \cline{1-1}  & Lack of common communication protocols & 3\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: I4.0 and LSS integration barriers. **Financial plausibility--**The high implementation cost associated with integrating I4.0 and LSS appears to be the most critical barrier, with 28% of the reviewed articles mentioning it. Adopting innovative technologies represents a considerable capital cost, and some companies may refrain from acquiring them [12]. Technology investments are critical, especially in sectors where products or services do not compensate for the (capital) costs generated [12]. Another aspect contributing to high costs is the length of the implementation process [23; 91], which may depend on multiple factors, such as the size of the company, its current level of technology adoption, and the target level of integration, among others.