## 5 Discussion
Based on the results of process testing (Table 7), we determined the following improvement outcome for our H1: Combining various quality tools (for example, KANBAN, SS, flow chart, affinity diagram, OPL, Pareto analysis, Ishikawa diagram, layout) in divisions of the mother manufacturing company with different geographical locations (America, Africa, Asia, and Europe) increases production and improves processes' performance. Figure 15: New model of synergy of quality tools and methods. Source: authors. **The hypothesis was confirmed. **  
The processes that were nonfunctional and ineffective were improved. The processes were set at the level of \"mostly effective and functional\" after the implementation of quality tools in the year 2023. The combinations of quality management tools, according to Figure 13, introduce a new approach to innovation in the processes in divisions of the manufacturing company, without the influence of geographical location. This model can be used in various industrial companies. Implementation of quality tools brings many improvements in the areas of cost, time, downtime, material flow, transport, layout, claim process, documentation, location, marks, defects, safety, absence, risks, training, working conditions, and others. Process optimization is a pillar of Industry 4.0 in synergy with Quality 4.0, with an orientation towards innovation, as presented in the article by [PERSON] et al. (2022). Such pillars of Industry 4.0 are supported by digitalization, and the main goal of strategy direction is sustainable development in the sense of a circular economy, as presented in the research of [PERSON] et al. (2021). All processes (supply, transport, storage, production, marketing, design, and delivery) are interconnected and are reflected in the business performance of the processes through the performance indicators (KPI--key performance indicators) that were presented by [PERSON] et al. (2020) and [PERSON] et al. (2015). [PERSON] et al. (2022) commented in their research that the performance model must include process results in terms of SMART criteria. SMART is an acronym that stands for Specific, Measurable, Achievable, Realistic, and Timely. SMART incorporates all of these criteria to increase the chances of achieving a defined goal, as presented in the article by [PERSON] et al. (2020). Such an approach allows manufacturing companies to be competitive. The implementation of quality management tools creates a basic foundation of innovation, sustainability, optimization, digitalization, and efficiency, as presented in the research of [PERSON] et al. (2022), [PERSON] et al. (2020), [PERSON] et al. (2022), [PERSON] et al. (2023), and [PERSON] et al. (2021). The improvement model of processes (Figure 16) must contain the pillars of Industry 4.0--optimization, digitalization, efficiency, and automation. [PERSON] et al. (2021) argued that using quality instruments increases performance, with an emphasis on added value and business development. Using quality tools and methods introduces a proactive approach to optimization of costs and increases the sustainability of processes [53]. In each area of management, quality instruments and their synergy in various processes can be used to great effect.