## 6 Results  
The applicability of the proposed framework was tested through a series of experiments. More specifically, the validation focused on two main dimensions. Firstly, the achieved performance was evaluated versus the performance before implementing the proposed framework. Secondly, the evaluation of the main interface for providing PSS functionalities was carried out.  
For the validation of the developed IPSS platform, the AR mobile application and the supported functionalities, a set of Key Performance Indicators (KPIs), was set. These KPIs are illustrated in Figure 9 and are relevant to the \"Processing Time\" and the \"Energy Consumption\" (see Figure 8). Likewise, the \"Energy Cost Savings\" as well as \"Added Production Cost\" per year (see Figure 8) were calculated. From the results, it becomes obvious that a significant reduction in energy consumption is feasible for Mold 1 and Mold 3. On the contrary, for Mold 2 both values have risen as a consequence of less demanding maintenance activities. Despite that, the overall performance of the proposed PSS framework appears to be beneficial for the mold-making industry, resulting to an energy reduction equal to 11%.  
In particular, it can be concluded that the use of the mobile AR application on the shopfloor level facilitated shopfloor technicians in reducing mold inspection time by up to 50%. Further to that, it has also been observed that the malfunction documentation, due to the annotation creation on the 3D component of the mold, has been reduced by approximately 70%. Finally, one of the findings of this research is that the mold maker had issues with the on-time delivery of the repaired molds, as illustrated in Figure 9.  
Participants were also given questionnaires to fill out in order to record their opinion regarding the functionalities provided with the mobile tool. Moreover, several webinars and workshops were held during the development phase of the tool, which helped to improve its status. The method presented in this research work is part of an EU research program, therefore, the end-users (i.e., the mold-making industry) participated in the design, testing, and validation phases of the method. Concretely, discussions and physical meetings were organized in order to establish the key requirements, which led to the creation of the KPIs (Key Performance Indicators). Then, the research team proceeded with the development of functional mockups in order to present and discuss the application (Augmented Reality application) functionalities and agree on the information content.  
Figure 9: Validation results. Comparison of metrics before the implementation of the framework versus after the implementation.  
As soon as the fully functioning application was developed, the research team, in close cooperation with the mold-making industry, performed several tests, and the results were compiled and presented in Section 6 of the revised version of the manuscript. It is stressed that several application test meetings were organized in order to calibrate the AR application (calibration of the visualizations with respect to the physical environment).  
Regarding the on-time delivery of the molds, an approximate 20% rise has also been observed, indicating that the shopfloor of the mold-making industry was more efficient, thus more capable of meeting the deadlines. As a result of the implementation of the proposed IPSS, an approximate 20% rise in on-time mold deliveries has also been observed. This is justified by increased and more efficient communication between the OEM and the client, as well as between the OEM and the energy supplier. Consequently, the three parties could efficiently collaborate with each other in order to build an appropriate maintenance plan that could be followed more easily and accomplished in a timely manner.