# Conceiving a Digital Twin for a Flexible Manufacturing System
## 4 Conclusions  
In the present work, specific modules of an ERP/MES system combined with multisensors and PLC programming were used to create a digital entity capable of simulating and exchanging information, in real time, for the operation of a flexible manufacturing system composed of CNC machines, robotic arms, and pallet conveyors. The main conclusions are listed below:  
* Information such as production rate, queue management, feed stock, and equipment and pallet status can be easily accessed by operators and managers at any time during the production process.
* Information can be accessed in real time at different levels of the factory, facilitating decision-making by staff. For example, pallet conveyor speed can be adjusted to improve queue management.
* The combination of the physical entity of the FMS and the digital twin created in this work with artificial intelligence, cloud computing, IOT-based communication, and augmented reality, will enable the conception of a metaverse capable of operating in a smart and autonomous factory.
* With the DT, simulations of manufacturing orders were carried out, and the results obtained were close to the actual manufacturing times in the FMS, for a small batch of parts.
* The arithmetic mean roughness (\(R_{d}\)) of the machined surfaces was equal to 0.25 \(\upmu\)m, which corresponds to a degree of tolerance ISO \(\Gamma\)I2-IT3, i.e., with the equipment available in the FMS and the proper selection of cutting parameters, parts can be manufactured with a high degree of precision and surface finish. This shows the high capability of the process in terms of quality.
* The integrated manufacturing system composed of the FMS and the DT is an appropriate environment for training and dissemination of enabling technologies of Industry 4.0, as well as for further research in this area of knowledge. The following future works are suggested:
* Develop an application for mobile phones to monitor the simulation of the DT in real time.
* Use cloud computing to store information about the manufacturing system and make it available to operators and managers, so that they are able to make the best decisions regarding the process.
* Use an open-source process control platform to replace Amatrol CIMSoft. Such a platform should allow the integration of heterogeneous data from different devices and communication protocols.
* Develop algorithms for determining appropriate pallet conveyor speed based on queue formation.  
Conceptualization, supervision, methodology, validation, L.C.M. ([PERSON]); simulations, programmable logic controller and robot arm programming, L.C.M. ([PERSON]), J.B.R., J.B.G. and R.E.N.d.M.; formal analysis, L.R.M. and M.T.S.; writing--original draft preparation, J.B.R., J.B.G. and R.E.N.d.M.; writing--review and editing, J.C.E.F., L.N.L.d.L., W.H.H., M.T.S. and L.C.M. ([PERSON]). All authors have read and agreed to the published version of the manuscript.  
Thanks are due to Elkartek 2022 project LANVERSO, and in some sections (simulations) to Basque government university group IT 1573-22.  
Not applicable.  
The authors would like to thank the Espirito Santo Technology Foundation (FEST), as well as the collaboration between the Brazilian groups and the Basque University group \(\Gamma\)I 573-22.