A practical example of a Digital Twin is presented as a result of a collaboration, initiated by Programmabureau Smart Industry, between the Metaalunie, University of Groningen, Hanze University, STODT, and Siemens. With this Digital Twin, present at three locations, the group wants to show manufacturers what they can do with a virtual copy of the real thing. In addition, it wants to demonstrate that this technology is now available to small and medium-sized enterprises.
(Technishow has been rearranged for the 1st-4th of September 2020)
“In the manufacturing industry, a Digital Twin is often seen as a CAD/CAM solution. As CAD/CAM provides a digital image of reality, this is partly correct. However, we mostly speak of a Digital Twin when you link data of the real world to a digital model to use it for simulation and optimisation. That is what we want to make clear and show people at the Technishow," says Daniel Kofman of Siemens. A Digital Twin is a virtual representation of a physical product or process, which is used to understand and predict the performance characteristics of its actual production. By integrating simulation, data analysis, and machine learning capabilities, Digital Twins can demonstrate the impact of design changes, environmental conditions and endless other variables. This eliminates the need for actual prototypes, shortens the development time and improves the quality of the product or process. For a machine tool, a Digital Twin means that CAD/CAM is supplemented with real-time data from the machine, its automation, the workpiece, tools, and clamping. This eliminates the need for a dry-run to discover uncertain factors that are not included in a CAD/CAM simulation. “When the post-processor generates the movements of a machine tool and you do not take into account the behaviour and settings of the actually used CNC, it can still go wrong in the actual situation. With a Digital Twin, you can include peculiarities of the CNC machine in the simulation, which makes it almost 100% reliable. Another exciting new development is that robot milling has been made more accurate. By calculating the cutting forces of the process in the Digital Twin, the deviation of the robot during the cutting process can be determined, which can then be compensated for in the NC program of the Sinumerik," says Kofman.
Rard Metz of Metaalunie adds: “We want to use the Digital Twin at the Technishow to promote offline programming. There are still many companies that are not doing this and this must change. Offline programming, certainly with a Digital Twin, offers so many benefits."
Groningen, Hengelo and Utrecht come together
The Digital Twin at the Technishow is a result of the cooperation between the University of Groningen, the Hanze University and STODT Hengelo. At the same time as the Technishow is held, a congress is organised in Groningen, Nederland Digitaal, where students can attend a workshop in Siemens NX and are accompanied when programming a product for a five-axis machining centre. The NC programme that is programmed and tested by the students with the help of the Digital Twin, is then sent to STODT. Thanks to the Digital Twin, STODT can run the programme blind without first carrying out a dry-run. Thanks to a live video connection at the Factory of the Future stand at the Technishow, its visitors can see what is happening in Groningen and Hengelo. In addition, a demonstrator at the stand will present a virtual model of the machine tool at STODT, including the operations that are carried out. The demonstrator is a screen with a virtual display of the machining area, combined with genuine CNC control. The machine data from the CNC machine of STODT is transferred to the Siemens Mindsphere cloud platform via the ‘Manage MyMachine’ app. At the Technishow this information will be shown live, so visitors can see what the power of the machine is, which programme is being used, what the production time is, etc. The data from the actual machine tool is also sent back to Groningen to feed real-time data to the Digital Twin. This information is used by the Digital Twin to evolve and is constantly updated to reflect any change in the physical counterpart. This creates a closed-loop, which allows continuous process optimisation. “What is presented here is also useful for 'Facility Sharing'. The moment that you, as an engineer, have the Digital Twin of machines in someone else's production facilities at your disposal, you can prepare the process with your own expertise and outsource a more flexible production," says Hans Ouwehand of Siemens.
More attention to software
“SMEs in the manufacturing sector are very hardware-oriented. Metaalunie, and FPT-Vimag and its members, would like the focus to shift more towards software. Smart Industry is about this digitisation and the opportunities it offers. Low-wage countries are knocking on our doors and the next competitive victory in efficiency will be won with software solutions in particular. Research shows that, at the moment, 23% of manufacturing companies are interested in digitisation transition, but a large part does not know how and where to start. At the Technishow these companies can gain inspiration. We want to make the other 77% percent aware of the possibilities of digitisation by showing them examples. Hence the cooperation with STODT, to show how accessible digitisation can be and how easily it can be used in practice," said Metz. Together with Siemens Digital Industries, STODT is building a digital factory in Hengelo in which data-based CAM programming is standard and orders are directly sent from the ERP system to the machines. Within this fully automated production environment, future CNC machine operators will attend training and courses to learn how to improve processes and reduce costs, shorten delivery times and have more flexibility. Machining companies can get acquainted with the latest industrial software in the digital field lab. Bob Selker of STODT says: “Digitisation in the machining sector is also a must.”
Kofman adds: “Companies don’t hesitate to invest a few hundred thousand Euros in a new machine or automation solution, but find it difficult to pay a similar amount for a download link to software with which much more profit could be gained. Software can improve the efficiency of existing machines, making the investment in your machine much more cost-effective. That awareness needs to be created."
Virtual is the future
The Dutch industry is far ahead when it comes to advanced CAD/CAM systems. The step towards a Digital Twin can therefore be made quite quickly. And, according to Metz, this also offers a solution for the shortage of professionals. A Digital Twin prevents errors in the production process so that employees with less knowledge of production technology are able to keep a machine tool operational. Kofman sees a Digital Twin also as a solution for a digital learning environment in technical education. “With digital machine tools, schools are able to educate students in a more flexible way and make use of the latest technology. The moment a Digital Twin of a machine tool does exactly the same as the actual machine, schools need to invest less inexpensive machine tools and part of the education can be carried out with a digital mock-up."
Digital Twin for each step
The term ‘Digital Twin’ is, like the terms ‘Industry 4.0’ and ‘Smart Industry’, a collective name. For each step in the product development, you can find different Digital Twin applications. You can unleash a Digital Twin on the product, the production, and the performance. A Digital Twin can be used during the development of a product. This product can be a workpiece, but also, for example, a complete machine or production line. Various concepts can be considered, while it can also be tested on how these products work in the actual world. As an example, the complete automation of a machine can be developed in the virtual environment. With actual hardware (Hardware in the Loop) or with a simulated CNC (Software in the Loop), the configuration of the CNC and the development of the PLC program can be completed and fully tested before the actual machine is constructed. The entire production, such as milling, can be prepared with a virtual machine before a new machine is delivered. This allows the production to be started on day one. This eliminates the need for multiple prototypes, shortens the total development time and improves the quality of the final manufactured product. A Digital Twin for the complete production can help validate how well a production process works on the work floor, whereby the entire logistics around the machine can be optimised before something is actually brought into production. By simulating the process using a Digital Twin and by analysing why things happen, companies can create a production environment that remains efficient under various conditions. Think about what happens when using AGVs or the analysis of bottlenecks in production. By constantly generating production data and using these in a Digital Twin, companies can avoid costly downtime of equipment and even predict when maintenance will be required. This constant flow of accurate information enables production processes to be faster, more efficient and more reliable. Finally, there is the possibility to transfer the measured performance data of products, machines and processes to a Digital Twin. These data can be analysed in a virtual environment to provide useful insights for further decision-making. Compare it with the vast amount of data that is collected during a Formula 1 race to improve the performance of the car in the future. Thanks to a Digital Twin in all process steps, companies are able to improve product and production system efficiency, reduce the number of prototypes and produce first-time-right.
The video below shows another example of the benefits of a Digital Twin.