Reducing commissioning times – that is the immediate aim of Autefa Solutions Germany GmbH, a well-known manufacturer of textile fiber baling presses, productionlines and machines for the production of nonwovens as well as automation technologies, which is used in the beverage industry, for example. Digitalizing important parts of the line with perfectly interconnecting Siemens software tools represents an up-to-date method of achieving such a goal. The company plans to let future bale presses reach technical readiness in the form of a digital twin before they get commissioned in the real word – a process which, ideally, will take half as long as usual. In the current project, the company used a digital process to verify the concept for the world's fastest bale press with automatic packaging.
Machinery and equipment manufacturers in the textile industry tend to operate in a global environment, whereby staying one step ahead of their competitors is now more important than ever. They need to be technologically better, more cost-efficient and faster, and they have to offer users genuine added value. With these goals in mind, Autefa Solutions Germany GmbH is increasingly opting for digitalized processes such as virtual commissioning. The globally operating company from Friedberg near Augsburg has established a new, large-scale conceptual approach for a bale press line, which also includes a virtual 3D model. A "digital twin" will be used to simulate the integrated processes of the bale press, film inserters and wrapping, ultrasonic sealing system, strapping, transport and transfer fork. The processes will then be optimized and a first press, together with peripheral equipment, will undergo virtual commissioning.
Using this method, the idea is to shorten the time-to-market for equipment in general, to commence real-world commissioning with a PLC program that is almost completely finalized and in which most of the errors have been eliminated, and to enter productive operation earlier. Moreover, the company wants to be able to modernize existing equipment in advance on a digital twin without interrupting production and running the risk of errors.
New concept to achieve significantly higher output of up to 62 bales an hour
With four pre-presses (80 t), three main presses (300 t) and three rotating transfer forks – in each case with one unit acting alternately as a stand-by reserve – the machine builder is aiming for maximum availability. Integrated subprocesses of the major production line components – which feature harmonious and dynamic intermeshing and are finely honed in terms of timing – are critical in achieving enhanced overall performance. "This helps us to realize an output of up to 62 completely packed and strapped bales per hour per press – which is unmatched anywhere in the world," says Dirk Falise, the company's Global Sales Director Baling.
"As we prefer to deploy automation equipment from Siemens anyway, using an end-to-end solution from Siemens for the simulation was an obvious choice because the interfaces were automatically matched to one another and the components are available for a virtual world," says Rudolf Kuhn, Head of Technology & Planning at the Autefa Group. A high-performance simulation platform was set up together with Siemens' local sales team and specialist consultants.
The NX Mechatronics Concept Designer (MCD) is the key component for the "kinematization" and visualization of major process steps – in this case a main press plus the associated peripheral equipment. This was used to quickly generate a detailed "moving" production line model based on existing 3D design data. The SIMIT simulation platform is linked via Shared Memory and communicates with SIMATIC S7-PLCSIM, a software-based SIMATIC PLC. The program can then be tested in the usual way, with SIMIT signaling errors and the MCD supplying a concrete visualization of the resulting traversing.
"The powerful opportunities of the Siemens simulation tools can be accessed very intuitively and quickly, and result in an end-to-end digital model even of the more complex parts of the line," says Simon Griesbeck, who "kinematized" the digital twin with 16 axes and then got it up and running as part of his bachelor thesis for his cooperative study course in Mechatronics. "Once the parts of the line have been created, they can be simulated either separately or in interaction with one another; they can also be rotated through all three axes and enlarged to any size. This makes processes and interdependencies transparent and easy to understand. Any design errors can be recognized – in the case concerned an incorrectly mounted hydraulic cylinder – and eliminated without having to change the construction of the actual part itself. Changes can then be transferred back to the design."
Using SIMIT and SIMATIC S7-PLCSIM, the PLC program, including all safety-related interlockings, is simulated and optimized by means of software-in-the-loop. Logic errors, which previously could often not be recognized and eliminated until real-world commissioning, can now be corrected in the digital twin. When the commissioning engineer comes to the site, he already has an almost fully developed program at his disposal, which, among other things, considerably shortens the time to the start of production.
In future, the plan is to have interaction between the mechanical design process and the simulation right from the very beginning and, ideally, to use the digital twin for devising the concept and preparing the bid. Further aims of the machine builder are to create digital standards, to reduce the number of different versions and to reuse optimized modules in the simulation time and time again.
The digital twin in the MCD makes complex interdependencies and motion sequences transparent and comprehensible so that collisions (contour violations) of system parts can be reliably avoided. That prevents costly damage and the associated lost time.
The same applies to subsequent design changes, which can also be verified in advance without interfering with ongoing production and then implemented more quickly.
SIMIT and the PLC virtualized with SIMATIC S7-PLCSIM help to recognize and eliminate errors in the sequence program so that real-world commissioning begins with a program already in the advanced stages of development. Any errors are detected before the machine is delivered to the user, which means a major reduction in commissioning time.
Moreover, the digital twin is an ideal platform for training both the company's own maintenance technicians as well as the machine operator's operating staff. As a result, the latter are very familiar with the system right from the very beginning, can operate it reliably and quickly remedy those small faults that can have a negative impact on both availability and productivity.
As early as the development phase, the HMI interfaces themselves can also be designed to suit the operator's specific requirements.
This makes processes transparent and comprehensible, and errors in the design and PLC program can be detected at an early stage. In this way, virtual commissioning shortens real-world commissioning considerably. Autefa's immediate goal is to halve commissioning times.
Tackling the future with digitalization
We are convinced that digitalization will deliver the added value both we and our customers are seeking.Rudolf Kuhn, Head of Technology & Planning at the Autefa-Group
The Technical Director of the Autefa Group also sees the analysis of ongoing production data as a further emerging field of application, be it for the continuous improvement of processes and product quality or the early detection and planning of forthcoming maintenance, and ultimately further increasing availability.
Digitalization makes complex technologies easier to understand
A further reason for Autefa to choose the path of digitalization was so that the company could visualize real-world line concepts to make them easier for potential customers to grasp. To this end, a SIMATIC HMI Comfort Panel and various control elements were integrated into the simulation via additional servers. The virtual baling press can then be operated and monitored as in actual manual or automatic operation. The digital twin was premiered at the Autefa Solutions Germany and Siemens booths at the ITMA in Barcelona.