HOLZ automation GmbH can produce the wood-straw building elements for an entire house in just one production shift - with efficient motion control from Siemens.
Sustainable construction is an important issue for society as a whole. One way to reduce the carbon footprint is to use renewable, natural materials, such as straw. This highly sustainable insulation material has been used by humans for centuries. However, for straw to be processed fully automatically into finished building elements, an intelligent system concept is required, and above all, a powerful and flexible motion control solution.
The Motion Control solution covers axis synchronization, module transport, press movement and potentially even more processes in the future. This results in a scalable, standardized solution and more efficiency and flexibility.
All functions have been engineered in the TIA Portal. With the cam editor of the SIMATIC S7-1500 T-CPU, the complex synchronous movement of all axes within the baling press can quickly be adjusted and modified.
Siemens automation solutions enable traceability and quality management. SIMATIC Industrial Edge is used to monitor the wear of saw blades and readjust the trimming device accordingly.
The key component around which the new system for automatic building element production was developed comes – quite appropriately – from agriculture: "We bought a baling press and converted it so that we could automate it," recalls Jürgen Holz, Managing Director at HOLZ automation GmbH. A bold step, Jürgen Holz continues: "We come from special machine construction for assembly and testing tasks of precision parts such as gear and drive shafts for the automotive industry. Here we have defined properties – but the natural material straw places completely different demands on the process. Managing the fluctuations in material properties, such as different stalk lengths and restorative forces, cleanly and automatically, was indeed a challenge."
For Alexander Fromm, Head of Software and Development at HOLZ automation GmbH, this was an exciting task: "We had to electrify a hydromechanical press from agriculture for use in an automated industrial process. There were no templates for this." It was important to him that HOLZ automation GmbH would be able to cover the numerous processes – axis synchronization, module transport, press movement – with one system, "including tasks that we don't yet know about." The choice therefore fell on a Motion Control solution from Siemens: "We coordinated the drives together and developed the concept. This resulted in a scalable, standardized solution that allows us to be efficient and flexible."
In the plant’s current six stations, the building elements are assembled from wooden components, fitted with a back panel, and then equipped with precisely pressed straw fillings by robots. For the final touch, protruding straw is trimmed flush, creating a straight wall element that can be plastered or further processed. In addition to the central SIMATIC S7-1500 T-CPU with integrated safety functions for the baling press, each of the six production stations has a distributed SIMATIC ET 200SP Controller as an I-Device. A total of 16 axes are controlled in this way – 10 synchronous axes and 6 positioning axes. This also includes the plant safety components and communication with the currently six robots.
HOLZ automation GmbH developed and validated both the mechanical and electrical design of the system step by step, “so that the solution would work right away,” Alexander Fromm recalls. To do this, he used the trace function in TIA Portal, among other things, to validate the system behavior and signals of all components involved. The result was a mature, modular, and flexible system that also allows for mobile set-up “this allows us to easily take the system to where the houses are being built or the straw is being harvested. This shortens transport routes for materials and building elements and thus reduces emissions.” The coordinated, standardized automation, the pretested libraries, and the intuitive operation support efficient commissioning – another advantage of the solution.
As the lead developer, Alexander Fromm benefited not only during the engineering phase from the simple drive control via technology objects and the integrated functions for plant safety. The integrated motion control solution also supported him in making simple modifications and optimizations. A particular highlight for Alexander Fromm: the servo drives in the baling press. "The servomechanical solution with different drive sizes and mechanical kinematics requires a high level of drive dynamization. Previously, we would have scheduled two weeks just to correctly regulate and coordinate the six synchronous axes; with the One-Button Tuning of the SINAMICS servo drives, we were done in two hours.
The building elements have already found their first application: The new production hall was converted with interior walls made of wood and straw. The system is extremely flexible: “We can connect our process directly with planning systems from architects or construction companies via open interfaces. Our product range today includes 108 different building components in a variety of widths and shapes – and we also plan to provide the building components with clay plaster in another station. Thanks to the modular plant concept, this is not a problem."
Globally, people are looking for solutions to build affordably and sustainably. I am convinced that this is only possible with automation. And with Siemens, we have found the right partner.