The Hedrich Group (Hedrich) is the technology leader in the field of vacuum plant manufacturing. To meet rising demand for wind turbines, the company has developed a method for casting rotor blades using vacuum infusion, which enhances the structural strength of the finished product. The entire process is controlled using automation technology from Siemens. Alongside simple, intuitive handling and improved quality during the production process, Hedrich has benefitted in particular by a 70 percent reduction in engineering time and exceptionally high plant availability.
The rotor blades used in a wind turbine can be up to 60 meters in length and have to withstand wind speeds of 100 kilometers an hour and over. This calls for outstanding structural strength, which can be compromised by air inclusions. This makes it vital that any inclusions be either repaired or ideally avoided altogether. The second option is now possible using a fully automated vacuum infusion method developed by Hedrich for casting rotor blades. A Simatic S7-1200 controller from Siemens has a pivotal role to play in this innovative process.
Smart control solution from the outset
The production process starts with the conditioning, degassing and dehumidifying of the raw material, which is a mixture of resin and hardener. A Simatic ET 200SP distributed I/O is used here as the head controller. The conditioned material is then pumped into a ring line which can be up to 500 meters in length, from where it is transported through as many as eight infusion stations into the rotor blade half shells. Every infusion station, known as an Infucube, is equipped with a Simatic S7-1200 controller, enabling it to operate independently. Also connected to the controller are sensors and a scale. This allows each Simatic controller to monitor the correct switching of valves and ensure that the material continues to flow until each half shell is completely full.
Smart independent "local" controllers
Because the controllers of each Infucube work independently, Hedrich is able to ideally distribute its monitoring capacities. The solution also reduces the engineering workload. Unlike the previous solution which meant the infusion stations could only be regulated through the head controller, now engineering takes place independently of the number of connected Infucubes. "Today we work with a single program version for the main and secondary controllers and only need to adjust the parameters for each plant, shortening the project engineering time by up to 70 percent," says a delighted Peter Rektorschek, Head of Digital Solutions at Hedrich. This allows customers to easily add any number of Infucubes to a system or exchange defective cubes while the process is running, reducing downtimes and increasing plant availability.
Automation solution with extensive benefits
All the relevant process data can be accessed at any time using a Simatic KTP400 Basic Panel. In addition to simplified engineering using the TIA (Totally Integrated Automation) Portal engineering framework, Rektorschek was impressed by two additional benefits of the automation system: "The easy accessibility of the controllers via remote maintenance is also an important point for us. It's also possible to connect the plants to the IoT operating system MindSphere with ease."