KRAIBURG TPE Corporation in Duluth, Ga. is a manufacturer of custom-made thermoplastic elastomer (TPE) compounds for a variety of market applications in the automotive, medical, general industrial and myriad consumer sectors. At the Duluth facility, the product development department routinely evaluates material batches and new custom compounds for performance and customer specification viability. As an integral step in that process, KRAIBURG TPE engineers utilize sophisticated co-rotating, twin-screw extruder technology provided by KraussMaffei Berstorff, from its facility in Florence, Ky.
Owing to the substantial varieties of color, durometer and the wide-ranging performance properties required at KRAIBURG TPE, monitoring every aspect of the machine performance is critical. This includes all temperatures, speeds, pressures and torque on the extruder itself, plus an underwater pelletizer, gear pump and multiple loss-of-weight feeders used on the line.
For the latest machine installed at the KRAIBURG TPE facility, as senior application engineer at KraussMaffei Bertstorff, David Frankenberg, explains, “The lab extrusion line is used for both process and product development assessment. A key requirement was the generation of all data in real time, as part of the management system to be used, as well as the condition monitoring system needed for predictive maintenance strategies being employed.” In cooperation with the KRAIBURG TPE team and after evaluating the competitors for the control scheme, KraussMaffei turned to Siemens for assistance, as this supplier was able to bring a pre-configured and highly cost-effective solution to the requirements on this machine.
As Frankenberg and his electrical engineering associate Martin Gonzalez detailed, the Siemens EXT3370 application package represented a blending of the current PLC technology and drives platform with an HMI capable of providing all graphics and multiple data screens on a single display. In addition, the system had the ability to feed the “big data” directly to the KRAIBURG TPE process data archival & analysis system, where it would reside for real-time and long-range performance evaluation by the product development, quality and process teams. All speeds, pressures, temperatures and other parameters can be instantly assessed, using set point and actual value data on the display, either at the machine HMI or a remote monitor within the KRAIBURG TPE network.
On the KraussMaffei Bertstorff machine, the control system comprises the software solution, Siemens drives and motors, the ability to monitor up to 32 separate temperature zones, touch screen technology on a 15” HMI and scalability on the drives to accept the ancillary equipment being monitored at the KRAIBURG TPE facility. In this way, a truly customized solution was devised using an entirely standard and thus highly cost-effective array of components, according to Frankenberg. As an additional benefit, he noted, the training needed was minimal, owing to the plain language on the control with no need for knowledge of high-level programming skills. Finally, all compound recipes can be easily transferred via USB for portability and security.
Allen Donn, product development engineer at KRAIBURG TPE, along with his team of engineers and tech specialists, evaluated the installation and commissioning of the machine at the Duluth facility. “The data transfer from the PLC into the same process data archival & analysis system that we use for our other lines at KRAIBURG TPE. A simple Excel file is generated with any parameters desired for analysis, plus we can easily exchange data between R&D and production here. The result is that our ability to utilize production machinery more efficiently has increased substantially with the use of the new KraussMaffei Bertstorff machine in our test department, as the control system gives us real-time hard data we can use to make adjustments on new recipes and entirely new materials.” KRAIBURG TPE performs extensive new compound property performance testing on its TPE formulae and the time compression realized by using the new extruder line in this “real world” R&D operation is providing substantial advantages for the compounder.
KRAIBURG TPE typically runs materials in the 20-80 Shore A hardness range and, as an example, might test out a variety of adhesion grades for over-molding onto polycarbonate, nylon, or other substrates, Donn explained. “When we can pull the data from any machine in the system, adjust it, run it on the R&D machine, and then feed that data back into production, it makes a huge difference in our efficiencies.” In one instance, shortly after the KraussMaffei machine was installed, KRAIBURG TPE engineers were testing 15 compound varieties on the machine very quickly, compared to using production equipment to do that task. “I could look into the software to compare all set point and actual values, remotely, over the entire test period,” Donn noted. He added that the substantial raw material cost savings of more tests, faster results and less waste all contribute to an improved profitability for the company, as well.