A number of companies in the packaging machine industry have chosen electrical servo technology–mainly to replace motion axes previously powered by pneumatic systems. Multivac, for example, recently switched to servo technology. “We have found that this technology increases controllability and reduces noise emission,” said Guido Spix, CTO Multivac, “which helps us increase the number of production cycles.”
The packaging machine company uses motion control systems from Kollmorgen to reduce energy consumption, increase the overall machine effectiveness and improve safety of packaging processes.
Besides machine and operator safety, for Multivac, this also includes safe packaging processes. The traceability and controllability of Kollmorgen’s servo technology for example, helped Multivac design a more efficient sealing process for deep drawn packages with the additional benefit of improved food safety. This approach is currently used on the high performance deep draw machines, designed for mid-size to large loads.
Compared to traditional mostly pneumatic-driven lifting units, the new lines of R2XX to R5XX machines use a motor-gearbox combination to deep draw and seal the foil. These units use a knee lever mechanism to lift the molding tools – some weighing several hundred kilograms. They withstand the high bonding pressure of up to 20 tons, ensuring the two foils seal securely. Being a strategic motion control partner for Multivac, Kollmorgen implemented a compact unit consisting of an AKM® servo motor and a cycloidal gear drive for the lifting axis. Kollmorgen calculated and selected the optimal motor size and gear drive type in close cooperation with Multivac´s engineering development teams.
Two important aspects for the drive train selection were the overall unit length and overload capacity. The model HKS03 six-point lift unit features a servo gear motor with brake having a total length of 307 mm and an acceleration torque of 1400 Nm. These results are possible thanks to the high power density of the AKM servo motors, the overall length of the cycloidal gear drive, and the fact that the unit comes without end bells and clutches. Piston rods convert the rotary to linear lifting motion.
This solution has three advantages. Firstly, the energy efficiency of the machine increases because the pneumatic system was replaced as the power source to create the required pressure for the deep draw and sealing operation. Secondly, the geometry of the piston rods creates an extreme closing force at the end of travel, which improves food safety. Finally, the high sealing force results in a more secure and thus reliable sealing process.
The two-component epoxy coat used for the hygienic design conforms with FDA 21 CFR 175.300 and is resistant against acids, bases and established cleaning agents with a pH range of 2 to 12. In a long-term test performed by the company EcoLab, this coat withstood exposure to an equivalent of more than 2000 washdown cycles including disinfecting treatments. Kollmorgen’s washdown gear motor comes standard with a white coating, significantly improving the machine operators’ ability to detect dirt and biofilms on the surface during cleaning operations.
A stainless steel-like coating is offered as an option. The surface of both coats is water repellent and aqueous liquids will run off more easily, which leads to decreased formation of residue on the surface. Hence, the company’s standard of a “perfectly clean” gear motor can seamlessly be incorporated in the MULTIVAC Hygienic Design concept applied to all deep draw packaging machines.
The concept of the current motion and automation technology used on the deep draw machine follows the requirements of Multivac: more flexibility by combining several axes interchangeably and at the same time, smaller control units, plus an increase in dynamic performance for better productivity. In summary, thanks to Multivac’s and Kollmorgen’s close cooperation in this project, the entire pneumatic system was replaced by a highly efficient electrical solution. After the first successful practice runs, Multivac determined a reduction in energy consumption for the R 095 e-concept of at least 20% compared to similar models.