At home in the small South-West German town of Allmersbach, the company employs around 1300 people; its operating performance in 2018 was 259 million euros, and with exports accounting for more than 80 percent of turnover Harro Höfliger is a leading global packaging partner for the pharmaceutical and medical technology sectors as well as the chemical, food and consumer goods industries. With a large portfolio of standard machines and platform technologies, Harro Höfliger develops and manufactures efficient and customized packaging solutions – for individual process steps or complete production lines.

Almost every Harro Höfliger project involves solutions for specific subprocesses – and the product forming machine for dishwasher pads was no exception. The developers had to come up with a dosing solution for introducing a liquid component which in spite of the product’s high viscosity is both precise and reliable. Furthermore, the customer was looking for a compact and power dense solution that would not only fit neatly into the limited installation space but is also capable of withstanding the corrosive effects of the dosed product, not to mention the regular equipment cleaning cycles. Last but not least, the ability to access the dosing stations online for optimization or servicing was a key criterion – understandably, in view of the fact that four out of five Harro Höfliger machines are destined for international clients, many of them overseas.

Size d40 (outer diameter in mm), stainless steel small servo drives in the cyber^® dynamic line with a ratio i=30.67 are installed in two dosing stations of the product forming machine for dishwasher tabs along with SIM2010D compact servo drives in the cyber^® simco^® line with IP20 protection and a ProfiNet interface. Full stainless steel was chosen because if the product leaks, the detergent substances have a corrosive effect on surfaces and, what’s more, the equipment can be cleaned externally. It is clearly a big advantage here that the complete gearbox is integrated in the stainless steel housing – in other words, with no seal to the motor.

The motors and drives are connected using single-cable technology that is integration-friendly and compatible with drag chains. No parameterization is necessary because the motor and servo drive are synchronized via their electronic identification plate (plug & play), so that commissioning the equipment is a simple matter. The high current resolution of the servo drive enables dynamic and highly precise control of the small servo motors, which are designed with optimized mass inertia. The motors act directly on the dosing augers, which in turn ensure high, repeatable dosing precision with just a few grams of liquid per pad.

The discharge behavior can be adapted to different product viscosities in this way. For example, the developers programmed a short reverse rotation of the auger in the servo drive, so that if a product strand forms between the discharge opening and the cavity, it is automatically cut off. This simultaneously prevents too much product from being dosed into individual pads and there is no contamination of the future sealing surface. If the dosing augers have different discharge rates and tolerances, they can thus be compensated in the process, as can different product properties. Thanks to our small servo drive systems, it is even possible to run different products on the machine at once.

The single-source availability of the motor and the servo drive means technically optimized solutions at any time with no interface risks – also in other applications such as powder dosing or as a drive solution for screwing on caps. Yet regardless of where the machine is installed and what it is used for, both manufacturer and end customers can rely on worldwide support from the WITTENSTEIN service network – as confirmed by a recent assignment in the USA.