Drives & Controls October 2022

33 www.drivesncontrols.com October 2022 MACHINE BUILDING AND OPERATION n Actuators make bulk-bagging process more flexible U S-based Thiele Technologies builds packaging machines that measure, fill and seal bags. It can trace its history back to 1931 when the first Deltaseal bag-sealing machine was built. In 1995, the firm was acquired by Barry- Wehmiller, which combined it with Frontier Equipment. In 2018, the brands operating under the Thiele Technologies banner became part of BW Flexible Systems and BW Integrated Systems. Thiele supplies high-speed packaging and converting systems to industries including food and beverage, horticulture, pharmaceuticals, medical devices, cosmetics and petrochemicals. Whether the product is fertiliser or sugar, the bags used to store and transport bulk materials need to be filled accurately. Customers need to receive the agreed amount. It’s also crucial that the bags are sealed securely, and that this process can be completed repeatedly at speed. Despite the high repeatability of Thiele’s machines, its customers from the pet food market were increasingly asking for machines that could fill inconsistently sized bags. Their customers – large retail chains – were demanding more durable bags, so they changed from paper designs to woven poly types. But using these lower-cost bags was resulting in inconsistent sizes – varying by as much as 2cm – which slowed down the filling and sealing process, and affected quality. To resolve this dilemma, Thiele developed a bag-top reference mechanism that compensates for varying bag lengths. The automated system removes the need for manual set-up and adjustment. The result is increased repeatability and productivity of the bagging process. To achieve this, Thiele uses four rodless electric screw actuators to position the incoming bags precisely before they are inserted into the filling and sealing line. Two of the actuators adjust the bags’ vertical position, catching and lowering them to a precise reference point determined by a vision system controlled by the bagging machine’s PLC. The bags are centred in their trays by two horizontally mounted actuators. The horizontal actuators include two carriers riding on a screw, with right-hand threads on one half, and left-hand threads on the other. As the screw turns, each pair of carriers moves towards the other to centre the bag in the tray. The actuators are joined by a coupler and are powered by a single servomotor, connected by a compact 180- degree belt drive. Once the bags are vertically aligned and centred, they are picked up by a pneumatic arm and inserted into the filling and sealing line. Improving repeatability was a key objective. The new machine achieves a tolerance for positioning the tops of the bags of less than 1mm. Even when bag dimensions vary, this level of precision is maintained. The mechanism also allows the operator to change the filling and sealing specification to suit the bag size with the push of a button. The programmable actuators also allow the machine users to adjust bag size recipes automatically to help speed changeovers. This avoids the need to rely on a machine operator to ensure repeatability, and eliminates the time and wastage incurred in a manual, trial-and-error sizing set-ups. Thiele wanted to use electric, rather than pneumatic actuators, because of the speed and accuracy they provide. It chose Tolomatic B3S10 actuators which incorporate a stainless-steel band that seals the actuator from particles, extending its lifetime and reducing the need for maintenance. The actuators are customisable, allowing Thiele to choose between multiple motor and drive configurations to offer the flexibility needed for a broad range of applications. This flexibility also makes it much easier to update bagging systems already in operation. n Tolomatic actuators are available in the UK from Inmoco. When some pet food manufacturers changed to lower-cost bags with inconsistent sizes, this affected the accuracy and productivity of their bulk bagging processes. A manufacturer of bagging machines came to their rescue by developing a flexible bag-positioning system based on electric actuators. Thiele’s bagging machines can now handle bags with inconsistent sizes