Palletising robots at Clariant

Waxes ensure that plastics, for example, are easier to process and that printing inks adhere better. They are also used in the manufacture of shoe creams, automobile polishes and floor care products. Clariant produces a wide range of such wax additives in Gersthofen. These are based on fossil waxes (montan waxes) as well as synthetic products. “We manufacture waxes in the form of powder, granulate and also flakes,” reports Dr. Norbert Pechler, Plant Manager PE-Wax at Clariant. In the past, packaging was mainly carried out manually. As the products emerged from manufacturing, they were put into bags by the workers. Filling was carried out using non-automated scales and the bags were then stacked on pallets by hand. “However, this was very time-consuming. To become more effective, we needed to automate both the filling and the palletising process,” says Dr. Pechler.

An important criterion for Clariant was the space requirement. “We wanted a compact solution. In particular, the decisive factor for us was the height of the palletising equipment,” remarks Pechler. Following an invitation to tender, the chemical company finally decided on the BEUMER robotpac®. “This articulated arm robot stacks bags gently, with high reliability and first-class accuracy and quality,” says Peter Schmidt, Regional Sales Manager for Southern Germany at BEUMER.

Thanks to its extremely high flexibility, the BEUMER robotpac® can also handle very complex processes with varying frame parameters reliably and economically. This also convinced the chemical experts: “With the BEUMER robotpac® we can process three different forms in parallel – powder, granulate and flakes. This is not possible with a layer palletizer,” says Pechler.

The palletizing robot has a multi-program for all packing patterns. A press of a button is all that is required to switch over the BEUMER robotpac® for changes in size or material. “The system is extremely user-friendly and can be flexibly adapted to suit different conditions of use. The user does not need any specific knowledge of robots to do this,” emphasizes Schmidt. “It is also very robust. This ensures reliable operation even under extreme conditions,” explains Schmidt. The drives work reliably, economically and quietly. If the palletising robot is equipped with an additional drive axis and a motor which is incorporated into the control system, it can even be traversed freely on a rail.

The various waxes in bags pass to the palletising equipment in different formats via three roller conveyors. “A scanner uses a label attached to each bag to detect which bag is to go onto which pallet,” explains Pechler. The BEUMER robotpac® moves to the pick-up position quietly and with maximum acceleration until shortly before its destination. The finger gripper picks up the bags from a lift unit on the take-off roller conveyor and moves them to the destination. Here, the fingers open while the slide plates remain in the closed position. This ensures that the bag is laterally guided during the set-down operation. The finger gripper is a high-performance tool which has been designed for maximum palletising capacities. A prerequisite for these high capacities and the associated accelerations is that bags must retain their shape and the contents must not have a tendency to flow. The forks move under the bag and it is secured during transportation by a pressure device. The robot moves to the pallet with a vertical movement. “We guarantee very accurate setting down due to the fact that only a vertical movement is necessary,” explains Schmidt. The forks open and the stripper pushes the bag off the forks. The gripper system leaves the pallet in a vertical direction and moves towards the roller conveyor with maximum acceleration. The cycle starts again from the beginning. “Empty pallets can also be removed from the magazine with the same tool. This obviates the need for a pallet separator,” says Schmidt. This has resulted in lower procurement costs and a smaller system footprint.

Precise stacking pattern

An ultrasonic system accurately measures the stack height. This enables the set-down position of the packaged product to be calculated exactly and the product to be deposited accurately and carefully. It ensures an optimum stacking pattern. “This is not only a sign of quality, but also guarantees high stability during transportation and storage. It also enables reliable incorporation into the downstream packaging processes,” says Schmidt. However, this not only enables Clariant to deliver to customers significantly faster. “We also save one worker per shift whom we can deploy more effectively elsewhere”, sums up Pechler.