The production of paper cups, for example for "coffee to go", is literally a "hot thing". High temperatures are generated inside the machines in the cup moulding units due to frequent acceleration and deceleration. Michael Hörauf Maschinenfabrik GmbH & Co. KG has found a solution to the temperature problem with the help of Yaskawa. In machines of the "BMP 100" series, GA700 frequency inverters significantly reduce the mechanical loads on the drive technology and the resulting temperatures.
The Michael Hörauf Maschinenfabrik GmbH & Co. KG from the Swabian town of Donzdorf is in the Packaging technology specialises in machines for the production of paper cups and containers. In addition to high-end machines for the rational Production of paper cups customised solutions for branded companies for the in-house production of Packaging made from paper composites developed.
The machines from the BMP-100 series are designed for Production of single-wall beverage and packaging cups. The "BMP 100 Super" model is suitable for producing up to 160 large-volume packaging cups per minute, which can later be filled with snacks, pasta, ice cream or popcorn. The "BMP 100 Compact", on the other hand, can produce up to 180 cups per minute for hot and cold drinks. Both machines process cut segments of paper and paper composites as well as roll material.
Drive elements get too hot for paper
The centrepiece of the machine is the Moulded cup unit. This is one with Core mandrels equipped with a so-called star. It has a diameter of around one metre. These core mandrels are rotated in front of the various processing stations. Among other things, the paper for the cup wall is fed in, moulded and glued, the base element is integrated and the top edge of the cup is formed.
With maximum 180 cycles per minute the star must be accelerated and decelerated very frequently. This mechanically very demanding drive task is performed by an asynchronous motor.
When braking, the following always occur Two regenerative operating states which can lead to problems. On the one hand, voltage peaks can occur that place a heavy load on the BMP 100 drives and thus lead to failures. On the other hand, the Braking energy is converted into heat, which can cause temperatures at the braking resistor to rise up to 80 degrees Celsius.
In the case of the BMP 100 machines, these special conditions would actually have required the braking resistors to be installed in a switch cabinet and the excess heat to be dissipated at great expense. After all, paper is a highly flammable material.
Voltage peaks reduced by 30 per cent
The design engineers at Michael Hörauf Maschinenfabrik were therefore looking for a solution that, above all, produced less heat. They found what they were looking for at Yaskawa. The Japanese Manufacturer of servo drives, Frequency inverters and Industrial robots offers the GA700 frequency inverter for applications such as the one described. According to the company, it is resilient and durable and works at outside temperatures of up to 50 degrees Celsius without any loss of performance. The GA700 is designed for ten years of continuous operation at a maximum output of 80 per cent.
Hörauf Maschinenfabrik benefited above all from the use of a highly dynamic Current vector control (Open Loop Vector Control) in conjunction with the frequency inverter. For both asynchronous and permanent magnet synchronous motors, this means that the full torque is achieved even at very low speeds without encoder feedback. The asynchronous motor in the BMP 100 in particular has a high degree of control rigidity as a result.
Specifically, this technical feature of the GA700 The overshoot of the mechanics, the generator effects and the voltage peaks have been minimised. The latter have been reduced by up to 30 per cent, resulting in less regenerative energy. The temperature of the braking resistors now corresponds to the ambient temperature.
Commissioning possible without expert knowledge
The GA700 frequency inverter offers further advantages. For example, it continuously optimises its application parameters during operation. With integrated performance features such as a EMC filterWith its high level of safety, the internal 24-volt DC power supply with an additional 150 milliamperes for supplying external sensors and the guarantee of functional safety in accordance with STO SIL3, the frequency inverter is also suitable for applications with a higher risk level. External safety measures can then be dispensed with.
The model is also equipped with an SD card slot, a Bluetooth interface and a real-time clock. The clock, including storage and transmission options, makes work easier for service technicians. The detailed Recording of load profiles becomes possible.
The electronic module is operated via the integrated control panel, on the PC or via smartphone app. The "Yaskawa DriveWizard Mobile App" allows the parameters to be set in the Cloud or share them with other employees. In any case, Yaskawa promises that the devices can be put into operation quickly, even without expert knowledge.
