A paper cup - a simple everyday item that is thrown away as soon as you have drunk your coffee. What no-one expects: The manufacture of this cup is highly complicated, precision and dynamics are demanded from the machines. The new Drusula 1200S punching machine from the packaging machine manufacturer Weyhmüller easily meets these requirements with a Baumüller drive and control system.
The Weyhmüller packaging company, based in Neu-Ulm, is entering a particularly dynamic punching machine onto the market with its Drusula 1200S. The machine punches cup blanks out of paper. With a flexopress that can be integrated optionally, partial printing of the paper can also take place directly in the system. Baumüller contributed significantly to the complete automation, from the control unit to the motor, to the dynamics and efficiency of the new Weyhmüller machine.
Dynamics and comfort
The Drusula 1200S was developed as early as 2004 and could only be optimized recently by enhancement. Blanks of different sizes with a material strength up to 400 µm can be manufactured by the machine, with a 1250 mm web width. Through constructive changes in both the mechanism as well as the electrics, productivity could be increased considerably, and the punching rate could be raised from 350 to 450 strokes/minute. However, new challenges also emerged for the developer as a result. The vibrations in the machine were significantly stronger, caused by the higher speed. However, the machine manufacturers tackled this problem with a sophisticated trick: Opposing weights balanced out the imbalance.
By using innovative cable entries that run along the top of the machine and not along the bottom as before, the wiring costs could also be reduced, and access to all sides of the machine improved. The machine manufacturers were also able to comfortably changeover the tool and rolls with a trolley it developed itself. The standard rapid product change in the packaging industry is no a longer a problem thanks to these optional accessories.
The punch and printing mechanism in the Drusula 1200S have been made as independent modules and equipped with two separate Baumüller control units. “Each individual customer comes to us with different requirements,” explains Heinrich Peitz, Managing Director at Weyhmüller, “We take this into consideration as early as the development stage and allow for the necessary level of flexibility with modular solutions.” The user can therefore quickly and easily react to subsequent changes in its production process.
With a complete drive and automation package made up of a control unit, electronics, motor and customer support, Baumüller supported the optimization of the Drusula 1200S.
A highlight in the automation of the punching machine is the combination of safety controls and standard control functionalities in one device.
The safePLC by Baumüller covers all control tasks so that a separate safety control is not necessary, which saves wiring costs, and also has the advantage that no data has to be exchanged. The new Drusula 1200S punch has a web width of 1250 mm between the system control and the safety controls. The safety functions are implemented in the drive technology and triggered directly via the fieldbus. In this way, no time is wasted, which the high cycle rate and high level of machine productivity require. The Drusula 1200S has enhanced safety functions that are activated depending on the operating state of the machine. Baumüller used its converter series b maXX 5000 for the drive technology and the decision was taken on the one hand because of the machine safety of this series. The devices in the b maXX 5000 family also provide a flexible safety concept, in which different safety packages can be selected with pluggable safety modules in accordance with EN 62061 and EN 13849. In addition, it also involved a space-saving modular system, which handles several axes with one inlet and in the event of servicing, individual axes can be exchanged easily and quickly. The safePLC covers safety functions and standard control functionalities
Less is more
The complete system has been fitted with Baumüller servo motors. For this purpose, five drives are used in the punch, and three drives in the printer. During the construction of the Drusula 1200S, drive experts could save a complete drive and therefore positively influence the energy efficiency of the machine. The stopper drive in the feed became obsolete after the developer decided to run the feed via a cam. As a slippage which caused the paper to rip could occur in the previous solution, depending on the quality of the paper, the new construction also significantly protected the material. In this way, the know-how of the Baumüller specialists could optimize the efficiency and function of the machine. As this solution required a highly dynamic braking system and the acceleration of the motor concerned, a water-cooled DSD2 motor was used for this purpose, which offers the high dynamics and best start-stop qualities required for this challenging application.
Teamwork success factor
During the course of the entire project, Baumüller acted as a partner for the manufacturer of the packaging machine, Weyhmüller, in all issues regarding automation and drive technology. In this way, the functions and machine visualization were programmed by an external partner for the machine manufacturer, who was given ongoing support from Baumüller at all times. “As a medium-sized company, we highly appreciate the support of such a long-term partner,” said Peitz, “This is the way to create innovations that benefit our customers.” Even after the development finished, Baumüller was able to support the machine manufacturer and continues to be a contact for commissioning and servicing. Training sessions are also part of the services provided, which Weyhmüller is happy to utilize to be able to properly equip its employees with skills for handling the new machine.
Weyhmüller could increase the cycle rates for its new punching machine with support from Baumüller and as a result, the operator achieved a significantly higher rate of productivity. Close collaboration between machine manufacturers and automation specialists created an efficient system and the optimization potential was fully utilized. Thanks to long-term collaboration, beyond the development stage, Weyhmüller and its customers also have the entire Baumüller know-how at their disposal for upcoming commissioning and service calls.