Servo drive technology for everyday use

Previously, the punching process was carried out using hydraulic drives. Although these offered high power density and were robust, they did not meet the required accuracy and caused high maintenance and energy costs. That is why the machine builder now relies on STOBER drive technology. In addition to drive controllers and servo motors, different gearboxes are used, ranging from powerful designs for demanding tasks to a cost effective economy variant.

For the production of ID cards such as national identity cards, up to eight different films are automatically taken from sheets or rolls and combined. The system aligns the films, checks the material thickness and stacks them in the correct position. It then transfers the film stack to the laminating unit, which bonds the layers into a sheet.  The laminated sheet is then fed to the punching unit.  After the punching process, the cards are checked for dimensional accuracy, surface quality, RFID function and other possible features before they are stacked in a magazine. Hydraulic drives were previously used for triple punching. These are characterised by a high power density, infinitely variable adjustment and a robust design. In practice, however, there were limits to the adjustment accuracy and the reproducibility of the results, along with higher maintenance costs and susceptibility to leaks.

Tiepner wanted to optimize the design of the axes, make the unit more compact, increase energy efficiency and ensure simple commissioning. To achieve this, the punching unit was to be converted from a hydraulic to a servo drive. During operation, electric drives are often more economical in terms of energy consumption, while hydraulic systems can quickly become cost-intensive.  Electric drives are also easier to maintain. Oil leaks are simply not an issue. Temperature fluctuations also have little effect on the performance of electric drives. In hydraulic systems, in contrast, performance can depend heavily on how hot or cold the oil is.

"We've been in contact since 2020. Back then, we supplied a drive solution, and our customer is still very satisfied with it today," reports Florian Sonnenberg, Account Manager at STOBER.  During the first on-site meeting about the new project, he gained a thorough overview of the systems, their functions and their wide range of applications. He was enthusiastic about what he saw.

"We supplied our SI6 series drive controllers as a multi-axis drive system," reports Sonnenberg. Thanks to their compact design, they require little space in the control cabinet.  At the same time, they offer a range of useful functions. "But more important than the compactness of the SI6 is the fact that it eliminates the need for redundant supply modules," continues Sonnenberg: "A whole series of drive controllers can be connected to the central PS6 supply module.  This also removes the need for separate fuses and cabling for each individual axis."

The installed components include compact EZ synchronous servo motors. This series offers maximum torque, high dynamics and low torque ripple.

Depending on the requirements for torque, speed, smooth operation, efficiency and size, different gearboxes are used in the systems. These include the P series planetary gearboxes with extremely high efficiency and the helical gearing typical of STOBER, which ensures smooth and quiet operation. The P series is complemented by the highly economical PE series planetary gearboxes. 

They also have helical gearing – a feature that is unique in this product and price class.

"In addition to drives for demanding positioning tasks with high dynamics, we also need drives for lifting and conveying," explains Sonnenberg.

These drives have to meet all of the high quality standards of the machines with regard to smooth operation, backlash stability and service life. The KLM geared motor – a combination of a helical bevel gearbox and Lean motor in a direct attachment configuration – provides the user with an extremely energy-efficient drive that is particularly suitable for automation applications, for example, as a lifting unit for unpunched card sheets.

The KLM is very compact, and its robust housing geometry ensures a long service life. It owes its high energy efficiency to the IE5 efficiency class of the Lean motor. In addition, users benefit from low installation effort.

With Lean motors, the SI6 series drive controllers determine position and speed without an encoder and provide infinitely variable speed control.  This reduces cabling work, simplifies commissioning and lowers costs. Communication takes place via PROFINET.

STOBER supplied a high-performance system with coordinated components. Design engineers get everything from a single source and benefit from an experienced contact who supports them in implementing all drive tasks. 

The systems are now more precise and flexible. They process sheets of 3×6 to 3×10 cards, i.e., 18 to 30 cards per sheet. Users benefit from shorter setup times, intuitive operation and a flexible design. At maximum output, around 12,000 cards can be produced per hour.  

www.stober.co.uk