Perfected on the digital twin

Industry 4.0, digitalization, and big data are nothing new for Grenzebach. Now the high-tech company is introducing its first virtually optimized tin-air speed stacker for machine and plant engineering.

For many years, the automation experts at Grenzebach have been simulating such things as material flow in complex plants for manufacturing and processing flat glass. To do this, the company relies on the Plant ­Simulation 3D software from Siemens, its preferred supplier of control and drive technology. With its Grenzebach Application Server, the company also provides a platform for the data-based optimization of its systems. Grenzebach and Siemens are on the same wavelength when it comes to many areas relating to digitalization, and they continually apply their expertise synergistically to generate innovative solutions.

Innovative and powerful

The latest project involved the development of the new tin-air speed stacker. This innovative 3-axis fast stacker is named for its ability to pick up glass sheets from the top (or air side) as well as from the bottom (tin side). It can stack all types of glass sheets on a rack – up to 20 per minute. This corresponds to about a 30-percent higher stacking rate, making the innovation one of the highest-performance stackers in its class on the market.

This initial project has already proved that the digital twin saves both costs and development time and helps minimize risks.
Roland Jenning, head of Innovation at Grenzebach

Siemens was involved in the development project from the very start and assisted the Grenzebach engineers with developing the concept and selecting suitable control and drive technology. A Simotion D445 motion controller with a Handling Advanced universal library plus modular Sinamics S120 converters and Simotics S servomotors are used.

First-time generation of a digital twin

“Also, in order to come to grips with potential kinematic singularities similar to those of an articulated-arm robot, we decided to build a digital twin first,” says Roland Jenning, head of Innovation at Grenzebach. What they built was a virtual mechatronic model of the stacker that could be simulated and optimized in detail on a PC. Specialists from Siemens contributed a ­mathematical model for Simotion.

The digital twin was created using the NX Mechatronics Concept Designer (MCD) software from Siemens, based on Grenzebach’s mechanical 3D design. This design was entered into MCD and supplemented with relevant properties to create a model that can be graphically animated. The first motion control program for Simotion had already been created, so it was possible to prepare for virtual commissioning at an early stage. This parallelization of formerly sequential development steps is a tremendous time-saving benefit of the digitalized approach.

Faster to market

A hardware-in-the-loop setup was chosen to realistically simulate the programmed motion sequences on the digital twin. For this, the designated Simotion CPU is connected to the kinematic model in the MCD via a Simit simulation unit, and actions, reactions, and signal propagation times are parameterized in a behavior model. This makes it possible to emulate the interaction among all the participants connected to the Simotion CPU via Profinet. The program can then be tested as usual using the Simotion Scout engineering program, with MCD graphically animating the resulting traversing motions and Simit indicating errors. This allows any vulnerabilities to be visualized in three dimensions and sequences to be successively optimized.


This all takes place without manufacturing a single actual component and having to alter it multiple times. In the end, a largely fault-free program is transferred to the first real machine. This speeds up the actual commissioning time and reduces the time to market.


“This initial project has already proved that the digital twin saves both costs and development time and helps minimize risks,” says Jenning. And the digital twin’s usefulness doesn’t stop there. Once it’s been generated, it can also be used to virtually simulate and verify future changes or sequences for new rack or product versions in advance – without interfering with ongoing production.

Egbert Wenninger, 52, has been Senior Vice President of the Glass Business Unit at Grenzebach ­Maschinenbau GmbH in Asbach-Bäumenheim, Germany, since 2017. After graduating as an electrotechnical engineer from the Technical University of Munich, he worked as a project engineer at Pfister Systemtechnik GmbH in Augsburg for two and a half years starting in 1992. He joined Grenzebach Maschinenbau GmbH in 1995 and remained for the next 17 years, first serving as Vice President of Sales Glass Technology and later as a member of the ­Management Team. In 2012, he became Managing Director of EME GmbH in Lohr, before returning to Grenzebach as CSO in 2016.

Wenninger has been involved with VDMA’s activities since 2009. Since 2011, he has been a Member of the Board of the Glass Technology Forum and its Chairman since October 2017. From 2010 to 2012, he served on the board of the Photovoltaic Production Resources working group. Since 2009, he has also represented the VDMA on the glasstec Advisory Board.


Picture credits: Siemens AG


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