EMO Hannover 2013 Showcases Virtual Tool Development in a German-American Alliance

“At first, we got pitying smiles,” recalls Dr.-Ing. Claus Itterheim, Managing Director of ISBE GmbH from Stuttgart, looking back to 2006, when he premiered his program for virtual tool design. The development manager of a machine tool manufacturer even said, it was “just a laughable business model” without any future whatsoever.

Today, Claus Itterheim is gratified to note that the sceptics at this company have also begun some comparable development work. The Swabian company is meanwhile well-known on the tool scene and among relevant users, thanks not least to its consultancy capabilities and its programs themed around tool development. Its specialities include simulation programs, which are a part of many manufacturers' systematized tool development work.

Simulation Does Not Replace Humans: The encouraging message from Stuttgart is this: even the most ingenious simulation does not replace a smart employee. To quote Dr. Itterheim: “In Germany’s university scene, unfortunately only a handful of people are researching  metal-cutting, plus the relevant tools and their development, compared to all other technologies around.” These few experts also include his colleague Dr.-Ing. Kay Marschalkowski, who in March of this year reported from the development front at the 2^nd ISBE User Conference in Dortmund.

“By factoring in physical process variables, we are able to simulate the stress between the tool and the workpiece during the metal-cutting process. On this basis, even complex 5-axis processes can be reliably optimized. A stress collective of this kind can also be used in further FEM analyses for investigating the clamping situation of a tool or component.” This is one example described by the Head of the Tool Engineering Centre. “This means I can generate a database with relative accuracy, so as to provide the designer with guidelines for dimensioning and optimizing clamping devices or machinery structures. If you are thoroughly familiar with your metal-cutting processes, you also have a good description of the important boundary conditions involved.”

Collaboration with a Think Tank in the U.S.: The Swabians owe insights of this kind to the simulation programs of their long-standing cooperation partner Third Wave Systems (TWS), Inc. in Minneapolis, Minn. “Some tool manufacturers from our customer base drew our attention to a software package called AdvantEdge from the USA , said to be very well suited for high-precision FEM simulation of metal-cutting processes,” recalls Dr. Itterheim. “Following some tests with our own data, we decided in 2008 to enter into an alliance with TWS.” Meanwhile, it’s not only this software that’s being used by ISBE’s customers: the Production Module has also proved most efficacious, used to optimize NC programs for milling and turning with the aid of simulation also based on FEM data. Cross-frontier alliances of this kind are seen by Nick Shannon, Sales & Application Engineer at TWS, as an essential precondition for global engineering that “synergizes the unique developments on the individual markets to form a holistic corporate capability.”

But where does simulation come up against its limits? Can everything really be precisely predicted and optimized in a virtual environment? “Metal-cutting is an extremely complex phenomenon, with many unknown boundary conditions,” explains TWS’ Development Manager Dr. Shuji Usui. “So there is a lot of development work still needed in order to research this operation further.” To which his German partner Dr. Itterheim adds: “First we have to know from the customer what his actual goal is when it comes to optimizing his metal-cutting operation. Only then can we advise him which software and which approach will give him the best results. It’s completely wrong to simply sell the customer a software package and then to leave him alone with it."

The First (Virtual) Step Is the Hardest: Before you start simulating, first do the studying. There are some refinements to bear in mind here. “The FEM metal-cutting simulation has to be subjected to the same systematized approach as the entire virtual tool design process,” explains Dr. Itterheim. “Pure 2D simulations, for analyzing different cutting and clearance angles or edge preparation constitute the first foundations for bringing transparency into the metal-cutting process. Initial conclusions can be drawn on the chip shape. For this purpose, simple 2D cross-sections of the cutting edge suffice as a geometrical basis.”

But why are special simulation systems needed for metal-cutting applications? Can’t the development engineers also cover that with their CAD/CAM software? To quote Dr. Usui: “The designers of machine tools can admittedly analyze the structure of the entire machine very well, but they lack comprehensive knowledge of what actually happens at the tool’s cutting edge.” ISBE’s Managing Director Dr. Itterheim adds: “The designer should not run his simulations with constant characteristics, but with the dynamic parameters we have determined with the Production Module. This is essential if the simulation is to reveal what actual forces or moments are influencing his machine’s behaviour during milling or turning, for example.”

The simulation experts from Stuttgart and Minneapolis will be communicating these messages at the EMO Hannover 2013 in two ways: (1)  by showcasing new software on their shared stand and (2) by giving a joint presentation at the conference entitled “New Production Technologies for the Aerospace Sector” hosted by the Institute for Production Technology and Machine Tools (IFW) at Hanover University (EMO Hannover, 18 to 19 September 2013, Convention Centre).

Author: Nikolaus Fecht, specialist journalist from Gelsenkirchen