Simulation
The „less“ more for your tool

“We are now up to five times faster in simulation and offer preparation...”

The time window in the offer phase and from the placing of order to try-out and sampling is getting shorter and shorter in the toolmaking. At the same time the demands on process quality are increasing. HERU Werkzeugbau, the sheet metal specialist located in the Sauerland region therefore uses AutoForm to complete its workflow from the preliminary calculation to the final die surfaces and methods gaplessly with AutoForm.

In the Lennetal, as in many other parts of the Sauerland region, the metal processing has a long tradition. Well-usable hydropower, the iron ore deposits, smelting plants and the later steel works in the neighbouring Siegerland contributed also to this, as did the Ruhr-Sieg railway, inaugurated in 1861. Grevenbrück, now a district of Lennestadt, is located on this still important connection to the Ruhr area. And here, in a beautiful new building, HERU Werkzeugbau is located since 2004. “We are dealing with trend-setting tool technologies in the field of sheet metal forming and cover the entire process chain from component optimization and tool design to established series productions including staff training on the tool”, explains Thomas Teipel, who heads the technical sales department at HERU. And his colleague Philipp Nüschen from the design department adds: “Without AutoForm almost everything we do in the field of sheet metal forming today, would not be possible.” As head of the design department, Nüschen is the boss of an eight-person engineering team and is additionally responsible for the project management at HERU. “With this modular system we now map all important stages of our processes from method planning and calculation in the offer phase to the die surfaces.”

The head of the design department indicates: with a classic CAD system – HERU uses Autodesk Inventor for designing and CATIA V5 for the die surfaces – it is only possible to a very limited extend to quickly create a reliable rough method for a tool, for example after a customer inquiry. Even, when further steps come into play, such as the rapid proof of the feasibility of component and process, the simulation-based determination of trimming contours and drawbeads, the verification of the dimensional accuracy or the compensation of springback, tools from specialists are required. One of the first addresses in this field is AutoForm, a software company that was founded in 1995 as a spin-off company of ETH Zürich and is now one of the world’s leading solution providers in this field with more than 400 employees.

In addition to the consistency of the individual modules with which AutoForm scores points, Nüschen is convinced of the well-thought-out functions which considerably facilitate the everyday toolmaking routine at HERU (fig.1 and fig. 2). This is also confirmed by Sales Director Teipel. As an important example, he mentions the AutoForm Planning & Bidding Solution which has virtually started a new era at HERU. “In the past, a lot of preliminary calculations were based on empirical values, practically at a rough estimate.” Today, AutoForm offers here a secure basis for preliminary costing. For this reason, at HERU a licence is exclusively used by the sales department to prepare offers. Teipel describes today’s procedure as follows: “When the customer sends the data set – i.e. CAD model and drawing – by e-mail as part of the inquiry, both are first checked by us before we prepare the offer.” This begins with a feasibility study and possible counter proposals. “This is because 80 percent of the drawings are not correct in terms of shape and position.” This also includes a tolerance evaluation. “A conclusion can be that a component can be manufactured, but not with the required tolerances.” AutoForm already comes into play at this stage, namely, to create the rough method, which also serves as the basis for preliminary costing. This takes place in the design department of Nüschen. With just a few mouse clicks, the part is at first processed in AutoForm-Stamping Adviser, examined for feasibility problems and the first estimation of the material usage is made. “Here, we define the individual stations and can thus see whether the part can be produced at all”, Nüschen explains the procedure (fig. 3). In the next step, the semi-automatically generated method concept is then processed or supplemented and adapted to the material requirements and the own production guidelines of HERU. “In AutoForm we immediately see whether we have problem areas somewhere that may crack or whether there is a material thickening somewhere, for example.”

This is now the data with which the sales department then uses the AutoForm-CostEstimator to generate the preliminary costing largely automatically. “We basically have two planning workstations in use - in the sales and engineering department. This creates a cycle during the offer phase in which, with the same file, it is worked associatively together. In this way, technically necessary changes to the method can be directly fed back into the cost calculation, “explains Teipel. “Another good thing in this context is also that we work with different cost standards which we have stored.” This is an especially important aspect that AutoForm offers here. The HERU specific figures are stored in these cost standards, including all design and manufacturing steps (fig. 4). In addition, the employee’s empirical knowledge is also included. In this way, it is now possible to cover different component categories. “For example, which materials are used, how do I proceed from the process or do I have to mill or erode.” That is why the sales manager also speaks of a calculation scheme” with which I can create an extremely realistic preliminary calculation, including the hours required, practically at the push of a button. These are of course the pure costs of manufacturing. In addition, there are material overheads, profit, pre-financing, and other costs such as those for parts that may have to be produced. “We are still working this out manually for the finished offer”.

AutoForum is also the backbone for the next steps. If the sales department and the customer said yes, the department of Nüschen will start further work on the basis of the rough method already established. “At this point the colleague no longer has to start from scratch but can rely on the data already generated, because this forms the basis of the offer. The AutoForm-DieDesigner used initially, generates the parametric concept surfaces required for all operations. “Therefore surfaces, that we frequently have to modify in the early phase,” reports Nüschen and adds: “This module offers the possibility to generate concept geometries much faster than native CAD surfaces which we then use to simulate the entire forming process and for the first return analysis in the AutoForm-FormingSolver.”On the basis of the knowledge gained in this way, the final generation of the parametric CAD die surfaces and the complete, detailed method planning for all deep-drawing and subsequent operations now takes place in the AutoFormProcessDesignerforCATIA. Here, too, the data from the concept phase is reused. The data of the rough method is transferred to the CAD world with AutoForm-QuickLinkforCATIA and with as little loss of information as possible. The AutoFormProcessDesignerforCATIA is used to work directly in the CATIA environment. Nüschen is convinced of the extremely high quality of the (free-form) surfaces generated by the AutoForm-ProcessDesignerforCATIA, as well as of the speed with which the method plan can be implemented. “Even, “Class A” requirements are met. From these surface data the NC data, with which the die surfaces are milled, can also be derived via CAM software. “While we are still working on the final die surfaces, we are already beginning with the tool design”, Nüschen points out to the parallel beginning procedure. “We start the tool design when the incremental simulation based on DieDesigner surfaces is secure, i.e. the part can be produced. This saves us a lot of time.” If the die surfaces and the method from AutoForm-ProcessDesignerforCATIA are available, these are once again transferred to AutoForm for a so-called “validation” simulation, including the springback compensation, Nüschen continues. A further loop via the AutoForm-ProcessDesignerforCATIA then results in the final milling data (fig. 5, fig.6 and fig.7).

Even in the period before AutoForm, HERU has already simulated, Nüschen remembers. However, the forming simulation could not start until the die surfaces were previously created in CATIA. “These have arisen from our experience which means a time expenditure of a factor of 10 compared to today.” In addition, the derived method was often not free of errors, which resulted in their modification during the construction phase. “That was often Sisyphean work, we sometimes had to re-mill five or six times”, describes the head of the design department the situation at that time. From a commercial point of view, we were very quickly in the red area. “Today, with AutoForm we get a validated statement that we can rely on”. Teipel is similarly positive. “We have increased the quality of the component while at the same time reducing the correction loops, which often account for 40 percent of the lead times”, emphasizes the sales manager summing up the current situation as follows: “We are now up to five times faster in simulation and offer preparation”. In addition, the offer has become more precise and more reliable in terms of calculation. This is also a very important factor for us. Also, the entire process is more stable: “Today, we no longer jeopardise deadlines and can give our customers binding deadlines for high-quality components”. (fig. 8 and fig.9).